2 Copyright (C) 2005, 2006, 2007
3 Free Software Foundation, Inc.
4 This is part of the GNU Fortran manual.
5 For copying conditions, see the file gfortran.texi.
7 Permission is granted to copy, distribute and/or modify this document
8 under the terms of the GNU Free Documentation License, Version 1.2 or
9 any later version published by the Free Software Foundation; with the
10 Invariant Sections being ``GNU General Public License'' and ``Funding
11 Free Software'', the Front-Cover texts being (a) (see below), and with
12 the Back-Cover Texts being (b) (see below). A copy of the license is
13 included in the gfdl(7) man page.
16 Some basic guidelines for editing this document:
18 (1) The intrinsic procedures are to be listed in alphabetical order.
19 (2) The generic name is to be used.
20 (3) The specific names are included in the function index and in a
21 table at the end of the node (See ABS entry).
22 (4) Try to maintain the same style for each entry.
28 \gdef\acos{\mathop{\rm acos}\nolimits}
29 \gdef\asin{\mathop{\rm asin}\nolimits}
30 \gdef\atan{\mathop{\rm atan}\nolimits}
31 \gdef\acosh{\mathop{\rm acosh}\nolimits}
32 \gdef\asinh{\mathop{\rm asinh}\nolimits}
33 \gdef\atanh{\mathop{\rm atanh}\nolimits}
37 @node Intrinsic Procedures
38 @chapter Intrinsic Procedures
39 @cindex intrinsic procedures
42 * Introduction: Introduction to Intrinsics
43 * @code{ABORT}: ABORT, Abort the program
44 * @code{ABS}: ABS, Absolute value
45 * @code{ACCESS}: ACCESS, Checks file access modes
46 * @code{ACHAR}: ACHAR, Character in @acronym{ASCII} collating sequence
47 * @code{ACOS}: ACOS, Arccosine function
48 * @code{ACOSH}: ACOSH, Hyperbolic arccosine function
49 * @code{ADJUSTL}: ADJUSTL, Left adjust a string
50 * @code{ADJUSTR}: ADJUSTR, Right adjust a string
51 * @code{AIMAG}: AIMAG, Imaginary part of complex number
52 * @code{AINT}: AINT, Truncate to a whole number
53 * @code{ALARM}: ALARM, Set an alarm clock
54 * @code{ALL}: ALL, Determine if all values are true
55 * @code{ALLOCATED}: ALLOCATED, Status of allocatable entity
56 * @code{AND}: AND, Bitwise logical AND
57 * @code{ANINT}: ANINT, Nearest whole number
58 * @code{ANY}: ANY, Determine if any values are true
59 * @code{ASIN}: ASIN, Arcsine function
60 * @code{ASINH}: ASINH, Hyperbolic arcsine function
61 * @code{ASSOCIATED}: ASSOCIATED, Status of a pointer or pointer/target pair
62 * @code{ATAN}: ATAN, Arctangent function
63 * @code{ATAN2}: ATAN2, Arctangent function
64 * @code{ATANH}: ATANH, Hyperbolic arctangent function
65 * @code{BESJ0}: BESJ0, Bessel function of the first kind of order 0
66 * @code{BESJ1}: BESJ1, Bessel function of the first kind of order 1
67 * @code{BESJN}: BESJN, Bessel function of the first kind
68 * @code{BESY0}: BESY0, Bessel function of the second kind of order 0
69 * @code{BESY1}: BESY1, Bessel function of the second kind of order 1
70 * @code{BESYN}: BESYN, Bessel function of the second kind
71 * @code{BIT_SIZE}: BIT_SIZE, Bit size inquiry function
72 * @code{BTEST}: BTEST, Bit test function
73 * @code{C_ASSOCIATED}: C_ASSOCIATED, Status of a C pointer
74 * @code{C_F_POINTER}: C_F_POINTER, Convert C into Fortran pointer
75 * @code{C_F_PROCPOINTER}: C_F_PROCPOINTER, Convert C into Fortran procedure pointer
76 * @code{C_FUNLOC}: C_FUNLOC, Obtain the C address of a procedure
77 * @code{C_LOC}: C_LOC, Obtain the C address of an object
78 * @code{CEILING}: CEILING, Integer ceiling function
79 * @code{CHAR}: CHAR, Integer-to-character conversion function
80 * @code{CHDIR}: CHDIR, Change working directory
81 * @code{CHMOD}: CHMOD, Change access permissions of files
82 * @code{CMPLX}: CMPLX, Complex conversion function
83 * @code{COMMAND_ARGUMENT_COUNT}: COMMAND_ARGUMENT_COUNT, Get number of command line arguments
84 * @code{COMPLEX}: COMPLEX, Complex conversion function
85 * @code{CONJG}: CONJG, Complex conjugate function
86 * @code{COS}: COS, Cosine function
87 * @code{COSH}: COSH, Hyperbolic cosine function
88 * @code{COUNT}: COUNT, Count occurrences of TRUE in an array
89 * @code{CPU_TIME}: CPU_TIME, CPU time subroutine
90 * @code{CSHIFT}: CSHIFT, Circular shift elements of an array
91 * @code{CTIME}: CTIME, Subroutine (or function) to convert a time into a string
92 * @code{DATE_AND_TIME}: DATE_AND_TIME, Date and time subroutine
93 * @code{DBLE}: DBLE, Double precision conversion function
94 * @code{DCMPLX}: DCMPLX, Double complex conversion function
95 * @code{DFLOAT}: DFLOAT, Double precision conversion function
96 * @code{DIGITS}: DIGITS, Significant digits function
97 * @code{DIM}: DIM, Positive difference
98 * @code{DOT_PRODUCT}: DOT_PRODUCT, Dot product function
99 * @code{DPROD}: DPROD, Double product function
100 * @code{DREAL}: DREAL, Double real part function
101 * @code{DTIME}: DTIME, Execution time subroutine (or function)
102 * @code{EOSHIFT}: EOSHIFT, End-off shift elements of an array
103 * @code{EPSILON}: EPSILON, Epsilon function
104 * @code{ERF}: ERF, Error function
105 * @code{ERFC}: ERFC, Complementary error function
106 * @code{ETIME}: ETIME, Execution time subroutine (or function)
107 * @code{EXIT}: EXIT, Exit the program with status.
108 * @code{EXP}: EXP, Exponential function
109 * @code{EXPONENT}: EXPONENT, Exponent function
110 * @code{FDATE}: FDATE, Subroutine (or function) to get the current time as a string
111 * @code{FGET}: FGET, Read a single character in stream mode from stdin
112 * @code{FGETC}: FGETC, Read a single character in stream mode
113 * @code{FLOAT}: FLOAT, Convert integer to default real
114 * @code{FLOOR}: FLOOR, Integer floor function
115 * @code{FLUSH}: FLUSH, Flush I/O unit(s)
116 * @code{FNUM}: FNUM, File number function
117 * @code{FPUT}: FPUT, Write a single character in stream mode to stdout
118 * @code{FPUTC}: FPUTC, Write a single character in stream mode
119 * @code{FRACTION}: FRACTION, Fractional part of the model representation
120 * @code{FREE}: FREE, Memory de-allocation subroutine
121 * @code{FSEEK}: FSEEK, Low level file positioning subroutine
122 * @code{FSTAT}: FSTAT, Get file status
123 * @code{FTELL}: FTELL, Current stream position
124 * @code{GERROR}: GERROR, Get last system error message
125 * @code{GETARG}: GETARG, Get command line arguments
126 * @code{GET_COMMAND}: GET_COMMAND, Get the entire command line
127 * @code{GET_COMMAND_ARGUMENT}: GET_COMMAND_ARGUMENT, Get command line arguments
128 * @code{GETCWD}: GETCWD, Get current working directory
129 * @code{GETENV}: GETENV, Get an environmental variable
130 * @code{GET_ENVIRONMENT_VARIABLE}: GET_ENVIRONMENT_VARIABLE, Get an environmental variable
131 * @code{GETGID}: GETGID, Group ID function
132 * @code{GETLOG}: GETLOG, Get login name
133 * @code{GETPID}: GETPID, Process ID function
134 * @code{GETUID}: GETUID, User ID function
135 * @code{GMTIME}: GMTIME, Convert time to GMT info
136 * @code{HOSTNM}: HOSTNM, Get system host name
137 * @code{HUGE}: HUGE, Largest number of a kind
138 * @code{IACHAR}: IACHAR, Code in @acronym{ASCII} collating sequence
139 * @code{IAND}: IAND, Bitwise logical and
140 * @code{IARGC}: IARGC, Get the number of command line arguments
141 * @code{IBCLR}: IBCLR, Clear bit
142 * @code{IBITS}: IBITS, Bit extraction
143 * @code{IBSET}: IBSET, Set bit
144 * @code{ICHAR}: ICHAR, Character-to-integer conversion function
145 * @code{IDATE}: IDATE, Current local time (day/month/year)
146 * @code{IEOR}: IEOR, Bitwise logical exclusive or
147 * @code{IERRNO}: IERRNO, Function to get the last system error number
148 * @code{INDEX}: INDEX, Position of a substring within a string
149 * @code{INT}: INT, Convert to integer type
150 * @code{INT2}: INT2, Convert to 16-bit integer type
151 * @code{INT8}: INT8, Convert to 64-bit integer type
152 * @code{IOR}: IOR, Bitwise logical or
153 * @code{IRAND}: IRAND, Integer pseudo-random number
154 * @code{ISATTY}: ISATTY, Whether a unit is a terminal device
155 * @code{ISHFT}: ISHFT, Shift bits
156 * @code{ISHFTC}: ISHFTC, Shift bits circularly
157 * @code{ITIME}: ITIME, Current local time (hour/minutes/seconds)
158 * @code{KILL}: KILL, Send a signal to a process
159 * @code{KIND}: KIND, Kind of an entity
160 * @code{LBOUND}: LBOUND, Lower dimension bounds of an array
161 * @code{LEN}: LEN, Length of a character entity
162 * @code{LEN_TRIM}: LEN_TRIM, Length of a character entity without trailing blank characters
163 * @code{LGE}: LGE, Lexical greater than or equal
164 * @code{LGT}: LGT, Lexical greater than
165 * @code{LINK}: LINK, Create a hard link
166 * @code{LLE}: LLE, Lexical less than or equal
167 * @code{LLT}: LLT, Lexical less than
168 * @code{LNBLNK}: LNBLNK, Index of the last non-blank character in a string
169 * @code{LOC}: LOC, Returns the address of a variable
170 * @code{LOG}: LOG, Logarithm function
171 * @code{LOG10}: LOG10, Base 10 logarithm function
172 * @code{LOGICAL}: LOGICAL, Convert to logical type
173 * @code{LONG}: LONG, Convert to integer type
174 * @code{LSHIFT}: LSHIFT, Left shift bits
175 * @code{LSTAT}: LSTAT, Get file status
176 * @code{LTIME}: LTIME, Convert time to local time info
177 * @code{MALLOC}: MALLOC, Dynamic memory allocation function
178 * @code{MATMUL}: MATMUL, matrix multiplication
179 * @code{MAX}: MAX, Maximum value of an argument list
180 * @code{MAXEXPONENT}: MAXEXPONENT, Maximum exponent of a real kind
181 * @code{MAXLOC}: MAXLOC, Location of the maximum value within an array
182 * @code{MAXVAL}: MAXVAL, Maximum value of an array
183 * @code{MCLOCK}: MCLOCK, Time function
184 * @code{MCLOCK8}: MCLOCK8, Time function (64-bit)
185 * @code{MERGE}: MERGE, Merge arrays
186 * @code{MIN}: MIN, Minimum value of an argument list
187 * @code{MINEXPONENT}: MINEXPONENT, Minimum exponent of a real kind
188 * @code{MINLOC}: MINLOC, Location of the minimum value within an array
189 * @code{MINVAL}: MINVAL, Minimum value of an array
190 * @code{MOD}: MOD, Remainder function
191 * @code{MODULO}: MODULO, Modulo function
192 * @code{MOVE_ALLOC}: MOVE_ALLOC, Move allocation from one object to another
193 * @code{MVBITS}: MVBITS, Move bits from one integer to another
194 * @code{NEAREST}: NEAREST, Nearest representable number
195 * @code{NEW_LINE}: NEW_LINE, New line character
196 * @code{NINT}: NINT, Nearest whole number
197 * @code{NOT}: NOT, Logical negation
198 * @code{NULL}: NULL, Function that returns an disassociated pointer
199 * @code{OR}: OR, Bitwise logical OR
200 * @code{PACK}: PACK, Pack an array into an array of rank one
201 * @code{PERROR}: PERROR, Print system error message
202 * @code{PRECISION}: PRECISION, Decimal precision of a real kind
203 * @code{PRESENT}: PRESENT, Determine whether an optional dummy argument is specified
204 * @code{PRODUCT}: PRODUCT, Product of array elements
205 * @code{RADIX}: RADIX, Base of a data model
206 * @code{RANDOM_NUMBER}: RANDOM_NUMBER, Pseudo-random number
207 * @code{RANDOM_SEED}: RANDOM_SEED, Initialize a pseudo-random number sequence
208 * @code{RAND}: RAND, Real pseudo-random number
209 * @code{RANGE}: RANGE, Decimal exponent range of a real kind
210 * @code{RAN}: RAN, Real pseudo-random number
211 * @code{REAL}: REAL, Convert to real type
212 * @code{RENAME}: RENAME, Rename a file
213 * @code{REPEAT}: REPEAT, Repeated string concatenation
214 * @code{RESHAPE}: RESHAPE, Function to reshape an array
215 * @code{RRSPACING}: RRSPACING, Reciprocal of the relative spacing
216 * @code{RSHIFT}: RSHIFT, Right shift bits
217 * @code{SCALE}: SCALE, Scale a real value
218 * @code{SCAN}: SCAN, Scan a string for the presence of a set of characters
219 * @code{SECNDS}: SECNDS, Time function
220 * @code{SECOND}: SECOND, CPU time function
221 * @code{SELECTED_INT_KIND}: SELECTED_INT_KIND, Choose integer kind
222 * @code{SELECTED_REAL_KIND}: SELECTED_REAL_KIND, Choose real kind
223 * @code{SET_EXPONENT}: SET_EXPONENT, Set the exponent of the model
224 * @code{SHAPE}: SHAPE, Determine the shape of an array
225 * @code{SIGN}: SIGN, Sign copying function
226 * @code{SIGNAL}: SIGNAL, Signal handling subroutine (or function)
227 * @code{SIN}: SIN, Sine function
228 * @code{SINH}: SINH, Hyperbolic sine function
229 * @code{SIZE}: SIZE, Function to determine the size of an array
230 * @code{SIZEOF}: SIZEOF, Determine the size in bytes of an expression
231 * @code{SLEEP}: SLEEP, Sleep for the specified number of seconds
232 * @code{SNGL}: SNGL, Convert double precision real to default real
233 * @code{SPACING}: SPACING, Smallest distance between two numbers of a given type
234 * @code{SPREAD}: SPREAD, Add a dimension to an array
235 * @code{SQRT}: SQRT, Square-root function
236 * @code{SRAND}: SRAND, Reinitialize the random number generator
237 * @code{STAT}: STAT, Get file status
238 * @code{SUM}: SUM, Sum of array elements
239 * @code{SYMLNK}: SYMLNK, Create a symbolic link
240 * @code{SYSTEM}: SYSTEM, Execute a shell command
241 * @code{SYSTEM_CLOCK}: SYSTEM_CLOCK, Time function
242 * @code{TAN}: TAN, Tangent function
243 * @code{TANH}: TANH, Hyperbolic tangent function
244 * @code{TIME}: TIME, Time function
245 * @code{TIME8}: TIME8, Time function (64-bit)
246 * @code{TINY}: TINY, Smallest positive number of a real kind
247 * @code{TRANSFER}: TRANSFER, Transfer bit patterns
248 * @code{TRANSPOSE}: TRANSPOSE, Transpose an array of rank two
249 * @code{TRIM}: TRIM, Remove trailing blank characters of a string
250 * @code{TTYNAM}: TTYNAM, Get the name of a terminal device.
251 * @code{UBOUND}: UBOUND, Upper dimension bounds of an array
252 * @code{UMASK}: UMASK, Set the file creation mask
253 * @code{UNLINK}: UNLINK, Remove a file from the file system
254 * @code{UNPACK}: UNPACK, Unpack an array of rank one into an array
255 * @code{VERIFY}: VERIFY, Scan a string for the absence of a set of characters
256 * @code{XOR}: XOR, Bitwise logical exclusive or
259 @node Introduction to Intrinsics
260 @section Introduction to intrinsic procedures
262 The intrinsic procedures provided by GNU Fortran include all of the
263 intrinsic procedures required by the Fortran 95 standard, a set of
264 intrinsic procedures for backwards compatibility with G77, and a small
265 selection of intrinsic procedures from the Fortran 2003 standard. Any
266 conflict between a description here and a description in either the
267 Fortran 95 standard or the Fortran 2003 standard is unintentional, and
268 the standard(s) should be considered authoritative.
270 The enumeration of the @code{KIND} type parameter is processor defined in
271 the Fortran 95 standard. GNU Fortran defines the default integer type and
272 default real type by @code{INTEGER(KIND=4)} and @code{REAL(KIND=4)},
273 respectively. The standard mandates that both data types shall have
274 another kind, which have more precision. On typical target architectures
275 supported by @command{gfortran}, this kind type parameter is @code{KIND=8}.
276 Hence, @code{REAL(KIND=8)} and @code{DOUBLE PRECISION} are equivalent.
277 In the description of generic intrinsic procedures, the kind type parameter
278 will be specified by @code{KIND=*}, and in the description of specific
279 names for an intrinsic procedure the kind type parameter will be explicitly
280 given (e.g., @code{REAL(KIND=4)} or @code{REAL(KIND=8)}). Finally, for
281 brevity the optional @code{KIND=} syntax will be omitted.
283 Many of the intrinsic procedures take one or more optional arguments.
284 This document follows the convention used in the Fortran 95 standard,
285 and denotes such arguments by square brackets.
287 GNU Fortran offers the @option{-std=f95} and @option{-std=gnu} options,
288 which can be used to restrict the set of intrinsic procedures to a
289 given standard. By default, @command{gfortran} sets the @option{-std=gnu}
290 option, and so all intrinsic procedures described here are accepted. There
291 is one caveat. For a select group of intrinsic procedures, @command{g77}
292 implemented both a function and a subroutine. Both classes
293 have been implemented in @command{gfortran} for backwards compatibility
294 with @command{g77}. It is noted here that these functions and subroutines
295 cannot be intermixed in a given subprogram. In the descriptions that follow,
296 the applicable standard for each intrinsic procedure is noted.
301 @section @code{ABORT} --- Abort the program
303 @cindex program termination, with core dump
304 @cindex terminate program, with core dump
308 @item @emph{Description}:
309 @code{ABORT} causes immediate termination of the program. On operating
310 systems that support a core dump, @code{ABORT} will produce a core dump,
311 which is suitable for debugging purposes.
313 @item @emph{Standard}:
317 Non-elemental subroutine
322 @item @emph{Return value}:
325 @item @emph{Example}:
328 integer :: i = 1, j = 2
329 if (i /= j) call abort
330 end program test_abort
333 @item @emph{See also}:
334 @ref{EXIT}, @ref{KILL}
341 @section @code{ABS} --- Absolute value
348 @cindex absolute value
351 @item @emph{Description}:
352 @code{ABS(X)} computes the absolute value of @code{X}.
354 @item @emph{Standard}:
355 F77 and later, has overloads that are GNU extensions
361 @code{RESULT = ABS(X)}
363 @item @emph{Arguments}:
364 @multitable @columnfractions .15 .70
365 @item @var{X} @tab The type of the argument shall be an @code{INTEGER(*)},
366 @code{REAL(*)}, or @code{COMPLEX(*)}.
369 @item @emph{Return value}:
370 The return value is of the same type and
371 kind as the argument except the return value is @code{REAL(*)} for a
372 @code{COMPLEX(*)} argument.
374 @item @emph{Example}:
379 complex :: z = (-1.e0,0.e0)
386 @item @emph{Specific names}:
387 @multitable @columnfractions .20 .20 .20 .25
388 @item Name @tab Argument @tab Return type @tab Standard
389 @item @code{CABS(Z)} @tab @code{COMPLEX(4) Z} @tab @code{REAL(4)} @tab F77 and later
390 @item @code{DABS(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
391 @item @code{IABS(I)} @tab @code{INTEGER(4) I} @tab @code{INTEGER(4)} @tab F77 and later
392 @item @code{ZABS(Z)} @tab @code{COMPLEX(8) Z} @tab @code{COMPLEX(8)} @tab GNU extension
393 @item @code{CDABS(Z)} @tab @code{COMPLEX(8) Z} @tab @code{COMPLEX(8)} @tab GNU extension
400 @section @code{ACCESS} --- Checks file access modes
402 @cindex file system, access mode
405 @item @emph{Description}:
406 @code{ACCESS(NAME, MODE)} checks whether the file @var{NAME}
407 exists, is readable, writable or executable. Except for the
408 executable check, @code{ACCESS} can be replaced by
409 Fortran 95's @code{INQUIRE}.
411 @item @emph{Standard}:
418 @code{RESULT = ACCESS(NAME, MODE)}
420 @item @emph{Arguments}:
421 @multitable @columnfractions .15 .70
422 @item @var{NAME} @tab Scalar @code{CHARACTER} with the file name.
423 Tailing blank are ignored unless the character @code{achar(0)} is
424 present, then all characters up to and excluding @code{achar(0)} are
426 @item @var{MODE} @tab Scalar @code{CHARACTER} with the file access mode,
427 may be any concatenation of @code{"r"} (readable), @code{"w"} (writable)
428 and @code{"x"} (executable), or @code{" "} to check for existence.
431 @item @emph{Return value}:
432 Returns a scalar @code{INTEGER}, which is @code{0} if the file is
433 accessible in the given mode; otherwise or if an invalid argument
434 has been given for @code{MODE} the value @code{1} is returned.
436 @item @emph{Example}:
440 character(len=*), parameter :: file = 'test.dat'
441 character(len=*), parameter :: file2 = 'test.dat '//achar(0)
442 if(access(file,' ') == 0) print *, trim(file),' is exists'
443 if(access(file,'r') == 0) print *, trim(file),' is readable'
444 if(access(file,'w') == 0) print *, trim(file),' is writable'
445 if(access(file,'x') == 0) print *, trim(file),' is executable'
446 if(access(file2,'rwx') == 0) &
447 print *, trim(file2),' is readable, writable and executable'
448 end program access_test
450 @item @emph{Specific names}:
451 @item @emph{See also}:
458 @section @code{ACHAR} --- Character in @acronym{ASCII} collating sequence
460 @cindex @acronym{ASCII} collating sequence
461 @cindex collating sequence, @acronym{ASCII}
464 @item @emph{Description}:
465 @code{ACHAR(I)} returns the character located at position @code{I}
466 in the @acronym{ASCII} collating sequence.
468 @item @emph{Standard}:
475 @code{RESULT = ACHAR(I)}
477 @item @emph{Arguments}:
478 @multitable @columnfractions .15 .70
479 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
482 @item @emph{Return value}:
483 The return value is of type @code{CHARACTER} with a length of one. The
484 kind type parameter is the same as @code{KIND('A')}.
486 @item @emph{Example}:
491 end program test_achar
495 See @ref{ICHAR} for a discussion of converting between numerical values
496 and formatted string representations.
498 @item @emph{See also}:
499 @ref{CHAR}, @ref{IACHAR}, @ref{ICHAR}
506 @section @code{ACOS} --- Arccosine function
509 @cindex trigonometric function, cosine, inverse
510 @cindex cosine, inverse
513 @item @emph{Description}:
514 @code{ACOS(X)} computes the arccosine of @var{X} (inverse of @code{COS(X)}).
516 @item @emph{Standard}:
523 @code{RESULT = ACOS(X)}
525 @item @emph{Arguments}:
526 @multitable @columnfractions .15 .70
527 @item @var{X} @tab The type shall be @code{REAL(*)} with a magnitude that is
531 @item @emph{Return value}:
532 The return value is of type @code{REAL(*)} and it lies in the
533 range @math{ 0 \leq \acos(x) \leq \pi}. The kind type parameter
534 is the same as @var{X}.
536 @item @emph{Example}:
539 real(8) :: x = 0.866_8
541 end program test_acos
544 @item @emph{Specific names}:
545 @multitable @columnfractions .20 .20 .20 .25
546 @item Name @tab Argument @tab Return type @tab Standard
547 @item @code{DACOS(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
550 @item @emph{See also}:
551 Inverse function: @ref{COS}
558 @section @code{ACOSH} --- Hyperbolic arccosine function
561 @cindex area hyperbolic cosine
562 @cindex hyperbolic arccosine
563 @cindex hyperbolic function, cosine, inverse
564 @cindex cosine, hyperbolic, inverse
567 @item @emph{Description}:
568 @code{ACOSH(X)} computes the hyperbolic arccosine of @var{X} (inverse of
571 @item @emph{Standard}:
578 @code{RESULT = ACOSH(X)}
580 @item @emph{Arguments}:
581 @multitable @columnfractions .15 .70
582 @item @var{X} @tab The type shall be @code{REAL(*)} with a magnitude that is
583 greater or equal to one.
586 @item @emph{Return value}:
587 The return value is of type @code{REAL(*)} and it lies in the
588 range @math{0 \leq \acosh (x) \leq \infty}.
590 @item @emph{Example}:
593 REAL(8), DIMENSION(3) :: x = (/ 1.0, 2.0, 3.0 /)
598 @item @emph{Specific names}:
599 @multitable @columnfractions .20 .20 .20 .25
600 @item Name @tab Argument @tab Return type @tab Standard
601 @item @code{DACOSH(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab GNU extension
604 @item @emph{See also}:
605 Inverse function: @ref{COSH}
611 @section @code{ADJUSTL} --- Left adjust a string
613 @cindex string, adjust left
614 @cindex adjust string
617 @item @emph{Description}:
618 @code{ADJUSTL(STR)} will left adjust a string by removing leading spaces.
619 Spaces are inserted at the end of the string as needed.
621 @item @emph{Standard}:
628 @code{RESULT = ADJUSTL(STR)}
630 @item @emph{Arguments}:
631 @multitable @columnfractions .15 .70
632 @item @var{STR} @tab The type shall be @code{CHARACTER}.
635 @item @emph{Return value}:
636 The return value is of type @code{CHARACTER} where leading spaces
637 are removed and the same number of spaces are inserted on the end
640 @item @emph{Example}:
643 character(len=20) :: str = ' gfortran'
646 end program test_adjustl
649 @item @emph{See also}:
650 @ref{ADJUSTR}, @ref{TRIM}
656 @section @code{ADJUSTR} --- Right adjust a string
658 @cindex string, adjust right
659 @cindex adjust string
662 @item @emph{Description}:
663 @code{ADJUSTR(STR)} will right adjust a string by removing trailing spaces.
664 Spaces are inserted at the start of the string as needed.
666 @item @emph{Standard}:
673 @code{RESULT = ADJUSTR(STR)}
675 @item @emph{Arguments}:
676 @multitable @columnfractions .15 .70
677 @item @var{STR} @tab The type shall be @code{CHARACTER}.
680 @item @emph{Return value}:
681 The return value is of type @code{CHARACTER} where trailing spaces
682 are removed and the same number of spaces are inserted at the start
685 @item @emph{Example}:
688 character(len=20) :: str = 'gfortran'
691 end program test_adjustr
694 @item @emph{See also}:
695 @ref{ADJUSTL}, @ref{TRIM}
701 @section @code{AIMAG} --- Imaginary part of complex number
706 @cindex complex numbers, imaginary part
709 @item @emph{Description}:
710 @code{AIMAG(Z)} yields the imaginary part of complex argument @code{Z}.
711 The @code{IMAG(Z)} and @code{IMAGPART(Z)} intrinsic functions are provided
712 for compatibility with @command{g77}, and their use in new code is
713 strongly discouraged.
715 @item @emph{Standard}:
716 F77 and later, has overloads that are GNU extensions
722 @code{RESULT = AIMAG(Z)}
724 @item @emph{Arguments}:
725 @multitable @columnfractions .15 .70
726 @item @var{Z} @tab The type of the argument shall be @code{COMPLEX(*)}.
729 @item @emph{Return value}:
730 The return value is of type real with the
731 kind type parameter of the argument.
733 @item @emph{Example}:
738 z4 = cmplx(1.e0_4, 0.e0_4)
739 z8 = cmplx(0.e0_8, 1.e0_8)
740 print *, aimag(z4), dimag(z8)
741 end program test_aimag
744 @item @emph{Specific names}:
745 @multitable @columnfractions .20 .20 .20 .25
746 @item Name @tab Argument @tab Return type @tab Standard
747 @item @code{DIMAG(Z)} @tab @code{COMPLEX(8) Z} @tab @code{REAL(8)} @tab GNU extension
748 @item @code{IMAG(Z)} @tab @code{COMPLEX(*) Z} @tab @code{REAL(*)} @tab GNU extension
749 @item @code{IMAGPART(Z)} @tab @code{COMPLEX(*) Z} @tab @code{REAL(*)} @tab GNU extension
756 @section @code{AINT} --- Truncate to a whole number
760 @cindex rounding, floor
763 @item @emph{Description}:
764 @code{AINT(X [, KIND])} truncates its argument to a whole number.
766 @item @emph{Standard}:
773 @code{RESULT = AINT(X [, KIND])}
775 @item @emph{Arguments}:
776 @multitable @columnfractions .15 .70
777 @item @var{X} @tab The type of the argument shall be @code{REAL(*)}.
778 @item @var{KIND} @tab (Optional) An @code{INTEGER(*)} initialization
779 expression indicating the kind parameter of
783 @item @emph{Return value}:
784 The return value is of type real with the kind type parameter of the
785 argument if the optional @var{KIND} is absent; otherwise, the kind
786 type parameter will be given by @var{KIND}. If the magnitude of
787 @var{X} is less than one, then @code{AINT(X)} returns zero. If the
788 magnitude is equal to or greater than one, then it returns the largest
789 whole number that does not exceed its magnitude. The sign is the same
790 as the sign of @var{X}.
792 @item @emph{Example}:
799 print *, aint(x4), dint(x8)
801 end program test_aint
804 @item @emph{Specific names}:
805 @multitable @columnfractions .20 .20 .20 .25
806 @item Name @tab Argument @tab Return type @tab Standard
807 @item @code{DINT(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
814 @section @code{ALARM} --- Execute a routine after a given delay
816 @cindex delayed execution
819 @item @emph{Description}:
820 @code{ALARM(SECONDS, HANDLER [, STATUS])} causes external subroutine @var{HANDLER}
821 to be executed after a delay of @var{SECONDS} by using @code{alarm(2)} to
822 set up a signal and @code{signal(2)} to catch it. If @var{STATUS} is
823 supplied, it will be returned with the number of seconds remaining until
824 any previously scheduled alarm was due to be delivered, or zero if there
825 was no previously scheduled alarm.
827 @item @emph{Standard}:
834 @code{CALL ALARM(SECONDS, HANDLER [, STATUS])}
836 @item @emph{Arguments}:
837 @multitable @columnfractions .15 .70
838 @item @var{SECONDS} @tab The type of the argument shall be a scalar
839 @code{INTEGER}. It is @code{INTENT(IN)}.
840 @item @var{HANDLER} @tab Signal handler (@code{INTEGER FUNCTION} or
841 @code{SUBROUTINE}) or dummy/global @code{INTEGER} scalar. The scalar
842 values may be either @code{SIG_IGN=1} to ignore the alarm generated
843 or @code{SIG_DFL=0} to set the default action. It is @code{INTENT(IN)}.
844 @item @var{STATUS} @tab (Optional) @var{STATUS} shall be a scalar
845 variable of the default @code{INTEGER} kind. It is @code{INTENT(OUT)}.
848 @item @emph{Example}:
851 external handler_print
853 call alarm (3, handler_print, i)
856 end program test_alarm
858 This will cause the external routine @var{handler_print} to be called
865 @section @code{ALL} --- All values in @var{MASK} along @var{DIM} are true
867 @cindex array, apply condition
868 @cindex array, condition testing
871 @item @emph{Description}:
872 @code{ALL(MASK [, DIM])} determines if all the values are true in @var{MASK}
873 in the array along dimension @var{DIM}.
875 @item @emph{Standard}:
879 transformational function
882 @code{RESULT = ALL(MASK [, DIM])}
884 @item @emph{Arguments}:
885 @multitable @columnfractions .15 .70
886 @item @var{MASK} @tab The type of the argument shall be @code{LOGICAL(*)} and
887 it shall not be scalar.
888 @item @var{DIM} @tab (Optional) @var{DIM} shall be a scalar integer
889 with a value that lies between one and the rank of @var{MASK}.
892 @item @emph{Return value}:
893 @code{ALL(MASK)} returns a scalar value of type @code{LOGICAL(*)} where
894 the kind type parameter is the same as the kind type parameter of
895 @var{MASK}. If @var{DIM} is present, then @code{ALL(MASK, DIM)} returns
896 an array with the rank of @var{MASK} minus 1. The shape is determined from
897 the shape of @var{MASK} where the @var{DIM} dimension is elided.
901 @code{ALL(MASK)} is true if all elements of @var{MASK} are true.
902 It also is true if @var{MASK} has zero size; otherwise, it is false.
904 If the rank of @var{MASK} is one, then @code{ALL(MASK,DIM)} is equivalent
905 to @code{ALL(MASK)}. If the rank is greater than one, then @code{ALL(MASK,DIM)}
906 is determined by applying @code{ALL} to the array sections.
909 @item @emph{Example}:
913 l = all((/.true., .true., .true./))
918 integer a(2,3), b(2,3)
922 print *, all(a .eq. b, 1)
923 print *, all(a .eq. b, 2)
924 end subroutine section
932 @section @code{ALLOCATED} --- Status of an allocatable entity
934 @cindex allocation, status
937 @item @emph{Description}:
938 @code{ALLOCATED(X)} checks the status of whether @var{X} is allocated.
940 @item @emph{Standard}:
947 @code{RESULT = ALLOCATED(X)}
949 @item @emph{Arguments}:
950 @multitable @columnfractions .15 .70
951 @item @var{X} @tab The argument shall be an @code{ALLOCATABLE} array.
954 @item @emph{Return value}:
955 The return value is a scalar @code{LOGICAL} with the default logical
956 kind type parameter. If @var{X} is allocated, @code{ALLOCATED(X)}
957 is @code{.TRUE.}; otherwise, it returns the @code{.TRUE.}
959 @item @emph{Example}:
961 program test_allocated
963 real(4), allocatable :: x(:)
964 if (allocated(x) .eqv. .false.) allocate(x(i))
965 end program test_allocated
972 @section @code{AND} --- Bitwise logical AND
974 @cindex bitwise logical and
975 @cindex logical and, bitwise
978 @item @emph{Description}:
979 Bitwise logical @code{AND}.
981 This intrinsic routine is provided for backwards compatibility with
982 GNU Fortran 77. For integer arguments, programmers should consider
983 the use of the @ref{IAND} intrinsic defined by the Fortran standard.
985 @item @emph{Standard}:
989 Non-elemental function
992 @code{RESULT = AND(I, J)}
994 @item @emph{Arguments}:
995 @multitable @columnfractions .15 .70
996 @item @var{I} @tab The type shall be either @code{INTEGER(*)} or @code{LOGICAL}.
997 @item @var{J} @tab The type shall be either @code{INTEGER(*)} or @code{LOGICAL}.
1000 @item @emph{Return value}:
1001 The return type is either @code{INTEGER(*)} or @code{LOGICAL} after
1002 cross-promotion of the arguments.
1004 @item @emph{Example}:
1007 LOGICAL :: T = .TRUE., F = .FALSE.
1009 DATA a / Z'F' /, b / Z'3' /
1011 WRITE (*,*) AND(T, T), AND(T, F), AND(F, T), AND(F, F)
1012 WRITE (*,*) AND(a, b)
1016 @item @emph{See also}:
1017 F95 elemental function: @ref{IAND}
1023 @section @code{ANINT} --- Nearest whole number
1027 @cindex rounding, ceiling
1030 @item @emph{Description}:
1031 @code{ANINT(X [, KIND])} rounds its argument to the nearest whole number.
1033 @item @emph{Standard}:
1039 @item @emph{Syntax}:
1040 @code{RESULT = ANINT(X [, KIND])}
1042 @item @emph{Arguments}:
1043 @multitable @columnfractions .15 .70
1044 @item @var{X} @tab The type of the argument shall be @code{REAL(*)}.
1045 @item @var{KIND} @tab (Optional) An @code{INTEGER(*)} initialization
1046 expression indicating the kind parameter of
1050 @item @emph{Return value}:
1051 The return value is of type real with the kind type parameter of the
1052 argument if the optional @var{KIND} is absent; otherwise, the kind
1053 type parameter will be given by @var{KIND}. If @var{X} is greater than
1054 zero, then @code{ANINT(X)} returns @code{AINT(X+0.5)}. If @var{X} is
1055 less than or equal to zero, then it returns @code{AINT(X-0.5)}.
1057 @item @emph{Example}:
1064 print *, anint(x4), dnint(x8)
1066 end program test_anint
1069 @item @emph{Specific names}:
1070 @multitable @columnfractions .20 .20 .20 .25
1071 @item Name @tab Argument @tab Return type @tab Standard
1072 @item @code{DNINT(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
1079 @section @code{ANY} --- Any value in @var{MASK} along @var{DIM} is true
1081 @cindex array, apply condition
1082 @cindex array, condition testing
1085 @item @emph{Description}:
1086 @code{ANY(MASK [, DIM])} determines if any of the values in the logical array
1087 @var{MASK} along dimension @var{DIM} are @code{.TRUE.}.
1089 @item @emph{Standard}:
1093 transformational function
1095 @item @emph{Syntax}:
1096 @code{RESULT = ANY(MASK [, DIM])}
1098 @item @emph{Arguments}:
1099 @multitable @columnfractions .15 .70
1100 @item @var{MASK} @tab The type of the argument shall be @code{LOGICAL(*)} and
1101 it shall not be scalar.
1102 @item @var{DIM} @tab (Optional) @var{DIM} shall be a scalar integer
1103 with a value that lies between one and the rank of @var{MASK}.
1106 @item @emph{Return value}:
1107 @code{ANY(MASK)} returns a scalar value of type @code{LOGICAL(*)} where
1108 the kind type parameter is the same as the kind type parameter of
1109 @var{MASK}. If @var{DIM} is present, then @code{ANY(MASK, DIM)} returns
1110 an array with the rank of @var{MASK} minus 1. The shape is determined from
1111 the shape of @var{MASK} where the @var{DIM} dimension is elided.
1115 @code{ANY(MASK)} is true if any element of @var{MASK} is true;
1116 otherwise, it is false. It also is false if @var{MASK} has zero size.
1118 If the rank of @var{MASK} is one, then @code{ANY(MASK,DIM)} is equivalent
1119 to @code{ANY(MASK)}. If the rank is greater than one, then @code{ANY(MASK,DIM)}
1120 is determined by applying @code{ANY} to the array sections.
1123 @item @emph{Example}:
1127 l = any((/.true., .true., .true./))
1132 integer a(2,3), b(2,3)
1136 print *, any(a .eq. b, 1)
1137 print *, any(a .eq. b, 2)
1138 end subroutine section
1139 end program test_any
1146 @section @code{ASIN} --- Arcsine function
1149 @cindex trigonometric function, sine, inverse
1150 @cindex sine, inverse
1153 @item @emph{Description}:
1154 @code{ASIN(X)} computes the arcsine of its @var{X} (inverse of @code{SIN(X)}).
1156 @item @emph{Standard}:
1162 @item @emph{Syntax}:
1163 @code{RESULT = ASIN(X)}
1165 @item @emph{Arguments}:
1166 @multitable @columnfractions .15 .70
1167 @item @var{X} @tab The type shall be @code{REAL(*)}, and a magnitude that is
1171 @item @emph{Return value}:
1172 The return value is of type @code{REAL(*)} and it lies in the
1173 range @math{-\pi / 2 \leq \asin (x) \leq \pi / 2}. The kind type
1174 parameter is the same as @var{X}.
1176 @item @emph{Example}:
1179 real(8) :: x = 0.866_8
1181 end program test_asin
1184 @item @emph{Specific names}:
1185 @multitable @columnfractions .20 .20 .20 .25
1186 @item Name @tab Argument @tab Return type @tab Standard
1187 @item @code{DASIN(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
1190 @item @emph{See also}:
1191 Inverse function: @ref{SIN}
1198 @section @code{ASINH} --- Hyperbolic arcsine function
1201 @cindex area hyperbolic sine
1202 @cindex hyperbolic arcsine
1203 @cindex hyperbolic function, sine, inverse
1204 @cindex sine, hyperbolic, inverse
1207 @item @emph{Description}:
1208 @code{ASINH(X)} computes the hyperbolic arcsine of @var{X} (inverse of @code{SINH(X)}).
1210 @item @emph{Standard}:
1216 @item @emph{Syntax}:
1217 @code{RESULT = ASINH(X)}
1219 @item @emph{Arguments}:
1220 @multitable @columnfractions .15 .70
1221 @item @var{X} @tab The type shall be @code{REAL(*)}, with @var{X} a real number.
1224 @item @emph{Return value}:
1225 The return value is of type @code{REAL(*)} and it lies in the
1226 range @math{-\infty \leq \asinh (x) \leq \infty}.
1228 @item @emph{Example}:
1231 REAL(8), DIMENSION(3) :: x = (/ -1.0, 0.0, 1.0 /)
1232 WRITE (*,*) ASINH(x)
1236 @item @emph{Specific names}:
1237 @multitable @columnfractions .20 .20 .20 .25
1238 @item Name @tab Argument @tab Return type @tab Standard
1239 @item @code{DASINH(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab GNU extension.
1242 @item @emph{See also}:
1243 Inverse function: @ref{SINH}
1249 @section @code{ASSOCIATED} --- Status of a pointer or pointer/target pair
1251 @cindex pointer, status
1252 @cindex association status
1255 @item @emph{Description}:
1256 @code{ASSOCIATED(PTR [, TGT])} determines the status of the pointer @var{PTR}
1257 or if @var{PTR} is associated with the target @var{TGT}.
1259 @item @emph{Standard}:
1265 @item @emph{Syntax}:
1266 @code{RESULT = ASSOCIATED(PTR [, TGT])}
1268 @item @emph{Arguments}:
1269 @multitable @columnfractions .15 .70
1270 @item @var{PTR} @tab @var{PTR} shall have the @code{POINTER} attribute and
1271 it can be of any type.
1272 @item @var{TGT} @tab (Optional) @var{TGT} shall be a @code{POINTER} or
1273 a @code{TARGET}. It must have the same type, kind type parameter, and
1274 array rank as @var{PTR}.
1276 The status of neither @var{PTR} nor @var{TGT} can be undefined.
1278 @item @emph{Return value}:
1279 @code{ASSOCIATED(PTR)} returns a scalar value of type @code{LOGICAL(4)}.
1280 There are several cases:
1282 @item (A) If the optional @var{TGT} is not present, then @code{ASSOCIATED(PTR)}
1283 is true if @var{PTR} is associated with a target; otherwise, it returns false.
1284 @item (B) If @var{TGT} is present and a scalar target, the result is true if
1286 is not a 0 sized storage sequence and the target associated with @var{PTR}
1287 occupies the same storage units. If @var{PTR} is disassociated, then the
1289 @item (C) If @var{TGT} is present and an array target, the result is true if
1290 @var{TGT} and @var{PTR} have the same shape, are not 0 sized arrays, are
1291 arrays whose elements are not 0 sized storage sequences, and @var{TGT} and
1292 @var{PTR} occupy the same storage units in array element order.
1293 As in case(B), the result is false, if @var{PTR} is disassociated.
1294 @item (D) If @var{TGT} is present and an scalar pointer, the result is true if
1295 target associated with @var{PTR} and the target associated with @var{TGT}
1296 are not 0 sized storage sequences and occupy the same storage units.
1297 The result is false, if either @var{TGT} or @var{PTR} is disassociated.
1298 @item (E) If @var{TGT} is present and an array pointer, the result is true if
1299 target associated with @var{PTR} and the target associated with @var{TGT}
1300 have the same shape, are not 0 sized arrays, are arrays whose elements are
1301 not 0 sized storage sequences, and @var{TGT} and @var{PTR} occupy the same
1302 storage units in array element order.
1303 The result is false, if either @var{TGT} or @var{PTR} is disassociated.
1306 @item @emph{Example}:
1308 program test_associated
1310 real, target :: tgt(2) = (/1., 2./)
1311 real, pointer :: ptr(:)
1313 if (associated(ptr) .eqv. .false.) call abort
1314 if (associated(ptr,tgt) .eqv. .false.) call abort
1315 end program test_associated
1318 @item @emph{See also}:
1325 @section @code{ATAN} --- Arctangent function
1328 @cindex trigonometric function, tangent, inverse
1329 @cindex tangent, inverse
1332 @item @emph{Description}:
1333 @code{ATAN(X)} computes the arctangent of @var{X}.
1335 @item @emph{Standard}:
1341 @item @emph{Syntax}:
1342 @code{RESULT = ATAN(X)}
1344 @item @emph{Arguments}:
1345 @multitable @columnfractions .15 .70
1346 @item @var{X} @tab The type shall be @code{REAL(*)}.
1349 @item @emph{Return value}:
1350 The return value is of type @code{REAL(*)} and it lies in the
1351 range @math{ - \pi / 2 \leq \atan (x) \leq \pi / 2}.
1353 @item @emph{Example}:
1356 real(8) :: x = 2.866_8
1358 end program test_atan
1361 @item @emph{Specific names}:
1362 @multitable @columnfractions .20 .20 .20 .25
1363 @item Name @tab Argument @tab Return type @tab Standard
1364 @item @code{DATAN(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
1367 @item @emph{See also}:
1368 Inverse function: @ref{TAN}
1375 @section @code{ATAN2} --- Arctangent function
1378 @cindex trigonometric function, tangent, inverse
1379 @cindex tangent, inverse
1382 @item @emph{Description}:
1383 @code{ATAN2(Y,X)} computes the arctangent of the complex number
1386 @item @emph{Standard}:
1392 @item @emph{Syntax}:
1393 @code{RESULT = ATAN2(Y,X)}
1395 @item @emph{Arguments}:
1396 @multitable @columnfractions .15 .70
1397 @item @var{Y} @tab The type shall be @code{REAL(*)}.
1398 @item @var{X} @tab The type and kind type parameter shall be the same as @var{Y}.
1399 If @var{Y} is zero, then @var{X} must be nonzero.
1402 @item @emph{Return value}:
1403 The return value has the same type and kind type parameter as @var{Y}.
1404 It is the principal value of the complex number @math{X + i Y}. If
1405 @var{X} is nonzero, then it lies in the range @math{-\pi \le \atan (x) \leq \pi}.
1406 The sign is positive if @var{Y} is positive. If @var{Y} is zero, then
1407 the return value is zero if @var{X} is positive and @math{\pi} if @var{X}
1408 is negative. Finally, if @var{X} is zero, then the magnitude of the result
1411 @item @emph{Example}:
1414 real(4) :: x = 1.e0_4, y = 0.5e0_4
1416 end program test_atan2
1419 @item @emph{Specific names}:
1420 @multitable @columnfractions .20 .20 .20 .25
1421 @item Name @tab Argument @tab Return type @tab Standard
1422 @item @code{DATAN2(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
1429 @section @code{ATANH} --- Hyperbolic arctangent function
1432 @cindex area hyperbolic tangent
1433 @cindex hyperbolic arctangent
1434 @cindex hyperbolic function, tangent, inverse
1435 @cindex tangent, hyperbolic, inverse
1438 @item @emph{Description}:
1439 @code{ATANH(X)} computes the hyperbolic arctangent of @var{X} (inverse
1442 @item @emph{Standard}:
1448 @item @emph{Syntax}:
1449 @code{RESULT = ATANH(X)}
1451 @item @emph{Arguments}:
1452 @multitable @columnfractions .15 .70
1453 @item @var{X} @tab The type shall be @code{REAL(*)} with a magnitude
1454 that is less than or equal to one.
1457 @item @emph{Return value}:
1458 The return value is of type @code{REAL(*)} and it lies in the
1459 range @math{-\infty \leq \atanh(x) \leq \infty}.
1461 @item @emph{Example}:
1464 REAL, DIMENSION(3) :: x = (/ -1.0, 0.0, 1.0 /)
1465 WRITE (*,*) ATANH(x)
1469 @item @emph{Specific names}:
1470 @multitable @columnfractions .20 .20 .20 .25
1471 @item Name @tab Argument @tab Return type @tab Standard
1472 @item @code{DATANH(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab GNU extension
1475 @item @emph{See also}:
1476 Inverse function: @ref{TANH}
1482 @section @code{BESJ0} --- Bessel function of the first kind of order 0
1485 @cindex Bessel function, first kind
1488 @item @emph{Description}:
1489 @code{BESJ0(X)} computes the Bessel function of the first kind of order 0
1492 @item @emph{Standard}:
1498 @item @emph{Syntax}:
1499 @code{RESULT = BESJ0(X)}
1501 @item @emph{Arguments}:
1502 @multitable @columnfractions .15 .70
1503 @item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
1506 @item @emph{Return value}:
1507 The return value is of type @code{REAL(*)} and it lies in the
1508 range @math{ - 0.4027... \leq Bessel (0,x) \leq 1}.
1510 @item @emph{Example}:
1513 real(8) :: x = 0.0_8
1515 end program test_besj0
1518 @item @emph{Specific names}:
1519 @multitable @columnfractions .20 .20 .20 .25
1520 @item Name @tab Argument @tab Return type @tab Standard
1521 @item @code{DBESJ0(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab GNU extension
1528 @section @code{BESJ1} --- Bessel function of the first kind of order 1
1531 @cindex Bessel function, first kind
1534 @item @emph{Description}:
1535 @code{BESJ1(X)} computes the Bessel function of the first kind of order 1
1538 @item @emph{Standard}:
1544 @item @emph{Syntax}:
1545 @code{RESULT = BESJ1(X)}
1547 @item @emph{Arguments}:
1548 @multitable @columnfractions .15 .70
1549 @item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
1552 @item @emph{Return value}:
1553 The return value is of type @code{REAL(*)} and it lies in the
1554 range @math{ - 0.5818... \leq Bessel (0,x) \leq 0.5818 }.
1556 @item @emph{Example}:
1559 real(8) :: x = 1.0_8
1561 end program test_besj1
1564 @item @emph{Specific names}:
1565 @multitable @columnfractions .20 .20 .20 .25
1566 @item Name @tab Argument @tab Return type @tab Standard
1567 @item @code{DBESJ1(X)}@tab @code{REAL(8) X} @tab @code{REAL(8)} @tab GNU extension
1574 @section @code{BESJN} --- Bessel function of the first kind
1577 @cindex Bessel function, first kind
1580 @item @emph{Description}:
1581 @code{BESJN(N, X)} computes the Bessel function of the first kind of order
1584 If both arguments are arrays, their ranks and shapes shall conform.
1586 @item @emph{Standard}:
1592 @item @emph{Syntax}:
1593 @code{RESULT = BESJN(N, X)}
1595 @item @emph{Arguments}:
1596 @multitable @columnfractions .15 .70
1597 @item @var{N} @tab Shall be a scalar or an array of type @code{INTEGER(*)}.
1598 @item @var{X} @tab Shall be a scalar or an array of type @code{REAL(*)}.
1601 @item @emph{Return value}:
1602 The return value is a scalar of type @code{REAL(*)}.
1604 @item @emph{Example}:
1607 real(8) :: x = 1.0_8
1609 end program test_besjn
1612 @item @emph{Specific names}:
1613 @multitable @columnfractions .20 .20 .20 .25
1614 @item Name @tab Argument @tab Return type @tab Standard
1615 @item @code{DBESJN(X)} @tab @code{INTEGER(*) N} @tab @code{REAL(8)} @tab GNU extension
1616 @item @tab @code{REAL(8) X} @tab @tab
1623 @section @code{BESY0} --- Bessel function of the second kind of order 0
1626 @cindex Bessel function, second kind
1629 @item @emph{Description}:
1630 @code{BESY0(X)} computes the Bessel function of the second kind of order 0
1633 @item @emph{Standard}:
1639 @item @emph{Syntax}:
1640 @code{RESULT = BESY0(X)}
1642 @item @emph{Arguments}:
1643 @multitable @columnfractions .15 .70
1644 @item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
1647 @item @emph{Return value}:
1648 The return value is a scalar of type @code{REAL(*)}.
1650 @item @emph{Example}:
1653 real(8) :: x = 0.0_8
1655 end program test_besy0
1658 @item @emph{Specific names}:
1659 @multitable @columnfractions .20 .20 .20 .25
1660 @item Name @tab Argument @tab Return type @tab Standard
1661 @item @code{DBESY0(X)}@tab @code{REAL(8) X} @tab @code{REAL(8)} @tab GNU extension
1668 @section @code{BESY1} --- Bessel function of the second kind of order 1
1671 @cindex Bessel function, second kind
1674 @item @emph{Description}:
1675 @code{BESY1(X)} computes the Bessel function of the second kind of order 1
1678 @item @emph{Standard}:
1684 @item @emph{Syntax}:
1685 @code{RESULT = BESY1(X)}
1687 @item @emph{Arguments}:
1688 @multitable @columnfractions .15 .70
1689 @item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
1692 @item @emph{Return value}:
1693 The return value is a scalar of type @code{REAL(*)}.
1695 @item @emph{Example}:
1698 real(8) :: x = 1.0_8
1700 end program test_besy1
1703 @item @emph{Specific names}:
1704 @multitable @columnfractions .20 .20 .20 .25
1705 @item Name @tab Argument @tab Return type @tab Standard
1706 @item @code{DBESY1(X)}@tab @code{REAL(8) X} @tab @code{REAL(8)} @tab GNU extension
1713 @section @code{BESYN} --- Bessel function of the second kind
1716 @cindex Bessel function, second kind
1719 @item @emph{Description}:
1720 @code{BESYN(N, X)} computes the Bessel function of the second kind of order
1723 If both arguments are arrays, their ranks and shapes shall conform.
1725 @item @emph{Standard}:
1731 @item @emph{Syntax}:
1732 @code{RESULT = BESYN(N, X)}
1734 @item @emph{Arguments}:
1735 @multitable @columnfractions .15 .70
1736 @item @var{N} @tab Shall be a scalar or an array of type @code{INTEGER(*)}.
1737 @item @var{X} @tab Shall be a scalar or an array of type @code{REAL(*)}.
1740 @item @emph{Return value}:
1741 The return value is a scalar of type @code{REAL(*)}.
1743 @item @emph{Example}:
1746 real(8) :: x = 1.0_8
1748 end program test_besyn
1751 @item @emph{Specific names}:
1752 @multitable @columnfractions .20 .20 .20 .25
1753 @item Name @tab Argument @tab Return type @tab Standard
1754 @item @code{DBESYN(N,X)} @tab @code{INTEGER(*) N} @tab @code{REAL(8)} @tab GNU extension
1755 @item @tab @code{REAL(8) X} @tab @tab
1762 @section @code{BIT_SIZE} --- Bit size inquiry function
1764 @cindex bits, number of
1765 @cindex size of a variable, in bits
1768 @item @emph{Description}:
1769 @code{BIT_SIZE(I)} returns the number of bits (integer precision plus sign bit)
1770 represented by the type of @var{I}.
1772 @item @emph{Standard}:
1778 @item @emph{Syntax}:
1779 @code{RESULT = BIT_SIZE(I)}
1781 @item @emph{Arguments}:
1782 @multitable @columnfractions .15 .70
1783 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
1786 @item @emph{Return value}:
1787 The return value is of type @code{INTEGER(*)}
1789 @item @emph{Example}:
1791 program test_bit_size
1796 end program test_bit_size
1803 @section @code{BTEST} --- Bit test function
1805 @cindex bits, testing
1808 @item @emph{Description}:
1809 @code{BTEST(I,POS)} returns logical @code{.TRUE.} if the bit at @var{POS}
1812 @item @emph{Standard}:
1818 @item @emph{Syntax}:
1819 @code{RESULT = BTEST(I, POS)}
1821 @item @emph{Arguments}:
1822 @multitable @columnfractions .15 .70
1823 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
1824 @item @var{POS} @tab The type shall be @code{INTEGER(*)}.
1827 @item @emph{Return value}:
1828 The return value is of type @code{LOGICAL}
1830 @item @emph{Example}:
1833 integer :: i = 32768 + 1024 + 64
1837 bool = btest(i, pos)
1840 end program test_btest
1846 @section @code{C_ASSOCIATED} --- Status of a C pointer
1847 @fnindex C_ASSOCIATED
1848 @cindex associatation status, C pointer
1849 @cindex pointer, C associatation status
1852 @item @emph{Description}:
1853 @code{C_ASSOICATED(c_prt1[, c_ptr2])} determines the status of the C pointer @var{c_ptr1}
1854 or if @var{c_ptr1} is associated with the target @var{c_ptr2}.
1856 @item @emph{Standard}:
1862 @item @emph{Syntax}:
1863 @code{RESULT = C_ASSOICATED(c_prt1[, c_ptr2])}
1865 @item @emph{Arguments}:
1866 @multitable @columnfractions .15 .70
1867 @item @var{c_ptr1} @tab Scalar of the type @code{C_PTR} or @code{C_FUNPTR}.
1868 @item @var{c_ptr2} @tab (Optional) Scalar of the same type as @var{c_ptr1}.
1871 @item @emph{Return value}:
1872 The return value is of type @code{LOGICAL}; it is @code{.false.} if either
1873 @var{c_ptr1} is a C NULL pointer or if @var{c_ptr1} and @var{c_ptr2}
1874 point to different addresses.
1876 @item @emph{Example}:
1878 subroutine association_test(a,b)
1879 use iso_c_binding, only: c_associated, c_loc, c_ptr
1883 if(c_associated(b, c_loc(a))) &
1884 stop 'b and a do not point to same target'
1885 end subroutine association_test
1888 @item @emph{See also}:
1889 @ref{C_LOC}, @ref{C_FUNLOC}
1894 @section @code{C_FUNLOC} --- Obtain the C address of a procedure
1896 @cindex pointer, C address of procedures
1899 @item @emph{Description}:
1900 @code{C_FUNLOC(x)} determines the C address of the argument.
1902 @item @emph{Standard}:
1908 @item @emph{Syntax}:
1909 @code{RESULT = C_FUNLOC(x)}
1911 @item @emph{Arguments}:
1912 @multitable @columnfractions .15 .70
1913 @item @var{x} @tab Interoperable function or pointer to such function.
1916 @item @emph{Return value}:
1917 The return value is of type @code{C_FUNPTR} and contains the C address
1920 @item @emph{Example}:
1926 subroutine sub(a) bind(c)
1936 subroutine my_routine(p) bind(c,name='myC_func')
1938 type(c_funptr), intent(in) :: p
1941 call my_routine(c_funloc(sub))
1945 @item @emph{See also}:
1946 @ref{C_ASSOCIATED}, @ref{C_LOC}, @ref{C_F_POINTER}, @ref{C_F_PROCPOINTER}
1950 @node C_F_PROCPOINTER
1951 @section @code{C_F_PROCPOINTER} --- Convert C into Fortran procedure pointer
1952 @fnindex C_F_PROCPOINTER
1953 @cindex pointer, C address of pointers
1956 @item @emph{Description}:
1957 @code{C_F_PROCPOINTER(cptr, fptr)} Assign the target of the C function pointer
1958 @var{cptr} to the Fortran procedure pointer @var{fptr}.
1960 Note: Due to the currently lacking support of procedure pointers in GNU Fortran
1961 this function is not fully operable.
1963 @item @emph{Standard}:
1969 @item @emph{Syntax}:
1970 @code{CALL C_F_PROCPOINTER(cptr, fptr)}
1972 @item @emph{Arguments}:
1973 @multitable @columnfractions .15 .70
1974 @item @var{cptr} @tab scalar of the type @code{C_FUNPTR}. It is
1976 @item @var{fptr} @tab procedure pointer interoperable with @var{cptr}. It is
1980 @item @emph{Example}:
1988 real(c_float), intent(in) :: a
1989 real(c_float) :: func
1993 function getIterFunc() bind(c,name="getIterFunc")
1995 type(c_funptr) :: getIterFunc
1998 type(c_funptr) :: cfunptr
1999 procedure(func), pointer :: myFunc
2000 cfunptr = getIterFunc()
2001 call c_f_procpointer(cfunptr, myFunc)
2005 @item @emph{See also}:
2006 @ref{C_LOC}, @ref{C_F_POINTER}
2011 @section @code{C_F_POINTER} --- Convert C into Fortran pointer
2012 @fnindex C_F_POINTER
2013 @cindex pointer, convert C to Fortran
2016 @item @emph{Description}:
2017 @code{C_F_POINTER(cptr, fptr[, shape])} Assign the target the C pointer
2018 @var{cptr} to the Fortran pointer @var{fptr} and specify its
2021 @item @emph{Standard}:
2027 @item @emph{Syntax}:
2028 @code{CALL C_F_POINTER(cptr, fptr[, shape])}
2030 @item @emph{Arguments}:
2031 @multitable @columnfractions .15 .70
2032 @item @var{cptr} @tab scalar of the type @code{C_PTR}. It is
2034 @item @var{fptr} @tab pointer interoperable with @var{cptr}. It is
2036 @item @var{shape} @tab (Optional) Rank-one array of type @code{INTEGER}
2037 with @code{INTENT(IN)}. It shall be present
2038 if and only if @var{fptr} is an array. The size
2039 must be equal to the rank of @var{fptr}.
2042 @item @emph{Example}:
2048 subroutine my_routine(p) bind(c,name='myC_func')
2050 type(c_ptr), intent(out) :: p
2054 real,pointer :: a(:)
2055 call my_routine(cptr)
2056 call c_f_pointer(cptr, a, [12])
2060 @item @emph{See also}:
2061 @ref{C_LOC}, @ref{C_F_PROCPOINTER}
2066 @section @code{C_LOC} --- Obtain the C address of an object
2068 @cindex procedure pointer, convert C to Fortran
2071 @item @emph{Description}:
2072 @code{C_LOC(x)} determines the C address of the argument.
2074 @item @emph{Standard}:
2080 @item @emph{Syntax}:
2081 @code{RESULT = C_LOC(x)}
2083 @item @emph{Arguments}:
2084 @multitable @columnfractions .15 .70
2085 @item @var{x} @tab Associated scalar pointer or interoperatable scalar
2086 or allocated allocatable variable with @code{TARGET}
2090 @item @emph{Return value}:
2091 The return value is of type @code{C_PTR} and contains the C address
2094 @item @emph{Example}:
2096 subroutine association_test(a,b)
2097 use iso_c_binding, only: c_associated, c_loc, c_ptr
2101 if(c_associated(b, c_loc(a))) &
2102 stop 'b and a do not point to same target'
2103 end subroutine association_test
2106 @item @emph{See also}:
2107 @ref{C_ASSOCIATED}, @ref{C_FUNLOC}, @ref{C_F_POINTER}, @ref{C_F_PROCPOINTER}
2112 @section @code{CEILING} --- Integer ceiling function
2115 @cindex rounding, ceiling
2118 @item @emph{Description}:
2119 @code{CEILING(X)} returns the least integer greater than or equal to @var{X}.
2121 @item @emph{Standard}:
2127 @item @emph{Syntax}:
2128 @code{RESULT = CEILING(X [, KIND])}
2130 @item @emph{Arguments}:
2131 @multitable @columnfractions .15 .70
2132 @item @var{X} @tab The type shall be @code{REAL(*)}.
2133 @item @var{KIND} @tab (Optional) An @code{INTEGER(*)} initialization
2134 expression indicating the kind parameter of
2138 @item @emph{Return value}:
2139 The return value is of type @code{INTEGER(KIND)}
2141 @item @emph{Example}:
2143 program test_ceiling
2146 print *, ceiling(x) ! returns 64
2147 print *, ceiling(y) ! returns -63
2148 end program test_ceiling
2151 @item @emph{See also}:
2152 @ref{FLOOR}, @ref{NINT}
2159 @section @code{CHAR} --- Character conversion function
2161 @cindex conversion, to character
2164 @item @emph{Description}:
2165 @code{CHAR(I [, KIND])} returns the character represented by the integer @var{I}.
2167 @item @emph{Standard}:
2173 @item @emph{Syntax}:
2174 @code{RESULT = CHAR(I [, KIND])}
2176 @item @emph{Arguments}:
2177 @multitable @columnfractions .15 .70
2178 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
2179 @item @var{KIND} @tab (Optional) An @code{INTEGER(*)} initialization
2180 expression indicating the kind parameter of
2184 @item @emph{Return value}:
2185 The return value is of type @code{CHARACTER(1)}
2187 @item @emph{Example}:
2193 print *, i, c ! returns 'J'
2194 end program test_char
2198 See @ref{ICHAR} for a discussion of converting between numerical values
2199 and formatted string representations.
2201 @item @emph{See also}:
2202 @ref{ACHAR}, @ref{IACHAR}, @ref{ICHAR}
2209 @section @code{CHDIR} --- Change working directory
2211 @cindex system, working directory
2214 @item @emph{Description}:
2215 Change current working directory to a specified path.
2217 This intrinsic is provided in both subroutine and function forms; however,
2218 only one form can be used in any given program unit.
2220 @item @emph{Standard}:
2224 Subroutine, non-elemental function
2226 @item @emph{Syntax}:
2227 @multitable @columnfractions .80
2228 @item @code{CALL CHDIR(NAME [, STATUS])}
2229 @item @code{STATUS = CHDIR(NAME)}
2232 @item @emph{Arguments}:
2233 @multitable @columnfractions .15 .70
2234 @item @var{NAME} @tab The type shall be @code{CHARACTER(*)} and shall
2235 specify a valid path within the file system.
2236 @item @var{STATUS} @tab (Optional) @code{INTEGER} status flag of the default
2237 kind. Returns 0 on success, and a system specific
2238 and non-zero error code otherwise.
2241 @item @emph{Example}:
2244 CHARACTER(len=255) :: path
2246 WRITE(*,*) TRIM(path)
2249 WRITE(*,*) TRIM(path)
2253 @item @emph{See also}:
2260 @section @code{CHMOD} --- Change access permissions of files
2262 @cindex file system, change access mode
2265 @item @emph{Description}:
2266 @code{CHMOD} changes the permissions of a file. This function invokes
2267 @code{/bin/chmod} and might therefore not work on all platforms.
2269 This intrinsic is provided in both subroutine and function forms; however,
2270 only one form can be used in any given program unit.
2272 @item @emph{Standard}:
2276 Subroutine, non-elemental function
2278 @item @emph{Syntax}:
2279 @multitable @columnfractions .80
2280 @item @code{CALL CHMOD(NAME, MODE[, STATUS])}
2281 @item @code{STATUS = CHMOD(NAME, MODE)}
2284 @item @emph{Arguments}:
2285 @multitable @columnfractions .15 .70
2286 @item @var{NAME} @tab Scalar @code{CHARACTER} with the file name.
2287 Trailing blanks are ignored unless the character @code{achar(0)} is
2288 present, then all characters up to and excluding @code{achar(0)} are
2289 used as the file name.
2291 @item @var{MODE} @tab Scalar @code{CHARACTER} giving the file permission.
2292 @var{MODE} uses the same syntax as the @var{MODE} argument of
2295 @item @var{STATUS} @tab (optional) scalar @code{INTEGER}, which is
2296 @code{0} on success and non-zero otherwise.
2299 @item @emph{Return value}:
2300 In either syntax, @var{STATUS} is set to @code{0} on success and non-zero
2303 @item @emph{Example}:
2304 @code{CHMOD} as subroutine
2309 call chmod('test.dat','u+x',status)
2310 print *, 'Status: ', status
2311 end program chmod_test
2313 @code{CHMOD} as non-elemental function:
2318 status = chmod('test.dat','u+x')
2319 print *, 'Status: ', status
2320 end program chmod_test
2328 @section @code{CMPLX} --- Complex conversion function
2330 @cindex complex numbers, conversion to
2331 @cindex conversion, to complex
2334 @item @emph{Description}:
2335 @code{CMPLX(X [, Y [, KIND]])} returns a complex number where @var{X} is converted to
2336 the real component. If @var{Y} is present it is converted to the imaginary
2337 component. If @var{Y} is not present then the imaginary component is set to
2338 0.0. If @var{X} is complex then @var{Y} must not be present.
2340 @item @emph{Standard}:
2346 @item @emph{Syntax}:
2347 @code{RESULT = CMPLX(X [, Y [, KIND]])}
2349 @item @emph{Arguments}:
2350 @multitable @columnfractions .15 .70
2351 @item @var{X} @tab The type may be @code{INTEGER(*)}, @code{REAL(*)},
2352 or @code{COMPLEX(*)}.
2353 @item @var{Y} @tab (Optional; only allowed if @var{X} is not
2354 @code{COMPLEX(*)}.) May be @code{INTEGER(*)}
2356 @item @var{KIND} @tab (Optional) An @code{INTEGER(*)} initialization
2357 expression indicating the kind parameter of
2361 @item @emph{Return value}:
2362 The return value is of @code{COMPLEX} type, with a kind equal to
2363 @var{KIND} if it is specified. If @var{KIND} is not specified, the
2364 result is of the default @code{COMPLEX} kind, regardless of the kinds of
2365 @var{X} and @var{Y}.
2367 @item @emph{Example}:
2374 print *, z, cmplx(x)
2375 end program test_cmplx
2378 @item @emph{See also}:
2384 @node COMMAND_ARGUMENT_COUNT
2385 @section @code{COMMAND_ARGUMENT_COUNT} --- Get number of command line arguments
2386 @fnindex COMMAND_ARGUMENT_COUNT
2387 @cindex command-line arguments
2388 @cindex command-line arguments, number of
2389 @cindex arguments, to program
2392 @item @emph{Description}:
2393 @code{COMMAND_ARGUMENT_COUNT()} returns the number of arguments passed on the
2394 command line when the containing program was invoked.
2396 @item @emph{Standard}:
2402 @item @emph{Syntax}:
2403 @code{RESULT = COMMAND_ARGUMENT_COUNT()}
2405 @item @emph{Arguments}:
2406 @multitable @columnfractions .15 .70
2410 @item @emph{Return value}:
2411 The return value is of type @code{INTEGER(4)}
2413 @item @emph{Example}:
2415 program test_command_argument_count
2417 count = command_argument_count()
2419 end program test_command_argument_count
2422 @item @emph{See also}:
2423 @ref{GET_COMMAND}, @ref{GET_COMMAND_ARGUMENT}
2429 @section @code{COMPLEX} --- Complex conversion function
2431 @cindex complex numbers, conversion to
2432 @cindex conversion, to complex
2435 @item @emph{Description}:
2436 @code{COMPLEX(X, Y)} returns a complex number where @var{X} is converted
2437 to the real component and @var{Y} is converted to the imaginary
2440 @item @emph{Standard}:
2446 @item @emph{Syntax}:
2447 @code{RESULT = COMPLEX(X, Y)}
2449 @item @emph{Arguments}:
2450 @multitable @columnfractions .15 .70
2451 @item @var{X} @tab The type may be @code{INTEGER(*)} or @code{REAL(*)}.
2452 @item @var{Y} @tab The type may be @code{INTEGER(*)} or @code{REAL(*)}.
2455 @item @emph{Return value}:
2456 If @var{X} and @var{Y} are both of @code{INTEGER} type, then the return
2457 value is of default @code{COMPLEX} type.
2459 If @var{X} and @var{Y} are of @code{REAL} type, or one is of @code{REAL}
2460 type and one is of @code{INTEGER} type, then the return value is of
2461 @code{COMPLEX} type with a kind equal to that of the @code{REAL}
2462 argument with the highest precision.
2464 @item @emph{Example}:
2466 program test_complex
2469 print *, complex(i, x)
2470 end program test_complex
2473 @item @emph{See also}:
2480 @section @code{CONJG} --- Complex conjugate function
2483 @cindex complex conjugate
2486 @item @emph{Description}:
2487 @code{CONJG(Z)} returns the conjugate of @var{Z}. If @var{Z} is @code{(x, y)}
2488 then the result is @code{(x, -y)}
2490 @item @emph{Standard}:
2491 F77 and later, has overloads that are GNU extensions
2496 @item @emph{Syntax}:
2499 @item @emph{Arguments}:
2500 @multitable @columnfractions .15 .70
2501 @item @var{Z} @tab The type shall be @code{COMPLEX(*)}.
2504 @item @emph{Return value}:
2505 The return value is of type @code{COMPLEX(*)}.
2507 @item @emph{Example}:
2510 complex :: z = (2.0, 3.0)
2511 complex(8) :: dz = (2.71_8, -3.14_8)
2516 end program test_conjg
2519 @item @emph{Specific names}:
2520 @multitable @columnfractions .20 .20 .20 .25
2521 @item Name @tab Argument @tab Return type @tab Standard
2522 @item @code{DCONJG(Z)} @tab @code{COMPLEX(8) Z} @tab @code{COMPLEX(8)} @tab GNU extension
2529 @section @code{COS} --- Cosine function
2535 @cindex trigonometric function, cosine
2539 @item @emph{Description}:
2540 @code{COS(X)} computes the cosine of @var{X}.
2542 @item @emph{Standard}:
2543 F77 and later, has overloads that are GNU extensions
2548 @item @emph{Syntax}:
2549 @code{RESULT = COS(X)}
2551 @item @emph{Arguments}:
2552 @multitable @columnfractions .15 .70
2553 @item @var{X} @tab The type shall be @code{REAL(*)} or
2557 @item @emph{Return value}:
2558 The return value is of type @code{REAL(*)} and it lies in the
2559 range @math{ -1 \leq \cos (x) \leq 1}. The kind type
2560 parameter is the same as @var{X}.
2562 @item @emph{Example}:
2567 end program test_cos
2570 @item @emph{Specific names}:
2571 @multitable @columnfractions .20 .20 .20 .25
2572 @item Name @tab Argument @tab Return type @tab Standard
2573 @item @code{DCOS(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
2574 @item @code{CCOS(X)} @tab @code{COMPLEX(4) X} @tab @code{COMPLEX(4)} @tab F77 and later
2575 @item @code{ZCOS(X)} @tab @code{COMPLEX(8) X} @tab @code{COMPLEX(8)} @tab GNU extension
2576 @item @code{CDCOS(X)} @tab @code{COMPLEX(8) X} @tab @code{COMPLEX(8)} @tab GNU extension
2579 @item @emph{See also}:
2580 Inverse function: @ref{ACOS}
2587 @section @code{COSH} --- Hyperbolic cosine function
2590 @cindex hyperbolic cosine
2591 @cindex hyperbolic function, cosine
2592 @cindex cosine, hyperbolic
2595 @item @emph{Description}:
2596 @code{COSH(X)} computes the hyperbolic cosine of @var{X}.
2598 @item @emph{Standard}:
2604 @item @emph{Syntax}:
2607 @item @emph{Arguments}:
2608 @multitable @columnfractions .15 .70
2609 @item @var{X} @tab The type shall be @code{REAL(*)}.
2612 @item @emph{Return value}:
2613 The return value is of type @code{REAL(*)} and it is positive
2614 (@math{ \cosh (x) \geq 0 }.
2616 @item @emph{Example}:
2619 real(8) :: x = 1.0_8
2621 end program test_cosh
2624 @item @emph{Specific names}:
2625 @multitable @columnfractions .20 .20 .20 .25
2626 @item Name @tab Argument @tab Return type @tab Standard
2627 @item @code{DCOSH(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
2630 @item @emph{See also}:
2631 Inverse function: @ref{ACOSH}
2638 @section @code{COUNT} --- Count function
2640 @cindex array, conditionally count elements
2641 @cindex array, element counting
2642 @cindex array, number of elements
2645 @item @emph{Description}:
2646 @code{COUNT(MASK [, DIM])} counts the number of @code{.TRUE.} elements of
2647 @var{MASK} along the dimension of @var{DIM}. If @var{DIM} is omitted it is
2648 taken to be @code{1}. @var{DIM} is a scaler of type @code{INTEGER} in the
2649 range of @math{1 /leq DIM /leq n)} where @math{n} is the rank of @var{MASK}.
2651 @item @emph{Standard}:
2655 transformational function
2657 @item @emph{Syntax}:
2658 @code{RESULT = COUNT(MASK [, DIM])}
2660 @item @emph{Arguments}:
2661 @multitable @columnfractions .15 .70
2662 @item @var{MASK} @tab The type shall be @code{LOGICAL}.
2663 @item @var{DIM} @tab The type shall be @code{INTEGER}.
2666 @item @emph{Return value}:
2667 The return value is of type @code{INTEGER} with rank equal to that of
2670 @item @emph{Example}:
2673 integer, dimension(2,3) :: a, b
2674 logical, dimension(2,3) :: mask
2675 a = reshape( (/ 1, 2, 3, 4, 5, 6 /), (/ 2, 3 /))
2676 b = reshape( (/ 0, 7, 3, 4, 5, 8 /), (/ 2, 3 /))
2677 print '(3i3)', a(1,:)
2678 print '(3i3)', a(2,:)
2680 print '(3i3)', b(1,:)
2681 print '(3i3)', b(2,:)
2684 print '(3l3)', mask(1,:)
2685 print '(3l3)', mask(2,:)
2687 print '(3i3)', count(mask)
2689 print '(3i3)', count(mask, 1)
2691 print '(3i3)', count(mask, 2)
2692 end program test_count
2699 @section @code{CPU_TIME} --- CPU elapsed time in seconds
2701 @cindex time, elapsed
2704 @item @emph{Description}:
2705 Returns a @code{REAL(*)} value representing the elapsed CPU time in
2706 seconds. This is useful for testing segments of code to determine
2709 @item @emph{Standard}:
2715 @item @emph{Syntax}:
2716 @code{CALL CPU_TIME(TIME)}
2718 @item @emph{Arguments}:
2719 @multitable @columnfractions .15 .70
2720 @item @var{TIME} @tab The type shall be @code{REAL(*)} with @code{INTENT(OUT)}.
2723 @item @emph{Return value}:
2726 @item @emph{Example}:
2728 program test_cpu_time
2729 real :: start, finish
2730 call cpu_time(start)
2731 ! put code to test here
2732 call cpu_time(finish)
2733 print '("Time = ",f6.3," seconds.")',finish-start
2734 end program test_cpu_time
2737 @item @emph{See also}:
2738 @ref{SYSTEM_CLOCK}, @ref{DATE_AND_TIME}
2744 @section @code{CSHIFT} --- Circular shift elements of an array
2746 @cindex array, shift circularly
2747 @cindex array, permutation
2748 @cindex array, rotate
2751 @item @emph{Description}:
2752 @code{CSHIFT(ARRAY, SHIFT [, DIM])} performs a circular shift on elements of
2753 @var{ARRAY} along the dimension of @var{DIM}. If @var{DIM} is omitted it is
2754 taken to be @code{1}. @var{DIM} is a scaler of type @code{INTEGER} in the
2755 range of @math{1 /leq DIM /leq n)} where @math{n} is the rank of @var{ARRAY}.
2756 If the rank of @var{ARRAY} is one, then all elements of @var{ARRAY} are shifted
2757 by @var{SHIFT} places. If rank is greater than one, then all complete rank one
2758 sections of @var{ARRAY} along the given dimension are shifted. Elements
2759 shifted out one end of each rank one section are shifted back in the other end.
2761 @item @emph{Standard}:
2765 Transformational function
2767 @item @emph{Syntax}:
2768 @code{RESULT = CSHIFT(ARRAY, SHIFT [, DIM])}
2770 @item @emph{Arguments}:
2771 @multitable @columnfractions .15 .70
2772 @item @var{ARRAY} @tab Shall be an array of any type.
2773 @item @var{SHIFT} @tab The type shall be @code{INTEGER}.
2774 @item @var{DIM} @tab The type shall be @code{INTEGER}.
2777 @item @emph{Return value}:
2778 Returns an array of same type and rank as the @var{ARRAY} argument.
2780 @item @emph{Example}:
2783 integer, dimension(3,3) :: a
2784 a = reshape( (/ 1, 2, 3, 4, 5, 6, 7, 8, 9 /), (/ 3, 3 /))
2785 print '(3i3)', a(1,:)
2786 print '(3i3)', a(2,:)
2787 print '(3i3)', a(3,:)
2788 a = cshift(a, SHIFT=(/1, 2, -1/), DIM=2)
2790 print '(3i3)', a(1,:)
2791 print '(3i3)', a(2,:)
2792 print '(3i3)', a(3,:)
2793 end program test_cshift
2800 @section @code{CTIME} --- Convert a time into a string
2802 @cindex time, conversion to string
2803 @cindex conversion, to string
2806 @item @emph{Description}:
2807 @code{CTIME} converts a system time value, such as returned by
2808 @code{TIME8()}, to a string of the form @samp{Sat Aug 19 18:13:14 1995}.
2810 This intrinsic is provided in both subroutine and function forms; however,
2811 only one form can be used in any given program unit.
2813 @item @emph{Standard}:
2819 @item @emph{Syntax}:
2820 @multitable @columnfractions .80
2821 @item @code{CALL CTIME(TIME, RESULT)}.
2822 @item @code{RESULT = CTIME(TIME)}, (not recommended).
2825 @item @emph{Arguments}:
2826 @multitable @columnfractions .15 .70
2827 @item @var{TIME} @tab The type shall be of type @code{INTEGER(KIND=8)}.
2828 @item @var{RESULT} @tab The type shall be of type @code{CHARACTER}.
2831 @item @emph{Return value}:
2832 The converted date and time as a string.
2834 @item @emph{Example}:
2838 character(len=30) :: date
2841 ! Do something, main part of the program
2844 print *, 'Program was started on ', date
2845 end program test_ctime
2848 @item @emph{See Also}:
2849 @ref{GMTIME}, @ref{LTIME}, @ref{TIME}, @ref{TIME8}
2855 @section @code{DATE_AND_TIME} --- Date and time subroutine
2856 @fnindex DATE_AND_TIME
2857 @cindex date, current
2858 @cindex current date
2859 @cindex time, current
2860 @cindex current time
2863 @item @emph{Description}:
2864 @code{DATE_AND_TIME(DATE, TIME, ZONE, VALUES)} gets the corresponding date and
2865 time information from the real-time system clock. @var{DATE} is
2866 @code{INTENT(OUT)} and has form ccyymmdd. @var{TIME} is @code{INTENT(OUT)} and
2867 has form hhmmss.sss. @var{ZONE} is @code{INTENT(OUT)} and has form (+-)hhmm,
2868 representing the difference with respect to Coordinated Universal Time (UTC).
2869 Unavailable time and date parameters return blanks.
2871 @var{VALUES} is @code{INTENT(OUT)} and provides the following:
2873 @multitable @columnfractions .15 .30 .40
2874 @item @tab @code{VALUE(1)}: @tab The year
2875 @item @tab @code{VALUE(2)}: @tab The month
2876 @item @tab @code{VALUE(3)}: @tab The day of the month
2877 @item @tab @code{VALUE(4)}: @tab Time difference with UTC in minutes
2878 @item @tab @code{VALUE(5)}: @tab The hour of the day
2879 @item @tab @code{VALUE(6)}: @tab The minutes of the hour
2880 @item @tab @code{VALUE(7)}: @tab The seconds of the minute
2881 @item @tab @code{VALUE(8)}: @tab The milliseconds of the second
2884 @item @emph{Standard}:
2890 @item @emph{Syntax}:
2891 @code{CALL DATE_AND_TIME([DATE, TIME, ZONE, VALUES])}
2893 @item @emph{Arguments}:
2894 @multitable @columnfractions .15 .70
2895 @item @var{DATE} @tab (Optional) The type shall be @code{CHARACTER(8)} or larger.
2896 @item @var{TIME} @tab (Optional) The type shall be @code{CHARACTER(10)} or larger.
2897 @item @var{ZONE} @tab (Optional) The type shall be @code{CHARACTER(5)} or larger.
2898 @item @var{VALUES}@tab (Optional) The type shall be @code{INTEGER(8)}.
2901 @item @emph{Return value}:
2904 @item @emph{Example}:
2906 program test_time_and_date
2907 character(8) :: date
2908 character(10) :: time
2909 character(5) :: zone
2910 integer,dimension(8) :: values
2911 ! using keyword arguments
2912 call date_and_time(date,time,zone,values)
2913 call date_and_time(DATE=date,ZONE=zone)
2914 call date_and_time(TIME=time)
2915 call date_and_time(VALUES=values)
2916 print '(a,2x,a,2x,a)', date, time, zone
2917 print '(8i5))', values
2918 end program test_time_and_date
2921 @item @emph{See also}:
2922 @ref{CPU_TIME}, @ref{SYSTEM_CLOCK}
2928 @section @code{DBLE} --- Double conversion function
2930 @cindex conversion, to real
2933 @item @emph{Description}:
2934 @code{DBLE(X)} Converts @var{X} to double precision real type.
2936 @item @emph{Standard}:
2942 @item @emph{Syntax}:
2943 @code{RESULT = DBLE(X)}
2945 @item @emph{Arguments}:
2946 @multitable @columnfractions .15 .70
2947 @item @var{X} @tab The type shall be @code{INTEGER(*)}, @code{REAL(*)},
2948 or @code{COMPLEX(*)}.
2951 @item @emph{Return value}:
2952 The return value is of type double precision real.
2954 @item @emph{Example}:
2959 complex :: z = (2.3,1.14)
2960 print *, dble(x), dble(i), dble(z)
2961 end program test_dble
2964 @item @emph{See also}:
2965 @ref{DFLOAT}, @ref{FLOAT}, @ref{REAL}
2971 @section @code{DCMPLX} --- Double complex conversion function
2973 @cindex complex numbers, conversion to
2974 @cindex conversion, to complex
2977 @item @emph{Description}:
2978 @code{DCMPLX(X [,Y])} returns a double complex number where @var{X} is
2979 converted to the real component. If @var{Y} is present it is converted to the
2980 imaginary component. If @var{Y} is not present then the imaginary component is
2981 set to 0.0. If @var{X} is complex then @var{Y} must not be present.
2983 @item @emph{Standard}:
2989 @item @emph{Syntax}:
2990 @code{RESULT = DCMPLX(X [, Y])}
2992 @item @emph{Arguments}:
2993 @multitable @columnfractions .15 .70
2994 @item @var{X} @tab The type may be @code{INTEGER(*)}, @code{REAL(*)},
2995 or @code{COMPLEX(*)}.
2996 @item @var{Y} @tab (Optional if @var{X} is not @code{COMPLEX(*)}.) May be
2997 @code{INTEGER(*)} or @code{REAL(*)}.
3000 @item @emph{Return value}:
3001 The return value is of type @code{COMPLEX(8)}
3003 @item @emph{Example}:
3013 print *, dcmplx(x,i)
3014 end program test_dcmplx
3021 @section @code{DFLOAT} --- Double conversion function
3023 @cindex conversion, to real
3026 @item @emph{Description}:
3027 @code{DFLOAT(X)} Converts @var{X} to double precision real type.
3029 @item @emph{Standard}:
3035 @item @emph{Syntax}:
3036 @code{RESULT = DFLOAT(X)}
3038 @item @emph{Arguments}:
3039 @multitable @columnfractions .15 .70
3040 @item @var{X} @tab The type shall be @code{INTEGER(*)}.
3043 @item @emph{Return value}:
3044 The return value is of type double precision real.
3046 @item @emph{Example}:
3051 end program test_dfloat
3054 @item @emph{See also}:
3055 @ref{DBLE}, @ref{FLOAT}, @ref{REAL}
3061 @section @code{DIGITS} --- Significant digits function
3063 @cindex model representation, significant digits
3066 @item @emph{Description}:
3067 @code{DIGITS(X)} returns the number of significant digits of the internal model
3068 representation of @var{X}. For example, on a system using a 32-bit
3069 floating point representation, a default real number would likely return 24.
3071 @item @emph{Standard}:
3077 @item @emph{Syntax}:
3078 @code{RESULT = DIGITS(X)}
3080 @item @emph{Arguments}:
3081 @multitable @columnfractions .15 .70
3082 @item @var{X} @tab The type may be @code{INTEGER(*)} or @code{REAL(*)}.
3085 @item @emph{Return value}:
3086 The return value is of type @code{INTEGER}.
3088 @item @emph{Example}:
3091 integer :: i = 12345
3097 end program test_digits
3104 @section @code{DIM} --- Positive difference
3108 @cindex positive difference
3111 @item @emph{Description}:
3112 @code{DIM(X,Y)} returns the difference @code{X-Y} if the result is positive;
3113 otherwise returns zero.
3115 @item @emph{Standard}:
3121 @item @emph{Syntax}:
3122 @code{RESULT = DIM(X, Y)}
3124 @item @emph{Arguments}:
3125 @multitable @columnfractions .15 .70
3126 @item @var{X} @tab The type shall be @code{INTEGER(*)} or @code{REAL(*)}
3127 @item @var{Y} @tab The type shall be the same type and kind as @var{X}.
3130 @item @emph{Return value}:
3131 The return value is of type @code{INTEGER(*)} or @code{REAL(*)}.
3133 @item @emph{Example}:
3139 x = dim(4.345_8, 2.111_8)
3142 end program test_dim
3145 @item @emph{Specific names}:
3146 @multitable @columnfractions .20 .20 .20 .25
3147 @item Name @tab Argument @tab Return type @tab Standard
3148 @item @code{IDIM(X,Y)} @tab @code{INTEGER(4) X,Y} @tab @code{INTEGER(4)} @tab F77 and later
3149 @item @code{DDIM(X,Y)} @tab @code{REAL(8) X,Y} @tab @code{REAL(8)} @tab F77 and later
3156 @section @code{DOT_PRODUCT} --- Dot product function
3157 @fnindex DOT_PRODUCT
3159 @cindex vector product
3160 @cindex product, vector
3163 @item @emph{Description}:
3164 @code{DOT_PRODUCT(X,Y)} computes the dot product multiplication of two vectors
3165 @var{X} and @var{Y}. The two vectors may be either numeric or logical
3166 and must be arrays of rank one and of equal size. If the vectors are
3167 @code{INTEGER(*)} or @code{REAL(*)}, the result is @code{SUM(X*Y)}. If the
3168 vectors are @code{COMPLEX(*)}, the result is @code{SUM(CONJG(X)*Y)}. If the
3169 vectors are @code{LOGICAL}, the result is @code{ANY(X.AND.Y)}.
3171 @item @emph{Standard}:
3175 transformational function
3177 @item @emph{Syntax}:
3178 @code{RESULT = DOT_PRODUCT(X, Y)}
3180 @item @emph{Arguments}:
3181 @multitable @columnfractions .15 .70
3182 @item @var{X} @tab The type shall be numeric or @code{LOGICAL}, rank 1.
3183 @item @var{Y} @tab The type shall be numeric or @code{LOGICAL}, rank 1.
3186 @item @emph{Return value}:
3187 If the arguments are numeric, the return value is a scaler of numeric type,
3188 @code{INTEGER(*)}, @code{REAL(*)}, or @code{COMPLEX(*)}. If the arguments are
3189 @code{LOGICAL}, the return value is @code{.TRUE.} or @code{.FALSE.}.
3191 @item @emph{Example}:
3193 program test_dot_prod
3194 integer, dimension(3) :: a, b
3201 print *, dot_product(a,b)
3202 end program test_dot_prod
3209 @section @code{DPROD} --- Double product function
3211 @cindex product, double-precision
3214 @item @emph{Description}:
3215 @code{DPROD(X,Y)} returns the product @code{X*Y}.
3217 @item @emph{Standard}:
3223 @item @emph{Syntax}:
3224 @code{RESULT = DPROD(X, Y)}
3226 @item @emph{Arguments}:
3227 @multitable @columnfractions .15 .70
3228 @item @var{X} @tab The type shall be @code{REAL}.
3229 @item @var{Y} @tab The type shall be @code{REAL}.
3232 @item @emph{Return value}:
3233 The return value is of type @code{REAL(8)}.
3235 @item @emph{Example}:
3243 end program test_dprod
3250 @section @code{DREAL} --- Double real part function
3252 @cindex complex numbers, real part
3255 @item @emph{Description}:
3256 @code{DREAL(Z)} returns the real part of complex variable @var{Z}.
3258 @item @emph{Standard}:
3264 @item @emph{Syntax}:
3265 @code{RESULT = DREAL(Z)}
3267 @item @emph{Arguments}:
3268 @multitable @columnfractions .15 .70
3269 @item @var{Z} @tab The type shall be @code{COMPLEX(8)}.
3272 @item @emph{Return value}:
3273 The return value is of type @code{REAL(8)}.
3275 @item @emph{Example}:
3278 complex(8) :: z = (1.3_8,7.2_8)
3280 end program test_dreal
3283 @item @emph{See also}:
3291 @section @code{DTIME} --- Execution time subroutine (or function)
3293 @cindex time, elapsed
3294 @cindex elapsed time
3297 @item @emph{Description}:
3298 @code{DTIME(TARRAY, RESULT)} initially returns the number of seconds of runtime
3299 since the start of the process's execution in @var{RESULT}. @var{TARRAY}
3300 returns the user and system components of this time in @code{TARRAY(1)} and
3301 @code{TARRAY(2)} respectively. @var{RESULT} is equal to @code{TARRAY(1) +
3304 Subsequent invocations of @code{DTIME} return values accumulated since the
3305 previous invocation.
3307 On some systems, the underlying timings are represented using types with
3308 sufficiently small limits that overflows (wrap around) are possible, such as
3309 32-bit types. Therefore, the values returned by this intrinsic might be, or
3310 become, negative, or numerically less than previous values, during a single
3311 run of the compiled program.
3313 If @code{DTIME} is invoked as a function, it can not be invoked as a
3314 subroutine, and vice versa.
3316 @var{TARRAY} and @var{RESULT} are @code{INTENT(OUT)} and provide the following:
3318 @multitable @columnfractions .15 .30 .40
3319 @item @tab @code{TARRAY(1)}: @tab User time in seconds.
3320 @item @tab @code{TARRAY(2)}: @tab System time in seconds.
3321 @item @tab @code{RESULT}: @tab Run time since start in seconds.
3324 @item @emph{Standard}:
3330 @item @emph{Syntax}:
3331 @multitable @columnfractions .80
3332 @item @code{CALL DTIME(TARRAY, RESULT)}.
3333 @item @code{RESULT = DTIME(TARRAY)}, (not recommended).
3336 @item @emph{Arguments}:
3337 @multitable @columnfractions .15 .70
3338 @item @var{TARRAY}@tab The type shall be @code{REAL, DIMENSION(2)}.
3339 @item @var{RESULT}@tab The type shall be @code{REAL}.
3342 @item @emph{Return value}:
3343 Elapsed time in seconds since the start of program execution.
3345 @item @emph{Example}:
3349 real, dimension(2) :: tarray
3351 call dtime(tarray, result)
3355 do i=1,100000000 ! Just a delay
3358 call dtime(tarray, result)
3362 end program test_dtime
3369 @section @code{EOSHIFT} --- End-off shift elements of an array
3371 @cindex array, shift
3374 @item @emph{Description}:
3375 @code{EOSHIFT(ARRAY, SHIFT[,BOUNDARY, DIM])} performs an end-off shift on
3376 elements of @var{ARRAY} along the dimension of @var{DIM}. If @var{DIM} is
3377 omitted it is taken to be @code{1}. @var{DIM} is a scaler of type
3378 @code{INTEGER} in the range of @math{1 /leq DIM /leq n)} where @math{n} is the
3379 rank of @var{ARRAY}. If the rank of @var{ARRAY} is one, then all elements of
3380 @var{ARRAY} are shifted by @var{SHIFT} places. If rank is greater than one,
3381 then all complete rank one sections of @var{ARRAY} along the given dimension are
3382 shifted. Elements shifted out one end of each rank one section are dropped. If
3383 @var{BOUNDARY} is present then the corresponding value of from @var{BOUNDARY}
3384 is copied back in the other end. If @var{BOUNDARY} is not present then the
3385 following are copied in depending on the type of @var{ARRAY}.
3387 @multitable @columnfractions .15 .80
3388 @item @emph{Array Type} @tab @emph{Boundary Value}
3389 @item Numeric @tab 0 of the type and kind of @var{ARRAY}.
3390 @item Logical @tab @code{.FALSE.}.
3391 @item Character(@var{len}) @tab @var{len} blanks.
3394 @item @emph{Standard}:
3398 Transformational function
3400 @item @emph{Syntax}:
3401 @code{RESULT = EOSHIFT(ARRAY, SHIFT [, BOUNDARY, DIM])}
3403 @item @emph{Arguments}:
3404 @multitable @columnfractions .15 .70
3405 @item @var{ARRAY} @tab May be any type, not scaler.
3406 @item @var{SHIFT} @tab The type shall be @code{INTEGER}.
3407 @item @var{BOUNDARY} @tab Same type as @var{ARRAY}.
3408 @item @var{DIM} @tab The type shall be @code{INTEGER}.
3411 @item @emph{Return value}:
3412 Returns an array of same type and rank as the @var{ARRAY} argument.
3414 @item @emph{Example}:
3416 program test_eoshift
3417 integer, dimension(3,3) :: a
3418 a = reshape( (/ 1, 2, 3, 4, 5, 6, 7, 8, 9 /), (/ 3, 3 /))
3419 print '(3i3)', a(1,:)
3420 print '(3i3)', a(2,:)
3421 print '(3i3)', a(3,:)
3422 a = EOSHIFT(a, SHIFT=(/1, 2, 1/), BOUNDARY=-5, DIM=2)
3424 print '(3i3)', a(1,:)
3425 print '(3i3)', a(2,:)
3426 print '(3i3)', a(3,:)
3427 end program test_eoshift
3434 @section @code{EPSILON} --- Epsilon function
3436 @cindex model representation, epsilon
3439 @item @emph{Description}:
3440 @code{EPSILON(X)} returns a nearly negligible number relative to @code{1}.
3442 @item @emph{Standard}:
3448 @item @emph{Syntax}:
3449 @code{RESULT = EPSILON(X)}
3451 @item @emph{Arguments}:
3452 @multitable @columnfractions .15 .70
3453 @item @var{X} @tab The type shall be @code{REAL(*)}.
3456 @item @emph{Return value}:
3457 The return value is of same type as the argument.
3459 @item @emph{Example}:
3461 program test_epsilon
3466 end program test_epsilon
3473 @section @code{ERF} --- Error function
3475 @cindex error function
3478 @item @emph{Description}:
3479 @code{ERF(X)} computes the error function of @var{X}.
3481 @item @emph{Standard}:
3487 @item @emph{Syntax}:
3488 @code{RESULT = ERF(X)}
3490 @item @emph{Arguments}:
3491 @multitable @columnfractions .15 .70
3492 @item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
3495 @item @emph{Return value}:
3496 The return value is a scalar of type @code{REAL(*)} and it is positive
3497 (@math{ - 1 \leq erf (x) \leq 1 }.
3499 @item @emph{Example}:
3502 real(8) :: x = 0.17_8
3504 end program test_erf
3507 @item @emph{Specific names}:
3508 @multitable @columnfractions .20 .20 .20 .25
3509 @item Name @tab Argument @tab Return type @tab Standard
3510 @item @code{DERF(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab GNU extension
3517 @section @code{ERFC} --- Error function
3519 @cindex error function, complementary
3522 @item @emph{Description}:
3523 @code{ERFC(X)} computes the complementary error function of @var{X}.
3525 @item @emph{Standard}:
3531 @item @emph{Syntax}:
3532 @code{RESULT = ERFC(X)}
3534 @item @emph{Arguments}:
3535 @multitable @columnfractions .15 .70
3536 @item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
3539 @item @emph{Return value}:
3540 The return value is a scalar of type @code{REAL(*)} and it is positive
3541 (@math{ 0 \leq erfc (x) \leq 2 }.
3543 @item @emph{Example}:
3546 real(8) :: x = 0.17_8
3548 end program test_erfc
3551 @item @emph{Specific names}:
3552 @multitable @columnfractions .20 .20 .20 .25
3553 @item Name @tab Argument @tab Return type @tab Standard
3554 @item @code{DERFC(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab GNU extension
3561 @section @code{ETIME} --- Execution time subroutine (or function)
3563 @cindex time, elapsed
3566 @item @emph{Description}:
3567 @code{ETIME(TARRAY, RESULT)} returns the number of seconds of runtime
3568 since the start of the process's execution in @var{RESULT}. @var{TARRAY}
3569 returns the user and system components of this time in @code{TARRAY(1)} and
3570 @code{TARRAY(2)} respectively. @var{RESULT} is equal to @code{TARRAY(1) + TARRAY(2)}.
3572 On some systems, the underlying timings are represented using types with
3573 sufficiently small limits that overflows (wrap around) are possible, such as
3574 32-bit types. Therefore, the values returned by this intrinsic might be, or
3575 become, negative, or numerically less than previous values, during a single
3576 run of the compiled program.
3578 If @code{ETIME} is invoked as a function, it can not be invoked as a
3579 subroutine, and vice versa.
3581 @var{TARRAY} and @var{RESULT} are @code{INTENT(OUT)} and provide the following:
3583 @multitable @columnfractions .15 .30 .60
3584 @item @tab @code{TARRAY(1)}: @tab User time in seconds.
3585 @item @tab @code{TARRAY(2)}: @tab System time in seconds.
3586 @item @tab @code{RESULT}: @tab Run time since start in seconds.
3589 @item @emph{Standard}:
3595 @item @emph{Syntax}:
3596 @multitable @columnfractions .80
3597 @item @code{CALL ETIME(TARRAY, RESULT)}.
3598 @item @code{RESULT = ETIME(TARRAY)}, (not recommended).
3601 @item @emph{Arguments}:
3602 @multitable @columnfractions .15 .70
3603 @item @var{TARRAY}@tab The type shall be @code{REAL, DIMENSION(2)}.
3604 @item @var{RESULT}@tab The type shall be @code{REAL}.
3607 @item @emph{Return value}:
3608 Elapsed time in seconds since the start of program execution.
3610 @item @emph{Example}:
3614 real, dimension(2) :: tarray
3616 call ETIME(tarray, result)
3620 do i=1,100000000 ! Just a delay
3623 call ETIME(tarray, result)
3627 end program test_etime
3630 @item @emph{See also}:
3638 @section @code{EXIT} --- Exit the program with status.
3640 @cindex program termination
3641 @cindex terminate program
3644 @item @emph{Description}:
3645 @code{EXIT} causes immediate termination of the program with status. If status
3646 is omitted it returns the canonical @emph{success} for the system. All Fortran
3647 I/O units are closed.
3649 @item @emph{Standard}:
3655 @item @emph{Syntax}:
3656 @code{CALL EXIT([STATUS])}
3658 @item @emph{Arguments}:
3659 @multitable @columnfractions .15 .70
3660 @item @var{STATUS} @tab Shall be an @code{INTEGER} of the default kind.
3663 @item @emph{Return value}:
3664 @code{STATUS} is passed to the parent process on exit.
3666 @item @emph{Example}:
3669 integer :: STATUS = 0
3670 print *, 'This program is going to exit.'
3672 end program test_exit
3675 @item @emph{See also}:
3676 @ref{ABORT}, @ref{KILL}
3682 @section @code{EXP} --- Exponential function
3688 @cindex exponential function
3689 @cindex logarithmic function, inverse
3692 @item @emph{Description}:
3693 @code{EXP(X)} computes the base @math{e} exponential of @var{X}.
3695 @item @emph{Standard}:
3696 F77 and later, has overloads that are GNU extensions
3701 @item @emph{Syntax}:
3702 @code{RESULT = EXP(X)}
3704 @item @emph{Arguments}:
3705 @multitable @columnfractions .15 .70
3706 @item @var{X} @tab The type shall be @code{REAL(*)} or
3710 @item @emph{Return value}:
3711 The return value has same type and kind as @var{X}.
3713 @item @emph{Example}:
3718 end program test_exp
3721 @item @emph{Specific names}:
3722 @multitable @columnfractions .20 .20 .20 .25
3723 @item Name @tab Argument @tab Return type @tab Standard
3724 @item @code{DEXP(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
3725 @item @code{CEXP(X)} @tab @code{COMPLEX(4) X} @tab @code{COMPLEX(4)} @tab F77 and later
3726 @item @code{ZEXP(X)} @tab @code{COMPLEX(8) X} @tab @code{COMPLEX(8)} @tab GNU extension
3727 @item @code{CDEXP(X)} @tab @code{COMPLEX(8) X} @tab @code{COMPLEX(8)} @tab GNU extension
3734 @section @code{EXPONENT} --- Exponent function
3736 @cindex real number, exponent
3737 @cindex floating point, exponent
3740 @item @emph{Description}:
3741 @code{EXPONENT(X)} returns the value of the exponent part of @var{X}. If @var{X}
3742 is zero the value returned is zero.
3744 @item @emph{Standard}:
3750 @item @emph{Syntax}:
3751 @code{RESULT = EXPONENT(X)}
3753 @item @emph{Arguments}:
3754 @multitable @columnfractions .15 .70
3755 @item @var{X} @tab The type shall be @code{REAL(*)}.
3758 @item @emph{Return value}:
3759 The return value is of type default @code{INTEGER}.
3761 @item @emph{Example}:
3763 program test_exponent
3768 print *, exponent(0.0)
3769 end program test_exponent
3776 @section @code{FDATE} --- Get the current time as a string
3778 @cindex time, current
3779 @cindex current time
3780 @cindex date, current
3781 @cindex current date
3784 @item @emph{Description}:
3785 @code{FDATE(DATE)} returns the current date (using the same format as
3786 @code{CTIME}) in @var{DATE}. It is equivalent to @code{CALL CTIME(DATE,
3789 If @code{FDATE} is invoked as a function, it can not be invoked as a
3790 subroutine, and vice versa.
3792 @var{DATE} is an @code{INTENT(OUT)} @code{CHARACTER} variable.
3794 @item @emph{Standard}:
3800 @item @emph{Syntax}:
3801 @multitable @columnfractions .80
3802 @item @code{CALL FDATE(DATE)}.
3803 @item @code{DATE = FDATE()}, (not recommended).
3806 @item @emph{Arguments}:
3807 @multitable @columnfractions .15 .70
3808 @item @var{DATE}@tab The type shall be of type @code{CHARACTER}.
3811 @item @emph{Return value}:
3812 The current date as a string.
3814 @item @emph{Example}:
3818 character(len=30) :: date
3820 print *, 'Program started on ', date
3821 do i = 1, 100000000 ! Just a delay
3825 print *, 'Program ended on ', date
3826 end program test_fdate
3833 @section @code{FLOAT} --- Convert integer to default real
3835 @cindex conversion, to real
3838 @item @emph{Description}:
3839 @code{FLOAT(I)} converts the integer @var{I} to a default real value.
3841 @item @emph{Standard}:
3847 @item @emph{Syntax}:
3848 @code{RESULT = FLOAT(I)}
3850 @item @emph{Arguments}:
3851 @multitable @columnfractions .15 .70
3852 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
3855 @item @emph{Return value}:
3856 The return value is of type default @code{REAL}.
3858 @item @emph{Example}:
3862 if (float(i) /= 1.) call abort
3863 end program test_float
3866 @item @emph{See also}:
3867 @ref{DBLE}, @ref{DFLOAT}, @ref{REAL}
3873 @section @code{FGET} --- Read a single character in stream mode from stdin
3875 @cindex read character, stream mode
3876 @cindex stream mode, read character
3877 @cindex file operation, read character
3880 @item @emph{Description}:
3881 Read a single character in stream mode from stdin by bypassing normal
3882 formatted output. Stream I/O should not be mixed with normal record-oriented
3883 (formatted or unformatted) I/O on the same unit; the results are unpredictable.
3885 This intrinsic routine is provided for backwards compatibility with
3886 @command{g77}. GNU Fortran provides the Fortran 2003 Stream facility.
3887 Programmers should consider the use of new stream IO feature in new code
3888 for future portability. See also @ref{Fortran 2003 status}.
3890 @item @emph{Standard}:
3894 Non-elemental subroutine
3896 @item @emph{Syntax}:
3897 @code{CALL FGET(C [, STATUS])}
3899 @item @emph{Arguments}:
3900 @multitable @columnfractions .15 .70
3901 @item @var{C} @tab The type shall be @code{CHARACTER}.
3902 @item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER}.
3903 Returns 0 on success, -1 on end-of-file, and a
3904 system specific positive error code otherwise.
3907 @item @emph{Example}:
3910 INTEGER, PARAMETER :: strlen = 100
3911 INTEGER :: status, i = 1
3912 CHARACTER(len=strlen) :: str = ""
3914 WRITE (*,*) 'Enter text:'
3916 CALL fget(str(i:i), status)
3917 if (status /= 0 .OR. i > strlen) exit
3920 WRITE (*,*) TRIM(str)
3924 @item @emph{See also}:
3925 @ref{FGETC}, @ref{FPUT}, @ref{FPUTC}
3931 @section @code{FGETC} --- Read a single character in stream mode
3933 @cindex read character, stream mode
3934 @cindex stream mode, read character
3935 @cindex file operation, read character
3938 @item @emph{Description}:
3939 Read a single character in stream mode by bypassing normal formatted output.
3940 Stream I/O should not be mixed with normal record-oriented (formatted or
3941 unformatted) I/O on the same unit; the results are unpredictable.
3943 This intrinsic routine is provided for backwards compatibility with
3944 @command{g77}. GNU Fortran provides the Fortran 2003 Stream facility.
3945 Programmers should consider the use of new stream IO feature in new code
3946 for future portability. See also @ref{Fortran 2003 status}.
3948 @item @emph{Standard}:
3952 Non-elemental subroutine
3954 @item @emph{Syntax}:
3955 @code{CALL FGETC(UNIT, C [, STATUS])}
3957 @item @emph{Arguments}:
3958 @multitable @columnfractions .15 .70
3959 @item @var{UNIT} @tab The type shall be @code{INTEGER}.
3960 @item @var{C} @tab The type shall be @code{CHARACTER}.
3961 @item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER}. Returns 0 on success,
3962 -1 on end-of-file and a system specific positive error code otherwise.
3965 @item @emph{Example}:
3968 INTEGER :: fd = 42, status
3971 OPEN(UNIT=fd, FILE="/etc/passwd", ACTION="READ", STATUS = "OLD")
3973 CALL fgetc(fd, c, status)
3974 IF (status /= 0) EXIT
3981 @item @emph{See also}:
3982 @ref{FGET}, @ref{FPUT}, @ref{FPUTC}
3988 @section @code{FLOOR} --- Integer floor function
3991 @cindex rounding, floor
3994 @item @emph{Description}:
3995 @code{FLOOR(X)} returns the greatest integer less than or equal to @var{X}.
3997 @item @emph{Standard}:
4003 @item @emph{Syntax}:
4004 @code{RESULT = FLOOR(X [, KIND])}
4006 @item @emph{Arguments}:
4007 @multitable @columnfractions .15 .70
4008 @item @var{X} @tab The type shall be @code{REAL(*)}.
4009 @item @var{KIND} @tab (Optional) An @code{INTEGER(*)} initialization
4010 expression indicating the kind parameter of
4014 @item @emph{Return value}:
4015 The return value is of type @code{INTEGER(KIND)}
4017 @item @emph{Example}:
4022 print *, floor(x) ! returns 63
4023 print *, floor(y) ! returns -64
4024 end program test_floor
4027 @item @emph{See also}:
4028 @ref{CEILING}, @ref{NINT}
4035 @section @code{FLUSH} --- Flush I/O unit(s)
4037 @cindex file operation, flush
4040 @item @emph{Description}:
4041 Flushes Fortran unit(s) currently open for output. Without the optional
4042 argument, all units are flushed, otherwise just the unit specified.
4044 @item @emph{Standard}:
4048 Non-elemental subroutine
4050 @item @emph{Syntax}:
4051 @code{CALL FLUSH(UNIT)}
4053 @item @emph{Arguments}:
4054 @multitable @columnfractions .15 .70
4055 @item @var{UNIT} @tab (Optional) The type shall be @code{INTEGER}.
4059 Beginning with the Fortran 2003 standard, there is a @code{FLUSH}
4060 statement that should be preferred over the @code{FLUSH} intrinsic.
4067 @section @code{FNUM} --- File number function
4069 @cindex file operation, file number
4072 @item @emph{Description}:
4073 @code{FNUM(UNIT)} returns the POSIX file descriptor number corresponding to the
4074 open Fortran I/O unit @code{UNIT}.
4076 @item @emph{Standard}:
4080 Non-elemental function
4082 @item @emph{Syntax}:
4083 @code{RESULT = FNUM(UNIT)}
4085 @item @emph{Arguments}:
4086 @multitable @columnfractions .15 .70
4087 @item @var{UNIT} @tab The type shall be @code{INTEGER}.
4090 @item @emph{Return value}:
4091 The return value is of type @code{INTEGER}
4093 @item @emph{Example}:
4097 open (unit=10, status = "scratch")
4101 end program test_fnum
4108 @section @code{FPUT} --- Write a single character in stream mode to stdout
4110 @cindex write character, stream mode
4111 @cindex stream mode, write character
4112 @cindex file operation, write character
4115 @item @emph{Description}:
4116 Write a single character in stream mode to stdout by bypassing normal
4117 formatted output. Stream I/O should not be mixed with normal record-oriented
4118 (formatted or unformatted) I/O on the same unit; the results are unpredictable.
4120 This intrinsic routine is provided for backwards compatibility with
4121 @command{g77}. GNU Fortran provides the Fortran 2003 Stream facility.
4122 Programmers should consider the use of new stream IO feature in new code
4123 for future portability. See also @ref{Fortran 2003 status}.
4125 @item @emph{Standard}:
4129 Non-elemental subroutine
4131 @item @emph{Syntax}:
4132 @code{CALL FPUT(C [, STATUS])}
4134 @item @emph{Arguments}:
4135 @multitable @columnfractions .15 .70
4136 @item @var{C} @tab The type shall be @code{CHARACTER}.
4137 @item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER}. Returns 0 on success,
4138 -1 on end-of-file and a system specific positive error code otherwise.
4141 @item @emph{Example}:
4144 CHARACTER(len=10) :: str = "gfortran"
4146 DO i = 1, len_trim(str)
4152 @item @emph{See also}:
4153 @ref{FPUTC}, @ref{FGET}, @ref{FGETC}
4159 @section @code{FPUTC} --- Write a single character in stream mode
4161 @cindex write character, stream mode
4162 @cindex stream mode, write character
4163 @cindex file operation, write character
4166 @item @emph{Description}:
4167 Write a single character in stream mode by bypassing normal formatted
4168 output. Stream I/O should not be mixed with normal record-oriented
4169 (formatted or unformatted) I/O on the same unit; the results are unpredictable.
4171 This intrinsic routine is provided for backwards compatibility with
4172 @command{g77}. GNU Fortran provides the Fortran 2003 Stream facility.
4173 Programmers should consider the use of new stream IO feature in new code
4174 for future portability. See also @ref{Fortran 2003 status}.
4176 @item @emph{Standard}:
4180 Non-elemental subroutine
4182 @item @emph{Syntax}:
4183 @code{CALL FPUTC(UNIT, C [, STATUS])}
4185 @item @emph{Arguments}:
4186 @multitable @columnfractions .15 .70
4187 @item @var{UNIT} @tab The type shall be @code{INTEGER}.
4188 @item @var{C} @tab The type shall be @code{CHARACTER}.
4189 @item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER}. Returns 0 on success,
4190 -1 on end-of-file and a system specific positive error code otherwise.
4193 @item @emph{Example}:
4196 CHARACTER(len=10) :: str = "gfortran"
4197 INTEGER :: fd = 42, i
4199 OPEN(UNIT = fd, FILE = "out", ACTION = "WRITE", STATUS="NEW")
4200 DO i = 1, len_trim(str)
4201 CALL fputc(fd, str(i:i))
4207 @item @emph{See also}:
4208 @ref{FPUT}, @ref{FGET}, @ref{FGETC}
4214 @section @code{FRACTION} --- Fractional part of the model representation
4216 @cindex real number, fraction
4217 @cindex floating point, fraction
4220 @item @emph{Description}:
4221 @code{FRACTION(X)} returns the fractional part of the model
4222 representation of @code{X}.
4224 @item @emph{Standard}:
4230 @item @emph{Syntax}:
4231 @code{Y = FRACTION(X)}
4233 @item @emph{Arguments}:
4234 @multitable @columnfractions .15 .70
4235 @item @var{X} @tab The type of the argument shall be a @code{REAL}.
4238 @item @emph{Return value}:
4239 The return value is of the same type and kind as the argument.
4240 The fractional part of the model representation of @code{X} is returned;
4241 it is @code{X * RADIX(X)**(-EXPONENT(X))}.
4243 @item @emph{Example}:
4245 program test_fraction
4248 print *, fraction(x), x * radix(x)**(-exponent(x))
4249 end program test_fraction
4257 @section @code{FREE} --- Frees memory
4259 @cindex pointer, cray
4262 @item @emph{Description}:
4263 Frees memory previously allocated by @code{MALLOC()}. The @code{FREE}
4264 intrinsic is an extension intended to be used with Cray pointers, and is
4265 provided in GNU Fortran to allow user to compile legacy code. For
4266 new code using Fortran 95 pointers, the memory de-allocation intrinsic is
4269 @item @emph{Standard}:
4275 @item @emph{Syntax}:
4276 @code{CALL FREE(PTR)}
4278 @item @emph{Arguments}:
4279 @multitable @columnfractions .15 .70
4280 @item @var{PTR} @tab The type shall be @code{INTEGER}. It represents the
4281 location of the memory that should be de-allocated.
4284 @item @emph{Return value}:
4287 @item @emph{Example}:
4288 See @code{MALLOC} for an example.
4290 @item @emph{See also}:
4297 @section @code{FSEEK} --- Low level file positioning subroutine
4299 @cindex file operation, seek
4300 @cindex file operation, position
4303 @item @emph{Description}:
4304 Moves @var{UNIT} to the specified @var{OFFSET}. If @var{WHENCE}
4305 is set to 0, the @var{OFFSET} is taken as an absolute value @code{SEEK_SET},
4306 if set to 1, @var{OFFSET} is taken to be relative to the current position
4307 @code{SEEK_CUR}, and if set to 2 relative to the end of the file @code{SEEK_END}.
4308 On error, @var{STATUS} is set to a non-zero value. If @var{STATUS} the seek
4311 This intrinsic routine is not fully backwards compatible with @command{g77}.
4312 In @command{g77}, the @code{FSEEK} takes a statement label instead of a
4313 @var{STATUS} variable. If FSEEK is used in old code, change
4315 CALL FSEEK(UNIT, OFFSET, WHENCE, *label)
4320 CALL FSEEK(UNIT, OFFSET, WHENCE, status)
4321 IF (status /= 0) GOTO label
4324 Please note that GNU Fortran provides the Fortran 2003 Stream facility.
4325 Programmers should consider the use of new stream IO feature in new code
4326 for future portability. See also @ref{Fortran 2003 status}.
4328 @item @emph{Standard}:
4334 @item @emph{Syntax}:
4335 @code{CALL FSEEK(UNIT, OFFSET, WHENCE[, STATUS])}
4337 @item @emph{Arguments}:
4338 @multitable @columnfractions .15 .70
4339 @item @var{UNIT} @tab Shall be a scalar of type @code{INTEGER}.
4340 @item @var{OFFSET} @tab Shall be a scalar of type @code{INTEGER}.
4341 @item @var{WHENCE} @tab Shall be a scalar of type @code{INTEGER}.
4342 Its value shall be either 0, 1 or 2.
4343 @item @var{STATUS} @tab (Optional) shall be a scalar of type
4347 @item @emph{Example}:
4350 INTEGER, PARAMETER :: SEEK_SET = 0, SEEK_CUR = 1, SEEK_END = 2
4351 INTEGER :: fd, offset, ierr
4357 OPEN(UNIT=fd, FILE="fseek.test")
4358 CALL FSEEK(fd, offset, SEEK_SET, ierr) ! move to OFFSET
4359 print *, FTELL(fd), ierr
4361 CALL FSEEK(fd, 0, SEEK_END, ierr) ! move to end
4362 print *, FTELL(fd), ierr
4364 CALL FSEEK(fd, 0, SEEK_SET, ierr) ! move to beginning
4365 print *, FTELL(fd), ierr
4371 @item @emph{See also}:
4378 @section @code{FSTAT} --- Get file status
4380 @cindex file system, file status
4383 @item @emph{Description}:
4384 @code{FSTAT} is identical to @ref{STAT}, except that information about an
4385 already opened file is obtained.
4387 The elements in @code{BUFF} are the same as described by @ref{STAT}.
4389 @item @emph{Standard}:
4393 Non-elemental subroutine
4395 @item @emph{Syntax}:
4396 @code{CALL FSTAT(UNIT, BUFF [, STATUS])}
4398 @item @emph{Arguments}:
4399 @multitable @columnfractions .15 .70
4400 @item @var{UNIT} @tab An open I/O unit number of type @code{INTEGER}.
4401 @item @var{BUFF} @tab The type shall be @code{INTEGER(4), DIMENSION(13)}.
4402 @item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER(4)}. Returns 0
4403 on success and a system specific error code otherwise.
4406 @item @emph{Example}:
4407 See @ref{STAT} for an example.
4409 @item @emph{See also}:
4410 To stat a link: @ref{LSTAT}, to stat a file: @ref{STAT}
4416 @section @code{FTELL} --- Current stream position
4418 @cindex file operation, position
4421 @item @emph{Description}:
4422 Retrieves the current position within an open file.
4424 This intrinsic is provided in both subroutine and function forms; however,
4425 only one form can be used in any given program unit.
4427 @item @emph{Standard}:
4431 Subroutine, function
4433 @item @emph{Syntax}:
4434 @multitable @columnfractions .80
4435 @item @code{CALL FTELL(UNIT, OFFSET)}
4436 @item @code{OFFSET = FTELL(UNIT)}
4439 @item @emph{Arguments}:
4440 @multitable @columnfractions .15 .70
4441 @item @var{OFFSET} @tab Shall of type @code{INTEGER}.
4442 @item @var{UNIT} @tab Shall of type @code{INTEGER}.
4445 @item @emph{Return value}:
4446 In either syntax, @var{OFFSET} is set to the current offset of unit
4447 number @var{UNIT}, or to @math{-1} if the unit is not currently open.
4449 @item @emph{Example}:
4453 OPEN(10, FILE="temp.dat")
4459 @item @emph{See also}:
4466 @section @code{GERROR} --- Get last system error message
4468 @cindex system, error handling
4471 @item @emph{Description}:
4472 Returns the system error message corresponding to the last system error.
4473 This resembles the functionality of @code{strerror(3)} in C.
4475 @item @emph{Standard}:
4481 @item @emph{Syntax}:
4482 @code{CALL GERROR(RESULT)}
4484 @item @emph{Arguments}:
4485 @multitable @columnfractions .15 .70
4486 @item @var{RESULT} @tab Shall of type @code{CHARACTER(*)}.
4489 @item @emph{Example}:
4492 CHARACTER(len=100) :: msg
4498 @item @emph{See also}:
4499 @ref{IERRNO}, @ref{PERROR}
4505 @section @code{GETARG} --- Get command line arguments
4507 @cindex command-line arguments
4508 @cindex arguments, to program
4511 @item @emph{Description}:
4512 Retrieve the @var{N}th argument that was passed on the
4513 command line when the containing program was invoked.
4515 This intrinsic routine is provided for backwards compatibility with
4516 GNU Fortran 77. In new code, programmers should consider the use of
4517 the @ref{GET_COMMAND_ARGUMENT} intrinsic defined by the Fortran 2003
4520 @item @emph{Standard}:
4526 @item @emph{Syntax}:
4527 @code{CALL GETARG(N, ARG)}
4529 @item @emph{Arguments}:
4530 @multitable @columnfractions .15 .70
4531 @item @var{N} @tab Shall be of type @code{INTEGER(4)}, @math{@var{N} \geq 0}
4532 @item @var{ARG} @tab Shall be of type @code{CHARACTER(*)}.
4535 @item @emph{Return value}:
4536 After @code{GETARG} returns, the @var{ARG} argument holds the @var{N}th
4537 command line argument. If @var{ARG} can not hold the argument, it is
4538 truncated to fit the length of @var{ARG}. If there are less than @var{N}
4539 arguments specified at the command line, @var{ARG} will be filled with blanks.
4540 If @math{@var{N} = 0}, @var{ARG} is set to the name of the program (on systems
4541 that support this feature).
4543 @item @emph{Example}:
4547 CHARACTER(len=32) :: arg
4556 @item @emph{See also}:
4557 GNU Fortran 77 compatibility function: @ref{IARGC}
4559 F2003 functions and subroutines: @ref{GET_COMMAND}, @ref{GET_COMMAND_ARGUMENT},
4560 @ref{COMMAND_ARGUMENT_COUNT}
4566 @section @code{GET_COMMAND} --- Get the entire command line
4567 @fnindex GET_COMMAND
4568 @cindex command-line arguments
4569 @cindex arguments, to program
4572 @item @emph{Description}:
4573 Retrieve the entire command line that was used to invoke the program.
4575 @item @emph{Standard}:
4581 @item @emph{Syntax}:
4582 @code{CALL GET_COMMAND(CMD)}
4584 @item @emph{Arguments}:
4585 @multitable @columnfractions .15 .70
4586 @item @var{CMD} @tab Shall be of type @code{CHARACTER(*)}.
4589 @item @emph{Return value}:
4590 Stores the entire command line that was used to invoke the program in @var{ARG}.
4591 If @var{ARG} is not large enough, the command will be truncated.
4593 @item @emph{Example}:
4595 PROGRAM test_get_command
4596 CHARACTER(len=255) :: cmd
4597 CALL get_command(cmd)
4598 WRITE (*,*) TRIM(cmd)
4602 @item @emph{See also}:
4603 @ref{GET_COMMAND_ARGUMENT}, @ref{COMMAND_ARGUMENT_COUNT}
4608 @node GET_COMMAND_ARGUMENT
4609 @section @code{GET_COMMAND_ARGUMENT} --- Get command line arguments
4610 @fnindex GET_COMMAND_ARGUMENT
4611 @cindex command-line arguments
4612 @cindex arguments, to program
4615 @item @emph{Description}:
4616 Retrieve the @var{N}th argument that was passed on the
4617 command line when the containing program was invoked.
4619 @item @emph{Standard}:
4625 @item @emph{Syntax}:
4626 @code{CALL GET_COMMAND_ARGUMENT(N, ARG)}
4628 @item @emph{Arguments}:
4629 @multitable @columnfractions .15 .70
4630 @item @var{N} @tab Shall be of type @code{INTEGER(4)}, @math{@var{N} \geq 0}
4631 @item @var{ARG} @tab Shall be of type @code{CHARACTER(*)}.
4634 @item @emph{Return value}:
4635 After @code{GET_COMMAND_ARGUMENT} returns, the @var{ARG} argument holds the
4636 @var{N}th command line argument. If @var{ARG} can not hold the argument, it is
4637 truncated to fit the length of @var{ARG}. If there are less than @var{N}
4638 arguments specified at the command line, @var{ARG} will be filled with blanks.
4639 If @math{@var{N} = 0}, @var{ARG} is set to the name of the program (on systems
4640 that support this feature).
4642 @item @emph{Example}:
4644 PROGRAM test_get_command_argument
4646 CHARACTER(len=32) :: arg
4650 CALL get_command_argument(i, arg)
4651 IF (LEN_TRIM(arg) == 0) EXIT
4653 WRITE (*,*) TRIM(arg)
4659 @item @emph{See also}:
4660 @ref{GET_COMMAND}, @ref{COMMAND_ARGUMENT_COUNT}
4666 @section @code{GETCWD} --- Get current working directory
4668 @cindex system, working directory
4671 @item @emph{Description}:
4672 Get current working directory.
4674 @item @emph{Standard}:
4678 Non-elemental subroutine.
4680 @item @emph{Syntax}:
4681 @code{CALL GETCWD(CWD [, STATUS])}
4683 @item @emph{Arguments}:
4684 @multitable @columnfractions .15 .70
4685 @item @var{CWD} @tab The type shall be @code{CHARACTER(*)}.
4686 @item @var{STATUS} @tab (Optional) status flag. Returns 0 on success,
4687 a system specific and non-zero error code otherwise.
4690 @item @emph{Example}:
4693 CHARACTER(len=255) :: cwd
4695 WRITE(*,*) TRIM(cwd)
4699 @item @emph{See also}:
4706 @section @code{GETENV} --- Get an environmental variable
4708 @cindex environment variable
4711 @item @emph{Description}:
4712 Get the @var{VALUE} of the environmental variable @var{ENVVAR}.
4714 This intrinsic routine is provided for backwards compatibility with
4715 GNU Fortran 77. In new code, programmers should consider the use of
4716 the @ref{GET_ENVIRONMENT_VARIABLE} intrinsic defined by the Fortran
4719 @item @emph{Standard}:
4725 @item @emph{Syntax}:
4726 @code{CALL GETENV(ENVVAR, VALUE)}
4728 @item @emph{Arguments}:
4729 @multitable @columnfractions .15 .70
4730 @item @var{ENVVAR} @tab Shall be of type @code{CHARACTER(*)}.
4731 @item @var{VALUE} @tab Shall be of type @code{CHARACTER(*)}.
4734 @item @emph{Return value}:
4735 Stores the value of @var{ENVVAR} in @var{VALUE}. If @var{VALUE} is
4736 not large enough to hold the data, it is truncated. If @var{ENVVAR}
4737 is not set, @var{VALUE} will be filled with blanks.
4739 @item @emph{Example}:
4742 CHARACTER(len=255) :: homedir
4743 CALL getenv("HOME", homedir)
4744 WRITE (*,*) TRIM(homedir)
4748 @item @emph{See also}:
4749 @ref{GET_ENVIRONMENT_VARIABLE}
4754 @node GET_ENVIRONMENT_VARIABLE
4755 @section @code{GET_ENVIRONMENT_VARIABLE} --- Get an environmental variable
4756 @fnindex GET_ENVIRONMENT_VARIABLE
4757 @cindex environment variable
4760 @item @emph{Description}:
4761 Get the @var{VALUE} of the environmental variable @var{ENVVAR}.
4763 @item @emph{Standard}:
4769 @item @emph{Syntax}:
4770 @code{CALL GET_ENVIRONMENT_VARIABLE(ENVVAR, VALUE)}
4772 @item @emph{Arguments}:
4773 @multitable @columnfractions .15 .70
4774 @item @var{ENVVAR} @tab Shall be of type @code{CHARACTER(*)}.
4775 @item @var{VALUE} @tab Shall be of type @code{CHARACTER(*)}.
4778 @item @emph{Return value}:
4779 Stores the value of @var{ENVVAR} in @var{VALUE}. If @var{VALUE} is
4780 not large enough to hold the data, it is truncated. If @var{ENVVAR}
4781 is not set, @var{VALUE} will be filled with blanks.
4783 @item @emph{Example}:
4786 CHARACTER(len=255) :: homedir
4787 CALL get_environment_variable("HOME", homedir)
4788 WRITE (*,*) TRIM(homedir)
4796 @section @code{GETGID} --- Group ID function
4798 @cindex system, group id
4801 @item @emph{Description}:
4802 Returns the numerical group ID of the current process.
4804 @item @emph{Standard}:
4810 @item @emph{Syntax}:
4811 @code{RESULT = GETGID()}
4813 @item @emph{Return value}:
4814 The return value of @code{GETGID} is an @code{INTEGER} of the default
4818 @item @emph{Example}:
4819 See @code{GETPID} for an example.
4821 @item @emph{See also}:
4822 @ref{GETPID}, @ref{GETUID}
4828 @section @code{GETLOG} --- Get login name
4830 @cindex system, login name
4834 @item @emph{Description}:
4835 Gets the username under which the program is running.
4837 @item @emph{Standard}:
4843 @item @emph{Syntax}:
4844 @code{CALL GETLOG(LOGIN)}
4846 @item @emph{Arguments}:
4847 @multitable @columnfractions .15 .70
4848 @item @var{LOGIN} @tab Shall be of type @code{CHARACTER(*)}.
4851 @item @emph{Return value}:
4852 Stores the current user name in @var{LOGIN}. (On systems where POSIX
4853 functions @code{geteuid} and @code{getpwuid} are not available, and
4854 the @code{getlogin} function is not implemented either, this will
4855 return a blank string.)
4857 @item @emph{Example}:
4860 CHARACTER(32) :: login
4866 @item @emph{See also}:
4873 @section @code{GETPID} --- Process ID function
4875 @cindex system, process id
4879 @item @emph{Description}:
4880 Returns the numerical process identifier of the current process.
4882 @item @emph{Standard}:
4888 @item @emph{Syntax}:
4889 @code{RESULT = GETPID()}
4891 @item @emph{Return value}:
4892 The return value of @code{GETPID} is an @code{INTEGER} of the default
4896 @item @emph{Example}:
4899 print *, "The current process ID is ", getpid()
4900 print *, "Your numerical user ID is ", getuid()
4901 print *, "Your numerical group ID is ", getgid()
4905 @item @emph{See also}:
4906 @ref{GETGID}, @ref{GETUID}
4912 @section @code{GETUID} --- User ID function
4914 @cindex system, user id
4918 @item @emph{Description}:
4919 Returns the numerical user ID of the current process.
4921 @item @emph{Standard}:
4927 @item @emph{Syntax}:
4928 @code{RESULT = GETUID()}
4930 @item @emph{Return value}:
4931 The return value of @code{GETUID} is an @code{INTEGER} of the default
4935 @item @emph{Example}:
4936 See @code{GETPID} for an example.
4938 @item @emph{See also}:
4939 @ref{GETPID}, @ref{GETLOG}
4945 @section @code{GMTIME} --- Convert time to GMT info
4947 @cindex time, conversion to GMT info
4950 @item @emph{Description}:
4951 Given a system time value @var{STIME} (as provided by the @code{TIME8()}
4952 intrinsic), fills @var{TARRAY} with values extracted from it appropriate
4953 to the UTC time zone (Universal Coordinated Time, also known in some
4954 countries as GMT, Greenwich Mean Time), using @code{gmtime(3)}.
4956 @item @emph{Standard}:
4962 @item @emph{Syntax}:
4963 @code{CALL GMTIME(STIME, TARRAY)}
4965 @item @emph{Arguments}:
4966 @multitable @columnfractions .15 .70
4967 @item @var{STIME} @tab An @code{INTEGER(*)} scalar expression
4968 corresponding to a system time, with
4970 @item @var{TARRAY} @tab A default @code{INTEGER} array with 9 elements,
4971 with @code{INTENT(OUT)}.
4974 @item @emph{Return value}:
4975 The elements of @var{TARRAY} are assigned as follows:
4977 @item Seconds after the minute, range 0--59 or 0--61 to allow for leap
4979 @item Minutes after the hour, range 0--59
4980 @item Hours past midnight, range 0--23
4981 @item Day of month, range 0--31
4982 @item Number of months since January, range 0--12
4983 @item Years since 1900
4984 @item Number of days since Sunday, range 0--6
4985 @item Days since January 1
4986 @item Daylight savings indicator: positive if daylight savings is in
4987 effect, zero if not, and negative if the information is not
4991 @item @emph{See also}:
4992 @ref{CTIME}, @ref{LTIME}, @ref{TIME}, @ref{TIME8}
4999 @section @code{HOSTNM} --- Get system host name
5001 @cindex system, host name
5004 @item @emph{Description}:
5005 Retrieves the host name of the system on which the program is running.
5007 This intrinsic is provided in both subroutine and function forms; however,
5008 only one form can be used in any given program unit.
5010 @item @emph{Standard}:
5014 Subroutine, function
5016 @item @emph{Syntax}:
5017 @multitable @columnfractions .80
5018 @item @code{CALL HOSTNM(NAME[, STATUS])}
5019 @item @code{STATUS = HOSTNM(NAME)}
5022 @item @emph{Arguments}:
5023 @multitable @columnfractions .15 .70
5024 @item @var{NAME} @tab Shall of type @code{CHARACTER(*)}.
5025 @item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER}.
5026 Returns 0 on success, or a system specific error
5030 @item @emph{Return value}:
5031 In either syntax, @var{NAME} is set to the current hostname if it can
5032 be obtained, or to a blank string otherwise.
5039 @section @code{HUGE} --- Largest number of a kind
5041 @cindex limits, largest number
5042 @cindex model representation, largest number
5045 @item @emph{Description}:
5046 @code{HUGE(X)} returns the largest number that is not an infinity in
5047 the model of the type of @code{X}.
5049 @item @emph{Standard}:
5055 @item @emph{Syntax}:
5056 @code{RESULT = HUGE(X)}
5058 @item @emph{Arguments}:
5059 @multitable @columnfractions .15 .70
5060 @item @var{X} @tab Shall be of type @code{REAL} or @code{INTEGER}.
5063 @item @emph{Return value}:
5064 The return value is of the same type and kind as @var{X}
5066 @item @emph{Example}:
5068 program test_huge_tiny
5069 print *, huge(0), huge(0.0), huge(0.0d0)
5070 print *, tiny(0.0), tiny(0.0d0)
5071 end program test_huge_tiny
5078 @section @code{IACHAR} --- Code in @acronym{ASCII} collating sequence
5080 @cindex @acronym{ASCII} collating sequence
5081 @cindex collating sequence, @acronym{ASCII}
5082 @cindex conversion, to integer
5085 @item @emph{Description}:
5086 @code{IACHAR(C)} returns the code for the @acronym{ASCII} character
5087 in the first character position of @code{C}.
5089 @item @emph{Standard}:
5095 @item @emph{Syntax}:
5096 @code{RESULT = IACHAR(C)}
5098 @item @emph{Arguments}:
5099 @multitable @columnfractions .15 .70
5100 @item @var{C} @tab Shall be a scalar @code{CHARACTER}, with @code{INTENT(IN)}
5103 @item @emph{Return value}:
5104 The return value is of type @code{INTEGER} and of the default integer
5107 @item @emph{Example}:
5112 end program test_iachar
5116 See @ref{ICHAR} for a discussion of converting between numerical values
5117 and formatted string representations.
5119 @item @emph{See also}:
5120 @ref{ACHAR}, @ref{CHAR}, @ref{ICHAR}
5127 @section @code{IAND} --- Bitwise logical and
5129 @cindex bitwise logical and
5130 @cindex logical and, bitwise
5133 @item @emph{Description}:
5134 Bitwise logical @code{AND}.
5136 @item @emph{Standard}:
5142 @item @emph{Syntax}:
5143 @code{RESULT = IAND(I, J)}
5145 @item @emph{Arguments}:
5146 @multitable @columnfractions .15 .70
5147 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
5148 @item @var{J} @tab The type shall be @code{INTEGER(*)}, of the same
5149 kind as @var{I}. (As a GNU extension, different kinds are also
5153 @item @emph{Return value}:
5154 The return type is @code{INTEGER(*)}, of the same kind as the
5155 arguments. (If the argument kinds differ, it is of the same kind as
5156 the larger argument.)
5158 @item @emph{Example}:
5162 DATA a / Z'F' /, b / Z'3' /
5163 WRITE (*,*) IAND(a, b)
5167 @item @emph{See also}:
5168 @ref{IOR}, @ref{IEOR}, @ref{IBITS}, @ref{IBSET}, @ref{IBCLR}, @ref{NOT}
5175 @section @code{IARGC} --- Get the number of command line arguments
5177 @cindex command-line arguments
5178 @cindex command-line arguments, number of
5179 @cindex arguments, to program
5182 @item @emph{Description}:
5183 @code{IARGC()} returns the number of arguments passed on the
5184 command line when the containing program was invoked.
5186 This intrinsic routine is provided for backwards compatibility with
5187 GNU Fortran 77. In new code, programmers should consider the use of
5188 the @ref{COMMAND_ARGUMENT_COUNT} intrinsic defined by the Fortran 2003
5191 @item @emph{Standard}:
5195 Non-elemental Function
5197 @item @emph{Syntax}:
5198 @code{RESULT = IARGC()}
5200 @item @emph{Arguments}:
5203 @item @emph{Return value}:
5204 The number of command line arguments, type @code{INTEGER(4)}.
5206 @item @emph{Example}:
5209 @item @emph{See also}:
5210 GNU Fortran 77 compatibility subroutine: @ref{GETARG}
5212 F2003 functions and subroutines: @ref{GET_COMMAND}, @ref{GET_COMMAND_ARGUMENT},
5213 @ref{COMMAND_ARGUMENT_COUNT}
5219 @section @code{IBCLR} --- Clear bit
5225 @item @emph{Description}:
5226 @code{IBCLR} returns the value of @var{I} with the bit at position
5227 @var{POS} set to zero.
5229 @item @emph{Standard}:
5235 @item @emph{Syntax}:
5236 @code{RESULT = IBCLR(I, POS)}
5238 @item @emph{Arguments}:
5239 @multitable @columnfractions .15 .70
5240 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
5241 @item @var{POS} @tab The type shall be @code{INTEGER(*)}.
5244 @item @emph{Return value}:
5245 The return value is of type @code{INTEGER(*)} and of the same kind as
5248 @item @emph{See also}:
5249 @ref{IBITS}, @ref{IBSET}, @ref{IAND}, @ref{IOR}, @ref{IEOR}, @ref{MVBITS}
5256 @section @code{IBITS} --- Bit extraction
5259 @cindex bits, extract
5262 @item @emph{Description}:
5263 @code{IBITS} extracts a field of length @var{LEN} from @var{I},
5264 starting from bit position @var{POS} and extending left for @var{LEN}
5265 bits. The result is right-justified and the remaining bits are
5266 zeroed. The value of @code{POS+LEN} must be less than or equal to the
5267 value @code{BIT_SIZE(I)}.
5269 @item @emph{Standard}:
5275 @item @emph{Syntax}:
5276 @code{RESULT = IBITS(I, POS, LEN)}
5278 @item @emph{Arguments}:
5279 @multitable @columnfractions .15 .70
5280 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
5281 @item @var{POS} @tab The type shall be @code{INTEGER(*)}.
5282 @item @var{LEN} @tab The type shall be @code{INTEGER(*)}.
5285 @item @emph{Return value}:
5286 The return value is of type @code{INTEGER(*)} and of the same kind as
5289 @item @emph{See also}:
5290 @ref{BIT_SIZE}, @ref{IBCLR}, @ref{IBSET}, @ref{IAND}, @ref{IOR}, @ref{IEOR}
5296 @section @code{IBSET} --- Set bit
5301 @item @emph{Description}:
5302 @code{IBSET} returns the value of @var{I} with the bit at position
5303 @var{POS} set to one.
5305 @item @emph{Standard}:
5311 @item @emph{Syntax}:
5312 @code{RESULT = IBSET(I, POS)}
5314 @item @emph{Arguments}:
5315 @multitable @columnfractions .15 .70
5316 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
5317 @item @var{POS} @tab The type shall be @code{INTEGER(*)}.
5320 @item @emph{Return value}:
5321 The return value is of type @code{INTEGER(*)} and of the same kind as
5324 @item @emph{See also}:
5325 @ref{IBCLR}, @ref{IBITS}, @ref{IAND}, @ref{IOR}, @ref{IEOR}, @ref{MVBITS}
5332 @section @code{ICHAR} --- Character-to-integer conversion function
5334 @cindex conversion, to integer
5337 @item @emph{Description}:
5338 @code{ICHAR(C)} returns the code for the character in the first character
5339 position of @code{C} in the system's native character set.
5340 The correspondence between characters and their codes is not necessarily
5341 the same across different GNU Fortran implementations.
5343 @item @emph{Standard}:
5349 @item @emph{Syntax}:
5350 @code{RESULT = ICHAR(C)}
5352 @item @emph{Arguments}:
5353 @multitable @columnfractions .15 .70
5354 @item @var{C} @tab Shall be a scalar @code{CHARACTER}, with @code{INTENT(IN)}
5357 @item @emph{Return value}:
5358 The return value is of type @code{INTEGER} and of the default integer
5361 @item @emph{Example}:
5366 end program test_ichar
5370 No intrinsic exists to convert between a numeric value and a formatted
5371 character string representation -- for instance, given the
5372 @code{CHARACTER} value @code{'154'}, obtaining an @code{INTEGER} or
5373 @code{REAL} value with the value 154, or vice versa. Instead, this
5374 functionality is provided by internal-file I/O, as in the following
5379 character(len=10) string, string2
5382 ! Convert a string to a numeric value
5383 read (string,'(I10)') value
5386 ! Convert a value to a formatted string
5387 write (string2,'(I10)') value
5389 end program read_val
5392 @item @emph{See also}:
5393 @ref{ACHAR}, @ref{CHAR}, @ref{IACHAR}
5400 @section @code{IDATE} --- Get current local time subroutine (day/month/year)
5402 @cindex date, current
5403 @cindex current date
5406 @item @emph{Description}:
5407 @code{IDATE(TARRAY)} Fills @var{TARRAY} with the numerical values at the
5408 current local time. The day (in the range 1-31), month (in the range 1-12),
5409 and year appear in elements 1, 2, and 3 of @var{TARRAY}, respectively.
5410 The year has four significant digits.
5412 @item @emph{Standard}:
5418 @item @emph{Syntax}:
5419 @code{CALL IDATE(TARRAY)}
5421 @item @emph{Arguments}:
5422 @multitable @columnfractions .15 .70
5423 @item @var{TARRAY} @tab The type shall be @code{INTEGER, DIMENSION(3)} and
5424 the kind shall be the default integer kind.
5427 @item @emph{Return value}:
5430 @item @emph{Example}:
5433 integer, dimension(3) :: tarray
5438 end program test_idate
5445 @section @code{IEOR} --- Bitwise logical exclusive or
5447 @cindex bitwise logical exclusive or
5448 @cindex logical exclusive or, bitwise
5451 @item @emph{Description}:
5452 @code{IEOR} returns the bitwise boolean exclusive-OR of @var{I} and
5455 @item @emph{Standard}:
5461 @item @emph{Syntax}:
5462 @code{RESULT = IEOR(I, J)}
5464 @item @emph{Arguments}:
5465 @multitable @columnfractions .15 .70
5466 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
5467 @item @var{J} @tab The type shall be @code{INTEGER(*)}, of the same
5468 kind as @var{I}. (As a GNU extension, different kinds are also
5472 @item @emph{Return value}:
5473 The return type is @code{INTEGER(*)}, of the same kind as the
5474 arguments. (If the argument kinds differ, it is of the same kind as
5475 the larger argument.)
5477 @item @emph{See also}:
5478 @ref{IOR}, @ref{IAND}, @ref{IBITS}, @ref{IBSET}, @ref{IBCLR}, @ref{NOT}
5484 @section @code{IERRNO} --- Get the last system error number
5486 @cindex system, error handling
5489 @item @emph{Description}:
5490 Returns the last system error number, as given by the C @code{errno()}
5493 @item @emph{Standard}:
5497 Non-elemental function
5499 @item @emph{Syntax}:
5500 @code{RESULT = IERRNO()}
5502 @item @emph{Arguments}:
5505 @item @emph{Return value}:
5506 The return value is of type @code{INTEGER} and of the default integer
5509 @item @emph{See also}:
5516 @section @code{INDEX} --- Position of a substring within a string
5518 @cindex substring position
5519 @cindex string, find substring
5522 @item @emph{Description}:
5523 Returns the position of the start of the first occurrence of string
5524 @var{SUBSTRING} as a substring in @var{STRING}, counting from one. If
5525 @var{SUBSTRING} is not present in @var{STRING}, zero is returned. If
5526 the @var{BACK} argument is present and true, the return value is the
5527 start of the last occurrence rather than the first.
5529 @item @emph{Standard}:
5535 @item @emph{Syntax}:
5536 @code{RESULT = INDEX(STRING, SUBSTRING [, BACK])}
5538 @item @emph{Arguments}:
5539 @multitable @columnfractions .15 .70
5540 @item @var{STRING} @tab Shall be a scalar @code{CHARACTER(*)}, with
5542 @item @var{SUBSTRING} @tab Shall be a scalar @code{CHARACTER(*)}, with
5544 @item @var{BACK} @tab (Optional) Shall be a scalar @code{LOGICAL(*)}, with
5548 @item @emph{Return value}:
5549 The return value is of type @code{INTEGER} and of the default integer
5552 @item @emph{See also}:
5553 @ref{SCAN}, @ref{VERIFY}
5559 @section @code{INT} --- Convert to integer type
5563 @cindex conversion, to integer
5566 @item @emph{Description}:
5567 Convert to integer type
5569 @item @emph{Standard}:
5575 @item @emph{Syntax}:
5576 @code{RESULT = INT(A [, KIND))}
5578 @item @emph{Arguments}:
5579 @multitable @columnfractions .15 .70
5580 @item @var{A} @tab Shall be of type @code{INTEGER(*)},
5581 @code{REAL(*)}, or @code{COMPLEX(*)}.
5582 @item @var{KIND} @tab (Optional) An @code{INTEGER(*)} initialization
5583 expression indicating the kind parameter of
5587 @item @emph{Return value}:
5588 These functions return a @code{INTEGER(*)} variable or array under
5589 the following rules:
5593 If @var{A} is of type @code{INTEGER(*)}, @code{INT(A) = A}
5595 If @var{A} is of type @code{REAL(*)} and @math{|A| < 1}, @code{INT(A)} equals @code{0}.
5596 If @math{|A| \geq 1}, then @code{INT(A)} equals the largest integer that does not exceed
5597 the range of @var{A} and whose sign is the same as the sign of @var{A}.
5599 If @var{A} is of type @code{COMPLEX(*)}, rule B is applied to the real part of @var{A}.
5602 @item @emph{Example}:
5606 complex :: z = (-3.7, 1.0)
5608 print *, int(z), int(z,8)
5612 @item @emph{Specific names}:
5613 @multitable @columnfractions .20 .20 .20 .25
5614 @item Name @tab Argument @tab Return type @tab Standard
5615 @item @code{IFIX(A)} @tab @code{REAL(4) A} @tab @code{INTEGER} @tab F77 and later
5616 @item @code{IDINT(A)} @tab @code{REAL(8) A} @tab @code{INTEGER} @tab F77 and later
5624 @section @code{INT2} --- Convert to 16-bit integer type
5627 @cindex conversion, to integer
5630 @item @emph{Description}:
5631 Convert to a @code{KIND=2} integer type. This is equivalent to the
5632 standard @code{INT} intrinsic with an optional argument of
5633 @code{KIND=2}, and is only included for backwards compatibility.
5635 The @code{SHORT} intrinsic is equivalent to @code{INT2}.
5637 @item @emph{Standard}:
5643 @item @emph{Syntax}:
5644 @code{RESULT = INT2(A)}
5646 @item @emph{Arguments}:
5647 @multitable @columnfractions .15 .70
5648 @item @var{A} @tab Shall be of type @code{INTEGER(*)},
5649 @code{REAL(*)}, or @code{COMPLEX(*)}.
5652 @item @emph{Return value}:
5653 The return value is a @code{INTEGER(2)} variable.
5655 @item @emph{See also}:
5656 @ref{INT}, @ref{INT8}, @ref{LONG}
5662 @section @code{INT8} --- Convert to 64-bit integer type
5664 @cindex conversion, to integer
5667 @item @emph{Description}:
5668 Convert to a @code{KIND=8} integer type. This is equivalent to the
5669 standard @code{INT} intrinsic with an optional argument of
5670 @code{KIND=8}, and is only included for backwards compatibility.
5672 @item @emph{Standard}:
5678 @item @emph{Syntax}:
5679 @code{RESULT = INT8(A)}
5681 @item @emph{Arguments}:
5682 @multitable @columnfractions .15 .70
5683 @item @var{A} @tab Shall be of type @code{INTEGER(*)},
5684 @code{REAL(*)}, or @code{COMPLEX(*)}.
5687 @item @emph{Return value}:
5688 The return value is a @code{INTEGER(8)} variable.
5690 @item @emph{See also}:
5691 @ref{INT}, @ref{INT2}, @ref{LONG}
5697 @section @code{IOR} --- Bitwise logical or
5699 @cindex bitwise logical or
5700 @cindex logical or, bitwise
5703 @item @emph{Description}:
5704 @code{IEOR} returns the bitwise boolean OR of @var{I} and
5707 @item @emph{Standard}:
5713 @item @emph{Syntax}:
5714 @code{RESULT = IEOR(I, J)}
5716 @item @emph{Arguments}:
5717 @multitable @columnfractions .15 .70
5718 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
5719 @item @var{J} @tab The type shall be @code{INTEGER(*)}, of the same
5720 kind as @var{I}. (As a GNU extension, different kinds are also
5724 @item @emph{Return value}:
5725 The return type is @code{INTEGER(*)}, of the same kind as the
5726 arguments. (If the argument kinds differ, it is of the same kind as
5727 the larger argument.)
5729 @item @emph{See also}:
5730 @ref{IEOR}, @ref{IAND}, @ref{IBITS}, @ref{IBSET}, @ref{IBCLR}, @ref{NOT}
5736 @section @code{IRAND} --- Integer pseudo-random number
5738 @cindex random number generation
5741 @item @emph{Description}:
5742 @code{IRAND(FLAG)} returns a pseudo-random number from a uniform
5743 distribution between 0 and a system-dependent limit (which is in most
5744 cases 2147483647). If @var{FLAG} is 0, the next number
5745 in the current sequence is returned; if @var{FLAG} is 1, the generator
5746 is restarted by @code{CALL SRAND(0)}; if @var{FLAG} has any other value,
5747 it is used as a new seed with @code{SRAND}.
5749 @item @emph{Standard}:
5753 Non-elemental function
5755 @item @emph{Syntax}:
5756 @code{RESULT = IRAND(FLAG)}
5758 @item @emph{Arguments}:
5759 @multitable @columnfractions .15 .70
5760 @item @var{FLAG} @tab Shall be a scalar @code{INTEGER} of kind 4.
5763 @item @emph{Return value}:
5764 The return value is of @code{INTEGER(kind=4)} type.
5766 @item @emph{Example}:
5769 integer,parameter :: seed = 86456
5772 print *, irand(), irand(), irand(), irand()
5773 print *, irand(seed), irand(), irand(), irand()
5774 end program test_irand
5782 @section @code{ISATTY} --- Whether a unit is a terminal device.
5784 @cindex system, terminal
5787 @item @emph{Description}:
5788 Determine whether a unit is connected to a terminal device.
5790 @item @emph{Standard}:
5794 Non-elemental function.
5796 @item @emph{Syntax}:
5797 @code{RESULT = ISATTY(UNIT)}
5799 @item @emph{Arguments}:
5800 @multitable @columnfractions .15 .70
5801 @item @var{UNIT} @tab Shall be a scalar @code{INTEGER(*)}.
5804 @item @emph{Return value}:
5805 Returns @code{.TRUE.} if the @var{UNIT} is connected to a terminal
5806 device, @code{.FALSE.} otherwise.
5808 @item @emph{Example}:
5811 INTEGER(kind=1) :: unit
5813 write(*,*) isatty(unit=unit)
5817 @item @emph{See also}:
5824 @section @code{ISHFT} --- Shift bits
5829 @item @emph{Description}:
5830 @code{ISHFT} returns a value corresponding to @var{I} with all of the
5831 bits shifted @var{SHIFT} places. A value of @var{SHIFT} greater than
5832 zero corresponds to a left shift, a value of zero corresponds to no
5833 shift, and a value less than zero corresponds to a right shift. If the
5834 absolute value of @var{SHIFT} is greater than @code{BIT_SIZE(I)}, the
5835 value is undefined. Bits shifted out from the left end or right end are
5836 lost; zeros are shifted in from the opposite end.
5838 @item @emph{Standard}:
5844 @item @emph{Syntax}:
5845 @code{RESULT = ISHFT(I, SHIFT)}
5847 @item @emph{Arguments}:
5848 @multitable @columnfractions .15 .70
5849 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
5850 @item @var{SHIFT} @tab The type shall be @code{INTEGER(*)}.
5853 @item @emph{Return value}:
5854 The return value is of type @code{INTEGER(*)} and of the same kind as
5857 @item @emph{See also}:
5864 @section @code{ISHFTC} --- Shift bits circularly
5866 @cindex bits, shift circular
5869 @item @emph{Description}:
5870 @code{ISHFTC} returns a value corresponding to @var{I} with the
5871 rightmost @var{SIZE} bits shifted circularly @var{SHIFT} places; that
5872 is, bits shifted out one end are shifted into the opposite end. A value
5873 of @var{SHIFT} greater than zero corresponds to a left shift, a value of
5874 zero corresponds to no shift, and a value less than zero corresponds to
5875 a right shift. The absolute value of @var{SHIFT} must be less than
5876 @var{SIZE}. If the @var{SIZE} argument is omitted, it is taken to be
5877 equivalent to @code{BIT_SIZE(I)}.
5879 @item @emph{Standard}:
5885 @item @emph{Syntax}:
5886 @code{RESULT = ISHFTC(I, SHIFT [, SIZE])}
5888 @item @emph{Arguments}:
5889 @multitable @columnfractions .15 .70
5890 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
5891 @item @var{SHIFT} @tab The type shall be @code{INTEGER(*)}.
5892 @item @var{SIZE} @tab (Optional) The type shall be @code{INTEGER(*)};
5893 the value must be greater than zero and less than or equal to
5897 @item @emph{Return value}:
5898 The return value is of type @code{INTEGER(*)} and of the same kind as
5901 @item @emph{See also}:
5908 @section @code{ITIME} --- Get current local time subroutine (hour/minutes/seconds)
5910 @cindex time, current
5911 @cindex current time
5914 @item @emph{Description}:
5915 @code{IDATE(TARRAY)} Fills @var{TARRAY} with the numerical values at the
5916 current local time. The hour (in the range 1-24), minute (in the range 1-60),
5917 and seconds (in the range 1-60) appear in elements 1, 2, and 3 of @var{TARRAY},
5920 @item @emph{Standard}:
5926 @item @emph{Syntax}:
5927 @code{CALL ITIME(TARRAY)}
5929 @item @emph{Arguments}:
5930 @multitable @columnfractions .15 .70
5931 @item @var{TARRAY} @tab The type shall be @code{INTEGER, DIMENSION(3)}
5932 and the kind shall be the default integer kind.
5935 @item @emph{Return value}:
5939 @item @emph{Example}:
5942 integer, dimension(3) :: tarray
5947 end program test_itime
5954 @section @code{KILL} --- Send a signal to a process
5958 @item @emph{Description}:
5959 @item @emph{Standard}:
5960 Sends the signal specified by @var{SIGNAL} to the process @var{PID}.
5966 @item @emph{Syntax}:
5967 @code{CALL KILL(PID, SIGNAL [, STATUS])}
5969 @item @emph{Arguments}:
5970 @multitable @columnfractions .15 .70
5971 @item @var{PID} @tab Shall be a scalar @code{INTEGER}, with
5973 @item @var{SIGNAL} @tab Shall be a scalar @code{INTEGER}, with
5975 @item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER(4)} or
5976 @code{INTEGER(8)}. Returns 0 on success, or a
5977 system-specific error code otherwise.
5980 @item @emph{See also}:
5981 @ref{ABORT}, @ref{EXIT}
5987 @section @code{KIND} --- Kind of an entity
5992 @item @emph{Description}:
5993 @code{KIND(X)} returns the kind value of the entity @var{X}.
5995 @item @emph{Standard}:
6001 @item @emph{Syntax}:
6004 @item @emph{Arguments}:
6005 @multitable @columnfractions .15 .70
6006 @item @var{X} @tab Shall be of type @code{LOGICAL}, @code{INTEGER},
6007 @code{REAL}, @code{COMPLEX} or @code{CHARACTER}.
6010 @item @emph{Return value}:
6011 The return value is a scalar of type @code{INTEGER} and of the default
6014 @item @emph{Example}:
6017 integer,parameter :: kc = kind(' ')
6018 integer,parameter :: kl = kind(.true.)
6020 print *, "The default character kind is ", kc
6021 print *, "The default logical kind is ", kl
6022 end program test_kind
6030 @section @code{LBOUND} --- Lower dimension bounds of an array
6032 @cindex array, lower bound
6035 @item @emph{Description}:
6036 Returns the lower bounds of an array, or a single lower bound
6037 along the @var{DIM} dimension.
6038 @item @emph{Standard}:
6044 @item @emph{Syntax}:
6045 @code{RESULT = LBOUND(ARRAY [, DIM])}
6047 @item @emph{Arguments}:
6048 @multitable @columnfractions .15 .70
6049 @item @var{ARRAY} @tab Shall be an array, of any type.
6050 @item @var{DIM} @tab (Optional) Shall be a scalar @code{INTEGER(*)}.
6053 @item @emph{Return value}:
6054 If @var{DIM} is absent, the result is an array of the lower bounds of
6055 @var{ARRAY}. If @var{DIM} is present, the result is a scalar
6056 corresponding to the lower bound of the array along that dimension. If
6057 @var{ARRAY} is an expression rather than a whole array or array
6058 structure component, or if it has a zero extent along the relevant
6059 dimension, the lower bound is taken to be 1.
6061 @item @emph{See also}:
6068 @section @code{LEN} --- Length of a character entity
6070 @cindex string, length
6073 @item @emph{Description}:
6074 Returns the length of a character string. If @var{STRING} is an array,
6075 the length of an element of @var{STRING} is returned. Note that
6076 @var{STRING} need not be defined when this intrinsic is invoked, since
6077 only the length, not the content, of @var{STRING} is needed.
6079 @item @emph{Standard}:
6085 @item @emph{Syntax}:
6086 @code{L = LEN(STRING)}
6088 @item @emph{Arguments}:
6089 @multitable @columnfractions .15 .70
6090 @item @var{STRING} @tab Shall be a scalar or array of type
6091 @code{CHARACTER(*)}, with @code{INTENT(IN)}
6094 @item @emph{Return value}:
6095 The return value is an @code{INTEGER} of the default kind.
6097 @item @emph{See also}:
6098 @ref{LEN_TRIM}, @ref{ADJUSTL}, @ref{ADJUSTR}
6104 @section @code{LEN_TRIM} --- Length of a character entity without trailing blank characters
6106 @cindex string, length, without trailing whitespace
6109 @item @emph{Description}:
6110 Returns the length of a character string, ignoring any trailing blanks.
6112 @item @emph{Standard}:
6118 @item @emph{Syntax}:
6119 @code{RESULT = LEN_TRIM(STRING)}
6121 @item @emph{Arguments}:
6122 @multitable @columnfractions .15 .70
6123 @item @var{STRING} @tab Shall be a scalar of type @code{CHARACTER(*)},
6124 with @code{INTENT(IN)}
6127 @item @emph{Return value}:
6128 The return value is an @code{INTEGER} of the default kind.
6130 @item @emph{See also}:
6131 @ref{LEN}, @ref{ADJUSTL}, @ref{ADJUSTR}
6137 @section @code{LGE} --- Lexical greater than or equal
6139 @cindex lexical comparison of strings
6140 @cindex string, comparison
6143 @item @emph{Description}:
6144 Determines whether one string is lexically greater than or equal to
6145 another string, where the two strings are interpreted as containing
6146 ASCII character codes. If the String A and String B are not the same
6147 length, the shorter is compared as if spaces were appended to it to form
6148 a value that has the same length as the longer.
6150 In general, the lexical comparison intrinsics @code{LGE}, @code{LGT},
6151 @code{LLE}, and @code{LLT} differ from the corresponding intrinsic
6152 operators @code{.GE.}, @code{.GT.}, @code{.LE.}, and @code{.LT.}, in
6153 that the latter use the processor's character ordering (which is not
6154 ASCII on some targets), whereas the former always use the ASCII
6157 @item @emph{Standard}:
6163 @item @emph{Syntax}:
6164 @code{RESULT = LGE(STRING_A, STRING_B)}
6166 @item @emph{Arguments}:
6167 @multitable @columnfractions .15 .70
6168 @item @var{STRING_A} @tab Shall be of default @code{CHARACTER} type.
6169 @item @var{STRING_B} @tab Shall be of default @code{CHARACTER} type.
6172 @item @emph{Return value}:
6173 Returns @code{.TRUE.} if @code{STRING_A >= STRING_B}, and @code{.FALSE.}
6174 otherwise, based on the ASCII ordering.
6176 @item @emph{See also}:
6177 @ref{LGT}, @ref{LLE}, @ref{LLT}
6183 @section @code{LGT} --- Lexical greater than
6185 @cindex lexical comparison of strings
6186 @cindex string, comparison
6189 @item @emph{Description}:
6190 Determines whether one string is lexically greater than another string,
6191 where the two strings are interpreted as containing ASCII character
6192 codes. If the String A and String B are not the same length, the
6193 shorter is compared as if spaces were appended to it to form a value
6194 that has the same length as the longer.
6196 In general, the lexical comparison intrinsics @code{LGE}, @code{LGT},
6197 @code{LLE}, and @code{LLT} differ from the corresponding intrinsic
6198 operators @code{.GE.}, @code{.GT.}, @code{.LE.}, and @code{.LT.}, in
6199 that the latter use the processor's character ordering (which is not
6200 ASCII on some targets), whereas the former always use the ASCII
6203 @item @emph{Standard}:
6209 @item @emph{Syntax}:
6210 @code{RESULT = LGT(STRING_A, STRING_B)}
6212 @item @emph{Arguments}:
6213 @multitable @columnfractions .15 .70
6214 @item @var{STRING_A} @tab Shall be of default @code{CHARACTER} type.
6215 @item @var{STRING_B} @tab Shall be of default @code{CHARACTER} type.
6218 @item @emph{Return value}:
6219 Returns @code{.TRUE.} if @code{STRING_A > STRING_B}, and @code{.FALSE.}
6220 otherwise, based on the ASCII ordering.
6222 @item @emph{See also}:
6223 @ref{LGE}, @ref{LLE}, @ref{LLT}
6229 @section @code{LINK} --- Create a hard link
6231 @cindex file system, create link
6232 @cindex file system, hard link
6235 @item @emph{Description}:
6236 Makes a (hard) link from file @var{PATH1} to @var{PATH2}. A null
6237 character (@code{CHAR(0)}) can be used to mark the end of the names in
6238 @var{PATH1} and @var{PATH2}; otherwise, trailing blanks in the file
6239 names are ignored. If the @var{STATUS} argument is supplied, it
6240 contains 0 on success or a nonzero error code upon return; see
6243 This intrinsic is provided in both subroutine and function forms;
6244 however, only one form can be used in any given program unit.
6246 @item @emph{Standard}:
6250 Subroutine, non-elemental function
6252 @item @emph{Syntax}:
6253 @multitable @columnfractions .80
6254 @item @code{CALL LINK(PATH1, PATH2 [, STATUS])}
6255 @item @code{STATUS = LINK(PATH1, PATH2)}
6258 @item @emph{Arguments}:
6259 @multitable @columnfractions .15 .70
6260 @item @var{PATH1} @tab Shall be of default @code{CHARACTER} type.
6261 @item @var{PATH2} @tab Shall be of default @code{CHARACTER} type.
6262 @item @var{STATUS} @tab (Optional) Shall be of default @code{INTEGER} type.
6265 @item @emph{See also}:
6266 @ref{SYMLNK}, @ref{UNLINK}
6272 @section @code{LLE} --- Lexical less than or equal
6274 @cindex lexical comparison of strings
6275 @cindex string, comparison
6278 @item @emph{Description}:
6279 Determines whether one string is lexically less than or equal to another
6280 string, where the two strings are interpreted as containing ASCII
6281 character codes. If the String A and String B are not the same length,
6282 the shorter is compared as if spaces were appended to it to form a value
6283 that has the same length as the longer.
6285 In general, the lexical comparison intrinsics @code{LGE}, @code{LGT},
6286 @code{LLE}, and @code{LLT} differ from the corresponding intrinsic
6287 operators @code{.GE.}, @code{.GT.}, @code{.LE.}, and @code{.LT.}, in
6288 that the latter use the processor's character ordering (which is not
6289 ASCII on some targets), whereas the former always use the ASCII
6292 @item @emph{Standard}:
6298 @item @emph{Syntax}:
6299 @code{RESULT = LLE(STRING_A, STRING_B)}
6301 @item @emph{Arguments}:
6302 @multitable @columnfractions .15 .70
6303 @item @var{STRING_A} @tab Shall be of default @code{CHARACTER} type.
6304 @item @var{STRING_B} @tab Shall be of default @code{CHARACTER} type.
6307 @item @emph{Return value}:
6308 Returns @code{.TRUE.} if @code{STRING_A <= STRING_B}, and @code{.FALSE.}
6309 otherwise, based on the ASCII ordering.
6311 @item @emph{See also}:
6312 @ref{LGE}, @ref{LGT}, @ref{LLT}
6318 @section @code{LLT} --- Lexical less than
6320 @cindex lexical comparison of strings
6321 @cindex string, comparison
6324 @item @emph{Description}:
6325 Determines whether one string is lexically less than another string,
6326 where the two strings are interpreted as containing ASCII character
6327 codes. If the String A and String B are not the same length, the
6328 shorter is compared as if spaces were appended to it to form a value
6329 that has the same length as the longer.
6331 In general, the lexical comparison intrinsics @code{LGE}, @code{LGT},
6332 @code{LLE}, and @code{LLT} differ from the corresponding intrinsic
6333 operators @code{.GE.}, @code{.GT.}, @code{.LE.}, and @code{.LT.}, in
6334 that the latter use the processor's character ordering (which is not
6335 ASCII on some targets), whereas the former always use the ASCII
6338 @item @emph{Standard}:
6344 @item @emph{Syntax}:
6345 @code{RESULT = LLT(STRING_A, STRING_B)}
6347 @item @emph{Arguments}:
6348 @multitable @columnfractions .15 .70
6349 @item @var{STRING_A} @tab Shall be of default @code{CHARACTER} type.
6350 @item @var{STRING_B} @tab Shall be of default @code{CHARACTER} type.
6353 @item @emph{Return value}:
6354 Returns @code{.TRUE.} if @code{STRING_A < STRING_B}, and @code{.FALSE.}
6355 otherwise, based on the ASCII ordering.
6357 @item @emph{See also}:
6358 @ref{LGE}, @ref{LGT}, @ref{LLE}
6364 @section @code{LNBLNK} --- Index of the last non-blank character in a string
6366 @cindex string, find non-blank character
6369 @item @emph{Description}:
6370 Returns the length of a character string, ignoring any trailing blanks.
6371 This is identical to the standard @code{LEN_TRIM} intrinsic, and is only
6372 included for backwards compatibility.
6374 @item @emph{Standard}:
6380 @item @emph{Syntax}:
6381 @code{RESULT = LNBLNK(STRING)}
6383 @item @emph{Arguments}:
6384 @multitable @columnfractions .15 .70
6385 @item @var{STRING} @tab Shall be a scalar of type @code{CHARACTER(*)},
6386 with @code{INTENT(IN)}
6389 @item @emph{Return value}:
6390 The return value is of @code{INTEGER(kind=4)} type.
6392 @item @emph{See also}:
6393 @ref{INDEX}, @ref{LEN_TRIM}
6399 @section @code{LOC} --- Returns the address of a variable
6401 @cindex location of a variable in memory
6404 @item @emph{Description}:
6405 @code{LOC(X)} returns the address of @var{X} as an integer.
6407 @item @emph{Standard}:
6413 @item @emph{Syntax}:
6414 @code{RESULT = LOC(X)}
6416 @item @emph{Arguments}:
6417 @multitable @columnfractions .15 .70
6418 @item @var{X} @tab Variable of any type.
6421 @item @emph{Return value}:
6422 The return value is of type @code{INTEGER}, with a @code{KIND}
6423 corresponding to the size (in bytes) of a memory address on the target
6426 @item @emph{Example}:
6433 end program test_loc
6440 @section @code{LOG} --- Logarithm function
6447 @cindex exponential function, inverse
6448 @cindex logarithmic function
6451 @item @emph{Description}:
6452 @code{LOG(X)} computes the logarithm of @var{X}.
6454 @item @emph{Standard}:
6460 @item @emph{Syntax}:
6461 @code{RESULT = LOG(X)}
6463 @item @emph{Arguments}:
6464 @multitable @columnfractions .15 .70
6465 @item @var{X} @tab The type shall be @code{REAL(*)} or
6469 @item @emph{Return value}:
6470 The return value is of type @code{REAL(*)} or @code{COMPLEX(*)}.
6471 The kind type parameter is the same as @var{X}.
6473 @item @emph{Example}:
6476 real(8) :: x = 1.0_8
6477 complex :: z = (1.0, 2.0)
6480 end program test_log
6483 @item @emph{Specific names}:
6484 @multitable @columnfractions .20 .20 .20 .25
6485 @item Name @tab Argument @tab Return type @tab Standard
6486 @item @code{ALOG(X)} @tab @code{REAL(4) X} @tab @code{REAL(4)} @tab f95, gnu
6487 @item @code{DLOG(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab f95, gnu
6488 @item @code{CLOG(X)} @tab @code{COMPLEX(4) X} @tab @code{COMPLEX(4)} @tab f95, gnu
6489 @item @code{ZLOG(X)} @tab @code{COMPLEX(8) X} @tab @code{COMPLEX(8)} @tab f95, gnu
6490 @item @code{CDLOG(X)} @tab @code{COMPLEX(8) X} @tab @code{COMPLEX(8)} @tab f95, gnu
6497 @section @code{LOG10} --- Base 10 logarithm function
6501 @cindex exponential function, inverse
6502 @cindex logarithmic function
6505 @item @emph{Description}:
6506 @code{LOG10(X)} computes the base 10 logarithm of @var{X}.
6508 @item @emph{Standard}:
6514 @item @emph{Syntax}:
6515 @code{RESULT = LOG10(X)}
6517 @item @emph{Arguments}:
6518 @multitable @columnfractions .15 .70
6519 @item @var{X} @tab The type shall be @code{REAL(*)}.
6522 @item @emph{Return value}:
6523 The return value is of type @code{REAL(*)} or @code{COMPLEX(*)}.
6524 The kind type parameter is the same as @var{X}.
6526 @item @emph{Example}:
6529 real(8) :: x = 10.0_8
6531 end program test_log10
6534 @item @emph{Specific names}:
6535 @multitable @columnfractions .20 .20 .20 .25
6536 @item Name @tab Argument @tab Return type @tab Standard
6537 @item @code{ALOG10(X)} @tab @code{REAL(4) X} @tab @code{REAL(4)} @tab F95 and later
6538 @item @code{DLOG10(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F95 and later
6545 @section @code{LOGICAL} --- Convert to logical type
6547 @cindex conversion, to logical
6550 @item @emph{Description}:
6551 Converts one kind of @code{LOGICAL} variable to another.
6553 @item @emph{Standard}:
6559 @item @emph{Syntax}:
6560 @code{RESULT = LOGICAL(L [, KIND])}
6562 @item @emph{Arguments}:
6563 @multitable @columnfractions .15 .70
6564 @item @var{L} @tab The type shall be @code{LOGICAL(*)}.
6565 @item @var{KIND} @tab (Optional) An @code{INTEGER(*)} initialization
6566 expression indicating the kind parameter of
6570 @item @emph{Return value}:
6571 The return value is a @code{LOGICAL} value equal to @var{L}, with a
6572 kind corresponding to @var{KIND}, or of the default logical kind if
6573 @var{KIND} is not given.
6575 @item @emph{See also}:
6576 @ref{INT}, @ref{REAL}, @ref{CMPLX}
6582 @section @code{LONG} --- Convert to integer type
6584 @cindex conversion, to integer
6587 @item @emph{Description}:
6588 Convert to a @code{KIND=4} integer type, which is the same size as a C
6589 @code{long} integer. This is equivalent to the standard @code{INT}
6590 intrinsic with an optional argument of @code{KIND=4}, and is only
6591 included for backwards compatibility.
6593 @item @emph{Standard}:
6599 @item @emph{Syntax}:
6600 @code{RESULT = LONG(A)}
6602 @item @emph{Arguments}:
6603 @multitable @columnfractions .15 .70
6604 @item @var{A} @tab Shall be of type @code{INTEGER(*)},
6605 @code{REAL(*)}, or @code{COMPLEX(*)}.
6608 @item @emph{Return value}:
6609 The return value is a @code{INTEGER(4)} variable.
6611 @item @emph{See also}:
6612 @ref{INT}, @ref{INT2}, @ref{INT8}
6618 @section @code{LSHIFT} --- Left shift bits
6620 @cindex bits, shift left
6623 @item @emph{Description}:
6624 @code{LSHIFT} returns a value corresponding to @var{I} with all of the
6625 bits shifted left by @var{SHIFT} places. If the absolute value of
6626 @var{SHIFT} is greater than @code{BIT_SIZE(I)}, the value is undefined.
6627 Bits shifted out from the left end are lost; zeros are shifted in from
6630 This function has been superseded by the @code{ISHFT} intrinsic, which
6631 is standard in Fortran 95 and later.
6633 @item @emph{Standard}:
6639 @item @emph{Syntax}:
6640 @code{RESULT = LSHIFT(I, SHIFT)}
6642 @item @emph{Arguments}:
6643 @multitable @columnfractions .15 .70
6644 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
6645 @item @var{SHIFT} @tab The type shall be @code{INTEGER(*)}.
6648 @item @emph{Return value}:
6649 The return value is of type @code{INTEGER(*)} and of the same kind as
6652 @item @emph{See also}:
6653 @ref{ISHFT}, @ref{ISHFTC}, @ref{RSHIFT}
6660 @section @code{LSTAT} --- Get file status
6662 @cindex file system, file status
6665 @item @emph{Description}:
6666 @code{LSTAT} is identical to @ref{STAT}, except that if path is a symbolic link,
6667 then the link itself is statted, not the file that it refers to.
6669 The elements in @code{BUFF} are the same as described by @ref{STAT}.
6671 @item @emph{Standard}:
6675 Non-elemental subroutine
6677 @item @emph{Syntax}:
6678 @code{CALL LSTAT(FILE, BUFF [, STATUS])}
6680 @item @emph{Arguments}:
6681 @multitable @columnfractions .15 .70
6682 @item @var{FILE} @tab The type shall be @code{CHARACTER(*)}, a valid path within the file system.
6683 @item @var{BUFF} @tab The type shall be @code{INTEGER(4), DIMENSION(13)}.
6684 @item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER(4)}. Returns 0
6685 on success and a system specific error code otherwise.
6688 @item @emph{Example}:
6689 See @ref{STAT} for an example.
6691 @item @emph{See also}:
6692 To stat an open file: @ref{FSTAT}, to stat a file: @ref{STAT}
6698 @section @code{LTIME} --- Convert time to local time info
6700 @cindex time, conversion to local time info
6703 @item @emph{Description}:
6704 Given a system time value @var{STIME} (as provided by the @code{TIME8()}
6705 intrinsic), fills @var{TARRAY} with values extracted from it appropriate
6706 to the local time zone using @code{localtime(3)}.
6708 @item @emph{Standard}:
6714 @item @emph{Syntax}:
6715 @code{CALL LTIME(STIME, TARRAY)}
6717 @item @emph{Arguments}:
6718 @multitable @columnfractions .15 .70
6719 @item @var{STIME} @tab An @code{INTEGER(*)} scalar expression
6720 corresponding to a system time, with
6722 @item @var{TARRAY} @tab A default @code{INTEGER} array with 9 elements,
6723 with @code{INTENT(OUT)}.
6726 @item @emph{Return value}:
6727 The elements of @var{TARRAY} are assigned as follows:
6729 @item Seconds after the minute, range 0--59 or 0--61 to allow for leap
6731 @item Minutes after the hour, range 0--59
6732 @item Hours past midnight, range 0--23
6733 @item Day of month, range 0--31
6734 @item Number of months since January, range 0--12
6735 @item Years since 1900
6736 @item Number of days since Sunday, range 0--6
6737 @item Days since January 1
6738 @item Daylight savings indicator: positive if daylight savings is in
6739 effect, zero if not, and negative if the information is not
6743 @item @emph{See also}:
6744 @ref{CTIME}, @ref{GMTIME}, @ref{TIME}, @ref{TIME8}
6751 @section @code{MALLOC} --- Allocate dynamic memory
6753 @cindex pointer, cray
6756 @item @emph{Description}:
6757 @code{MALLOC(SIZE)} allocates @var{SIZE} bytes of dynamic memory and
6758 returns the address of the allocated memory. The @code{MALLOC} intrinsic
6759 is an extension intended to be used with Cray pointers, and is provided
6760 in GNU Fortran to allow the user to compile legacy code. For new code
6761 using Fortran 95 pointers, the memory allocation intrinsic is
6764 @item @emph{Standard}:
6768 Non-elemental function
6770 @item @emph{Syntax}:
6771 @code{PTR = MALLOC(SIZE)}
6773 @item @emph{Arguments}:
6774 @multitable @columnfractions .15 .70
6775 @item @var{SIZE} @tab The type shall be @code{INTEGER(*)}.
6778 @item @emph{Return value}:
6779 The return value is of type @code{INTEGER(K)}, with @var{K} such that
6780 variables of type @code{INTEGER(K)} have the same size as
6781 C pointers (@code{sizeof(void *)}).
6783 @item @emph{Example}:
6784 The following example demonstrates the use of @code{MALLOC} and
6785 @code{FREE} with Cray pointers. This example is intended to run on
6786 32-bit systems, where the default integer kind is suitable to store
6787 pointers; on 64-bit systems, ptr_x would need to be declared as
6788 @code{integer(kind=8)}.
6797 ptr_x = malloc(20*8)
6799 x(i) = sqrt(1.0d0 / i)
6807 end program test_malloc
6810 @item @emph{See also}:
6817 @section @code{MATMUL} --- matrix multiplication
6819 @cindex matrix multiplication
6820 @cindex product, matrix
6823 @item @emph{Description}:
6824 Performs a matrix multiplication on numeric or logical arguments.
6826 @item @emph{Standard}:
6830 Transformational function
6832 @item @emph{Syntax}:
6833 @code{RESULT = MATMUL(MATRIX_A, MATRIX_B)}
6835 @item @emph{Arguments}:
6836 @multitable @columnfractions .15 .70
6837 @item @var{MATRIX_A} @tab An array of @code{INTEGER(*)},
6838 @code{REAL(*)}, @code{COMPLEX(*)}, or
6839 @code{LOGICAL(*)} type, with a rank of
6841 @item @var{MATRIX_B} @tab An array of @code{INTEGER(*)},
6842 @code{REAL(*)}, or @code{COMPLEX(*)} type if
6843 @var{MATRIX_A} is of a numeric type;
6844 otherwise, an array of @code{LOGICAL(*)}
6845 type. The rank shall be one or two, and the
6846 first (or only) dimension of @var{MATRIX_B}
6847 shall be equal to the last (or only)
6848 dimension of @var{MATRIX_A}.
6851 @item @emph{Return value}:
6852 The matrix product of @var{MATRIX_A} and @var{MATRIX_B}. The type and
6853 kind of the result follow the usual type and kind promotion rules, as
6854 for the @code{*} or @code{.AND.} operators.
6856 @item @emph{See also}:
6862 @section @code{MAX} --- Maximum value of an argument list
6869 @cindex maximum value
6872 @item @emph{Description}:
6873 Returns the argument with the largest (most positive) value.
6875 @item @emph{Standard}:
6881 @item @emph{Syntax}:
6882 @code{RESULT = MAX(A1, A2 [, A3 [, ...]])}
6884 @item @emph{Arguments}:
6885 @multitable @columnfractions .15 .70
6886 @item @var{A1} @tab The type shall be @code{INTEGER(*)} or
6888 @item @var{A2}, @var{A3}, ... @tab An expression of the same type and kind
6889 as @var{A1}. (As a GNU extension,
6890 arguments of different kinds are
6894 @item @emph{Return value}:
6895 The return value corresponds to the maximum value among the arguments,
6896 and has the same type and kind as the first argument.
6898 @item @emph{Specific names}:
6899 @multitable @columnfractions .20 .20 .20 .25
6900 @item Name @tab Argument @tab Return type @tab Standard
6901 @item @code{MAX0(I)} @tab @code{INTEGER(4) I} @tab @code{INTEGER(4)} @tab F77 and later
6902 @item @code{AMAX0(I)} @tab @code{INTEGER(4) I} @tab @code{REAL(MAX(X))} @tab F77 and later
6903 @item @code{MAX1(X)} @tab @code{REAL(*) X} @tab @code{INT(MAX(X))} @tab F77 and later
6904 @item @code{AMAX1(X)} @tab @code{REAL(4) X} @tab @code{REAL(4)} @tab F77 and later
6905 @item @code{DMAX1(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
6908 @item @emph{See also}:
6909 @ref{MAXLOC} @ref{MAXVAL}, @ref{MIN}
6916 @section @code{MAXEXPONENT} --- Maximum exponent of a real kind
6917 @fnindex MAXEXPONENT
6918 @cindex model representation, maximum exponent
6921 @item @emph{Description}:
6922 @code{MAXEXPONENT(X)} returns the maximum exponent in the model of the
6925 @item @emph{Standard}:
6931 @item @emph{Syntax}:
6932 @code{RESULT = MAXEXPONENT(X)}
6934 @item @emph{Arguments}:
6935 @multitable @columnfractions .15 .70
6936 @item @var{X} @tab Shall be of type @code{REAL}.
6939 @item @emph{Return value}:
6940 The return value is of type @code{INTEGER} and of the default integer
6943 @item @emph{Example}:
6949 print *, minexponent(x), maxexponent(x)
6950 print *, minexponent(y), maxexponent(y)
6951 end program exponents
6958 @section @code{MAXLOC} --- Location of the maximum value within an array
6960 @cindex array, location of maximum element
6963 @item @emph{Description}:
6964 Determines the location of the element in the array with the maximum
6965 value, or, if the @var{DIM} argument is supplied, determines the
6966 locations of the maximum element along each row of the array in the
6967 @var{DIM} direction. If @var{MASK} is present, only the elements for
6968 which @var{MASK} is @code{.TRUE.} are considered. If more than one
6969 element in the array has the maximum value, the location returned is
6970 that of the first such element in array element order. If the array has
6971 zero size, or all of the elements of @var{MASK} are @code{.FALSE.}, then
6972 the result is an array of zeroes. Similarly, if @var{DIM} is supplied
6973 and all of the elements of @var{MASK} along a given row are zero, the
6974 result value for that row is zero.
6976 @item @emph{Standard}:
6980 Transformational function
6982 @item @emph{Syntax}:
6983 @multitable @columnfractions .80
6984 @item @code{RESULT = MAXLOC(ARRAY, DIM [, MASK])}
6985 @item @code{RESULT = MAXLOC(ARRAY [, MASK])}
6988 @item @emph{Arguments}:
6989 @multitable @columnfractions .15 .70
6990 @item @var{ARRAY} @tab Shall be an array of type @code{INTEGER(*)},
6991 @code{REAL(*)}, or @code{CHARACTER(*)}.
6992 @item @var{DIM} @tab (Optional) Shall be a scalar of type
6993 @code{INTEGER(*)}, with a value between one
6994 and the rank of @var{ARRAY}, inclusive. It
6995 may not be an optional dummy argument.
6996 @item @var{MASK} @tab Shall be an array of type @code{LOGICAL(*)},
6997 and conformable with @var{ARRAY}.
7000 @item @emph{Return value}:
7001 If @var{DIM} is absent, the result is a rank-one array with a length
7002 equal to the rank of @var{ARRAY}. If @var{DIM} is present, the result
7003 is an array with a rank one less than the rank of @var{ARRAY}, and a
7004 size corresponding to the size of @var{ARRAY} with the @var{DIM}
7005 dimension removed. If @var{DIM} is present and @var{ARRAY} has a rank
7006 of one, the result is a scalar. In all cases, the result is of default
7007 @code{INTEGER} type.
7009 @item @emph{See also}:
7010 @ref{MAX}, @ref{MAXVAL}
7017 @section @code{MAXVAL} --- Maximum value of an array
7019 @cindex array, maximum value
7020 @cindex maximum value
7023 @item @emph{Description}:
7024 Determines the maximum value of the elements in an array value, or, if
7025 the @var{DIM} argument is supplied, determines the maximum value along
7026 each row of the array in the @var{DIM} direction. If @var{MASK} is
7027 present, only the elements for which @var{MASK} is @code{.TRUE.} are
7028 considered. If the array has zero size, or all of the elements of
7029 @var{MASK} are @code{.FALSE.}, then the result is the most negative
7030 number of the type and kind of @var{ARRAY} if @var{ARRAY} is numeric, or
7031 a string of nulls if @var{ARRAY} is of character type.
7033 @item @emph{Standard}:
7037 Transformational function
7039 @item @emph{Syntax}:
7040 @multitable @columnfractions .80
7041 @item @code{RESULT = MAXVAL(ARRAY, DIM [, MASK])}
7042 @item @code{RESULT = MAXVAL(ARRAY [, MASK])}
7045 @item @emph{Arguments}:
7046 @multitable @columnfractions .15 .70
7047 @item @var{ARRAY} @tab Shall be an array of type @code{INTEGER(*)},
7048 @code{REAL(*)}, or @code{CHARACTER(*)}.
7049 @item @var{DIM} @tab (Optional) Shall be a scalar of type
7050 @code{INTEGER(*)}, with a value between one
7051 and the rank of @var{ARRAY}, inclusive. It
7052 may not be an optional dummy argument.
7053 @item @var{MASK} @tab Shall be an array of type @code{LOGICAL(*)},
7054 and conformable with @var{ARRAY}.
7057 @item @emph{Return value}:
7058 If @var{DIM} is absent, or if @var{ARRAY} has a rank of one, the result
7059 is a scalar. If @var{DIM} is present, the result is an array with a
7060 rank one less than the rank of @var{ARRAY}, and a size corresponding to
7061 the size of @var{ARRAY} with the @var{DIM} dimension removed. In all
7062 cases, the result is of the same type and kind as @var{ARRAY}.
7064 @item @emph{See also}:
7065 @ref{MAX}, @ref{MAXLOC}
7071 @section @code{MCLOCK} --- Time function
7073 @cindex time, clock ticks
7077 @item @emph{Description}:
7078 Returns the number of clock ticks since the start of the process, based
7079 on the UNIX function @code{clock(3)}.
7081 This intrinsic is not fully portable, such as to systems with 32-bit
7082 @code{INTEGER} types but supporting times wider than 32 bits. Therefore,
7083 the values returned by this intrinsic might be, or become, negative, or
7084 numerically less than previous values, during a single run of the
7087 @item @emph{Standard}:
7091 Non-elemental function
7093 @item @emph{Syntax}:
7094 @code{RESULT = MCLOCK()}
7096 @item @emph{Return value}:
7097 The return value is a scalar of type @code{INTEGER(4)}, equal to the
7098 number of clock ticks since the start of the process, or @code{-1} if
7099 the system does not support @code{clock(3)}.
7101 @item @emph{See also}:
7102 @ref{CTIME}, @ref{GMTIME}, @ref{LTIME}, @ref{MCLOCK}, @ref{TIME}
7109 @section @code{MCLOCK8} --- Time function (64-bit)
7111 @cindex time, clock ticks
7115 @item @emph{Description}:
7116 Returns the number of clock ticks since the start of the process, based
7117 on the UNIX function @code{clock(3)}.
7119 @emph{Warning:} this intrinsic does not increase the range of the timing
7120 values over that returned by @code{clock(3)}. On a system with a 32-bit
7121 @code{clock(3)}, @code{MCLOCK8()} will return a 32-bit value, even though
7122 it is converted to a 64-bit @code{INTEGER(8)} value. That means
7123 overflows of the 32-bit value can still occur. Therefore, the values
7124 returned by this intrinsic might be or become negative or numerically
7125 less than previous values during a single run of the compiled program.
7127 @item @emph{Standard}:
7131 Non-elemental function
7133 @item @emph{Syntax}:
7134 @code{RESULT = MCLOCK8()}
7136 @item @emph{Return value}:
7137 The return value is a scalar of type @code{INTEGER(8)}, equal to the
7138 number of clock ticks since the start of the process, or @code{-1} if
7139 the system does not support @code{clock(3)}.
7141 @item @emph{See also}:
7142 @ref{CTIME}, @ref{GMTIME}, @ref{LTIME}, @ref{MCLOCK}, @ref{TIME8}
7149 @section @code{MERGE} --- Merge variables
7151 @cindex array, merge arrays
7152 @cindex array, combine arrays
7155 @item @emph{Description}:
7156 Select values from two arrays according to a logical mask. The result
7157 is equal to @var{TSOURCE} if @var{MASK} is @code{.TRUE.}, or equal to
7158 @var{FSOURCE} if it is @code{.FALSE.}.
7160 @item @emph{Standard}:
7166 @item @emph{Syntax}:
7167 @code{RESULT = MERGE(TSOURCE, FSOURCE, MASK)}
7169 @item @emph{Arguments}:
7170 @multitable @columnfractions .15 .70
7171 @item @var{TSOURCE} @tab May be of any type.
7172 @item @var{FSOURCE} @tab Shall be of the same type and type parameters
7174 @item @var{MASK} @tab Shall be of type @code{LOGICAL(*)}.
7177 @item @emph{Return value}:
7178 The result is of the same type and type parameters as @var{TSOURCE}.
7185 @section @code{MIN} --- Minimum value of an argument list
7192 @cindex minimum value
7195 @item @emph{Description}:
7196 Returns the argument with the smallest (most negative) value.
7198 @item @emph{Standard}:
7204 @item @emph{Syntax}:
7205 @code{RESULT = MIN(A1, A2 [, A3, ...])}
7207 @item @emph{Arguments}:
7208 @multitable @columnfractions .15 .70
7209 @item @var{A1} @tab The type shall be @code{INTEGER(*)} or
7211 @item @var{A2}, @var{A3}, ... @tab An expression of the same type and kind
7212 as @var{A1}. (As a GNU extension,
7213 arguments of different kinds are
7217 @item @emph{Return value}:
7218 The return value corresponds to the maximum value among the arguments,
7219 and has the same type and kind as the first argument.
7221 @item @emph{Specific names}:
7222 @multitable @columnfractions .20 .20 .20 .25
7223 @item Name @tab Argument @tab Return type @tab Standard
7224 @item @code{MIN0(I)} @tab @code{INTEGER(4) I} @tab @code{INTEGER(4)} @tab F77 and later
7225 @item @code{AMIN0(I)} @tab @code{INTEGER(4) I} @tab @code{REAL(MIN(X))} @tab F77 and later
7226 @item @code{MIN1(X)} @tab @code{REAL(*) X} @tab @code{INT(MIN(X))} @tab F77 and later
7227 @item @code{AMIN1(X)} @tab @code{REAL(4) X} @tab @code{REAL(4)} @tab F77 and later
7228 @item @code{DMIN1(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
7231 @item @emph{See also}:
7232 @ref{MAX}, @ref{MINLOC}, @ref{MINVAL}
7238 @section @code{MINEXPONENT} --- Minimum exponent of a real kind
7239 @fnindex MINEXPONENT
7240 @cindex model representation, minimum exponent
7243 @item @emph{Description}:
7244 @code{MINEXPONENT(X)} returns the minimum exponent in the model of the
7247 @item @emph{Standard}:
7253 @item @emph{Syntax}:
7254 @code{RESULT = MINEXPONENT(X)}
7256 @item @emph{Arguments}:
7257 @multitable @columnfractions .15 .70
7258 @item @var{X} @tab Shall be of type @code{REAL}.
7261 @item @emph{Return value}:
7262 The return value is of type @code{INTEGER} and of the default integer
7265 @item @emph{Example}:
7266 See @code{MAXEXPONENT} for an example.
7272 @section @code{MINLOC} --- Location of the minimum value within an array
7274 @cindex array, location of minimum element
7277 @item @emph{Description}:
7278 Determines the location of the element in the array with the minimum
7279 value, or, if the @var{DIM} argument is supplied, determines the
7280 locations of the minimum element along each row of the array in the
7281 @var{DIM} direction. If @var{MASK} is present, only the elements for
7282 which @var{MASK} is @code{.TRUE.} are considered. If more than one
7283 element in the array has the minimum value, the location returned is
7284 that of the first such element in array element order. If the array has
7285 zero size, or all of the elements of @var{MASK} are @code{.FALSE.}, then
7286 the result is an array of zeroes. Similarly, if @var{DIM} is supplied
7287 and all of the elements of @var{MASK} along a given row are zero, the
7288 result value for that row is zero.
7290 @item @emph{Standard}:
7294 Transformational function
7296 @item @emph{Syntax}:
7297 @multitable @columnfractions .80
7298 @item @code{RESULT = MINLOC(ARRAY, DIM [, MASK])}
7299 @item @code{RESULT = MINLOC(ARRAY [, MASK])}
7302 @item @emph{Arguments}:
7303 @multitable @columnfractions .15 .70
7304 @item @var{ARRAY} @tab Shall be an array of type @code{INTEGER(*)},
7305 @code{REAL(*)}, or @code{CHARACTER(*)}.
7306 @item @var{DIM} @tab (Optional) Shall be a scalar of type
7307 @code{INTEGER(*)}, with a value between one
7308 and the rank of @var{ARRAY}, inclusive. It
7309 may not be an optional dummy argument.
7310 @item @var{MASK} @tab Shall be an array of type @code{LOGICAL(*)},
7311 and conformable with @var{ARRAY}.
7314 @item @emph{Return value}:
7315 If @var{DIM} is absent, the result is a rank-one array with a length
7316 equal to the rank of @var{ARRAY}. If @var{DIM} is present, the result
7317 is an array with a rank one less than the rank of @var{ARRAY}, and a
7318 size corresponding to the size of @var{ARRAY} with the @var{DIM}
7319 dimension removed. If @var{DIM} is present and @var{ARRAY} has a rank
7320 of one, the result is a scalar. In all cases, the result is of default
7321 @code{INTEGER} type.
7323 @item @emph{See also}:
7324 @ref{MIN}, @ref{MINVAL}
7331 @section @code{MINVAL} --- Minimum value of an array
7333 @cindex array, minimum value
7334 @cindex minimum value
7337 @item @emph{Description}:
7338 Determines the minimum value of the elements in an array value, or, if
7339 the @var{DIM} argument is supplied, determines the minimum value along
7340 each row of the array in the @var{DIM} direction. If @var{MASK} is
7341 present, only the elements for which @var{MASK} is @code{.TRUE.} are
7342 considered. If the array has zero size, or all of the elements of
7343 @var{MASK} are @code{.FALSE.}, then the result is @code{HUGE(ARRAY)} if
7344 @var{ARRAY} is numeric, or a string of @code{CHAR(255)} characters if
7345 @var{ARRAY} is of character type.
7347 @item @emph{Standard}:
7351 Transformational function
7353 @item @emph{Syntax}:
7354 @multitable @columnfractions .80
7355 @item @code{RESULT = MINVAL(ARRAY, DIM [, MASK])}
7356 @item @code{RESULT = MINVAL(ARRAY [, MASK])}
7359 @item @emph{Arguments}:
7360 @multitable @columnfractions .15 .70
7361 @item @var{ARRAY} @tab Shall be an array of type @code{INTEGER(*)},
7362 @code{REAL(*)}, or @code{CHARACTER(*)}.
7363 @item @var{DIM} @tab (Optional) Shall be a scalar of type
7364 @code{INTEGER(*)}, with a value between one
7365 and the rank of @var{ARRAY}, inclusive. It
7366 may not be an optional dummy argument.
7367 @item @var{MASK} @tab Shall be an array of type @code{LOGICAL(*)},
7368 and conformable with @var{ARRAY}.
7371 @item @emph{Return value}:
7372 If @var{DIM} is absent, or if @var{ARRAY} has a rank of one, the result
7373 is a scalar. If @var{DIM} is present, the result is an array with a
7374 rank one less than the rank of @var{ARRAY}, and a size corresponding to
7375 the size of @var{ARRAY} with the @var{DIM} dimension removed. In all
7376 cases, the result is of the same type and kind as @var{ARRAY}.
7378 @item @emph{See also}:
7379 @ref{MIN}, @ref{MINLOC}
7386 @section @code{MOD} --- Remainder function
7391 @cindex division, remainder
7394 @item @emph{Description}:
7395 @code{MOD(A,P)} computes the remainder of the division of A by P. It is
7396 calculated as @code{A - (INT(A/P) * P)}.
7398 @item @emph{Standard}:
7404 @item @emph{Syntax}:
7405 @code{RESULT = MOD(A, P)}
7407 @item @emph{Arguments}:
7408 @multitable @columnfractions .15 .70
7409 @item @var{A} @tab Shall be a scalar of type @code{INTEGER} or @code{REAL}
7410 @item @var{P} @tab Shall be a scalar of the same type as @var{A} and not
7414 @item @emph{Return value}:
7415 The kind of the return value is the result of cross-promoting
7416 the kinds of the arguments.
7418 @item @emph{Example}:
7422 print *, mod(17.5,5.5)
7423 print *, mod(17.5d0,5.5)
7424 print *, mod(17.5,5.5d0)
7427 print *, mod(-17.5,5.5)
7428 print *, mod(-17.5d0,5.5)
7429 print *, mod(-17.5,5.5d0)
7432 print *, mod(17.5,-5.5)
7433 print *, mod(17.5d0,-5.5)
7434 print *, mod(17.5,-5.5d0)
7435 end program test_mod
7438 @item @emph{Specific names}:
7439 @multitable @columnfractions .20 .20 .20 .25
7440 @item Name @tab Arguments @tab Return type @tab Standard
7441 @item @code{AMOD(A,P)} @tab @code{REAL(4)} @tab @code{REAL(4)} @tab F95 and later
7442 @item @code{DMOD(A,P)} @tab @code{REAL(8)} @tab @code{REAL(8)} @tab F95 and later
7449 @section @code{MODULO} --- Modulo function
7452 @cindex division, modulo
7455 @item @emph{Description}:
7456 @code{MODULO(A,P)} computes the @var{A} modulo @var{P}.
7458 @item @emph{Standard}:
7464 @item @emph{Syntax}:
7465 @code{RESULT = MODULO(A, P)}
7467 @item @emph{Arguments}:
7468 @multitable @columnfractions .15 .70
7469 @item @var{A} @tab Shall be a scalar of type @code{INTEGER} or @code{REAL}
7470 @item @var{P} @tab Shall be a scalar of the same type and kind as @var{A}
7473 @item @emph{Return value}:
7474 The type and kind of the result are those of the arguments.
7476 @item If @var{A} and @var{P} are of type @code{INTEGER}:
7477 @code{MODULO(A,P)} has the value @var{R} such that @code{A=Q*P+R}, where
7478 @var{Q} is an integer and @var{R} is between 0 (inclusive) and @var{P}
7480 @item If @var{A} and @var{P} are of type @code{REAL}:
7481 @code{MODULO(A,P)} has the value of @code{A - FLOOR (A / P) * P}.
7483 In all cases, if @var{P} is zero the result is processor-dependent.
7485 @item @emph{Example}:
7488 print *, modulo(17,3)
7489 print *, modulo(17.5,5.5)
7491 print *, modulo(-17,3)
7492 print *, modulo(-17.5,5.5)
7494 print *, modulo(17,-3)
7495 print *, modulo(17.5,-5.5)
7504 @section @code{MOVE_ALLOC} --- Move allocation from one object to another
7506 @cindex moving allocation
7507 @cindex allocation, moving
7510 @item @emph{Description}:
7511 @code{MOVE_ALLOC(SRC, DEST)} moves the allocation from @var{SRC} to
7512 @var{DEST}. @var{SRC} will become deallocated in the process.
7514 @item @emph{Standard}:
7520 @item @emph{Syntax}:
7521 @code{CALL MOVE_ALLOC(SRC, DEST)}
7523 @item @emph{Arguments}:
7524 @multitable @columnfractions .15 .70
7525 @item @var{SRC} @tab @code{ALLOCATABLE}, @code{INTENT(INOUT)}, may be
7526 of any type and kind.
7527 @item @var{DEST} @tab @code{ALLOCATABLE}, @code{INTENT(OUT)}, shall be
7528 of the same type, kind and rank as @var{SRC}
7531 @item @emph{Return value}:
7534 @item @emph{Example}:
7536 program test_move_alloc
7537 integer, allocatable :: a(:), b(:)
7541 call move_alloc(a, b)
7542 print *, allocated(a), allocated(b)
7544 end program test_move_alloc
7551 @section @code{MVBITS} --- Move bits from one integer to another
7556 @item @emph{Description}:
7557 Moves @var{LEN} bits from positions @var{FROMPOS} through
7558 @code{FROMPOS+LEN-1} of @var{FROM} to positions @var{TOPOS} through
7559 @code{TOPOS+LEN-1} of @var{TO}. The portion of argument @var{TO} not
7560 affected by the movement of bits is unchanged. The values of
7561 @code{FROMPOS+LEN-1} and @code{TOPOS+LEN-1} must be less than
7562 @code{BIT_SIZE(FROM)}.
7564 @item @emph{Standard}:
7568 Elemental subroutine
7570 @item @emph{Syntax}:
7571 @code{CALL MVBITS(FROM, FROMPOS, LEN, TO, TOPOS)}
7573 @item @emph{Arguments}:
7574 @multitable @columnfractions .15 .70
7575 @item @var{FROM} @tab The type shall be @code{INTEGER(*)}.
7576 @item @var{FROMPOS} @tab The type shall be @code{INTEGER(*)}.
7577 @item @var{LEN} @tab The type shall be @code{INTEGER(*)}.
7578 @item @var{TO} @tab The type shall be @code{INTEGER(*)}, of the
7579 same kind as @var{FROM}.
7580 @item @var{TOPOS} @tab The type shall be @code{INTEGER(*)}.
7583 @item @emph{See also}:
7584 @ref{IBCLR}, @ref{IBSET}, @ref{IBITS}, @ref{IAND}, @ref{IOR}, @ref{IEOR}
7590 @section @code{NEAREST} --- Nearest representable number
7592 @cindex real number, nearest different
7593 @cindex floating point, nearest different
7596 @item @emph{Description}:
7597 @code{NEAREST(X, S)} returns the processor-representable number nearest
7598 to @code{X} in the direction indicated by the sign of @code{S}.
7600 @item @emph{Standard}:
7606 @item @emph{Syntax}:
7607 @code{RESULT = NEAREST(X, S)}
7609 @item @emph{Arguments}:
7610 @multitable @columnfractions .15 .70
7611 @item @var{X} @tab Shall be of type @code{REAL}.
7612 @item @var{S} @tab (Optional) shall be of type @code{REAL} and
7616 @item @emph{Return value}:
7617 The return value is of the same type as @code{X}. If @code{S} is
7618 positive, @code{NEAREST} returns the processor-representable number
7619 greater than @code{X} and nearest to it. If @code{S} is negative,
7620 @code{NEAREST} returns the processor-representable number smaller than
7621 @code{X} and nearest to it.
7623 @item @emph{Example}:
7625 program test_nearest
7627 x = nearest(42.0, 1.0)
7628 y = nearest(42.0, -1.0)
7629 write (*,"(3(G20.15))") x, y, x - y
7630 end program test_nearest
7637 @section @code{NEW_LINE} --- New line character
7640 @cindex output, newline
7643 @item @emph{Description}:
7644 @code{NEW_LINE(C)} returns the new-line character.
7646 @item @emph{Standard}:
7652 @item @emph{Syntax}:
7653 @code{RESULT = NEW_LINE(C)}
7655 @item @emph{Arguments}:
7656 @multitable @columnfractions .15 .70
7657 @item @var{C} @tab The argument shall be a scalar or array of the
7658 type @code{CHARACTER}.
7661 @item @emph{Return value}:
7662 Returns a @var{CHARACTER} scalar of length one with the new-line character of
7663 the same kind as parameter @var{C}.
7665 @item @emph{Example}:
7669 write(*,'(A)') 'This is record 1.'//NEW_LINE('A')//'This is record 2.'
7677 @section @code{NINT} --- Nearest whole number
7680 @cindex rounding, nearest whole number
7683 @item @emph{Description}:
7684 @code{NINT(X)} rounds its argument to the nearest whole number.
7686 @item @emph{Standard}:
7692 @item @emph{Syntax}:
7693 @code{RESULT = NINT(X)}
7695 @item @emph{Arguments}:
7696 @multitable @columnfractions .15 .70
7697 @item @var{X} @tab The type of the argument shall be @code{REAL}.
7700 @item @emph{Return value}:
7701 Returns @var{A} with the fractional portion of its magnitude eliminated by
7702 rounding to the nearest whole number and with its sign preserved,
7703 converted to an @code{INTEGER} of the default kind.
7705 @item @emph{Example}:
7712 print *, nint(x4), idnint(x8)
7713 end program test_nint
7716 @item @emph{Specific names}:
7717 @multitable @columnfractions .25 .25 .25
7718 @item Name @tab Argument @tab Standard
7719 @item @code{IDNINT(X)} @tab @code{REAL(8)} @tab F95 and later
7722 @item @emph{See also}:
7723 @ref{CEILING}, @ref{FLOOR}
7730 @section @code{NOT} --- Logical negation
7732 @cindex bits, negate
7733 @cindex bitwise logical not
7734 @cindex logical not, bitwise
7737 @item @emph{Description}:
7738 @code{NOT} returns the bitwise boolean inverse of @var{I}.
7740 @item @emph{Standard}:
7746 @item @emph{Syntax}:
7747 @code{RESULT = NOT(I)}
7749 @item @emph{Arguments}:
7750 @multitable @columnfractions .15 .70
7751 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
7754 @item @emph{Return value}:
7755 The return type is @code{INTEGER(*)}, of the same kind as the
7758 @item @emph{See also}:
7759 @ref{IAND}, @ref{IEOR}, @ref{IOR}, @ref{IBITS}, @ref{IBSET}, @ref{IBCLR}
7766 @section @code{NULL} --- Function that returns an disassociated pointer
7768 @cindex pointer, status
7769 @cindex pointer, disassociated
7772 @item @emph{Description}:
7773 Returns a disassociated pointer.
7775 If @var{MOLD} is present, a dissassociated pointer of the same type is
7776 returned, otherwise the type is determined by context.
7778 In Fortran 95, @var{MOLD} is optional. Please note that F2003 includes
7779 cases where it is required.
7781 @item @emph{Standard}:
7785 Transformational function
7787 @item @emph{Syntax}:
7788 @code{PTR => NULL([MOLD])}
7790 @item @emph{Arguments}:
7791 @multitable @columnfractions .15 .70
7792 @item @var{MOLD} @tab (Optional) shall be a pointer of any association
7793 status and of any type.
7796 @item @emph{Return value}:
7797 A disassociated pointer.
7799 @item @emph{Example}:
7801 REAL, POINTER, DIMENSION(:) :: VEC => NULL ()
7804 @item @emph{See also}:
7811 @section @code{OR} --- Bitwise logical OR
7813 @cindex bitwise logical or
7814 @cindex logical or, bitwise
7817 @item @emph{Description}:
7818 Bitwise logical @code{OR}.
7820 This intrinsic routine is provided for backwards compatibility with
7821 GNU Fortran 77. For integer arguments, programmers should consider
7822 the use of the @ref{IOR} intrinsic defined by the Fortran standard.
7824 @item @emph{Standard}:
7828 Non-elemental function
7830 @item @emph{Syntax}:
7831 @code{RESULT = OR(X, Y)}
7833 @item @emph{Arguments}:
7834 @multitable @columnfractions .15 .70
7835 @item @var{X} @tab The type shall be either @code{INTEGER(*)} or @code{LOGICAL}.
7836 @item @var{Y} @tab The type shall be either @code{INTEGER(*)} or @code{LOGICAL}.
7839 @item @emph{Return value}:
7840 The return type is either @code{INTEGER(*)} or @code{LOGICAL}
7841 after cross-promotion of the arguments.
7843 @item @emph{Example}:
7846 LOGICAL :: T = .TRUE., F = .FALSE.
7848 DATA a / Z'F' /, b / Z'3' /
7850 WRITE (*,*) OR(T, T), OR(T, F), OR(F, T), OR(F, F)
7851 WRITE (*,*) OR(a, b)
7855 @item @emph{See also}:
7856 F95 elemental function: @ref{IOR}
7862 @section @code{PACK} --- Pack an array into an array of rank one
7864 @cindex array, packing
7865 @cindex array, reduce dimension
7866 @cindex array, gather elements
7869 @item @emph{Description}:
7870 Stores the elements of @var{ARRAY} in an array of rank one.
7872 The beginning of the resulting array is made up of elements whose @var{MASK}
7873 equals @code{TRUE}. Afterwards, positions are filled with elements taken from
7876 @item @emph{Standard}:
7880 Transformational function
7882 @item @emph{Syntax}:
7883 @code{RESULT = PACK(ARRAY, MASK[,VECTOR]}
7885 @item @emph{Arguments}:
7886 @multitable @columnfractions .15 .70
7887 @item @var{ARRAY} @tab Shall be an array of any type.
7888 @item @var{MASK} @tab Shall be an array of type @code{LOGICAL} and
7889 of the same size as @var{ARRAY}. Alternatively, it may be a @code{LOGICAL}
7891 @item @var{VECTOR} @tab (Optional) shall be an array of the same type
7892 as @var{ARRAY} and of rank one. If present, the number of elements in
7893 @var{VECTOR} shall be equal to or greater than the number of true elements
7894 in @var{MASK}. If @var{MASK} is scalar, the number of elements in
7895 @var{VECTOR} shall be equal to or greater than the number of elements in
7899 @item @emph{Return value}:
7900 The result is an array of rank one and the same type as that of @var{ARRAY}.
7901 If @var{VECTOR} is present, the result size is that of @var{VECTOR}, the
7902 number of @code{TRUE} values in @var{MASK} otherwise.
7904 @item @emph{Example}:
7905 Gathering non-zero elements from an array:
7909 m = (/ 1, 0, 0, 0, 5, 0 /)
7910 WRITE(*, FMT="(6(I0, ' '))") pack(m, m /= 0) ! "1 5"
7914 Gathering non-zero elements from an array and appending elements from @var{VECTOR}:
7918 m = (/ 1, 0, 0, 2 /)
7919 WRITE(*, FMT="(4(I0, ' '))") pack(m, m /= 0, (/ 0, 0, 3, 4 /)) ! "1 2 3 4"
7923 @item @emph{See also}:
7930 @section @code{PERROR} --- Print system error message
7932 @cindex system, error handling
7935 @item @emph{Description}:
7936 Prints (on the C @code{stderr} stream) a newline-terminated error
7937 message corresponding to the last system error. This is prefixed by
7938 @var{STRING}, a colon and a space. See @code{perror(3)}.
7940 @item @emph{Standard}:
7946 @item @emph{Syntax}:
7947 @code{CALL PERROR(STRING)}
7949 @item @emph{Arguments}:
7950 @multitable @columnfractions .15 .70
7951 @item @var{STRING} @tab A scalar of default @code{CHARACTER} type.
7954 @item @emph{See also}:
7961 @section @code{PRECISION} --- Decimal precision of a real kind
7963 @cindex model representation, precision
7966 @item @emph{Description}:
7967 @code{PRECISION(X)} returns the decimal precision in the model of the
7970 @item @emph{Standard}:
7976 @item @emph{Syntax}:
7977 @code{RESULT = PRECISION(X)}
7979 @item @emph{Arguments}:
7980 @multitable @columnfractions .15 .70
7981 @item @var{X} @tab Shall be of type @code{REAL} or @code{COMPLEX}.
7984 @item @emph{Return value}:
7985 The return value is of type @code{INTEGER} and of the default integer
7988 @item @emph{Example}:
7990 program prec_and_range
7991 real(kind=4) :: x(2)
7992 complex(kind=8) :: y
7994 print *, precision(x), range(x)
7995 print *, precision(y), range(y)
7996 end program prec_and_range
8003 @section @code{PRESENT} --- Determine whether an optional dummy argument is specified
8007 @item @emph{Description}:
8008 Determines whether an optional dummy argument is present.
8010 @item @emph{Standard}:
8016 @item @emph{Syntax}:
8017 @code{RESULT = PRESENT(A)}
8019 @item @emph{Arguments}:
8020 @multitable @columnfractions .15 .70
8021 @item @var{A} @tab May be of any type and may be a pointer, scalar or array
8022 value, or a dummy procedure. It shall be the name of an optional dummy argument
8023 accessible within the current subroutine or function.
8026 @item @emph{Return value}:
8027 Returns either @code{TRUE} if the optional argument @var{A} is present, or
8028 @code{FALSE} otherwise.
8030 @item @emph{Example}:
8032 PROGRAM test_present
8033 WRITE(*,*) f(), f(42) ! "F T"
8035 LOGICAL FUNCTION f(x)
8036 INTEGER, INTENT(IN), OPTIONAL :: x
8046 @section @code{PRODUCT} --- Product of array elements
8048 @cindex array, product
8049 @cindex array, multiply elements
8050 @cindex array, conditionally multiply elements
8051 @cindex multiply array elements
8054 @item @emph{Description}:
8055 Multiplies the elements of @var{ARRAY} along dimension @var{DIM} if
8056 the corresponding element in @var{MASK} is @code{TRUE}.
8058 @item @emph{Standard}:
8062 Transformational function
8064 @item @emph{Syntax}:
8065 @code{RESULT = PRODUCT(ARRAY[, MASK])}
8066 @code{RESULT = PRODUCT(ARRAY, DIM[, MASK])}
8068 @item @emph{Arguments}:
8069 @multitable @columnfractions .15 .70
8070 @item @var{ARRAY} @tab Shall be an array of type @code{INTEGER(*)},
8071 @code{REAL(*)} or @code{COMPLEX(*)}.
8072 @item @var{DIM} @tab (Optional) shall be a scalar of type
8073 @code{INTEGER} with a value in the range from 1 to n, where n
8074 equals the rank of @var{ARRAY}.
8075 @item @var{MASK} @tab (Optional) shall be of type @code{LOGICAL}
8076 and either be a scalar or an array of the same shape as @var{ARRAY}.
8079 @item @emph{Return value}:
8080 The result is of the same type as @var{ARRAY}.
8082 If @var{DIM} is absent, a scalar with the product of all elements in
8083 @var{ARRAY} is returned. Otherwise, an array of rank n-1, where n equals
8084 the rank of @var{ARRAY}, and a shape similar to that of @var{ARRAY} with
8085 dimension @var{DIM} dropped is returned.
8088 @item @emph{Example}:
8090 PROGRAM test_product
8091 INTEGER :: x(5) = (/ 1, 2, 3, 4 ,5 /)
8092 print *, PRODUCT(x) ! all elements, product = 120
8093 print *, PRODUCT(x, MASK=MOD(x, 2)==1) ! odd elements, product = 15
8097 @item @emph{See also}:
8104 @section @code{RADIX} --- Base of a model number
8106 @cindex model representation, base
8107 @cindex model representation, radix
8110 @item @emph{Description}:
8111 @code{RADIX(X)} returns the base of the model representing the entity @var{X}.
8113 @item @emph{Standard}:
8119 @item @emph{Syntax}:
8120 @code{RESULT = RADIX(X)}
8122 @item @emph{Arguments}:
8123 @multitable @columnfractions .15 .70
8124 @item @var{X} @tab Shall be of type @code{INTEGER} or @code{REAL}
8127 @item @emph{Return value}:
8128 The return value is a scalar of type @code{INTEGER} and of the default
8131 @item @emph{Example}:
8134 print *, "The radix for the default integer kind is", radix(0)
8135 print *, "The radix for the default real kind is", radix(0.0)
8136 end program test_radix
8144 @section @code{RAN} --- Real pseudo-random number
8146 @cindex random number generation
8149 @item @emph{Description}:
8150 For compatibility with HP FORTRAN 77/iX, the @code{RAN} intrinsic is
8151 provided as an alias for @code{RAND}. See @ref{RAND} for complete
8154 @item @emph{Standard}:
8158 Non-elemental function
8160 @item @emph{See also}:
8161 @ref{RAND}, @ref{RANDOM_NUMBER}
8167 @section @code{RAND} --- Real pseudo-random number
8169 @cindex random number generation
8172 @item @emph{Description}:
8173 @code{RAND(FLAG)} returns a pseudo-random number from a uniform
8174 distribution between 0 and 1. If @var{FLAG} is 0, the next number
8175 in the current sequence is returned; if @var{FLAG} is 1, the generator
8176 is restarted by @code{CALL SRAND(0)}; if @var{FLAG} has any other value,
8177 it is used as a new seed with @code{SRAND}.
8179 @item @emph{Standard}:
8183 Non-elemental function
8185 @item @emph{Syntax}:
8186 @code{RESULT = RAND(FLAG)}
8188 @item @emph{Arguments}:
8189 @multitable @columnfractions .15 .70
8190 @item @var{FLAG} @tab Shall be a scalar @code{INTEGER} of kind 4.
8193 @item @emph{Return value}:
8194 The return value is of @code{REAL} type and the default kind.
8196 @item @emph{Example}:
8199 integer,parameter :: seed = 86456
8202 print *, rand(), rand(), rand(), rand()
8203 print *, rand(seed), rand(), rand(), rand()
8204 end program test_rand
8207 @item @emph{See also}:
8208 @ref{SRAND}, @ref{RANDOM_NUMBER}
8215 @section @code{RANDOM_NUMBER} --- Pseudo-random number
8216 @fnindex RANDOM_NUMBER
8217 @cindex random number generation
8220 @item @emph{Description}:
8221 Returns a single pseudorandom number or an array of pseudorandom numbers
8222 from the uniform distribution over the range @math{ 0 \leq x < 1}.
8224 @item @emph{Standard}:
8230 @item @emph{Syntax}:
8231 @code{RANDOM_NUMBER(HARVEST)}
8233 @item @emph{Arguments}:
8234 @multitable @columnfractions .15 .70
8235 @item @var{HARVEST} @tab Shall be a scalar or an array of type @code{REAL(*)}.
8238 @item @emph{Example}:
8240 program test_random_number
8242 CALL init_random_seed() ! see example of RANDOM_SEED
8243 CALL RANDOM_NUMBER(r)
8248 The implemented random number generator is thread safe if used within
8249 OpenMP directives, i. e. its state will be consistent while called from
8250 multiple threads. Please note that the currently implemented KISS generator
8251 does not create random numbers in parallel from multiple sources, but in
8252 sequence from a single source. If your OpenMP-enabled application heavily
8253 relies on random numbers, you should consider employing a dedicated parallel
8254 random number generator instead.
8256 @item @emph{See also}:
8263 @section @code{RANDOM_SEED} --- Initialize a pseudo-random number sequence
8264 @fnindex RANDOM_SEED
8265 @cindex random number generation, seeding
8266 @cindex seeding a random number generator
8269 @item @emph{Description}:
8270 Restarts or queries the state of the pseudorandom number generator used by
8271 @code{RANDOM_NUMBER}.
8273 If @code{RANDOM_SEED} is called without arguments, it is initialized to
8274 a default state. The example below shows how to initialize the random
8275 seed based on the system's time.
8277 @item @emph{Standard}:
8283 @item @emph{Syntax}:
8284 @code{CALL RANDOM_SEED(SIZE, PUT, GET)}
8286 @item @emph{Arguments}:
8287 @multitable @columnfractions .15 .70
8288 @item @var{SIZE} @tab (Optional) Shall be a scalar and of type default
8289 @code{INTEGER}, with @code{INTENT(OUT)}. It specifies the minimum size
8290 of the arrays used with the @var{PUT} and @var{GET} arguments.
8291 @item @var{PUT} @tab (Optional) Shall be an array of type default
8292 @code{INTEGER} and rank one. It is @code{INTENT(IN)} and the size of
8293 the array must be larger than or equal to the number returned by the
8294 @var{SIZE} argument.
8295 @item @var{GET} @tab (Optional) Shall be an array of type default
8296 @code{INTEGER} and rank one. It is @code{INTENT(OUT)} and the size
8297 of the array must be larger than or equal to the number returned by
8298 the @var{SIZE} argument.
8301 @item @emph{Example}:
8303 SUBROUTINE init_random_seed()
8304 INTEGER :: i, n, clock
8305 INTEGER, DIMENSION(:), ALLOCATABLE :: seed
8307 CALL RANDOM_SEED(size = n)
8310 CALL SYSTEM_CLOCK(COUNT=clock)
8312 seed = clock + 37 * (/ (i - 1, i = 1, n) /)
8313 CALL RANDOM_SEED(PUT = seed)
8319 @item @emph{See also}:
8326 @section @code{RANGE} --- Decimal exponent range of a real kind
8328 @cindex model representation, range
8331 @item @emph{Description}:
8332 @code{RANGE(X)} returns the decimal exponent range in the model of the
8335 @item @emph{Standard}:
8341 @item @emph{Syntax}:
8342 @code{RESULT = RANGE(X)}
8344 @item @emph{Arguments}:
8345 @multitable @columnfractions .15 .70
8346 @item @var{X} @tab Shall be of type @code{REAL} or @code{COMPLEX}.
8349 @item @emph{Return value}:
8350 The return value is of type @code{INTEGER} and of the default integer
8353 @item @emph{Example}:
8354 See @code{PRECISION} for an example.
8360 @section @code{REAL} --- Convert to real type
8363 @cindex conversion, to real
8364 @cindex complex numbers, real part
8367 @item @emph{Description}:
8368 @code{REAL(X [, KIND])} converts its argument @var{X} to a real type. The
8369 @code{REALPART(X)} function is provided for compatibility with @command{g77},
8370 and its use is strongly discouraged.
8372 @item @emph{Standard}:
8378 @item @emph{Syntax}:
8379 @multitable @columnfractions .80
8380 @item @code{RESULT = REAL(X [, KIND])}
8381 @item @code{RESULT = REALPART(Z)}
8384 @item @emph{Arguments}:
8385 @multitable @columnfractions .15 .70
8386 @item @var{X} @tab Shall be @code{INTEGER(*)}, @code{REAL(*)}, or
8388 @item @var{KIND} @tab (Optional) An @code{INTEGER(*)} initialization
8389 expression indicating the kind parameter of
8393 @item @emph{Return value}:
8394 These functions return a @code{REAL(*)} variable or array under
8395 the following rules:
8399 @code{REAL(X)} is converted to a default real type if @var{X} is an
8400 integer or real variable.
8402 @code{REAL(X)} is converted to a real type with the kind type parameter
8403 of @var{X} if @var{X} is a complex variable.
8405 @code{REAL(X, KIND)} is converted to a real type with kind type
8406 parameter @var{KIND} if @var{X} is a complex, integer, or real
8410 @item @emph{Example}:
8413 complex :: x = (1.0, 2.0)
8414 print *, real(x), real(x,8), realpart(x)
8415 end program test_real
8418 @item @emph{See also}:
8419 @ref{DBLE}, @ref{DFLOAT}, @ref{FLOAT}
8426 @section @code{RENAME} --- Rename a file
8428 @cindex file system, rename file
8431 @item @emph{Description}:
8432 Renames a file from file @var{PATH1} to @var{PATH2}. A null
8433 character (@code{CHAR(0)}) can be used to mark the end of the names in
8434 @var{PATH1} and @var{PATH2}; otherwise, trailing blanks in the file
8435 names are ignored. If the @var{STATUS} argument is supplied, it
8436 contains 0 on success or a nonzero error code upon return; see
8439 This intrinsic is provided in both subroutine and function forms;
8440 however, only one form can be used in any given program unit.
8442 @item @emph{Standard}:
8446 Subroutine, non-elemental function
8448 @item @emph{Syntax}:
8449 @multitable @columnfractions .80
8450 @item @code{CALL RENAME(PATH1, PATH2 [, STATUS])}
8451 @item @code{STATUS = RENAME(PATH1, PATH2)}
8454 @item @emph{Arguments}:
8455 @multitable @columnfractions .15 .70
8456 @item @var{PATH1} @tab Shall be of default @code{CHARACTER} type.
8457 @item @var{PATH2} @tab Shall be of default @code{CHARACTER} type.
8458 @item @var{STATUS} @tab (Optional) Shall be of default @code{INTEGER} type.
8461 @item @emph{See also}:
8469 @section @code{REPEAT} --- Repeated string concatenation
8471 @cindex string, repeat
8472 @cindex string, concatenate
8475 @item @emph{Description}:
8476 Concatenates @var{NCOPIES} copies of a string.
8478 @item @emph{Standard}:
8482 Transformational function
8484 @item @emph{Syntax}:
8485 @code{RESULT = REPEAT(STRING, NCOPIES)}
8487 @item @emph{Arguments}:
8488 @multitable @columnfractions .15 .70
8489 @item @var{STRING} @tab Shall be scalar and of type @code{CHARACTER(*)}.
8490 @item @var{NCOPIES} @tab Shall be scalar and of type @code{INTEGER(*)}.
8493 @item @emph{Return value}:
8494 A new scalar of type @code{CHARACTER} built up from @var{NCOPIES} copies
8497 @item @emph{Example}:
8500 write(*,*) repeat("x", 5) ! "xxxxx"
8508 @section @code{RESHAPE} --- Function to reshape an array
8510 @cindex array, change dimensions
8511 @cindex array, transmogrify
8514 @item @emph{Description}:
8515 Reshapes @var{SOURCE} to correspond to @var{SHAPE}. If necessary,
8516 the new array may be padded with elements from @var{PAD} or permuted
8517 as defined by @var{ORDER}.
8519 @item @emph{Standard}:
8523 Transformational function
8525 @item @emph{Syntax}:
8526 @code{RESULT = RESHAPE(SOURCE, SHAPE[, PAD, ORDER])}
8528 @item @emph{Arguments}:
8529 @multitable @columnfractions .15 .70
8530 @item @var{SOURCE} @tab Shall be an array of any type.
8531 @item @var{SHAPE} @tab Shall be of type @code{INTEGER} and an
8532 array of rank one. Its values must be positive or zero.
8533 @item @var{PAD} @tab (Optional) shall be an array of the same
8534 type as @var{SOURCE}.
8535 @item @var{ORDER} @tab (Optional) shall be of type @code{INTEGER}
8536 and an array of the same shape as @var{SHAPE}. Its values shall
8537 be a permutation of the numbers from 1 to n, where n is the size of
8538 @var{SHAPE}. If @var{ORDER} is absent, the natural ordering shall
8542 @item @emph{Return value}:
8543 The result is an array of shape @var{SHAPE} with the same type as
8546 @item @emph{Example}:
8548 PROGRAM test_reshape
8549 INTEGER, DIMENSION(4) :: x
8550 WRITE(*,*) SHAPE(x) ! prints "4"
8551 WRITE(*,*) SHAPE(RESHAPE(x, (/2, 2/))) ! prints "2 2"
8555 @item @emph{See also}:
8562 @section @code{RRSPACING} --- Reciprocal of the relative spacing
8564 @cindex real number, relative spacing
8565 @cindex floating point, relative spacing
8569 @item @emph{Description}:
8570 @code{RRSPACING(X)} returns the reciprocal of the relative spacing of
8571 model numbers near @var{X}.
8573 @item @emph{Standard}:
8579 @item @emph{Syntax}:
8580 @code{RESULT = RRSPACING(X)}
8582 @item @emph{Arguments}:
8583 @multitable @columnfractions .15 .70
8584 @item @var{X} @tab Shall be of type @code{REAL}.
8587 @item @emph{Return value}:
8588 The return value is of the same type and kind as @var{X}.
8589 The value returned is equal to
8590 @code{ABS(FRACTION(X)) * FLOAT(RADIX(X))**DIGITS(X)}.
8592 @item @emph{See also}:
8599 @section @code{RSHIFT} --- Right shift bits
8601 @cindex bits, shift right
8604 @item @emph{Description}:
8605 @code{RSHIFT} returns a value corresponding to @var{I} with all of the
8606 bits shifted right by @var{SHIFT} places. If the absolute value of
8607 @var{SHIFT} is greater than @code{BIT_SIZE(I)}, the value is undefined.
8608 Bits shifted out from the left end are lost; zeros are shifted in from
8611 This function has been superseded by the @code{ISHFT} intrinsic, which
8612 is standard in Fortran 95 and later.
8614 @item @emph{Standard}:
8620 @item @emph{Syntax}:
8621 @code{RESULT = RSHIFT(I, SHIFT)}
8623 @item @emph{Arguments}:
8624 @multitable @columnfractions .15 .70
8625 @item @var{I} @tab The type shall be @code{INTEGER(*)}.
8626 @item @var{SHIFT} @tab The type shall be @code{INTEGER(*)}.
8629 @item @emph{Return value}:
8630 The return value is of type @code{INTEGER(*)} and of the same kind as
8633 @item @emph{See also}:
8634 @ref{ISHFT}, @ref{ISHFTC}, @ref{LSHIFT}
8641 @section @code{SCALE} --- Scale a real value
8643 @cindex real number, scale
8644 @cindex floating point, scale
8647 @item @emph{Description}:
8648 @code{SCALE(X,I)} returns @code{X * RADIX(X)**I}.
8650 @item @emph{Standard}:
8656 @item @emph{Syntax}:
8657 @code{RESULT = SCALE(X, I)}
8659 @item @emph{Arguments}:
8660 @multitable @columnfractions .15 .70
8661 @item @var{X} @tab The type of the argument shall be a @code{REAL}.
8662 @item @var{I} @tab The type of the argument shall be a @code{INTEGER}.
8665 @item @emph{Return value}:
8666 The return value is of the same type and kind as @var{X}.
8667 Its value is @code{X * RADIX(X)**I}.
8669 @item @emph{Example}:
8672 real :: x = 178.1387e-4
8674 print *, scale(x,i), x*radix(x)**i
8675 end program test_scale
8683 @section @code{SCAN} --- Scan a string for the presence of a set of characters
8685 @cindex string, find subset
8688 @item @emph{Description}:
8689 Scans a @var{STRING} for any of the characters in a @var{SET}
8692 If @var{BACK} is either absent or equals @code{FALSE}, this function
8693 returns the position of the leftmost character of @var{STRING} that is
8694 in @var{SET}. If @var{BACK} equals @code{TRUE}, the rightmost position
8695 is returned. If no character of @var{SET} is found in @var{STRING}, the
8698 @item @emph{Standard}:
8704 @item @emph{Syntax}:
8705 @code{RESULT = SCAN(STRING, SET[, BACK])}
8707 @item @emph{Arguments}:
8708 @multitable @columnfractions .15 .70
8709 @item @var{STRING} @tab Shall be of type @code{CHARACTER(*)}.
8710 @item @var{SET} @tab Shall be of type @code{CHARACTER(*)}.
8711 @item @var{BACK} @tab (Optional) shall be of type @code{LOGICAL}.
8714 @item @emph{Return value}:
8715 The return value is of type @code{INTEGER} and of the default
8718 @item @emph{Example}:
8721 WRITE(*,*) SCAN("FORTRAN", "AO") ! 2, found 'O'
8722 WRITE(*,*) SCAN("FORTRAN", "AO", .TRUE.) ! 6, found 'A'
8723 WRITE(*,*) SCAN("FORTRAN", "C++") ! 0, found none
8727 @item @emph{See also}:
8728 @ref{INDEX}, @ref{VERIFY}
8734 @section @code{SECNDS} --- Time function
8736 @cindex time, elapsed
8737 @cindex elapsed time
8740 @item @emph{Description}:
8741 @code{SECNDS(X)} gets the time in seconds from the real-time system clock.
8742 @var{X} is a reference time, also in seconds. If this is zero, the time in
8743 seconds from midnight is returned. This function is non-standard and its
8746 @item @emph{Standard}:
8750 Non-elemental function
8752 @item @emph{Syntax}:
8753 @code{RESULT = SECNDS (X)}
8755 @item @emph{Arguments}:
8756 @multitable @columnfractions .15 .70
8757 @item @var{T} @tab Shall be of type @code{REAL(4)}.
8758 @item @var{X} @tab Shall be of type @code{REAL(4)}.
8761 @item @emph{Return value}:
8764 @item @emph{Example}:
8769 print *, secnds (0.0) ! seconds since midnight
8770 t1 = secnds (0.0) ! reference time
8771 do i = 1, 10000000 ! do something
8773 t2 = secnds (t1) ! elapsed time
8774 print *, "Something took ", t2, " seconds."
8775 end program test_secnds
8782 @section @code{SECOND} --- CPU time function
8784 @cindex time, elapsed
8785 @cindex elapsed time
8788 @item @emph{Description}:
8789 Returns a @code{REAL(4)} value representing the elapsed CPU time in
8790 seconds. This provides the same functionality as the standard
8791 @code{CPU_TIME} intrinsic, and is only included for backwards
8794 This intrinsic is provided in both subroutine and function forms;
8795 however, only one form can be used in any given program unit.
8797 @item @emph{Standard}:
8801 Subroutine, non-elemental function
8803 @item @emph{Syntax}:
8804 @multitable @columnfractions .80
8805 @item @code{CALL SECOND(TIME)}
8806 @item @code{TIME = SECOND()}
8809 @item @emph{Arguments}:
8810 @multitable @columnfractions .15 .70
8811 @item @var{TIME} @tab Shall be of type @code{REAL(4)}.
8814 @item @emph{Return value}:
8815 In either syntax, @var{TIME} is set to the process's current runtime in
8818 @item @emph{See also}:
8825 @node SELECTED_INT_KIND
8826 @section @code{SELECTED_INT_KIND} --- Choose integer kind
8827 @fnindex SELECTED_INT_KIND
8828 @cindex integer kind
8829 @cindex kind, integer
8832 @item @emph{Description}:
8833 @code{SELECTED_INT_KIND(I)} return the kind value of the smallest integer
8834 type that can represent all values ranging from @math{-10^I} (exclusive)
8835 to @math{10^I} (exclusive). If there is no integer kind that accommodates
8836 this range, @code{SELECTED_INT_KIND} returns @math{-1}.
8838 @item @emph{Standard}:
8842 Transformational function
8844 @item @emph{Syntax}:
8845 @code{RESULT = SELECTED_INT_KIND(I)}
8847 @item @emph{Arguments}:
8848 @multitable @columnfractions .15 .70
8849 @item @var{I} @tab Shall be a scalar and of type @code{INTEGER}.
8852 @item @emph{Example}:
8854 program large_integers
8855 integer,parameter :: k5 = selected_int_kind(5)
8856 integer,parameter :: k15 = selected_int_kind(15)
8857 integer(kind=k5) :: i5
8858 integer(kind=k15) :: i15
8860 print *, huge(i5), huge(i15)
8862 ! The following inequalities are always true
8863 print *, huge(i5) >= 10_k5**5-1
8864 print *, huge(i15) >= 10_k15**15-1
8865 end program large_integers
8871 @node SELECTED_REAL_KIND
8872 @section @code{SELECTED_REAL_KIND} --- Choose real kind
8873 @fnindex SELECTED_REAL_KIND
8878 @item @emph{Description}:
8879 @code{SELECTED_REAL_KIND(P,R)} return the kind value of a real data type
8880 with decimal precision greater of at least @code{P} digits and exponent
8881 range greater at least @code{R}.
8883 @item @emph{Standard}:
8887 Transformational function
8889 @item @emph{Syntax}:
8890 @code{RESULT = SELECTED_REAL_KIND(P, R)}
8892 @item @emph{Arguments}:
8893 @multitable @columnfractions .15 .70
8894 @item @var{P} @tab (Optional) shall be a scalar and of type @code{INTEGER}.
8895 @item @var{R} @tab (Optional) shall be a scalar and of type @code{INTEGER}.
8897 At least one argument shall be present.
8899 @item @emph{Return value}:
8901 @code{SELECTED_REAL_KIND} returns the value of the kind type parameter of
8902 a real data type with decimal precision of at least @code{P} digits and a
8903 decimal exponent range of at least @code{R}. If more than one real data
8904 type meet the criteria, the kind of the data type with the smallest
8905 decimal precision is returned. If no real data type matches the criteria,
8908 @item -1 if the processor does not support a real data type with a
8909 precision greater than or equal to @code{P}
8910 @item -2 if the processor does not support a real type with an exponent
8911 range greater than or equal to @code{R}
8912 @item -3 if neither is supported.
8915 @item @emph{Example}:
8918 integer,parameter :: p6 = selected_real_kind(6)
8919 integer,parameter :: p10r100 = selected_real_kind(10,100)
8920 integer,parameter :: r400 = selected_real_kind(r=400)
8922 real(kind=p10r100) :: y
8923 real(kind=r400) :: z
8925 print *, precision(x), range(x)
8926 print *, precision(y), range(y)
8927 print *, precision(z), range(z)
8928 end program real_kinds
8935 @section @code{SET_EXPONENT} --- Set the exponent of the model
8936 @fnindex SET_EXPONENT
8937 @cindex real number, set exponent
8938 @cindex floating point, set exponent
8941 @item @emph{Description}:
8942 @code{SET_EXPONENT(X, I)} returns the real number whose fractional part
8943 is that that of @var{X} and whose exponent part is @var{I}.
8945 @item @emph{Standard}:
8951 @item @emph{Syntax}:
8952 @code{RESULT = SET_EXPONENT(X, I)}
8954 @item @emph{Arguments}:
8955 @multitable @columnfractions .15 .70
8956 @item @var{X} @tab Shall be of type @code{REAL}.
8957 @item @var{I} @tab Shall be of type @code{INTEGER}.
8960 @item @emph{Return value}:
8961 The return value is of the same type and kind as @var{X}.
8962 The real number whose fractional part
8963 is that that of @var{X} and whose exponent part if @var{I} is returned;
8964 it is @code{FRACTION(X) * RADIX(X)**I}.
8966 @item @emph{Example}:
8969 REAL :: x = 178.1387e-4
8971 PRINT *, SET_EXPONENT(x, i), FRACTION(x) * RADIX(x)**i
8980 @section @code{SHAPE} --- Determine the shape of an array
8982 @cindex array, shape
8985 @item @emph{Description}:
8986 Determines the shape of an array.
8988 @item @emph{Standard}:
8994 @item @emph{Syntax}:
8995 @code{RESULT = SHAPE(SOURCE)}
8997 @item @emph{Arguments}:
8998 @multitable @columnfractions .15 .70
8999 @item @var{SOURCE} @tab Shall be an array or scalar of any type.
9000 If @var{SOURCE} is a pointer it must be associated and allocatable
9001 arrays must be allocated.
9004 @item @emph{Return value}:
9005 An @code{INTEGER} array of rank one with as many elements as @var{SOURCE}
9006 has dimensions. The elements of the resulting array correspond to the extend
9007 of @var{SOURCE} along the respective dimensions. If @var{SOURCE} is a scalar,
9008 the result is the rank one array of size zero.
9010 @item @emph{Example}:
9013 INTEGER, DIMENSION(-1:1, -1:2) :: A
9014 WRITE(*,*) SHAPE(A) ! (/ 3, 4 /)
9015 WRITE(*,*) SIZE(SHAPE(42)) ! (/ /)
9019 @item @emph{See also}:
9020 @ref{RESHAPE}, @ref{SIZE}
9026 @section @code{SIGN} --- Sign copying function
9030 @cindex sign copying
9033 @item @emph{Description}:
9034 @code{SIGN(A,B)} returns the value of @var{A} with the sign of @var{B}.
9036 @item @emph{Standard}:
9042 @item @emph{Syntax}:
9043 @code{RESULT = SIGN(A, B)}
9045 @item @emph{Arguments}:
9046 @multitable @columnfractions .15 .70
9047 @item @var{A} @tab Shall be of type @code{INTEGER} or @code{REAL}
9048 @item @var{B} @tab Shall be of the same type and kind as @var{A}
9051 @item @emph{Return value}:
9052 The kind of the return value is that of @var{A} and @var{B}.
9053 If @math{B\ge 0} then the result is @code{ABS(A)}, else
9054 it is @code{-ABS(A)}.
9056 @item @emph{Example}:
9059 print *, sign(-12,1)
9060 print *, sign(-12,0)
9061 print *, sign(-12,-1)
9063 print *, sign(-12.,1.)
9064 print *, sign(-12.,0.)
9065 print *, sign(-12.,-1.)
9066 end program test_sign
9069 @item @emph{Specific names}:
9070 @multitable @columnfractions .20 .20 .20 .25
9071 @item Name @tab Arguments @tab Return type @tab Standard
9072 @item @code{ISIGN(A,P)} @tab @code{INTEGER(4)} @tab @code{INTEGER(4)} @tab f95, gnu
9073 @item @code{DSIGN(A,P)} @tab @code{REAL(8)} @tab @code{REAL(8)} @tab f95, gnu
9080 @section @code{SIGNAL} --- Signal handling subroutine (or function)
9082 @cindex system, signal handling
9085 @item @emph{Description}:
9086 @code{SIGNAL(NUMBER, HANDLER [, STATUS])} causes external subroutine
9087 @var{HANDLER} to be executed with a single integer argument when signal
9088 @var{NUMBER} occurs. If @var{HANDLER} is an integer, it can be used to
9089 turn off handling of signal @var{NUMBER} or revert to its default
9090 action. See @code{signal(2)}.
9092 If @code{SIGNAL} is called as a subroutine and the @var{STATUS} argument
9093 is supplied, it is set to the value returned by @code{signal(2)}.
9095 @item @emph{Standard}:
9099 Subroutine, non-elemental function
9101 @item @emph{Syntax}:
9102 @multitable @columnfractions .80
9103 @item @code{CALL SIGNAL(NUMBER, HANDLER [, STATUS])}
9104 @item @code{STATUS = SIGNAL(NUMBER, HANDLER)}
9107 @item @emph{Arguments}:
9108 @multitable @columnfractions .15 .70
9109 @item @var{NUMBER} @tab Shall be a scalar integer, with @code{INTENT(IN)}
9110 @item @var{HANDLER}@tab Signal handler (@code{INTEGER FUNCTION} or
9111 @code{SUBROUTINE}) or dummy/global @code{INTEGER} scalar.
9112 @code{INTEGER}. It is @code{INTENT(IN)}.
9113 @item @var{STATUS} @tab (Optional) @var{STATUS} shall be a scalar
9114 integer. It has @code{INTENT(OUT)}.
9117 @item @emph{Return value}:
9118 The @code{SIGNAL} function returns the value returned by @code{signal(2)}.
9120 @item @emph{Example}:
9124 external handler_print
9126 call signal (12, handler_print)
9130 end program test_signal
9137 @section @code{SIN} --- Sine function
9143 @cindex trigonometric function, sine
9147 @item @emph{Description}:
9148 @code{SIN(X)} computes the sine of @var{X}.
9150 @item @emph{Standard}:
9156 @item @emph{Syntax}:
9157 @code{RESULT = SIN(X)}
9159 @item @emph{Arguments}:
9160 @multitable @columnfractions .15 .70
9161 @item @var{X} @tab The type shall be @code{REAL(*)} or
9165 @item @emph{Return value}:
9166 The return value has same type and kind as @var{X}.
9168 @item @emph{Example}:
9173 end program test_sin
9176 @item @emph{Specific names}:
9177 @multitable @columnfractions .20 .20 .20 .25
9178 @item Name @tab Argument @tab Return type @tab Standard
9179 @item @code{DSIN(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab f95, gnu
9180 @item @code{CSIN(X)} @tab @code{COMPLEX(4) X} @tab @code{COMPLEX(4)} @tab f95, gnu
9181 @item @code{ZSIN(X)} @tab @code{COMPLEX(8) X} @tab @code{COMPLEX(8)} @tab f95, gnu
9182 @item @code{CDSIN(X)} @tab @code{COMPLEX(8) X} @tab @code{COMPLEX(8)} @tab f95, gnu
9185 @item @emph{See also}:
9192 @section @code{SINH} --- Hyperbolic sine function
9195 @cindex hyperbolic sine
9196 @cindex hyperbolic function, sine
9197 @cindex sine, hyperbolic
9200 @item @emph{Description}:
9201 @code{SINH(X)} computes the hyperbolic sine of @var{X}.
9203 @item @emph{Standard}:
9209 @item @emph{Syntax}:
9210 @code{RESULT = SINH(X)}
9212 @item @emph{Arguments}:
9213 @multitable @columnfractions .15 .70
9214 @item @var{X} @tab The type shall be @code{REAL(*)}.
9217 @item @emph{Return value}:
9218 The return value is of type @code{REAL(*)}.
9220 @item @emph{Example}:
9223 real(8) :: x = - 1.0_8
9225 end program test_sinh
9228 @item @emph{Specific names}:
9229 @multitable @columnfractions .20 .20 .20 .25
9230 @item Name @tab Argument @tab Return type @tab Standard
9231 @item @code{DSINH(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F95 and later
9234 @item @emph{See also}:
9241 @section @code{SIZE} --- Determine the size of an array
9244 @cindex array, number of elements
9245 @cindex array, count elements
9248 @item @emph{Description}:
9249 Determine the extent of @var{ARRAY} along a specified dimension @var{DIM},
9250 or the total number of elements in @var{ARRAY} if @var{DIM} is absent.
9252 @item @emph{Standard}:
9258 @item @emph{Syntax}:
9259 @code{RESULT = SIZE(ARRAY[, DIM])}
9261 @item @emph{Arguments}:
9262 @multitable @columnfractions .15 .70
9263 @item @var{ARRAY} @tab Shall be an array of any type. If @var{ARRAY} is
9264 a pointer it must be associated and allocatable arrays must be allocated.
9265 @item @var{DIM} @tab (Optional) shall be a scalar of type @code{INTEGER}
9266 and its value shall be in the range from 1 to n, where n equals the rank
9270 @item @emph{Return value}:
9271 The return value is of type @code{INTEGER} and of the default
9274 @item @emph{Example}:
9277 WRITE(*,*) SIZE((/ 1, 2 /)) ! 2
9281 @item @emph{See also}:
9282 @ref{SHAPE}, @ref{RESHAPE}
9287 @section @code{SIZEOF} --- Size in bytes of an expression
9289 @cindex expression size
9290 @cindex size of an expression
9293 @item @emph{Description}:
9294 @code{SIZEOF(X)} calculates the number of bytes of storage the
9295 expression @code{X} occupies.
9297 @item @emph{Standard}:
9303 @item @emph{Syntax}:
9304 @code{N = SIZEOF(X)}
9306 @item @emph{Arguments}:
9307 @multitable @columnfractions .15 .70
9308 @item @var{X} @tab The argument shall be of any type, rank or shape.
9311 @item @emph{Return value}:
9312 The return value is of type integer. Its value is the number of bytes
9313 occupied by the argument. If the argument has the @code{POINTER}
9314 attribute, the number of bytes of the storage area pointed to is
9315 returned. If the argument is of a derived type with @code{POINTER} or
9316 @code{ALLOCATABLE} components, the return value doesn't account for
9317 the sizes of the data pointed to by these components.
9319 @item @emph{Example}:
9323 print *, (sizeof(s)/sizeof(r) == 5)
9326 The example will print @code{.TRUE.} unless you are using a platform
9327 where default @code{REAL} variables are unusually padded.
9331 @section @code{SLEEP} --- Sleep for the specified number of seconds
9333 @cindex delayed execution
9336 @item @emph{Description}:
9337 Calling this subroutine causes the process to pause for @var{SECONDS} seconds.
9339 @item @emph{Standard}:
9345 @item @emph{Syntax}:
9346 @code{CALL SLEEP(SECONDS)}
9348 @item @emph{Arguments}:
9349 @multitable @columnfractions .15 .70
9350 @item @var{SECONDS} @tab The type shall be of default @code{INTEGER}.
9353 @item @emph{Example}:
9364 @section @code{SNGL} --- Convert double precision real to default real
9366 @cindex conversion, to real
9369 @item @emph{Description}:
9370 @code{SNGL(A)} converts the double precision real @var{A}
9371 to a default real value. This is an archaic form of @code{REAL}
9372 that is specific to one type for @var{A}.
9374 @item @emph{Standard}:
9380 @item @emph{Syntax}:
9381 @code{RESULT = SNGL(A)}
9383 @item @emph{Arguments}:
9384 @multitable @columnfractions .15 .70
9385 @item @var{A} @tab The type shall be a double precision @code{REAL}.
9388 @item @emph{Return value}:
9389 The return value is of type default @code{REAL}.
9391 @item @emph{See also}:
9398 @section @code{SPACING} --- Smallest distance between two numbers of a given type
9400 @cindex real number, relative spacing
9401 @cindex floating point, relative spacing
9404 @item @emph{Description}:
9405 Determines the distance between the argument @var{X} and the nearest
9406 adjacent number of the same type.
9408 @item @emph{Standard}:
9414 @item @emph{Syntax}:
9415 @code{RESULT = SPACING(X)}
9417 @item @emph{Arguments}:
9418 @multitable @columnfractions .15 .70
9419 @item @var{X} @tab Shall be of type @code{REAL(*)}.
9422 @item @emph{Return value}:
9423 The result is of the same type as the input argument @var{X}.
9425 @item @emph{Example}:
9427 PROGRAM test_spacing
9428 INTEGER, PARAMETER :: SGL = SELECTED_REAL_KIND(p=6, r=37)
9429 INTEGER, PARAMETER :: DBL = SELECTED_REAL_KIND(p=13, r=200)
9431 WRITE(*,*) spacing(1.0_SGL) ! "1.1920929E-07" on i686
9432 WRITE(*,*) spacing(1.0_DBL) ! "2.220446049250313E-016" on i686
9436 @item @emph{See also}:
9443 @section @code{SPREAD} --- Add a dimension to an array
9445 @cindex array, increase dimension
9446 @cindex array, duplicate elements
9447 @cindex array, duplicate dimensions
9450 @item @emph{Description}:
9451 Replicates a @var{SOURCE} array @var{NCOPIES} times along a specified
9452 dimension @var{DIM}.
9454 @item @emph{Standard}:
9458 Transformational function
9460 @item @emph{Syntax}:
9461 @code{RESULT = SPREAD(SOURCE, DIM, NCOPIES)}
9463 @item @emph{Arguments}:
9464 @multitable @columnfractions .15 .70
9465 @item @var{SOURCE} @tab Shall be a scalar or an array of any type and
9466 a rank less than seven.
9467 @item @var{DIM} @tab Shall be a scalar of type @code{INTEGER} with a
9468 value in the range from 1 to n+1, where n equals the rank of @var{SOURCE}.
9469 @item @var{NCOPIES} @tab Shall be a scalar of type @code{INTEGER}.
9472 @item @emph{Return value}:
9473 The result is an array of the same type as @var{SOURCE} and has rank n+1
9474 where n equals the rank of @var{SOURCE}.
9476 @item @emph{Example}:
9479 INTEGER :: a = 1, b(2) = (/ 1, 2 /)
9480 WRITE(*,*) SPREAD(A, 1, 2) ! "1 1"
9481 WRITE(*,*) SPREAD(B, 1, 2) ! "1 1 2 2"
9485 @item @emph{See also}:
9492 @section @code{SQRT} --- Square-root function
9502 @item @emph{Description}:
9503 @code{SQRT(X)} computes the square root of @var{X}.
9505 @item @emph{Standard}:
9511 @item @emph{Syntax}:
9512 @code{RESULT = SQRT(X)}
9514 @item @emph{Arguments}:
9515 @multitable @columnfractions .15 .70
9516 @item @var{X} @tab The type shall be @code{REAL(*)} or
9520 @item @emph{Return value}:
9521 The return value is of type @code{REAL(*)} or @code{COMPLEX(*)}.
9522 The kind type parameter is the same as @var{X}.
9524 @item @emph{Example}:
9527 real(8) :: x = 2.0_8
9528 complex :: z = (1.0, 2.0)
9531 end program test_sqrt
9534 @item @emph{Specific names}:
9535 @multitable @columnfractions .20 .20 .20 .25
9536 @item Name @tab Argument @tab Return type @tab Standard
9537 @item @code{DSQRT(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F95 and later
9538 @item @code{CSQRT(X)} @tab @code{COMPLEX(4) X} @tab @code{COMPLEX(4)} @tab F95 and later
9539 @item @code{ZSQRT(X)} @tab @code{COMPLEX(8) X} @tab @code{COMPLEX(8)} @tab GNU extension
9540 @item @code{CDSQRT(X)} @tab @code{COMPLEX(8) X} @tab @code{COMPLEX(8)} @tab GNU extension
9547 @section @code{SRAND} --- Reinitialize the random number generator
9549 @cindex random number generation, seeding
9550 @cindex seeding a random number generator
9553 @item @emph{Description}:
9554 @code{SRAND} reinitializes the pseudo-random number generator
9555 called by @code{RAND} and @code{IRAND}. The new seed used by the
9556 generator is specified by the required argument @var{SEED}.
9558 @item @emph{Standard}:
9562 Non-elemental subroutine
9564 @item @emph{Syntax}:
9565 @code{CALL SRAND(SEED)}
9567 @item @emph{Arguments}:
9568 @multitable @columnfractions .15 .70
9569 @item @var{SEED} @tab Shall be a scalar @code{INTEGER(kind=4)}.
9572 @item @emph{Return value}:
9575 @item @emph{Example}:
9576 See @code{RAND} and @code{IRAND} for examples.
9579 The Fortran 2003 standard specifies the intrinsic @code{RANDOM_SEED} to
9580 initialize the pseudo-random numbers generator and @code{RANDOM_NUMBER}
9581 to generate pseudo-random numbers. Please note that in
9582 GNU Fortran, these two sets of intrinsics (@code{RAND},
9583 @code{IRAND} and @code{SRAND} on the one hand, @code{RANDOM_NUMBER} and
9584 @code{RANDOM_SEED} on the other hand) access two independent
9585 pseudo-random number generators.
9587 @item @emph{See also}:
9588 @ref{RAND}, @ref{RANDOM_SEED}, @ref{RANDOM_NUMBER}
9595 @section @code{STAT} --- Get file status
9597 @cindex file system, file status
9600 @item @emph{Description}:
9601 This function returns information about a file. No permissions are required on
9602 the file itself, but execute (search) permission is required on all of the
9603 directories in path that lead to the file.
9605 The elements that are obtained and stored in the array @code{BUFF}:
9606 @multitable @columnfractions .15 .70
9607 @item @code{buff(1)} @tab Device ID
9608 @item @code{buff(2)} @tab Inode number
9609 @item @code{buff(3)} @tab File mode
9610 @item @code{buff(4)} @tab Number of links
9611 @item @code{buff(5)} @tab Owner's uid
9612 @item @code{buff(6)} @tab Owner's gid
9613 @item @code{buff(7)} @tab ID of device containing directory entry for file (0 if not available)
9614 @item @code{buff(8)} @tab File size (bytes)
9615 @item @code{buff(9)} @tab Last access time
9616 @item @code{buff(10)} @tab Last modification time
9617 @item @code{buff(11)} @tab Last file status change time
9618 @item @code{buff(12)} @tab Preferred I/O block size (-1 if not available)
9619 @item @code{buff(13)} @tab Number of blocks allocated (-1 if not available)
9622 Not all these elements are relevant on all systems.
9623 If an element is not relevant, it is returned as 0.
9626 @item @emph{Standard}:
9630 Non-elemental subroutine
9632 @item @emph{Syntax}:
9633 @code{CALL STAT(FILE,BUFF[,STATUS])}
9635 @item @emph{Arguments}:
9636 @multitable @columnfractions .15 .70
9637 @item @var{FILE} @tab The type shall be @code{CHARACTER(*)}, a valid path within the file system.
9638 @item @var{BUFF} @tab The type shall be @code{INTEGER(4), DIMENSION(13)}.
9639 @item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER(4)}. Returns 0
9640 on success and a system specific error code otherwise.
9643 @item @emph{Example}:
9646 INTEGER, DIMENSION(13) :: buff
9649 CALL STAT("/etc/passwd", buff, status)
9651 IF (status == 0) THEN
9652 WRITE (*, FMT="('Device ID:', T30, I19)") buff(1)
9653 WRITE (*, FMT="('Inode number:', T30, I19)") buff(2)
9654 WRITE (*, FMT="('File mode (octal):', T30, O19)") buff(3)
9655 WRITE (*, FMT="('Number of links:', T30, I19)") buff(4)
9656 WRITE (*, FMT="('Owner''s uid:', T30, I19)") buff(5)
9657 WRITE (*, FMT="('Owner''s gid:', T30, I19)") buff(6)
9658 WRITE (*, FMT="('Device where located:', T30, I19)") buff(7)
9659 WRITE (*, FMT="('File size:', T30, I19)") buff(8)
9660 WRITE (*, FMT="('Last access time:', T30, A19)") CTIME(buff(9))
9661 WRITE (*, FMT="('Last modification time', T30, A19)") CTIME(buff(10))
9662 WRITE (*, FMT="('Last status change time:', T30, A19)") CTIME(buff(11))
9663 WRITE (*, FMT="('Preferred block size:', T30, I19)") buff(12)
9664 WRITE (*, FMT="('No. of blocks allocated:', T30, I19)") buff(13)
9669 @item @emph{See also}:
9670 To stat an open file: @ref{FSTAT}, to stat a link: @ref{LSTAT}
9676 @section @code{SUM} --- Sum of array elements
9679 @cindex array, add elements
9680 @cindex array, conditionally add elements
9681 @cindex sum array elements
9684 @item @emph{Description}:
9685 Adds the elements of @var{ARRAY} along dimension @var{DIM} if
9686 the corresponding element in @var{MASK} is @code{TRUE}.
9688 @item @emph{Standard}:
9692 Transformational function
9694 @item @emph{Syntax}:
9695 @code{RESULT = SUM(ARRAY[, MASK])}
9696 @code{RESULT = SUM(ARRAY, DIM[, MASK])}
9698 @item @emph{Arguments}:
9699 @multitable @columnfractions .15 .70
9700 @item @var{ARRAY} @tab Shall be an array of type @code{INTEGER(*)},
9701 @code{REAL(*)} or @code{COMPLEX(*)}.
9702 @item @var{DIM} @tab (Optional) shall be a scalar of type
9703 @code{INTEGER} with a value in the range from 1 to n, where n
9704 equals the rank of @var{ARRAY}.
9705 @item @var{MASK} @tab (Optional) shall be of type @code{LOGICAL}
9706 and either be a scalar or an array of the same shape as @var{ARRAY}.
9709 @item @emph{Return value}:
9710 The result is of the same type as @var{ARRAY}.
9712 If @var{DIM} is absent, a scalar with the sum of all elements in @var{ARRAY}
9713 is returned. Otherwise, an array of rank n-1, where n equals the rank of
9714 @var{ARRAY},and a shape similar to that of @var{ARRAY} with dimension @var{DIM}
9715 dropped is returned.
9717 @item @emph{Example}:
9720 INTEGER :: x(5) = (/ 1, 2, 3, 4 ,5 /)
9721 print *, SUM(x) ! all elements, sum = 15
9722 print *, SUM(x, MASK=MOD(x, 2)==1) ! odd elements, sum = 9
9726 @item @emph{See also}:
9733 @section @code{SYMLNK} --- Create a symbolic link
9735 @cindex file system, create link
9736 @cindex file system, soft link
9739 @item @emph{Description}:
9740 Makes a symbolic link from file @var{PATH1} to @var{PATH2}. A null
9741 character (@code{CHAR(0)}) can be used to mark the end of the names in
9742 @var{PATH1} and @var{PATH2}; otherwise, trailing blanks in the file
9743 names are ignored. If the @var{STATUS} argument is supplied, it
9744 contains 0 on success or a nonzero error code upon return; see
9745 @code{symlink(2)}. If the system does not supply @code{symlink(2)},
9746 @code{ENOSYS} is returned.
9748 This intrinsic is provided in both subroutine and function forms;
9749 however, only one form can be used in any given program unit.
9751 @item @emph{Standard}:
9755 Subroutine, non-elemental function
9757 @item @emph{Syntax}:
9758 @multitable @columnfractions .80
9759 @item @code{CALL SYMLNK(PATH1, PATH2 [, STATUS])}
9760 @item @code{STATUS = SYMLNK(PATH1, PATH2)}
9763 @item @emph{Arguments}:
9764 @multitable @columnfractions .15 .70
9765 @item @var{PATH1} @tab Shall be of default @code{CHARACTER} type.
9766 @item @var{PATH2} @tab Shall be of default @code{CHARACTER} type.
9767 @item @var{STATUS} @tab (Optional) Shall be of default @code{INTEGER} type.
9770 @item @emph{See also}:
9771 @ref{LINK}, @ref{UNLINK}
9778 @section @code{SYSTEM} --- Execute a shell command
9780 @cindex system, system call
9783 @item @emph{Description}:
9784 Passes the command @var{COMMAND} to a shell (see @code{system(3)}). If
9785 argument @var{STATUS} is present, it contains the value returned by
9786 @code{system(3)}, which is presumably 0 if the shell command succeeded.
9787 Note that which shell is used to invoke the command is system-dependent
9788 and environment-dependent.
9790 This intrinsic is provided in both subroutine and function forms;
9791 however, only one form can be used in any given program unit.
9793 @item @emph{Standard}:
9797 Subroutine, non-elemental function
9799 @item @emph{Syntax}:
9800 @multitable @columnfractions .80
9801 @item @code{CALL SYSTEM(COMMAND [, STATUS])}
9802 @item @code{STATUS = SYSTEM(COMMAND)}
9805 @item @emph{Arguments}:
9806 @multitable @columnfractions .15 .70
9807 @item @var{COMMAND} @tab Shall be of default @code{CHARACTER} type.
9808 @item @var{STATUS} @tab (Optional) Shall be of default @code{INTEGER} type.
9811 @item @emph{See also}:
9817 @section @code{SYSTEM_CLOCK} --- Time function
9818 @fnindex SYSTEM_CLOCK
9819 @cindex time, clock ticks
9823 @item @emph{Description}:
9824 Determines the @var{COUNT} of milliseconds of wall clock time since
9825 the Epoch (00:00:00 UTC, January 1, 1970) modulo @var{COUNT_MAX},
9826 @var{COUNT_RATE} determines the number of clock ticks per second.
9827 @var{COUNT_RATE} and @var{COUNT_MAX} are constant and specific to
9830 If there is no clock, @var{COUNT} is set to @code{-HUGE(COUNT)}, and
9831 @var{COUNT_RATE} and @var{COUNT_MAX} are set to zero
9833 @item @emph{Standard}:
9839 @item @emph{Syntax}:
9840 @code{CALL SYSTEM_CLOCK([COUNT, COUNT_RATE, COUNT_MAX])}
9842 @item @emph{Arguments}:
9843 @item @emph{Arguments}:
9844 @multitable @columnfractions .15 .70
9845 @item @var{COUNT} @tab (Optional) shall be a scalar of type default
9846 @code{INTEGER} with @code{INTENT(OUT)}.
9847 @item @var{COUNT_RATE} @tab (Optional) shall be a scalar of type default
9848 @code{INTEGER} with @code{INTENT(OUT)}.
9849 @item @var{COUNT_MAX} @tab (Optional) shall be a scalar of type default
9850 @code{INTEGER} with @code{INTENT(OUT)}.
9853 @item @emph{Example}:
9855 PROGRAM test_system_clock
9856 INTEGER :: count, count_rate, count_max
9857 CALL SYSTEM_CLOCK(count, count_rate, count_max)
9858 WRITE(*,*) count, count_rate, count_max
9862 @item @emph{See also}:
9863 @ref{DATE_AND_TIME}, @ref{CPU_TIME}
9869 @section @code{TAN} --- Tangent function
9872 @cindex trigonometric function, tangent
9876 @item @emph{Description}:
9877 @code{TAN(X)} computes the tangent of @var{X}.
9879 @item @emph{Standard}:
9885 @item @emph{Syntax}:
9886 @code{RESULT = TAN(X)}
9888 @item @emph{Arguments}:
9889 @multitable @columnfractions .15 .70
9890 @item @var{X} @tab The type shall be @code{REAL(*)}.
9893 @item @emph{Return value}:
9894 The return value is of type @code{REAL(*)}. The kind type parameter is
9895 the same as @var{X}.
9897 @item @emph{Example}:
9900 real(8) :: x = 0.165_8
9902 end program test_tan
9905 @item @emph{Specific names}:
9906 @multitable @columnfractions .20 .20 .20 .25
9907 @item Name @tab Argument @tab Return type @tab Standard
9908 @item @code{DTAN(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F95 and later
9911 @item @emph{See also}:
9918 @section @code{TANH} --- Hyperbolic tangent function
9921 @cindex hyperbolic tangent
9922 @cindex hyperbolic function, tangent
9923 @cindex tangent, hyperbolic
9926 @item @emph{Description}:
9927 @code{TANH(X)} computes the hyperbolic tangent of @var{X}.
9929 @item @emph{Standard}:
9935 @item @emph{Syntax}:
9938 @item @emph{Arguments}:
9939 @multitable @columnfractions .15 .70
9940 @item @var{X} @tab The type shall be @code{REAL(*)}.
9943 @item @emph{Return value}:
9944 The return value is of type @code{REAL(*)} and lies in the range
9945 @math{ - 1 \leq tanh(x) \leq 1 }.
9947 @item @emph{Example}:
9950 real(8) :: x = 2.1_8
9952 end program test_tanh
9955 @item @emph{Specific names}:
9956 @multitable @columnfractions .20 .20 .20 .25
9957 @item Name @tab Argument @tab Return type @tab Standard
9958 @item @code{DTANH(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F95 and later
9961 @item @emph{See also}:
9968 @section @code{TIME} --- Time function
9970 @cindex time, current
9971 @cindex current time
9974 @item @emph{Description}:
9975 Returns the current time encoded as an integer (in the manner of the
9976 UNIX function @code{time(3)}). This value is suitable for passing to
9977 @code{CTIME()}, @code{GMTIME()}, and @code{LTIME()}.
9979 This intrinsic is not fully portable, such as to systems with 32-bit
9980 @code{INTEGER} types but supporting times wider than 32 bits. Therefore,
9981 the values returned by this intrinsic might be, or become, negative, or
9982 numerically less than previous values, during a single run of the
9985 See @ref{TIME8}, for information on a similar intrinsic that might be
9986 portable to more GNU Fortran implementations, though to fewer Fortran
9989 @item @emph{Standard}:
9993 Non-elemental function
9995 @item @emph{Syntax}:
9996 @code{RESULT = TIME()}
9998 @item @emph{Return value}:
9999 The return value is a scalar of type @code{INTEGER(4)}.
10001 @item @emph{See also}:
10002 @ref{CTIME}, @ref{GMTIME}, @ref{LTIME}, @ref{MCLOCK}, @ref{TIME8}
10009 @section @code{TIME8} --- Time function (64-bit)
10011 @cindex time, current
10012 @cindex current time
10015 @item @emph{Description}:
10016 Returns the current time encoded as an integer (in the manner of the
10017 UNIX function @code{time(3)}). This value is suitable for passing to
10018 @code{CTIME()}, @code{GMTIME()}, and @code{LTIME()}.
10020 @emph{Warning:} this intrinsic does not increase the range of the timing
10021 values over that returned by @code{time(3)}. On a system with a 32-bit
10022 @code{time(3)}, @code{TIME8()} will return a 32-bit value, even though
10023 it is converted to a 64-bit @code{INTEGER(8)} value. That means
10024 overflows of the 32-bit value can still occur. Therefore, the values
10025 returned by this intrinsic might be or become negative or numerically
10026 less than previous values during a single run of the compiled program.
10028 @item @emph{Standard}:
10031 @item @emph{Class}:
10032 Non-elemental function
10034 @item @emph{Syntax}:
10035 @code{RESULT = TIME8()}
10037 @item @emph{Return value}:
10038 The return value is a scalar of type @code{INTEGER(8)}.
10040 @item @emph{See also}:
10041 @ref{CTIME}, @ref{GMTIME}, @ref{LTIME}, @ref{MCLOCK8}, @ref{TIME}
10048 @section @code{TINY} --- Smallest positive number of a real kind
10050 @cindex limits, smallest number
10051 @cindex model representation, smallest number
10054 @item @emph{Description}:
10055 @code{TINY(X)} returns the smallest positive (non zero) number
10056 in the model of the type of @code{X}.
10058 @item @emph{Standard}:
10061 @item @emph{Class}:
10064 @item @emph{Syntax}:
10065 @code{RESULT = TINY(X)}
10067 @item @emph{Arguments}:
10068 @multitable @columnfractions .15 .70
10069 @item @var{X} @tab Shall be of type @code{REAL}.
10072 @item @emph{Return value}:
10073 The return value is of the same type and kind as @var{X}
10075 @item @emph{Example}:
10076 See @code{HUGE} for an example.
10082 @section @code{TRANSFER} --- Transfer bit patterns
10088 @item @emph{Description}:
10089 Interprets the bitwise representation of @var{SOURCE} in memory as if it
10090 is the representation of a variable or array of the same type and type
10091 parameters as @var{MOLD}.
10093 This is approximately equivalent to the C concept of @emph{casting} one
10096 @item @emph{Standard}:
10099 @item @emph{Class}:
10100 Transformational function
10102 @item @emph{Syntax}:
10103 @code{RESULT = TRANSFER(SOURCE, MOLD[, SIZE])}
10105 @item @emph{Arguments}:
10106 @multitable @columnfractions .15 .70
10107 @item @var{SOURCE} @tab Shall be a scalar or an array of any type.
10108 @item @var{MOLD} @tab Shall be a scalar or an array of any type.
10109 @item @var{SIZE} @tab (Optional) shall be a scalar of type
10113 @item @emph{Return value}:
10114 The result has the same type as @var{MOLD}, with the bit level
10115 representation of @var{SOURCE}. If @var{SIZE} is present, the result is
10116 a one-dimensional array of length @var{SIZE}. If @var{SIZE} is absent
10117 but @var{MOLD} is an array (of any size or shape), the result is a one-
10118 dimensional array of the minimum length needed to contain the entirety
10119 of the bitwise representation of @var{SOURCE}. If @var{SIZE} is absent
10120 and @var{MOLD} is a scalar, the result is a scalar.
10122 If the bitwise representation of the result is longer than that of
10123 @var{SOURCE}, then the leading bits of the result correspond to those of
10124 @var{SOURCE} and any trailing bits are filled arbitrarily.
10126 When the resulting bit representation does not correspond to a valid
10127 representation of a variable of the same type as @var{MOLD}, the results
10128 are undefined, and subsequent operations on the result cannot be
10129 guaranteed to produce sensible behavior. For example, it is possible to
10130 create @code{LOGICAL} variables for which @code{@var{VAR}} and
10131 @code{.NOT.@var{VAR}} both appear to be true.
10133 @item @emph{Example}:
10135 PROGRAM test_transfer
10136 integer :: x = 2143289344
10137 print *, transfer(x, 1.0) ! prints "NaN" on i686
10145 @section @code{TRANSPOSE} --- Transpose an array of rank two
10147 @cindex array, transpose
10148 @cindex matrix, transpose
10152 @item @emph{Description}:
10153 Transpose an array of rank two. Element (i, j) of the result has the value
10154 @code{MATRIX(j, i)}, for all i, j.
10156 @item @emph{Standard}:
10159 @item @emph{Class}:
10160 Transformational function
10162 @item @emph{Syntax}:
10163 @code{RESULT = TRANSPOSE(MATRIX)}
10165 @item @emph{Arguments}:
10166 @multitable @columnfractions .15 .70
10167 @item @var{MATRIX} @tab Shall be an array of any type and have a rank of two.
10170 @item @emph{Return value}:
10171 The result has the the same type as @var{MATRIX}, and has shape
10172 @code{(/ m, n /)} if @var{MATRIX} has shape @code{(/ n, m /)}.
10178 @section @code{TRIM} --- Remove trailing blank characters of a string
10180 @cindex string, remove trailing whitespace
10183 @item @emph{Description}:
10184 Removes trailing blank characters of a string.
10186 @item @emph{Standard}:
10189 @item @emph{Class}:
10190 Transformational function
10192 @item @emph{Syntax}:
10193 @code{RESULT = TRIM(STRING)}
10195 @item @emph{Arguments}:
10196 @multitable @columnfractions .15 .70
10197 @item @var{STRING} @tab Shall be a scalar of type @code{CHARACTER(*)}.
10200 @item @emph{Return value}:
10201 A scalar of type @code{CHARACTER(*)} which length is that of @var{STRING}
10202 less the number of trailing blanks.
10204 @item @emph{Example}:
10207 CHARACTER(len=10), PARAMETER :: s = "GFORTRAN "
10208 WRITE(*,*) LEN(s), LEN(TRIM(s)) ! "10 8", with/without trailing blanks
10212 @item @emph{See also}:
10213 @ref{ADJUSTL}, @ref{ADJUSTR}
10219 @section @code{TTYNAM} --- Get the name of a terminal device.
10221 @cindex system, terminal
10224 @item @emph{Description}:
10225 Get the name of a terminal device. For more information,
10226 see @code{ttyname(3)}.
10228 This intrinsic is provided in both subroutine and function forms;
10229 however, only one form can be used in any given program unit.
10231 @item @emph{Standard}:
10234 @item @emph{Class}:
10235 Subroutine, non-elemental function
10237 @item @emph{Syntax}:
10238 @multitable @columnfractions .80
10239 @item @code{CALL TTYNAM(UNIT, NAME)}
10240 @item @code{NAME = TTYNAM(UNIT)}
10243 @item @emph{Arguments}:
10244 @multitable @columnfractions .15 .70
10245 @item @var{UNIT} @tab Shall be a scalar @code{INTEGER(*)}.
10246 @item @var{NAME} @tab Shall be of type @code{CHARACTER(*)}.
10249 @item @emph{Example}:
10251 PROGRAM test_ttynam
10254 IF (isatty(unit=unit)) write(*,*) ttynam(unit)
10259 @item @emph{See also}:
10266 @section @code{UBOUND} --- Upper dimension bounds of an array
10268 @cindex array, upper bound
10271 @item @emph{Description}:
10272 Returns the upper bounds of an array, or a single upper bound
10273 along the @var{DIM} dimension.
10274 @item @emph{Standard}:
10277 @item @emph{Class}:
10280 @item @emph{Syntax}:
10281 @code{RESULT = UBOUND(ARRAY [, DIM])}
10283 @item @emph{Arguments}:
10284 @multitable @columnfractions .15 .70
10285 @item @var{ARRAY} @tab Shall be an array, of any type.
10286 @item @var{DIM} @tab (Optional) Shall be a scalar @code{INTEGER(*)}.
10289 @item @emph{Return value}:
10290 If @var{DIM} is absent, the result is an array of the upper bounds of
10291 @var{ARRAY}. If @var{DIM} is present, the result is a scalar
10292 corresponding to the upper bound of the array along that dimension. If
10293 @var{ARRAY} is an expression rather than a whole array or array
10294 structure component, or if it has a zero extent along the relevant
10295 dimension, the upper bound is taken to be the number of elements along
10296 the relevant dimension.
10298 @item @emph{See also}:
10305 @section @code{UMASK} --- Set the file creation mask
10307 @cindex file system, file creation mask
10310 @item @emph{Description}:
10311 Sets the file creation mask to @var{MASK} and returns the old value in
10312 argument @var{OLD} if it is supplied. See @code{umask(2)}.
10314 @item @emph{Standard}:
10317 @item @emph{Class}:
10320 @item @emph{Syntax}:
10321 @code{CALL UMASK(MASK [, OLD])}
10323 @item @emph{Arguments}:
10324 @multitable @columnfractions .15 .70
10325 @item @var{MASK} @tab Shall be a scalar of type @code{INTEGER(*)}.
10326 @item @var{MASK} @tab (Optional) Shall be a scalar of type
10335 @section @code{UNLINK} --- Remove a file from the file system
10337 @cindex file system, remove file
10340 @item @emph{Description}:
10341 Unlinks the file @var{PATH}. A null character (@code{CHAR(0)}) can be
10342 used to mark the end of the name in @var{PATH}; otherwise, trailing
10343 blanks in the file name are ignored. If the @var{STATUS} argument is
10344 supplied, it contains 0 on success or a nonzero error code upon return;
10345 see @code{unlink(2)}.
10347 This intrinsic is provided in both subroutine and function forms;
10348 however, only one form can be used in any given program unit.
10350 @item @emph{Standard}:
10353 @item @emph{Class}:
10354 Subroutine, non-elemental function
10356 @item @emph{Syntax}:
10357 @multitable @columnfractions .80
10358 @item @code{CALL UNLINK(PATH [, STATUS])}
10359 @item @code{STATUS = UNLINK(PATH)}
10362 @item @emph{Arguments}:
10363 @multitable @columnfractions .15 .70
10364 @item @var{PATH} @tab Shall be of default @code{CHARACTER} type.
10365 @item @var{STATUS} @tab (Optional) Shall be of default @code{INTEGER} type.
10368 @item @emph{See also}:
10369 @ref{LINK}, @ref{SYMLNK}
10375 @section @code{UNPACK} --- Unpack an array of rank one into an array
10377 @cindex array, unpacking
10378 @cindex array, increase dimension
10379 @cindex array, scatter elements
10382 @item @emph{Description}:
10383 Store the elements of @var{VECTOR} in an array of higher rank.
10385 @item @emph{Standard}:
10388 @item @emph{Class}:
10389 Transformational function
10391 @item @emph{Syntax}:
10392 @code{RESULT = UNPACK(VECTOR, MASK, FIELD)}
10394 @item @emph{Arguments}:
10395 @multitable @columnfractions .15 .70
10396 @item @var{VECTOR} @tab Shall be an array of any type and rank one. It
10397 shall have at least as many elements as @var{MASK} has @code{TRUE} values.
10398 @item @var{MASK} @tab Shall be an array of type @code{LOGICAL}.
10399 @item @var{FIELD} @tab Shall be of the sam type as @var{VECTOR} and have
10400 the same shape as @var{MASK}.
10403 @item @emph{Return value}:
10404 The resulting array corresponds to @var{FIELD} with @code{TRUE} elements
10405 of @var{MASK} replaced by values from @var{VECTOR} in array element order.
10407 @item @emph{Example}:
10409 PROGRAM test_unpack
10410 integer :: vector(2) = (/1,1/)
10411 logical :: mask(4) = (/ .TRUE., .FALSE., .FALSE., .TRUE. /)
10412 integer :: field(2,2) = 0, unity(2,2)
10414 ! result: unity matrix
10415 unity = unpack(vector, reshape(mask, (/2,2/)), field)
10419 @item @emph{See also}:
10420 @ref{PACK}, @ref{SPREAD}
10426 @section @code{VERIFY} --- Scan a string for the absence of a set of characters
10428 @cindex string, find missing set
10431 @item @emph{Description}:
10432 Verifies that all the characters in a @var{SET} are present in a @var{STRING}.
10434 If @var{BACK} is either absent or equals @code{FALSE}, this function
10435 returns the position of the leftmost character of @var{STRING} that is
10436 not in @var{SET}. If @var{BACK} equals @code{TRUE}, the rightmost position
10437 is returned. If all characters of @var{SET} are found in @var{STRING}, the
10440 @item @emph{Standard}:
10443 @item @emph{Class}:
10446 @item @emph{Syntax}:
10447 @code{RESULT = VERFIY(STRING, SET[, BACK])}
10449 @item @emph{Arguments}:
10450 @multitable @columnfractions .15 .70
10451 @item @var{STRING} @tab Shall be of type @code{CHARACTER(*)}.
10452 @item @var{SET} @tab Shall be of type @code{CHARACTER(*)}.
10453 @item @var{BACK} @tab (Optional) shall be of type @code{LOGICAL}.
10456 @item @emph{Return value}:
10457 The return value is of type @code{INTEGER} and of the default
10460 @item @emph{Example}:
10462 PROGRAM test_verify
10463 WRITE(*,*) VERIFY("FORTRAN", "AO") ! 1, found 'F'
10464 WRITE(*,*) VERIFY("FORTRAN", "FOO") ! 3, found 'R'
10465 WRITE(*,*) VERIFY("FORTRAN", "C++") ! 1, found 'F'
10466 WRITE(*,*) VERIFY("FORTRAN", "C++", .TRUE.) ! 7, found 'N'
10467 WRITE(*,*) VERIFY("FORTRAN", "FORTRAN") ! 0' found none
10471 @item @emph{See also}:
10472 @ref{SCAN}, @ref{INDEX}
10478 @section @code{XOR} --- Bitwise logical exclusive OR
10480 @cindex bitwise logical exclusive or
10481 @cindex logical exclusive or, bitwise
10484 @item @emph{Description}:
10485 Bitwise logical exclusive or.
10487 This intrinsic routine is provided for backwards compatibility with
10488 GNU Fortran 77. For integer arguments, programmers should consider
10489 the use of the @ref{IEOR} intrinsic defined by the Fortran standard.
10491 @item @emph{Standard}:
10494 @item @emph{Class}:
10495 Non-elemental function
10497 @item @emph{Syntax}:
10498 @code{RESULT = XOR(X, Y)}
10500 @item @emph{Arguments}:
10501 @multitable @columnfractions .15 .70
10502 @item @var{X} @tab The type shall be either @code{INTEGER(*)} or @code{LOGICAL}.
10503 @item @var{Y} @tab The type shall be either @code{INTEGER(*)} or @code{LOGICAL}.
10506 @item @emph{Return value}:
10507 The return type is either @code{INTEGER(*)} or @code{LOGICAL}
10508 after cross-promotion of the arguments.
10510 @item @emph{Example}:
10513 LOGICAL :: T = .TRUE., F = .FALSE.
10515 DATA a / Z'F' /, b / Z'3' /
10517 WRITE (*,*) XOR(T, T), XOR(T, F), XOR(F, T), XOR(F, F)
10518 WRITE (*,*) XOR(a, b)
10522 @item @emph{See also}:
10523 F95 elemental function: @ref{IEOR}