2006-10-04 Brooks Moses <bmoses@stanford.edu>

[pf3gnuchains/gcc-fork.git] / gcc / fortran / intrinsic.texi

@ignore
Copyright (C) 2005, 2006
Free Software Foundation, Inc.
This is part of the GNU Fortran manual.   
For copying conditions, see the file gfortran.texi.

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``GNU General Public License'' and ``Funding
Free Software'', the Front-Cover texts being (a) (see below), and with
the Back-Cover Texts being (b) (see below).  A copy of the license is
included in the gfdl(7) man page.


Some basic guidelines for editing this document:

  (1) The intrinsic procedures are to be listed in alphabetical order.
  (2) The generic name is to be use.
  (3) The specific names are included in the function index and in a
      table at the end of the node (See ABS entry).
  (4) Try to maintain the same style for each entry.


@end ignore

@tex
\gdef\acos{\mathop{\rm acos}\nolimits}
\gdef\asin{\mathop{\rm asin}\nolimits}
\gdef\atan{\mathop{\rm atan}\nolimits}
\gdef\acosh{\mathop{\rm acosh}\nolimits}
\gdef\asinh{\mathop{\rm asinh}\nolimits}
\gdef\atanh{\mathop{\rm atanh}\nolimits}
@end tex


@node Intrinsic Procedures
@chapter Intrinsic Procedures
@cindex Intrinsic Procedures

This portion of the document is incomplete and undergoing massive expansion 
and editing.  All contributions and corrections are strongly encouraged. 

Implemented intrinsics are fully functional and available to the user to apply. 
Some intrinsics have documentation yet to be completed as indicated by 'documentation pending'.

@menu
* Introduction:         Introduction
* @code{ABORT}:         ABORT,     Abort the program     
* @code{ABS}:           ABS,       Absolute value     
* @code{ACCESS}:        ACCESS,    Checks file access method
* @code{ACHAR}:         ACHAR,     Character in @acronym{ASCII} collating sequence
* @code{ACOS}:          ACOS,      Arccosine function
* @code{ACOSH}:         ACOSH,     Hyperbolic arccosine function
* @code{ADJUSTL}:       ADJUSTL,   Left adjust a string
* @code{ADJUSTR}:       ADJUSTR,   Right adjust a string
* @code{AIMAG}:         AIMAG,     Imaginary part of complex number
* @code{AINT}:          AINT,      Truncate to a whole number
* @code{ALARM}:         ALARM,     Set an alarm clock
* @code{ALL}:           ALL,       Determine if all values are true
* @code{ALLOCATED}:     ALLOCATED, Status of allocatable entity
* @code{AND}:           AND,       Bitwise logical AND
* @code{ANINT}:         ANINT,     Nearest whole number
* @code{ANY}:           ANY,       Determine if any values are true
* @code{ASIN}:          ASIN,      Arcsine function
* @code{ASINH}:         ASINH,     Hyperbolic arcsine function
* @code{ASSOCIATED}:    ASSOCIATED, Status of a pointer or pointer/target pair
* @code{ATAN}:          ATAN,      Arctangent function
* @code{ATAN2}:         ATAN2,     Arctangent function
* @code{ATANH}:         ATANH,     Hyperbolic arctangent function
* @code{BESJ0}:         BESJ0,     Bessel function of the first kind of order 0
* @code{BESJ1}:         BESJ1,     Bessel function of the first kind of order 1
* @code{BESJN}:         BESJN,     Bessel function of the first kind
* @code{BESY0}:         BESY0,     Bessel function of the second kind of order 0
* @code{BESY1}:         BESY1,     Bessel function of the second kind of order 1
* @code{BESYN}:         BESYN,     Bessel function of the second kind
* @code{BIT_SIZE}:      BIT_SIZE,  Bit size inquiry function
* @code{BTEST}:         BTEST,     Bit test function
* @code{CEILING}:       CEILING,   Integer ceiling function
* @code{CHAR}:          CHAR,      Integer-to-character conversion function
* @code{CHDIR}:         CHDIR,     Change working directory
* @code{CHMOD}:         CHMOD,     Change access permissions of files
* @code{CMPLX}:         CMPLX,     Complex conversion function
* @code{COMMAND_ARGUMENT_COUNT}: COMMAND_ARGUMENT_COUNT,  Command line argument count
* @code{CONJG}:         CONJG,     Complex conjugate function
* @code{COS}:           COS,       Cosine function
* @code{COSH}:          COSH,      Hyperbolic cosine function
* @code{COUNT}:         COUNT,     Count occurrences of TRUE in an array
* @code{CPU_TIME}:      CPU_TIME,  CPU time subroutine
* @code{CSHIFT}:        CSHIFT,    Circular array shift function
* @code{CTIME}:         CTIME,     Subroutine (or function) to convert a time into a string
* @code{DATE_AND_TIME}: DATE_AND_TIME, Date and time subroutine
* @code{DBLE}:          DBLE,      Double precision conversion function
* @code{DCMPLX}:        DCMPLX,    Double complex conversion function
* @code{DFLOAT}:        DFLOAT,    Double precision conversion function
* @code{DIGITS}:        DIGITS,    Significant digits function
* @code{DIM}:           DIM,       Dim function
* @code{DOT_PRODUCT}:   DOT_PRODUCT, Dot product function
* @code{DPROD}:         DPROD,     Double product function
* @code{DREAL}:         DREAL,     Double real part function
* @code{DTIME}:         DTIME,     Execution time subroutine (or function)
* @code{EOSHIFT}:       EOSHIFT,   End-off shift function
* @code{EPSILON}:       EPSILON,   Epsilon function
* @code{ERF}:           ERF,       Error function
* @code{ERFC}:          ERFC,      Complementary error function
* @code{ETIME}:         ETIME,     Execution time subroutine (or function)
* @code{EXIT}:          EXIT,      Exit the program with status.
* @code{EXP}:           EXP,       Exponential function
* @code{EXPONENT}:      EXPONENT,  Exponent function
* @code{FDATE}:         FDATE,     Subroutine (or function) to get the current time as a string
* @code{FGET}:          FGET,      Read a single character in stream mode from stdin
* @code{FGETC}:         FGETC,     Read a single character in stream mode
* @code{FLOAT}:         FLOAT,     Convert integer to default real
* @code{FLOOR}:         FLOOR,     Integer floor function
* @code{FLUSH}:         FLUSH,     Flush I/O unit(s)
* @code{FNUM}:          FNUM,      File number function
* @code{FPUT}:          FPUT,      Write a single character in stream mode to stdout
* @code{FPUTC}:         FPUTC,     Write a single character in stream mode
* @code{FRACTION}:      FRACTION,  Fractional part of the model representation
* @code{FREE}:          FREE,      Memory de-allocation subroutine
* @code{FSEEK}:         FSEEK,     Low level file positioning subroutine
* @code{FSTAT}:         FSTAT,     Get file status
* @code{FTELL}:         FTELL,     Current stream position
* @code{GETARG}:        GETARG,    Get command line arguments
* @code{GET_COMMAND}:   GET_COMMAND, Subroutine to retrieve the entire command line
* @code{GET_COMMAND_ARGUMENT}: GET_COMMAND_ARGUMENT, Subroutine to retrieve a command argument
* @code{GETCWD}:        GETCWD,    Get current working directory
* @code{GETENV}:        GETENV,    Get an environmental variable
* @code{GET_ENVIRONMENT_VARIABLE}: GET_ENVIRONMENT_VARIABLE, Get an environmental variable
* @code{GETGID}:        GETGID,    Group ID function
* @code{GETLOG}:        GETLOG,    Get login name
* @code{GETPID}:        GETPID,    Process ID function
* @code{GETUID}:        GETUID,    User ID function
* @code{GMTIME}:        GMTIME,    Convert time to GMT info
* @code{HOSTNM}:        HOSTNM,    Get system host name
* @code{HUGE}:          HUGE,      Largest number of a kind
* @code{IACHAR}:        IACHAR,    Code in @acronym{ASCII} collating sequence
* @code{IAND}:          IAND,      Bitwise logical and
* @code{IARGC}:         IARGC,     Get number of command line arguments
* @code{IBCLR}:         IBCLR,     Clear bit
* @code{IBITS}:         IBITS,     Bit extraction
* @code{IBSET}:         IBSET,     Set bit
* @code{ICHAR}:         ICHAR,     Character-to-integer conversion function
* @code{IDATE}:         IDATE,     Current local time (day/month/year)
* @code{IEOR}:          IEOR,      Bitwise logical exclusive or
* @code{IERRNO}:        IERRNO,    Function to get the last system error number
* @code{INDEX}:         INDEX,     Position of a substring within a string
* @code{INT}:           INT,       Convert to integer type
* @code{IOR}:           IOR,       Bitwise logical or
* @code{IRAND}:         IRAND,     Integer pseudo-random number
* @code{ISHFT}:         ISHFT,     Shift bits
* @code{ISHFTC}:        ISHFTC,    Shift bits circularly
* @code{ITIME}:         ITIME,     Current local time (hour/minutes/seconds)
* @code{KILL}:          KILL,      Send a signal to a process
* @code{KIND}:          KIND,      Kind of an entity
* @code{LBOUND}:        LBOUND,    Lower dimension bounds of an array
* @code{LEN}:           LEN,       Length of a character entity
* @code{LEN_TRIM}:      LEN_TRIM,  Length of a character entity without trailing blank characters
* @code{LGE}:           LGE,       Lexical greater than or equal
* @code{LGT}:           LGT,       Lexical greater than
* @code{LINK}:          LINK,      Create a hard link
* @code{LLE}:           LLE,       Lexical less than or equal
* @code{LLT}:           LLT,       Lexical less than
* @code{LNBLNK}:        LNBLNK,    Index of the last non-blank character in a string
* @code{LOC}:           LOC,       Returns the address of a variable
* @code{LOG}:           LOG,       Logarithm function
* @code{LOG10}:         LOG10,     Base 10 logarithm function 
* @code{LOGICAL}:       LOGICAL,   Convert to logical type
* @code{LSHIFT}:        LSHIFT,    Left shift bits
* @code{LTIME}:         LTIME,     Convert time to local time info
* @code{MALLOC}:        MALLOC,    Dynamic memory allocation function
* @code{MATMUL}:        MATMUL,    matrix multiplication
* @code{MAX}:           MAX,       Maximum value of an argument list
* @code{MAXEXPONENT}:   MAXEXPONENT, Maximum exponent of a real kind
* @code{MAXLOC}:        MAXLOC,    Location of the maximum value within an array
* @code{MAXVAL}:        MAXVAL,    Maximum value of an array
* @code{MERGE}:         MERGE,     Merge arrays
* @code{MIN}:           MIN,       Minimum value of an argument list
* @code{MINEXPONENT}:   MINEXPONENT, Minimum exponent of a real kind
* @code{MINLOC}:        MINLOC,    Location of the minimum value within an array
* @code{MINVAL}:        MINVAL,    Minimum value of an array
* @code{MOD}:           MOD,       Remainder function
* @code{MODULO}:        MODULO,    Modulo function
* @code{MVBITS}:        MVBITS,    Move bits from one integer to another
* @code{NEAREST}:       NEAREST,   Nearest representable number
* @code{NINT}:          NINT,      Nearest whole number
* @code{NOT}:           NOT,       Logical negation
* @code{NULL}:          NULL,      Function that returns an disassociated pointer
* @code{OR}:            OR,        Bitwise logical OR
* @code{PACK}:          PACK,      Pack an array into an array of rank one
* @code{PERROR}:        PERROR,    Print system error message
* @code{PRECISION}:     PRECISION, Decimal precision of a real kind
* @code{PRESENT}:       PRESENT,   Determine whether an optional argument is specified
* @code{PRODUCT}:       PRODUCT,   Product of array elements
* @code{RADIX}:         RADIX,     Base of a data model
* @code{RANDOM_NUMBER}: RANDOM_NUMBER, Pseudo-random number
* @code{RANDOM_SEED}:   RANDOM_SEED, Initialize a pseudo-random number sequence
* @code{RAND}:          RAND,      Real pseudo-random number
* @code{RANGE}:         RANGE,     Decimal exponent range of a real kind
* @code{RAN}:           RAN,       Real pseudo-random number
* @code{REAL}:          REAL,      Convert to real type 
* @code{RENAME}:        RENAME,    Rename a file
* @code{REPEAT}:        REPEAT,    Repeated string concatenation
* @code{RESHAPE}:       RESHAPE,   Function to reshape an array
* @code{RRSPACING}:     RRSPACING, Reciprocal of the relative spacing
* @code{RSHIFT}:        RSHIFT,    Right shift bits
* @code{SCALE}:         SCALE,     Scale a real value
* @code{SCAN}:          SCAN,      Scan a string for the presence of a set of characters
* @code{SECNDS}:        SECNDS,    Time function
@comment * @code{SECOND}:        SECOND,    (?)
@comment * @code{SECONDS}:       SECONDS,   (?)
* @code{SELECTED_INT_KIND}: SELECTED_INT_KIND,  Choose integer kind
* @code{SELECTED_REAL_KIND}: SELECTED_REAL_KIND,  Choose real kind
* @code{SET_EXPONENT}:  SET_EXPONENT, Set the exponent of the model
* @code{SHAPE}:         SHAPE,     Determine the shape of an array
* @code{SIGN}:          SIGN,      Sign copying function
* @code{SIGNAL}:        SIGNAL,    Signal handling subroutine (or function)
* @code{SIN}:           SIN,       Sine function
* @code{SINH}:          SINH,      Hyperbolic sine function
* @code{SIZE}:          SIZE,      Function to determine the size of an array
* @code{SNGL}:          SNGL,      Convert double precision real to default real
* @code{SPACING}:       SPACING,   Smallest distance between two numbers of a given type
* @code{SPREAD}:        SPREAD,    Add a dimension to an array 
* @code{SQRT}:          SQRT,      Square-root function
* @code{SRAND}:         SRAND,     Reinitialize the random number generator
* @code{STAT}:          STAT,      Get file status
* @code{SUM}:           SUM,       Sum of array elements
* @code{SYMLNK}:        SYMLNK,    Create a symbolic link
* @code{SYSTEM}:        SYSTEM,    Execute a shell command
* @code{SYSTEM_CLOCK}:  SYSTEM_CLOCK, Time function
* @code{TAN}:           TAN,       Tangent function
* @code{TANH}:          TANH,      Hyperbolic tangent function
* @code{TIME}:          TIME,      Time function
* @code{TINY}:          TINY,      Smallest positive number of a real kind
* @code{TRANSFER}:      TRANSFER,  Transfer bit patterns
* @code{TRANSPOSE}:     TRANSPOSE, Transpose an array of rank two
* @code{TRIM}:          TRIM,      Function to remove trailing blank characters of a string
* @code{UBOUND}:        UBOUND,    Upper dimension bounds of an array
* @code{UMASK}:         UMASK,     Set the file creation mask
* @code{UNLINK}:        UNLINK,    Remove a file from the file system
* @code{UNMASK}:        UNMASK,    (?)
* @code{UNPACK}:        UNPACK,    Unpack an array of rank one into an array
* @code{VERIFY}:        VERIFY,    Scan a string for the absence of a set of characters
* @code{XOR}:           XOR,       Bitwise logical exclusive or
@end menu

@node Introduction
@section Introduction to intrinsic procedures

GNU Fortran provides a rich set of intrinsic procedures that includes all
the intrinsic procedures required by the Fortran 95 standard, a set of
intrinsic procedures for backwards compatibility with Gnu Fortran 77
(i.e., @command{g77}), and a small selection of intrinsic procedures
from the Fortran 2003 standard.  Any description here, which conflicts with a 
description in either the Fortran 95 standard or the Fortran 2003 standard,
is unintentional and the standard(s) should be considered authoritative.

The enumeration of the @code{KIND} type parameter is processor defined in
the Fortran 95 standard.  GNU Fortran defines the default integer type and
default real type by @code{INTEGER(KIND=4)} and @code{REAL(KIND=4)},
respectively.  The standard mandates that both data types shall have
another kind, which have more precision.  On typical target architectures
supported by @command{gfortran}, this kind type parameter is @code{KIND=8}.
Hence, @code{REAL(KIND=8)} and @code{DOUBLE PRECISION} are equivalent.
In the description of generic intrinsic procedures, the kind type parameter
will be specified by @code{KIND=*}, and in the description of specific
names for an intrinsic procedure the kind type parameter will be explicitly
given (e.g., @code{REAL(KIND=4)} or @code{REAL(KIND=8)}).  Finally, for
brevity the optional @code{KIND=} syntax will be omitted.

Many of the intrinsics procedures take one or more optional arguments.
This document follows the convention used in the Fortran 95 standard,
and denotes such arguments by square brackets.

GNU Fortran offers the @option{-std=f95} and @option{-std=gnu} options,
which can be used to restrict the set of intrinsic procedures to a 
given standard.  By default, @command{gfortran} sets the @option{-std=gnu}
option, and so all intrinsic procedures described here are accepted.  There
is one caveat.  For a select group of intrinsic procedures, @command{g77}
implemented both a function and a subroutine.  Both classes 
have been implemented in @command{gfortran} for backwards compatibility
with @command{g77}.  It is noted here that these functions and subroutines
cannot be intermixed in a given subprogram.  In the descriptions that follow,
the applicable option(s) is noted.



@node ABORT
@section @code{ABORT} --- Abort the program  
@findex @code{ABORT} intrinsic
@cindex abort

@table @asis
@item @emph{Description}:
@code{ABORT} causes immediate termination of the program.  On operating
systems that support a core dump, @code{ABORT} will produce a core dump,
which is suitable for debugging purposes.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
non-elemental subroutine

@item @emph{Syntax}:
@code{CALL ABORT}

@item @emph{Return value}:
Does not return.

@item @emph{Example}:
@smallexample
program test_abort
  integer :: i = 1, j = 2
  if (i /= j) call abort
end program test_abort
@end smallexample

@item @emph{See also}:
@ref{EXIT}, @ref{KILL}

@end table



@node ABS
@section @code{ABS} --- Absolute value  
@findex @code{ABS} intrinsic
@findex @code{CABS} intrinsic
@findex @code{DABS} intrinsic
@findex @code{IABS} intrinsic
@findex @code{ZABS} intrinsic
@findex @code{CDABS} intrinsic
@cindex absolute value

@table @asis
@item @emph{Description}:
@code{ABS(X)} computes the absolute value of @code{X}.

@item @emph{Standard}:
F77 and later, has overloads that are GNU extensions

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = ABS(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type of the argument shall be an @code{INTEGER(*)},
@code{REAL(*)}, or @code{COMPLEX(*)}.
@end multitable

@item @emph{Return value}:
The return value is of the same type and
kind as the argument except the return value is @code{REAL(*)} for a
@code{COMPLEX(*)} argument.

@item @emph{Example}:
@smallexample
program test_abs
  integer :: i = -1
  real :: x = -1.e0
  complex :: z = (-1.e0,0.e0)
  i = abs(i)
  x = abs(x)
  x = abs(z)
end program test_abs
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument            @tab Return type       @tab Standard
@item @code{CABS(Z)}  @tab @code{COMPLEX(4) Z} @tab @code{REAL(4)}    @tab F77 and later
@item @code{DABS(X)}  @tab @code{REAL(8)    X} @tab @code{REAL(8)}    @tab F77 and later
@item @code{IABS(I)}  @tab @code{INTEGER(4) I} @tab @code{INTEGER(4)} @tab F77 and later
@item @code{ZABS(Z)}  @tab @code{COMPLEX(8) Z} @tab @code{COMPLEX(8)} @tab GNU extension
@item @code{CDABS(Z)} @tab @code{COMPLEX(8) Z} @tab @code{COMPLEX(8)} @tab GNU extension
@end multitable
@end table


@node ACCESS
@section @code{ACCESS} --- Checks file access method
@findex @code{ACCESS} 
@cindex file system functions

Not yet implemented in GNU Fortran.

@table @asis
@item @emph{Description}:

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@uref{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19292, g77 features lacking in gfortran}

@end table


@node ACHAR
@section @code{ACHAR} --- Character in @acronym{ASCII} collating sequence 
@findex @code{ACHAR} intrinsic
@cindex @acronym{ASCII} collating sequence

@table @asis
@item @emph{Description}:
@code{ACHAR(I)} returns the character located at position @code{I}
in the @acronym{ASCII} collating sequence.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{C = ACHAR(I)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{I} @tab The type shall be @code{INTEGER(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{CHARACTER} with a length of one.  The
kind type parameter is the same as  @code{KIND('A')}.

@item @emph{Example}:
@smallexample
program test_achar
  character c
  c = achar(32)
end program test_achar
@end smallexample
@end table



@node ACOS
@section @code{ACOS} --- Arccosine function 
@findex @code{ACOS} intrinsic
@findex @code{DACOS} intrinsic
@cindex trigonometric functions (inverse)

@table @asis
@item @emph{Description}:
@code{ACOS(X)} computes the arccosine of @var{X} (inverse of @code{COS(X)}).

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = ACOS(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)} with a magnitude that is
less than one.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} and it lies in the
range @math{ 0 \leq \acos(x) \leq \pi}. The kind type parameter 
is the same as @var{X}.

@item @emph{Example}:
@smallexample
program test_acos
  real(8) :: x = 0.866_8
  x = acos(x)
end program test_acos
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DACOS(X)} @tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab F77 and later
@end multitable

@item @emph{See also}:
Inverse function: @ref{COS}

@end table


@node ACOSH
@section @code{ACOSH} --- Hyperbolic arccosine function
@findex @code{ACOSH} intrinsic
@cindex hyperbolic arccosine
@cindex hyperbolic cosine (inverse)

@table @asis
@item @emph{Description}:
@code{ACOSH(X)} computes the area hyperbolic cosine of @var{X} (inverse of @code{COSH(X)}).

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = ACOSH(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)} with a magnitude that is
greater or equal to one.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} and it lies in the
range @math{0 \leq \acosh (x) \leq \infty}.

@item @emph{Example}:
@smallexample
PROGRAM test_acosh
  REAL(8), DIMENSION(3) :: x = (/ 1.0, 2.0, 3.0 /)
  WRITE (*,*) ACOSH(x)
END PROGRAM
@end smallexample

@item @emph{See also}:
Inverse function: @ref{COSH}
@end table



@node ADJUSTL
@section @code{ADJUSTL} --- Left adjust a string 
@findex @code{ADJUSTL} intrinsic
@cindex adjust string

@table @asis
@item @emph{Description}:
@code{ADJUSTL(STR)} will left adjust a string by removing leading spaces.
Spaces are inserted at the end of the string as needed.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{STR = ADJUSTL(STR)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{STR} @tab The type shall be @code{CHARACTER}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{CHARACTER} where leading spaces 
are removed and the same number of spaces are inserted on the end
of @var{STR}.

@item @emph{Example}:
@smallexample
program test_adjustl
  character(len=20) :: str = '   gfortran'
  str = adjustl(str)
  print *, str
end program test_adjustl
@end smallexample
@end table



@node ADJUSTR
@section @code{ADJUSTR} --- Right adjust a string 
@findex @code{ADJUSTR} intrinsic
@cindex adjust string

@table @asis
@item @emph{Description}:
@code{ADJUSTR(STR)} will right adjust a string by removing trailing spaces.
Spaces are inserted at the start of the string as needed.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{STR = ADJUSTR(STR)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{STR} @tab The type shall be @code{CHARACTER}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{CHARACTER} where trailing spaces 
are removed and the same number of spaces are inserted at the start
of @var{STR}.

@item @emph{Example}:
@smallexample
program test_adjustr
  character(len=20) :: str = 'gfortran'
  str = adjustr(str)
  print *, str
end program test_adjustr
@end smallexample
@end table



@node AIMAG
@section @code{AIMAG} --- Imaginary part of complex number  
@findex @code{AIMAG} intrinsic
@findex @code{DIMAG} intrinsic
@findex @code{IMAG} intrinsic
@findex @code{IMAGPART} intrinsic
@cindex Imaginary part

@table @asis
@item @emph{Description}:
@code{AIMAG(Z)} yields the imaginary part of complex argument @code{Z}.
The @code{IMAG(Z)} and @code{IMAGPART(Z)} intrinsic functions are provided
for compatibility with @command{g77}, and their use in new code is 
strongly discouraged.

@item @emph{Standard}:
F77 and later, has overloads that are GNU extensions

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = AIMAG(Z)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{Z} @tab The type of the argument shall be @code{COMPLEX(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type real with the
kind type parameter of the argument.

@item @emph{Example}:
@smallexample
program test_aimag
  complex(4) z4
  complex(8) z8
  z4 = cmplx(1.e0_4, 0.e0_4)
  z8 = cmplx(0.e0_8, 1.e0_8)
  print *, aimag(z4), dimag(z8)
end program test_aimag
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument            @tab Return type       @tab Standard
@item @code{DIMAG(Z)} @tab @code{COMPLEX(8) Z} @tab @code{REAL(8)}    @tab F95 and later
@item @code{IMAG(Z)}  @tab @code{COMPLEX(*) Z} @tab @code{REAL(*)}    @tab GNU extension
@item @code{IMAGPART(Z)} @tab @code{COMPLEX(*) Z} @tab @code{REAL(*)} @tab GNU extension
@end multitable
@end table



@node AINT
@section @code{AINT} --- Truncate to a whole number
@findex @code{AINT} intrinsic
@findex @code{DINT} intrinsic
@cindex whole number

@table @asis
@item @emph{Description}:
@code{AINT(X [, KIND])} truncates its argument to a whole number.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = AINT(X)} 
@code{X = AINT(X, KIND)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X}    @tab The type of the argument shall be @code{REAL(*)}.
@item @var{KIND} @tab (Optional) @var{KIND} shall be a scalar integer
initialization expression.
@end multitable

@item @emph{Return value}:
The return value is of type real with the kind type parameter of the
argument if the optional @var{KIND} is absent; otherwise, the kind
type parameter will be given by @var{KIND}.  If the magnitude of 
@var{X} is less than one, then @code{AINT(X)} returns zero.  If the
magnitude is equal to or greater than one, then it returns the largest
whole number that does not exceed its magnitude.  The sign is the same
as the sign of @var{X}. 

@item @emph{Example}:
@smallexample
program test_aint
  real(4) x4
  real(8) x8
  x4 = 1.234E0_4
  x8 = 4.321_8
  print *, aint(x4), dint(x8)
  x8 = aint(x4,8)
end program test_aint
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name           @tab Argument         @tab Return type      @tab Standard
@item @code{DINT(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)}   @tab F77 and later
@end multitable
@end table



@node ALARM
@section @code{ALARM} --- Execute a routine after a given delay
@findex @code{ALARM} intrinsic

@table @asis
@item @emph{Description}:
@code{ALARM(SECONDS, HANDLER [, STATUS])} causes external subroutine @var{HANDLER}
to be executed after a delay of @var{SECONDS} by using @code{alarm(1)} to
set up a signal and @code{signal(2)} to catch it. If @var{STATUS} is
supplied, it will be returned with the number of seconds remaining until
any previously scheduled alarm was due to be delivered, or zero if there
was no previously scheduled alarm.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@code{CALL ALARM(SECONDS, HANDLER)} 
@code{CALL ALARM(SECONDS, HANDLER, STATUS)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{SECONDS} @tab The type of the argument shall be a scalar
@code{INTEGER}. It is @code{INTENT(IN)}.
@item @var{HANDLER} @tab Signal handler (@code{INTEGER FUNCTION} or
@code{SUBROUTINE}) or dummy/global @code{INTEGER} scalar.
@code{INTEGER}. It is @code{INTENT(IN)}.
@item @var{STATUS}  @tab (Optional) @var{STATUS} shall be a scalar
@code{INTEGER} variable. It is @code{INTENT(OUT)}.
@end multitable

@item @emph{Example}:
@smallexample
program test_alarm
  external handler_print
  integer i
  call alarm (3, handler_print, i)
  print *, i
  call sleep(10)
end program test_alarm
@end smallexample
This will cause the external routine @var{handler_print} to be called
after 3 seconds.
@end table



@node ALL
@section @code{ALL} --- All values in @var{MASK} along @var{DIM} are true 
@findex @code{ALL} intrinsic
@cindex true values

@table @asis
@item @emph{Description}:
@code{ALL(MASK [, DIM])} determines if all the values are true in @var{MASK}
in the array along dimension @var{DIM}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
transformational function

@item @emph{Syntax}:
@code{L = ALL(MASK)} 
@code{L = ALL(MASK, DIM)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{MASK} @tab The type of the argument shall be @code{LOGICAL(*)} and
it shall not be scalar.
@item @var{DIM}  @tab (Optional) @var{DIM} shall be a scalar integer
with a value that lies between one and the rank of @var{MASK}.
@end multitable

@item @emph{Return value}:
@code{ALL(MASK)} returns a scalar value of type @code{LOGICAL(*)} where
the kind type parameter is the same as the kind type parameter of
@var{MASK}.  If @var{DIM} is present, then @code{ALL(MASK, DIM)} returns
an array with the rank of @var{MASK} minus 1.  The shape is determined from
the shape of @var{MASK} where the @var{DIM} dimension is elided. 

@table @asis
@item (A)
@code{ALL(MASK)} is true if all elements of @var{MASK} are true.
It also is true if @var{MASK} has zero size; otherwise, it is false.
@item (B)
If the rank of @var{MASK} is one, then @code{ALL(MASK,DIM)} is equivalent
to @code{ALL(MASK)}.  If the rank is greater than one, then @code{ALL(MASK,DIM)}
is determined by applying @code{ALL} to the array sections.
@end table

@item @emph{Example}:
@smallexample
program test_all
  logical l
  l = all((/.true., .true., .true./))
  print *, l
  call section
  contains
    subroutine section
      integer a(2,3), b(2,3)
      a = 1
      b = 1
      b(2,2) = 2
      print *, all(a .eq. b, 1)
      print *, all(a .eq. b, 2)
    end subroutine section
end program test_all
@end smallexample
@end table



@node ALLOCATED
@section @code{ALLOCATED} --- Status of an allocatable entity
@findex @code{ALLOCATED} intrinsic
@cindex allocation status

@table @asis
@item @emph{Description}:
@code{ALLOCATED(X)} checks the status of whether @var{X} is allocated.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{L = ALLOCATED(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X}    @tab The argument shall be an @code{ALLOCATABLE} array.
@end multitable

@item @emph{Return value}:
The return value is a scalar @code{LOGICAL} with the default logical
kind type parameter.  If @var{X} is allocated, @code{ALLOCATED(X)}
is @code{.TRUE.}; otherwise, it returns the @code{.TRUE.} 

@item @emph{Example}:
@smallexample
program test_allocated
  integer :: i = 4
  real(4), allocatable :: x(:)
  if (allocated(x) .eqv. .false.) allocate(x(i))
end program test_allocated
@end smallexample
@end table


@node AND
@section @code{AND} --- Bitwise logical AND
@findex @code{AND} intrinsic
@cindex bit operations

@table @asis
@item @emph{Description}:
Bitwise logical @code{AND}.

This intrinsic routine is provided for backwards compatibility with 
GNU Fortran 77.  For integer arguments, programmers should consider
the use of the @ref{IAND} intrinsic defined by the Fortran standard.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Non-elemental function

@item @emph{Syntax}:
@code{RESULT = AND(X, Y)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be either @code{INTEGER(*)} or @code{LOGICAL}.
@item @var{Y} @tab The type shall be either @code{INTEGER(*)} or @code{LOGICAL}.
@end multitable

@item @emph{Return value}:
The return type is either @code{INTEGER(*)} or @code{LOGICAL} after
cross-promotion of the arguments. 

@item @emph{Example}:
@smallexample
PROGRAM test_and
  LOGICAL :: T = .TRUE., F = ..FALSE.
  INTEGER :: a, b
  DATA a / Z'F' /, b / Z'3' /

  WRITE (*,*) AND(T, T), AND(T, F), AND(F, T), AND(F, F)
  WRITE (*,*) AND(a, b)
END PROGRAM
@end smallexample

@item @emph{See also}:
F95 elemental function: @ref{IAND}
@end table



@node ANINT
@section @code{ANINT} --- Nearest whole number
@findex @code{ANINT} intrinsic
@findex @code{DNINT} intrinsic
@cindex whole number

@table @asis
@item @emph{Description}:
@code{ANINT(X [, KIND])} rounds its argument to the nearest whole number.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = ANINT(X)}
@code{X = ANINT(X, KIND)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X}    @tab The type of the argument shall be @code{REAL(*)}.
@item @var{KIND} @tab (Optional) @var{KIND} shall be a scalar integer
initialization expression.
@end multitable

@item @emph{Return value}:
The return value is of type real with the kind type parameter of the
argument if the optional @var{KIND} is absent; otherwise, the kind
type parameter will be given by @var{KIND}.  If @var{X} is greater than
zero, then @code{ANINT(X)} returns @code{AINT(X+0.5)}.  If @var{X} is
less than or equal to zero, then it returns @code{AINT(X-0.5)}.

@item @emph{Example}:
@smallexample
program test_anint
  real(4) x4
  real(8) x8
  x4 = 1.234E0_4
  x8 = 4.321_8
  print *, anint(x4), dnint(x8)
  x8 = anint(x4,8)
end program test_anint
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument         @tab Return type      @tab Standard
@item @code{DNINT(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)}   @tab F77 and later
@end multitable
@end table



@node ANY
@section @code{ANY} --- Any value in @var{MASK} along @var{DIM} is true 
@findex @code{ANY} intrinsic
@cindex true values

@table @asis
@item @emph{Description}:
@code{ANY(MASK [, DIM])} determines if any of the values in the logical array
@var{MASK} along dimension @var{DIM} are @code{.TRUE.}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
transformational function

@item @emph{Syntax}:
@code{L = ANY(MASK)} 
@code{L = ANY(MASK, DIM)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{MASK} @tab The type of the argument shall be @code{LOGICAL(*)} and
it shall not be scalar.
@item @var{DIM}  @tab (Optional) @var{DIM} shall be a scalar integer
with a value that lies between one and the rank of @var{MASK}.
@end multitable

@item @emph{Return value}:
@code{ANY(MASK)} returns a scalar value of type @code{LOGICAL(*)} where
the kind type parameter is the same as the kind type parameter of
@var{MASK}.  If @var{DIM} is present, then @code{ANY(MASK, DIM)} returns
an array with the rank of @var{MASK} minus 1.  The shape is determined from
the shape of @var{MASK} where the @var{DIM} dimension is elided. 

@table @asis
@item (A)
@code{ANY(MASK)} is true if any element of @var{MASK} is true;
otherwise, it is false.  It also is false if @var{MASK} has zero size.
@item (B)
If the rank of @var{MASK} is one, then @code{ANY(MASK,DIM)} is equivalent
to @code{ANY(MASK)}.  If the rank is greater than one, then @code{ANY(MASK,DIM)}
is determined by applying @code{ANY} to the array sections.
@end table

@item @emph{Example}:
@smallexample
program test_any
  logical l
  l = any((/.true., .true., .true./))
  print *, l
  call section
  contains
    subroutine section
      integer a(2,3), b(2,3)
      a = 1
      b = 1
      b(2,2) = 2
      print *, any(a .eq. b, 1)
      print *, any(a .eq. b, 2)
    end subroutine section
end program test_any
@end smallexample
@end table



@node ASIN
@section @code{ASIN} --- Arcsine function 
@findex @code{ASIN} intrinsic
@findex @code{DASIN} intrinsic
@cindex trigonometric functions (inverse)

@table @asis
@item @emph{Description}:
@code{ASIN(X)} computes the arcsine of its @var{X} (inverse of @code{SIN(X)}).

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = ASIN(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}, and a magnitude that is
less than one.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} and it lies in the
range @math{-\pi / 2 \leq \asin (x) \leq \pi / 2}.  The kind type
parameter is the same as @var{X}.

@item @emph{Example}:
@smallexample
program test_asin
  real(8) :: x = 0.866_8
  x = asin(x)
end program test_asin
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DASIN(X)} @tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab F77 and later
@end multitable

@item @emph{See also}:
Inverse function: @ref{SIN}

@end table


@node ASINH
@section @code{ASINH} --- Hyperbolic arcsine function
@findex @code{ASINH} intrinsic
@cindex hyperbolic arcsine
@cindex hyperbolic sine (inverse)

@table @asis
@item @emph{Description}:
@code{ASINH(X)} computes the area hyperbolic sine of @var{X} (inverse of @code{SINH(X)}).

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = ASINH(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}, with @var{X} a real number.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} and it lies in the
range @math{-\infty \leq \asinh (x) \leq \infty}.

@item @emph{Example}:
@smallexample
PROGRAM test_asinh
  REAL(8), DIMENSION(3) :: x = (/ -1.0, 0.0, 1.0 /)
  WRITE (*,*) ASINH(x)
END PROGRAM
@end smallexample

@item @emph{See also}:
Inverse function: @ref{SINH}
@end table



@node ASSOCIATED
@section @code{ASSOCIATED} --- Status of a pointer or pointer/target pair 
@findex @code{ASSOCIATED} intrinsic
@cindex pointer status

@table @asis
@item @emph{Description}:
@code{ASSOCIATED(PTR [, TGT])} determines the status of the pointer @var{PTR}
or if @var{PTR} is associated with the target @var{TGT}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{L = ASSOCIATED(PTR)} 
@code{L = ASSOCIATED(PTR [, TGT])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{PTR} @tab @var{PTR} shall have the @code{POINTER} attribute and
it can be of any type.
@item @var{TGT} @tab (Optional) @var{TGT} shall be a @code{POINTER} or
a @code{TARGET}.  It must have the same type, kind type parameter, and
array rank as @var{PTR}.
@end multitable
The status of neither @var{PTR} nor @var{TGT} can be undefined.

@item @emph{Return value}:
@code{ASSOCIATED(PTR)} returns a scalar value of type @code{LOGICAL(4)}.
There are several cases:
@table @asis
@item (A) If the optional @var{TGT} is not present, then @code{ASSOCIATED(PTR)}
is true if @var{PTR} is associated with a target; otherwise, it returns false.
@item (B) If @var{TGT} is present and a scalar target, the result is true if
@var{TGT}
is not a 0 sized storage sequence and the target associated with @var{PTR}
occupies the same storage units.  If @var{PTR} is disassociated, then the 
result is false.
@item (C) If @var{TGT} is present and an array target, the result is true if
@var{TGT} and @var{PTR} have the same shape, are not 0 sized arrays, are
arrays whose elements are not 0 sized storage sequences, and @var{TGT} and
@var{PTR} occupy the same storage units in array element order.
As in case(B), the result is false, if @var{PTR} is disassociated.
@item (D) If @var{TGT} is present and an scalar pointer, the result is true if
target associated with @var{PTR} and the target associated with @var{TGT}
are not 0 sized storage sequences and occupy the same storage units.
The result is false, if either @var{TGT} or @var{PTR} is disassociated.
@item (E) If @var{TGT} is present and an array pointer, the result is true if
target associated with @var{PTR} and the target associated with @var{TGT}
have the same shape, are not 0 sized arrays, are arrays whose elements are
not 0 sized storage sequences, and @var{TGT} and @var{PTR} occupy the same
storage units in array element order.
The result is false, if either @var{TGT} or @var{PTR} is disassociated.
@end table

@item @emph{Example}:
@smallexample
program test_associated
   implicit none
   real, target  :: tgt(2) = (/1., 2./)
   real, pointer :: ptr(:)
   ptr => tgt
   if (associated(ptr)     .eqv. .false.) call abort
   if (associated(ptr,tgt) .eqv. .false.) call abort
end program test_associated
@end smallexample

@item @emph{See also}:
@ref{NULL}
@end table



@node ATAN
@section @code{ATAN} --- Arctangent function 
@findex @code{ATAN} intrinsic
@findex @code{DATAN} intrinsic
@cindex trigonometric functions (inverse)

@table @asis
@item @emph{Description}:
@code{ATAN(X)} computes the arctangent of @var{X}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = ATAN(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} and it lies in the
range @math{ - \pi / 2 \leq \atan (x) \leq \pi / 2}.

@item @emph{Example}:
@smallexample
program test_atan
  real(8) :: x = 2.866_8
  x = atan(x)
end program test_atan
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DATAN(X)} @tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab F77 and later
@end multitable

@item @emph{See also}:
Inverse function: @ref{TAN}

@end table



@node ATAN2
@section @code{ATAN2} --- Arctangent function 
@findex @code{ATAN2} intrinsic
@findex @code{DATAN2} intrinsic
@cindex trigonometric functions (inverse)

@table @asis
@item @emph{Description}:
@code{ATAN2(Y,X)} computes the arctangent of the complex number @math{X + i Y}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = ATAN2(Y,X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{Y} @tab The type shall be @code{REAL(*)}.
@item @var{X} @tab The type and kind type parameter shall be the same as @var{Y}.
If @var{Y} is zero, then @var{X} must be nonzero.
@end multitable

@item @emph{Return value}:
The return value has the same type and kind type parameter as @var{Y}.
It is the principal value of the complex number @math{X + i Y}.  If
@var{X} is nonzero, then it lies in the range @math{-\pi \le \atan (x) \leq \pi}.
The sign is positive if @var{Y} is positive.  If @var{Y} is zero, then
the return value is zero if @var{X} is positive and @math{\pi} if @var{X}
is negative.  Finally, if @var{X} is zero, then the magnitude of the result
is @math{\pi/2}.

@item @emph{Example}:
@smallexample
program test_atan2
  real(4) :: x = 1.e0_4, y = 0.5e0_4
  x = atan2(y,x)
end program test_atan2
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type    @tab Standard
@item @code{DATAN2(X)} @tab @code{REAL(8) X} @tab @code{REAL(8)} @tab F77 and later
@end multitable
@end table



@node ATANH
@section @code{ATANH} --- Hyperbolic arctangent function
@findex @code{ASINH} intrinsic
@cindex hyperbolic arctangent
@cindex hyperbolic tangent (inverse)

@table @asis
@item @emph{Description}:
@code{ATANH(X)} computes the area hyperbolic sine of @var{X} (inverse of @code{TANH(X)}).

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = ATANH(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)} with a magnitude that is less than or equal to one.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} and it lies in the
range @math{-\infty \leq \atanh(x) \leq \infty}.

@item @emph{Example}:
@smallexample
PROGRAM test_atanh
  REAL, DIMENSION(3) :: x = (/ -1.0, 0.0, 1.0 /)
  WRITE (*,*) ATANH(x)
END PROGRAM
@end smallexample

@item @emph{See also}:
Inverse function: @ref{TANH}
@end table




@node BESJ0
@section @code{BESJ0} --- Bessel function of the first kind of order 0
@findex @code{BESJ0} intrinsic
@findex @code{DBESJ0} intrinsic
@cindex Bessel

@table @asis
@item @emph{Description}:
@code{BESJ0(X)} computes the Bessel function of the first kind of order 0
of @var{X}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = BESJ0(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} and it lies in the
range @math{ - 0.4027... \leq Bessel (0,x) \leq 1}.

@item @emph{Example}:
@smallexample
program test_besj0
  real(8) :: x = 0.0_8
  x = besj0(x)
end program test_besj0
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DBESJ0(X)} @tab @code{REAL(8) X}  @tab @code{REAL(8)}   @tab GNU extension
@end multitable
@end table



@node BESJ1
@section @code{BESJ1} --- Bessel function of the first kind of order 1
@findex @code{BESJ1} intrinsic
@findex @code{DBESJ1} intrinsic
@cindex Bessel

@table @asis
@item @emph{Description}:
@code{BESJ1(X)} computes the Bessel function of the first kind of order 1
of @var{X}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = BESJ1(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} and it lies in the
range @math{ - 0.5818... \leq Bessel (0,x) \leq 0.5818 }.

@item @emph{Example}:
@smallexample
program test_besj1
  real(8) :: x = 1.0_8
  x = besj1(x)
end program test_besj1
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DBESJ1(X)}@tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab GNU extension
@end multitable
@end table



@node BESJN
@section @code{BESJN} --- Bessel function of the first kind
@findex @code{BESJN} intrinsic
@findex @code{DBESJN} intrinsic
@cindex Bessel

@table @asis
@item @emph{Description}:
@code{BESJN(N, X)} computes the Bessel function of the first kind of order
@var{N} of @var{X}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{Y = BESJN(N, X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{N} @tab The type shall be @code{INTEGER(*)}, and it shall be scalar.
@item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
@end multitable

@item @emph{Return value}:
The return value is a scalar of type @code{REAL(*)}.

@item @emph{Example}:
@smallexample
program test_besjn
  real(8) :: x = 1.0_8
  x = besjn(5,x)
end program test_besjn
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name             @tab Argument            @tab Return type       @tab Standard
@item @code{DBESJN(X)} @tab @code{INTEGER(*) N} @tab @code{REAL(8)}    @tab GNU extension
@item                  @tab @code{REAL(8) X}    @tab                   @tab
@end multitable
@end table



@node BESY0
@section @code{BESY0} --- Bessel function of the second kind of order 0
@findex @code{BESY0} intrinsic
@findex @code{DBESY0} intrinsic
@cindex Bessel

@table @asis
@item @emph{Description}:
@code{BESY0(X)} computes the Bessel function of the second kind of order 0
of @var{X}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = BESY0(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
@end multitable

@item @emph{Return value}:
The return value is a scalar of type @code{REAL(*)}.

@item @emph{Example}:
@smallexample
program test_besy0
  real(8) :: x = 0.0_8
  x = besy0(x)
end program test_besy0
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DBESY0(X)}@tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab GNU extension
@end multitable
@end table



@node BESY1
@section @code{BESY1} --- Bessel function of the second kind of order 1
@findex @code{BESY1} intrinsic
@findex @code{DBESY1} intrinsic
@cindex Bessel

@table @asis
@item @emph{Description}:
@code{BESY1(X)} computes the Bessel function of the second kind of order 1
of @var{X}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = BESY1(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
@end multitable

@item @emph{Return value}:
The return value is a scalar of type @code{REAL(*)}.

@item @emph{Example}:
@smallexample
program test_besy1
  real(8) :: x = 1.0_8
  x = besy1(x)
end program test_besy1
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DBESY1(X)}@tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab GNU extension
@end multitable
@end table



@node BESYN
@section @code{BESYN} --- Bessel function of the second kind
@findex @code{BESYN} intrinsic
@findex @code{DBESYN} intrinsic
@cindex Bessel

@table @asis
@item @emph{Description}:
@code{BESYN(N, X)} computes the Bessel function of the second kind of order
@var{N} of @var{X}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{Y = BESYN(N, X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{N} @tab The type shall be @code{INTEGER(*)}, and it shall be scalar.
@item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
@end multitable

@item @emph{Return value}:
The return value is a scalar of type @code{REAL(*)}.

@item @emph{Example}:
@smallexample
program test_besyn
  real(8) :: x = 1.0_8
  x = besyn(5,x)
end program test_besyn
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name               @tab Argument            @tab Return type     @tab Standard
@item @code{DBESYN(N,X)} @tab @code{INTEGER(*) N} @tab @code{REAL(8)}  @tab GNU extension
@item                    @tab @code{REAL(8)    X} @tab                 @tab 
@end multitable
@end table



@node BIT_SIZE
@section @code{BIT_SIZE} --- Bit size inquiry function
@findex @code{BIT_SIZE} intrinsic
@cindex bit_size

@table @asis
@item @emph{Description}:
@code{BIT_SIZE(I)} returns the number of bits (integer precision plus sign bit)
represented by the type of @var{I}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{I = BIT_SIZE(I)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{I} @tab The type shall be @code{INTEGER(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER(*)}

@item @emph{Example}:
@smallexample
program test_bit_size
    integer :: i = 123
    integer :: size
    size = bit_size(i)
    print *, size
end program test_bit_size
@end smallexample
@end table



@node BTEST
@section @code{BTEST} --- Bit test function
@findex @code{BTEST} intrinsic
@cindex BTEST

@table @asis
@item @emph{Description}:
@code{BTEST(I,POS)} returns logical @code{.TRUE.} if the bit at @var{POS}
in @var{I} is set.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{I = BTEST(I,POS)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{I} @tab The type shall be @code{INTEGER(*)}.
@item @var{POS} @tab The type shall be @code{INTEGER(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{LOGICAL}

@item @emph{Example}:
@smallexample
program test_btest
    integer :: i = 32768 + 1024 + 64
    integer :: pos
    logical :: bool
    do pos=0,16
        bool = btest(i, pos) 
        print *, pos, bool
    end do
end program test_btest
@end smallexample
@end table



@node CEILING
@section @code{CEILING} --- Integer ceiling function
@findex @code{CEILING} intrinsic
@cindex CEILING

@table @asis
@item @emph{Description}:
@code{CEILING(X)} returns the least integer greater than or equal to @var{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{I = CEILING(X[,KIND])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}.
@item @var{KIND} @tab (Optional) scalar integer initialization expression.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER(KIND)}

@item @emph{Example}:
@smallexample
program test_ceiling
    real :: x = 63.29
    real :: y = -63.59
    print *, ceiling(x) ! returns 64
    print *, ceiling(y) ! returns -63
end program test_ceiling
@end smallexample

@item @emph{See also}:
@ref{FLOOR}, @ref{NINT}

@end table



@node CHAR
@section @code{CHAR} --- Character conversion function
@findex @code{CHAR} intrinsic
@cindex conversion function (character)

@table @asis
@item @emph{Description}:
@code{CHAR(I,[KIND])} returns the character represented by the integer @var{I}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{C = CHAR(I[,KIND])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{I} @tab The type shall be @code{INTEGER(*)}.
@item @var{KIND} @tab Optional scaler integer initialization expression.
@end multitable

@item @emph{Return value}:
The return value is of type @code{CHARACTER(1)}

@item @emph{Example}:
@smallexample
program test_char
    integer :: i = 74
    character(1) :: c
    c = char(i)
    print *, i, c ! returns 'J'
end program test_char
@end smallexample

@item @emph{See also}:
@ref{ACHAR}, @ref{ICHAR}, @ref{IACHAR}

@end table


@node CHDIR
@section @code{CHDIR} --- Change working directory
@findex @code{CHDIR} intrinsic
@cindex file system functions

@table @asis
@item @emph{Description}:
Change current working directory to a specified @var{PATH}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Non-elemental subroutine

@item @emph{Syntax}:
@code{CALL chdir(PATH[,STATUS])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{PATH}   @tab The type shall be @code{CHARACTER(*)} and shall specify a valid path within the file system.
@item @var{STATUS} @tab (Optional) status flag. Returns 0 on success, 
                        a system specific and non-zero error code otherwise.
@end multitable

@item @emph{Example}:
@smallexample
PROGRAM test_chdir
  CHARACTER(len=255) :: path
  CALL getcwd(path)
  WRITE(*,*) TRIM(path)
  CALL chdir("/tmp")
  CALL getcwd(path)
  WRITE(*,*) TRIM(path)
END PROGRAM
@end smallexample

@item @emph{See also}:
@ref{GETCWD}
@end table



@node CHMOD
@section @code{CHMOD} --- Change access permissions of files
@findex @code{CHMOD} 
@cindex file system functions

Not yet implemented in GNU Fortran.

@table @asis
@item @emph{Description}:

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@uref{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19292, g77 features lacking in gfortran}

@end table


@node CMPLX
@section @code{CMPLX} --- Complex conversion function
@findex @code{CMPLX} intrinsic
@cindex CMPLX

@table @asis
@item @emph{Description}:
@code{CMPLX(X[,Y[,KIND]])} returns a complex number where @var{X} is converted to
the real component.  If @var{Y} is present it is converted to the imaginary
component.  If @var{Y} is not present then the imaginary component is set to
0.0.  If @var{X} is complex then @var{Y} must not be present.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{C = CMPLX(X[,Y[,KIND]])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type may be @code{INTEGER(*)}, @code{REAL(*)}, or @code{COMPLEX(*)}.
@item @var{Y} @tab Optional, allowed if @var{X} is not @code{COMPLEX(*)}.  May be @code{INTEGER(*)} or @code{REAL(*)}. 
@item @var{KIND} @tab Optional scaler integer initialization expression.
@end multitable

@item @emph{Return value}:
The return value is of type @code{COMPLEX(*)}

@item @emph{Example}:
@smallexample
program test_cmplx
    integer :: i = 42
    real :: x = 3.14
    complex :: z
    z = cmplx(i, x)
    print *, z, cmplx(x)
end program test_cmplx
@end smallexample
@end table



@node COMMAND_ARGUMENT_COUNT
@section @code{COMMAND_ARGUMENT_COUNT} --- Argument count function 
@findex @code{COMMAND_ARGUMENT_COUNT} intrinsic
@cindex command argument count

@table @asis
@item @emph{Description}:
@code{COMMAND_ARGUMENT_COUNT()} returns the number of arguments passed on the
command line when the containing program was invoked.

@item @emph{Standard}:
F2003

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{I = COMMAND_ARGUMENT_COUNT()}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item None
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER(4)}

@item @emph{Example}:
@smallexample
program test_command_argument_count
    integer :: count
    count = command_argument_count()
    print *, count
end program test_command_argument_count
@end smallexample
@end table



@node CONJG
@section @code{CONJG} --- Complex conjugate function 
@findex @code{CONJG} intrinsic
@findex @code{DCONJG} intrinsic
@cindex complex conjugate
@table @asis
@item @emph{Description}:
@code{CONJG(Z)} returns the conjugate of @var{Z}.  If @var{Z} is @code{(x, y)}
then the result is @code{(x, -y)}

@item @emph{Standard}:
F77 and later, has overloads that are GNU extensions

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{Z = CONJG(Z)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{Z} @tab The type shall be @code{COMPLEX(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{COMPLEX(*)}.

@item @emph{Example}:
@smallexample
program test_conjg
    complex :: z = (2.0, 3.0)
    complex(8) :: dz = (2.71_8, -3.14_8)
    z= conjg(z)
    print *, z
    dz = dconjg(dz)
    print *, dz
end program test_conjg
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name             @tab Argument             @tab Return type          @tab Standard
@item @code{DCONJG(Z)} @tab @code{COMPLEX(8) Z}  @tab @code{COMPLEX(8)}    @tab GNU extension
@end multitable
@end table



@node COS
@section @code{COS} --- Cosine function 
@findex @code{COS} intrinsic
@findex @code{DCOS} intrinsic
@findex @code{ZCOS} intrinsic
@findex @code{CDCOS} intrinsic
@cindex trigonometric functions

@table @asis
@item @emph{Description}:
@code{COS(X)} computes the cosine of @var{X}.

@item @emph{Standard}:
F77 and later, has overloads that are GNU extensions

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = COS(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)} or
@code{COMPLEX(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} and it lies in the
range @math{ -1 \leq \cos (x) \leq 1}.  The kind type
parameter is the same as @var{X}.

@item @emph{Example}:
@smallexample
program test_cos
  real :: x = 0.0
  x = cos(x)
end program test_cos
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument            @tab Return type       @tab Standard
@item @code{DCOS(X)}  @tab @code{REAL(8) X}    @tab @code{REAL(8)}    @tab F77 and later
@item @code{CCOS(X)}  @tab @code{COMPLEX(4) X} @tab @code{COMPLEX(4)} @tab F77 and later
@item @code{ZCOS(X)}  @tab @code{COMPLEX(8) X} @tab @code{COMPLEX(8)} @tab GNU extension
@item @code{CDCOS(X)} @tab @code{COMPLEX(8) X} @tab @code{COMPLEX(8)} @tab GNU extension
@end multitable

@item @emph{See also}:
Inverse function: @ref{ACOS}

@end table



@node COSH
@section @code{COSH} --- Hyperbolic cosine function 
@findex @code{COSH} intrinsic
@findex @code{DCOSH} intrinsic
@cindex hyperbolic cosine

@table @asis
@item @emph{Description}:
@code{COSH(X)} computes the hyperbolic cosine of @var{X}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = COSH(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} and it is positive
(@math{ \cosh (x) \geq 0 }.

@item @emph{Example}:
@smallexample
program test_cosh
  real(8) :: x = 1.0_8
  x = cosh(x)
end program test_cosh
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DCOSH(X)} @tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab F77 and later
@end multitable

@item @emph{See also}:
Inverse function: @ref{ACOSH}

@end table



@node COUNT
@section @code{COUNT} --- Count function
@findex @code{COUNT} intrinsic
@cindex count

@table @asis
@item @emph{Description}:
@code{COUNT(MASK[,DIM])} counts the number of @code{.TRUE.} elements of
@var{MASK} along the dimension of @var{DIM}.  If @var{DIM} is omitted it is
taken to be @code{1}.  @var{DIM} is a scaler of type @code{INTEGER} in the
range of @math{1 /leq DIM /leq n)} where @math{n} is the rank of @var{MASK}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
transformational function

@item @emph{Syntax}:
@code{I = COUNT(MASK[,DIM])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{MASK} @tab The type shall be @code{LOGICAL}.
@item @var{DIM}  @tab The type shall be @code{INTEGER}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER} with rank equal to that of
@var{MASK}.

@item @emph{Example}:
@smallexample
program test_count
    integer, dimension(2,3) :: a, b
    logical, dimension(2,3) :: mask
    a = reshape( (/ 1, 2, 3, 4, 5, 6 /), (/ 2, 3 /))
    b = reshape( (/ 0, 7, 3, 4, 5, 8 /), (/ 2, 3 /))
    print '(3i3)', a(1,:)
    print '(3i3)', a(2,:)
    print *
    print '(3i3)', b(1,:)
    print '(3i3)', b(2,:)
    print *
    mask = a.ne.b
    print '(3l3)', mask(1,:)
    print '(3l3)', mask(2,:)
    print *
    print '(3i3)', count(mask)
    print *
    print '(3i3)', count(mask, 1)
    print *
    print '(3i3)', count(mask, 2)
end program test_count
@end smallexample
@end table



@node CPU_TIME
@section @code{CPU_TIME} --- CPU elapsed time in seconds
@findex @code{CPU_TIME} intrinsic
@cindex CPU_TIME

@table @asis
@item @emph{Description}:
Returns a @code{REAL} value representing the elapsed CPU time in seconds.  This
is useful for testing segments of code to determine execution time.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@code{CPU_TIME(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL} with @code{INTENT(OUT)}.
@end multitable

@item @emph{Return value}:
None

@item @emph{Example}:
@smallexample
program test_cpu_time
    real :: start, finish
    call cpu_time(start)
        ! put code to test here
    call cpu_time(finish)
    print '("Time = ",f6.3," seconds.")',finish-start
end program test_cpu_time
@end smallexample
@end table



@node CSHIFT
@section @code{CSHIFT} --- Circular shift function
@findex @code{CSHIFT} intrinsic
@cindex bit manipulation

@table @asis
@item @emph{Description}:
@code{CSHIFT(ARRAY, SHIFT[,DIM])} performs a circular shift on elements of
@var{ARRAY} along the dimension of @var{DIM}.  If @var{DIM} is omitted it is
taken to be @code{1}.  @var{DIM} is a scaler of type @code{INTEGER} in the
range of @math{1 /leq DIM /leq n)} where @math{n} is the rank of @var{ARRAY}.
If the rank of @var{ARRAY} is one, then all elements of @var{ARRAY} are shifted
by @var{SHIFT} places.  If rank is greater than one, then all complete rank one
sections of @var{ARRAY} along the given dimension are shifted.  Elements
shifted out one end of each rank one section are shifted back in the other end.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
transformational function

@item @emph{Syntax}:
@code{A = CSHIFT(A, SHIFT[,DIM])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{ARRAY}  @tab May be any type, not scaler.
@item @var{SHIFT}  @tab The type shall be @code{INTEGER}.
@item @var{DIM}    @tab The type shall be @code{INTEGER}.
@end multitable

@item @emph{Return value}:
Returns an array of same type and rank as the @var{ARRAY} argument.

@item @emph{Example}:
@smallexample
program test_cshift
    integer, dimension(3,3) :: a
    a = reshape( (/ 1, 2, 3, 4, 5, 6, 7, 8, 9 /), (/ 3, 3 /))
    print '(3i3)', a(1,:)
    print '(3i3)', a(2,:)
    print '(3i3)', a(3,:)    
    a = cshift(a, SHIFT=(/1, 2, -1/), DIM=2)
    print *
    print '(3i3)', a(1,:)
    print '(3i3)', a(2,:)
    print '(3i3)', a(3,:)
end program test_cshift
@end smallexample
@end table


@node CTIME
@section @code{CTIME} --- Convert a time into a string
@findex @code{CTIME} intrinsic
@cindex ctime subroutine 

@table @asis
@item @emph{Description}:
@code{CTIME(T,S)} converts @var{T}, a system time value, such as returned
by @code{TIME8()}, to a string of the form @samp{Sat Aug 19 18:13:14
1995}, and returns that string into @var{S}.

If @code{CTIME} is invoked as a function, it can not be invoked as a
subroutine, and vice versa.

@var{T} is an @code{INTENT(IN)} @code{INTEGER(KIND=8)} variable.
@var{S} is an @code{INTENT(OUT)} @code{CHARACTER} variable.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@multitable @columnfractions .80
@item @code{CALL CTIME(T,S)}.
@item @code{S = CTIME(T)}, (not recommended).
@end multitable

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{S}@tab The type shall be of type @code{CHARACTER}.
@item @var{T}@tab The type shall be of type @code{INTEGER(KIND=8)}.
@end multitable

@item @emph{Return value}:
The converted date and time as a string.

@item @emph{Example}:
@smallexample
program test_ctime
    integer(8) :: i
    character(len=30) :: date
    i = time8()

    ! Do something, main part of the program
    
    call ctime(i,date)
    print *, 'Program was started on ', date
end program test_ctime
@end smallexample
@end table

@node DATE_AND_TIME
@section @code{DATE_AND_TIME} --- Date and time subroutine
@findex @code{DATE_AND_TIME} intrinsic
@cindex DATE_AND_TIME

@table @asis
@item @emph{Description}:
@code{DATE_AND_TIME(DATE, TIME, ZONE, VALUES)} gets the corresponding date and
time information from the real-time system clock.  @var{DATE} is
@code{INTENT(OUT)} and has form ccyymmdd.  @var{TIME} is @code{INTENT(OUT)} and
has form hhmmss.sss.  @var{ZONE} is @code{INTENT(OUT)} and has form (+-)hhmm,
representing the difference with respect to Coordinated Universal Time (UTC).
Unavailable time and date parameters return blanks.

@var{VALUES} is @code{INTENT(OUT)} and provides the following:

@multitable @columnfractions .15 .30 .60
@item @tab @code{VALUE(1)}: @tab The year
@item @tab @code{VALUE(2)}: @tab The month
@item @tab @code{VALUE(3)}: @tab The day of the month
@item @tab @code{VALUE(4)}: @tab Time difference with UTC in minutes
@item @tab @code{VALUE(5)}: @tab The hour of the day
@item @tab @code{VALUE(6)}: @tab The minutes of the hour
@item @tab @code{VALUE(7)}: @tab The seconds of the minute
@item @tab @code{VALUE(8)}: @tab The milliseconds of the second
@end multitable     

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@code{CALL DATE_AND_TIME([DATE, TIME, ZONE, VALUES])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{DATE}  @tab (Optional) The type shall be @code{CHARACTER(8)} or larger.
@item @var{TIME}  @tab (Optional) The type shall be @code{CHARACTER(10)} or larger.
@item @var{ZONE}  @tab (Optional) The type shall be @code{CHARACTER(5)} or larger.
@item @var{VALUES}@tab (Optional) The type shall be @code{INTEGER(8)}.
@end multitable

@item @emph{Return value}:
None

@item @emph{Example}:
@smallexample
program test_time_and_date
    character(8)  :: date
    character(10) :: time
    character(5)  :: zone
    integer,dimension(8) :: values
    ! using keyword arguments
    call date_and_time(date,time,zone,values)
    call date_and_time(DATE=date,ZONE=zone)
    call date_and_time(TIME=time)
    call date_and_time(VALUES=values)
    print '(a,2x,a,2x,a)', date, time, zone
    print '(8i5))', values
end program test_time_and_date
@end smallexample
@end table



@node DBLE
@section @code{DBLE} --- Double conversion function 
@findex @code{DBLE} intrinsic
@cindex double conversion

@table @asis
@item @emph{Description}:
@code{DBLE(X)} Converts @var{X} to double precision real type.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = DBLE(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{INTEGER(*)}, @code{REAL(*)}, or @code{COMPLEX(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type double precision real.

@item @emph{Example}:
@smallexample
program test_dble
    real    :: x = 2.18
    integer :: i = 5
    complex :: z = (2.3,1.14)
    print *, dble(x), dble(i), dble(z)
end program test_dble
@end smallexample

@item @emph{See also}:
@ref{DFLOAT}, @ref{FLOAT}, @ref{REAL}
@end table



@node DCMPLX
@section @code{DCMPLX} --- Double complex conversion function
@findex @code{DCMPLX} intrinsic
@cindex DCMPLX

@table @asis
@item @emph{Description}:
@code{DCMPLX(X [,Y])} returns a double complex number where @var{X} is
converted to the real component.  If @var{Y} is present it is converted to the
imaginary component.  If @var{Y} is not present then the imaginary component is
set to 0.0.  If @var{X} is complex then @var{Y} must not be present.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{C = DCMPLX(X)}
@code{C = DCMPLX(X,Y)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type may be @code{INTEGER(*)}, @code{REAL(*)}, or @code{COMPLEX(*)}.
@item @var{Y} @tab Optional if @var{X} is not @code{COMPLEX(*)}. May be @code{INTEGER(*)} or @code{REAL(*)}. 
@end multitable

@item @emph{Return value}:
The return value is of type @code{COMPLEX(8)}

@item @emph{Example}:
@smallexample
program test_dcmplx
    integer :: i = 42
    real :: x = 3.14
    complex :: z
    z = cmplx(i, x)
    print *, dcmplx(i)
    print *, dcmplx(x)
    print *, dcmplx(z)
    print *, dcmplx(x,i)
end program test_dcmplx
@end smallexample
@end table



@node DFLOAT
@section @code{DFLOAT} --- Double conversion function 
@findex @code{DFLOAT} intrinsic
@cindex double float conversion

@table @asis
@item @emph{Description}:
@code{DFLOAT(X)} Converts @var{X} to double precision real type.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = DFLOAT(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{INTEGER(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type double precision real.

@item @emph{Example}:
@smallexample
program test_dfloat
    integer :: i = 5
    print *, dfloat(i)
end program test_dfloat
@end smallexample

@item @emph{See also}:
@ref{DBLE}, @ref{FLOAT}, @ref{REAL}
@end table



@node DIGITS
@section @code{DIGITS} --- Significant digits function
@findex @code{DIGITS} intrinsic
@cindex digits, significant

@table @asis
@item @emph{Description}:
@code{DIGITS(X)} returns the number of significant digits of the internal model
representation of @var{X}.  For example, on a system using a 32-bit
floating point representation, a default real number would likely return 24.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{C = DIGITS(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type may be @code{INTEGER(*)} or @code{REAL(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER}.

@item @emph{Example}:
@smallexample
program test_digits
    integer :: i = 12345
    real :: x = 3.143
    real(8) :: y = 2.33
    print *, digits(i)
    print *, digits(x)
    print *, digits(y)
end program test_digits
@end smallexample
@end table



@node DIM
@section @code{DIM} --- Dim function
@findex @code{DIM} intrinsic
@findex @code{IDIM} intrinsic
@findex @code{DDIM} intrinsic
@cindex dim

@table @asis
@item @emph{Description}:
@code{DIM(X,Y)} returns the difference @code{X-Y} if the result is positive;
otherwise returns zero.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = DIM(X,Y)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{INTEGER(*)} or @code{REAL(*)}
@item @var{Y} @tab The type shall be the same type and kind as @var{X}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER(*)} or @code{REAL(*)}.

@item @emph{Example}:
@smallexample
program test_dim
    integer :: i
    real(8) :: x
    i = dim(4, 15)
    x = dim(4.345_8, 2.111_8)
    print *, i
    print *, x
end program test_dim
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name             @tab Argument              @tab Return type       @tab Standard
@item @code{IDIM(X,Y)} @tab @code{INTEGER(4) X,Y} @tab @code{INTEGER(4)} @tab F77 and later
@item @code{DDIM(X,Y)} @tab @code{REAL(8) X,Y}    @tab @code{REAL(8)}    @tab F77 and later
@end multitable
@end table



@node DOT_PRODUCT
@section @code{DOT_PRODUCT} --- Dot product function
@findex @code{DOT_PRODUCT} intrinsic
@cindex Dot product

@table @asis
@item @emph{Description}:
@code{DOT_PRODUCT(X,Y)} computes the dot product multiplication of two vectors
@var{X} and @var{Y}.  The two vectors may be either numeric or logical
and must be arrays of rank one and of equal size. If the vectors are
@code{INTEGER(*)} or @code{REAL(*)}, the result is @code{SUM(X*Y)}. If the
vectors are @code{COMPLEX(*)}, the result is @code{SUM(CONJG(X)*Y)}. If the 
vectors are @code{LOGICAL}, the result is @code{ANY(X.AND.Y)}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
transformational function

@item @emph{Syntax}:
@code{S = DOT_PRODUCT(X,Y)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be numeric or @code{LOGICAL}, rank 1.
@item @var{Y} @tab The type shall be numeric or @code{LOGICAL}, rank 1.
@end multitable

@item @emph{Return value}:
If the arguments are numeric, the return value is a scaler of numeric type,
@code{INTEGER(*)}, @code{REAL(*)}, or @code{COMPLEX(*)}.  If the arguments are
@code{LOGICAL}, the return value is @code{.TRUE.} or @code{.FALSE.}.

@item @emph{Example}:
@smallexample
program test_dot_prod
    integer, dimension(3) :: a, b
    a = (/ 1, 2, 3 /)
    b = (/ 4, 5, 6 /)
    print '(3i3)', a
    print *
    print '(3i3)', b
    print *
    print *, dot_product(a,b)
end program test_dot_prod
@end smallexample
@end table



@node DPROD
@section @code{DPROD} --- Double product function
@findex @code{DPROD} intrinsic
@cindex Double product

@table @asis
@item @emph{Description}:
@code{DPROD(X,Y)} returns the product @code{X*Y}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{D = DPROD(X,Y)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL}.
@item @var{Y} @tab The type shall be @code{REAL}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(8)}.

@item @emph{Example}:
@smallexample
program test_dprod
    integer :: i
    real :: x = 5.2
    real :: y = 2.3
    real(8) :: d
    d = dprod(x,y)
    print *, d
end program test_dprod
@end smallexample
@end table



@node DREAL
@section @code{DREAL} --- Double real part function
@findex @code{DREAL} intrinsic
@cindex Double real part

@table @asis
@item @emph{Description}:
@code{DREAL(Z)} returns the real part of complex variable @var{Z}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{D = DREAL(Z)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{Z} @tab The type shall be @code{COMPLEX(8)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(8)}.

@item @emph{Example}:
@smallexample
program test_dreal
    complex(8) :: z = (1.3_8,7.2_8)
    print *, dreal(z)
end program test_dreal
@end smallexample

@item @emph{See also}:
@ref{AIMAG}

@end table



@node DTIME
@section @code{DTIME} --- Execution time subroutine (or function)
@findex @code{DTIME} intrinsic
@cindex dtime subroutine 

@table @asis
@item @emph{Description}:
@code{DTIME(TARRAY, RESULT)} initially returns the number of seconds of runtime
since the start of the process's execution in @var{RESULT}.  @var{TARRAY}
returns the user and system components of this time in @code{TARRAY(1)} and
@code{TARRAY(2)} respectively. @var{RESULT} is equal to @code{TARRAY(1) +
TARRAY(2)}.

Subsequent invocations of @code{DTIME} return values accumulated since the
previous invocation.

On some systems, the underlying timings are represented using types with
sufficiently small limits that overflows (wrap around) are possible, such as
32-bit types. Therefore, the values returned by this intrinsic might be, or
become, negative, or numerically less than previous values, during a single
run of the compiled program.

If @code{DTIME} is invoked as a function, it can not be invoked as a
subroutine, and vice versa.

@var{TARRAY} and @var{RESULT} are @code{INTENT(OUT)} and provide the following:

@multitable @columnfractions .15 .30 .60
@item @tab @code{TARRAY(1)}: @tab User time in seconds.
@item @tab @code{TARRAY(2)}: @tab System time in seconds.
@item @tab @code{RESULT}: @tab Run time since start in seconds.
@end multitable

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@multitable @columnfractions .80
@item @code{CALL DTIME(TARRAY, RESULT)}.
@item @code{RESULT = DTIME(TARRAY)}, (not recommended).
@end multitable

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{TARRAY}@tab The type shall be @code{REAL, DIMENSION(2)}.
@item @var{RESULT}@tab The type shall be @code{REAL}.
@end multitable

@item @emph{Return value}:
Elapsed time in seconds since the start of program execution.

@item @emph{Example}:
@smallexample
program test_dtime
    integer(8) :: i, j
    real, dimension(2) :: tarray
    real :: result
    call dtime(tarray, result)
    print *, result
    print *, tarray(1)
    print *, tarray(2)   
    do i=1,100000000    ! Just a delay
        j = i * i - i
    end do
    call dtime(tarray, result)
    print *, result
    print *, tarray(1)
    print *, tarray(2)
end program test_dtime
@end smallexample
@end table



@node EOSHIFT
@section @code{EOSHIFT} --- End-off shift function
@findex @code{EOSHIFT} intrinsic
@cindex bit manipulation

@table @asis
@item @emph{Description}:
@code{EOSHIFT(ARRAY, SHIFT[,BOUNDARY, DIM])} performs an end-off shift on
elements of @var{ARRAY} along the dimension of @var{DIM}.  If @var{DIM} is
omitted it is taken to be @code{1}.  @var{DIM} is a scaler of type
@code{INTEGER} in the range of @math{1 /leq DIM /leq n)} where @math{n} is the
rank of @var{ARRAY}.  If the rank of @var{ARRAY} is one, then all elements of
@var{ARRAY} are shifted by @var{SHIFT} places.  If rank is greater than one,
then all complete rank one sections of @var{ARRAY} along the given dimension are
shifted.  Elements shifted out one end of each rank one section are dropped.  If
@var{BOUNDARY} is present then the corresponding value of from @var{BOUNDARY}
is copied back in the other end.  If @var{BOUNDARY} is not present then the
following are copied in depending on the type of @var{ARRAY}.

@multitable @columnfractions .15 .80
@item @emph{Array Type} @tab @emph{Boundary Value}
@item Numeric  @tab 0 of the type and kind of @var{ARRAY}.
@item Logical  @tab @code{.FALSE.}.
@item Character(@var{len}) @tab @var{len} blanks.
@end multitable

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
transformational function

@item @emph{Syntax}:
@code{A = EOSHIFT(A, SHIFT[,BOUNDARY, DIM])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{ARRAY}  @tab May be any type, not scaler.
@item @var{SHIFT}  @tab The type shall be @code{INTEGER}.
@item @var{BOUNDARY} @tab Same type as @var{ARRAY}. 
@item @var{DIM}    @tab The type shall be @code{INTEGER}.
@end multitable

@item @emph{Return value}:
Returns an array of same type and rank as the @var{ARRAY} argument.

@item @emph{Example}:
@smallexample
program test_eoshift
    integer, dimension(3,3) :: a
    a = reshape( (/ 1, 2, 3, 4, 5, 6, 7, 8, 9 /), (/ 3, 3 /))
    print '(3i3)', a(1,:)
    print '(3i3)', a(2,:)
    print '(3i3)', a(3,:)    
    a = EOSHIFT(a, SHIFT=(/1, 2, 1/), BOUNDARY=-5, DIM=2)
    print *
    print '(3i3)', a(1,:)
    print '(3i3)', a(2,:)
    print '(3i3)', a(3,:)
end program test_eoshift
@end smallexample
@end table



@node EPSILON
@section @code{EPSILON} --- Epsilon function
@findex @code{EPSILON} intrinsic
@cindex epsilon, significant

@table @asis
@item @emph{Description}:
@code{EPSILON(X)} returns a nearly negligible number relative to @code{1}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{C = EPSILON(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}.
@end multitable

@item @emph{Return value}:
The return value is of same type as the argument.

@item @emph{Example}:
@smallexample
program test_epsilon
    real :: x = 3.143
    real(8) :: y = 2.33
    print *, EPSILON(x)
    print *, EPSILON(y)
end program test_epsilon
@end smallexample
@end table



@node ERF
@section @code{ERF} --- Error function 
@findex @code{ERF} intrinsic
@cindex error function

@table @asis
@item @emph{Description}:
@code{ERF(X)} computes the error function of @var{X}.

@item @emph{Standard}:
GNU Extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = ERF(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
@end multitable

@item @emph{Return value}:
The return value is a scalar of type @code{REAL(*)} and it is positive
(@math{ - 1 \leq erf (x) \leq 1 }.

@item @emph{Example}:
@smallexample
program test_erf
  real(8) :: x = 0.17_8
  x = erf(x)
end program test_erf
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DERF(X)}  @tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab GNU extension
@end multitable
@end table



@node ERFC
@section @code{ERFC} --- Error function 
@findex @code{ERFC} intrinsic
@cindex error function

@table @asis
@item @emph{Description}:
@code{ERFC(X)} computes the complementary error function of @var{X}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = ERFC(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}, and it shall be scalar.
@end multitable

@item @emph{Return value}:
The return value is a scalar of type @code{REAL(*)} and it is positive
(@math{ 0 \leq erfc (x) \leq 2 }.

@item @emph{Example}:
@smallexample
program test_erfc
  real(8) :: x = 0.17_8
  x = erfc(x)
end program test_erfc
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DERFC(X)} @tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab GNU extension
@end multitable
@end table



@node ETIME
@section @code{ETIME} --- Execution time subroutine (or function)
@findex @code{ETIME} intrinsic
@cindex time functions

@table @asis
@item @emph{Description}:
@code{ETIME(TARRAY, RESULT)} returns the number of seconds of runtime
since the start of the process's execution in @var{RESULT}.  @var{TARRAY}
returns the user and system components of this time in @code{TARRAY(1)} and
@code{TARRAY(2)} respectively. @var{RESULT} is equal to @code{TARRAY(1) + TARRAY(2)}.

On some systems, the underlying timings are represented using types with
sufficiently small limits that overflows (wrap around) are possible, such as
32-bit types. Therefore, the values returned by this intrinsic might be, or
become, negative, or numerically less than previous values, during a single
run of the compiled program.

If @code{ETIME} is invoked as a function, it can not be invoked as a
subroutine, and vice versa.

@var{TARRAY} and @var{RESULT} are @code{INTENT(OUT)} and provide the following:

@multitable @columnfractions .15 .30 .60
@item @tab @code{TARRAY(1)}: @tab User time in seconds.
@item @tab @code{TARRAY(2)}: @tab System time in seconds.
@item @tab @code{RESULT}: @tab Run time since start in seconds.
@end multitable

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@multitable @columnfractions .8
@item @code{CALL ETIME(TARRAY, RESULT)}.
@item @code{RESULT = ETIME(TARRAY)}, (not recommended).
@end multitable

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{TARRAY}@tab The type shall be @code{REAL, DIMENSION(2)}.
@item @var{RESULT}@tab The type shall be @code{REAL}.
@end multitable

@item @emph{Return value}:
Elapsed time in seconds since the start of program execution.

@item @emph{Example}:
@smallexample
program test_etime
    integer(8) :: i, j
    real, dimension(2) :: tarray
    real :: result
    call ETIME(tarray, result)
    print *, result
    print *, tarray(1)
    print *, tarray(2)   
    do i=1,100000000    ! Just a delay
        j = i * i - i
    end do
    call ETIME(tarray, result)
    print *, result
    print *, tarray(1)
    print *, tarray(2)
end program test_etime
@end smallexample

@item @emph{See also}:
@ref{CPU_TIME}

@end table



@node EXIT
@section @code{EXIT} --- Exit the program with status. 
@findex @code{EXIT}
@cindex exit

@table @asis
@item @emph{Description}:
@code{EXIT} causes immediate termination of the program with status.  If status
is omitted it returns the canonical @emph{success} for the system.  All Fortran
I/O units are closed. 

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@code{CALL EXIT([STATUS])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{STATUS} @tab The type of the argument shall be @code{INTEGER(*)}.
@end multitable

@item @emph{Return value}:
@code{STATUS} is passed to the parent process on exit.

@item @emph{Example}:
@smallexample
program test_exit
  integer :: STATUS = 0
  print *, 'This program is going to exit.'
  call EXIT(STATUS)
end program test_exit
@end smallexample

@item @emph{See also}:
@ref{ABORT}, @ref{KILL}
@end table



@node EXP
@section @code{EXP} --- Exponential function 
@findex @code{EXP} intrinsic
@findex @code{DEXP} intrinsic
@findex @code{ZEXP} intrinsic
@findex @code{CDEXP} intrinsic
@cindex exponential

@table @asis
@item @emph{Description}:
@code{EXP(X)} computes the base @math{e} exponential of @var{X}.

@item @emph{Standard}:
F77 and later, has overloads that are GNU extensions

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = EXP(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)} or
@code{COMPLEX(*)}.
@end multitable

@item @emph{Return value}:
The return value has same type and kind as @var{X}.

@item @emph{Example}:
@smallexample
program test_exp
  real :: x = 1.0
  x = exp(x)
end program test_exp
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument             @tab Return type         @tab Standard
@item @code{DEXP(X)}  @tab @code{REAL(8) X}     @tab @code{REAL(8)}      @tab F77 and later
@item @code{CEXP(X)}  @tab @code{COMPLEX(4) X}  @tab @code{COMPLEX(4)}   @tab F77 and later
@item @code{ZEXP(X)}  @tab @code{COMPLEX(8) X}  @tab @code{COMPLEX(8)}   @tab GNU extension
@item @code{CDEXP(X)} @tab @code{COMPLEX(8) X}  @tab @code{COMPLEX(8)}   @tab GNU extension
@end multitable
@end table



@node EXPONENT
@section @code{EXPONENT} --- Exponent function 
@findex @code{EXPONENT} intrinsic
@cindex exponent function

@table @asis
@item @emph{Description}:
@code{EXPONENT(X)} returns the value of the exponent part of @var{X}. If @var{X}
is zero the value returned is zero. 

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{I = EXPONENT(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type default @code{INTEGER}.

@item @emph{Example}:
@smallexample
program test_exponent
  real :: x = 1.0
  integer :: i
  i = exponent(x)
  print *, i
  print *, exponent(0.0)
end program test_exponent
@end smallexample
@end table


@node FDATE
@section @code{FDATE} --- Get the current time as a string
@findex @code{FDATE} intrinsic
@cindex fdate subroutine 

@table @asis
@item @emph{Description}:
@code{FDATE(DATE)} returns the current date (using the same format as
@code{CTIME}) in @var{DATE}. It is equivalent to @code{CALL CTIME(DATE,
TIME8())}.

If @code{FDATE} is invoked as a function, it can not be invoked as a
subroutine, and vice versa.

@var{DATE} is an @code{INTENT(OUT)} @code{CHARACTER} variable.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@multitable @columnfractions .80
@item @code{CALL FDATE(DATE)}.
@item @code{DATE = FDATE()}, (not recommended).
@end multitable

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{DATE}@tab The type shall be of type @code{CHARACTER}.
@end multitable

@item @emph{Return value}:
The current date and time as a string.

@item @emph{Example}:
@smallexample
program test_fdate
    integer(8) :: i, j
    character(len=30) :: date
    call fdate(date)
    print *, 'Program started on ', date
    do i = 1, 100000000 ! Just a delay
        j = i * i - i
    end do
    call fdate(date)
    print *, 'Program ended on ', date
end program test_fdate
@end smallexample
@end table

@node FLOAT

@section @code{FLOAT} --- Convert integer to default real
@findex @code{FLOAT} intrinsic
@cindex conversion function (float)

@table @asis
@item @emph{Description}:
@code{FLOAT(I)} converts the integer @var{I} to a default real value.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = FLOAT(I)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{I} @tab The type shall be @code{INTEGER(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type default @code{REAL}

@item @emph{Example}:
@smallexample
program test_float
    integer :: i = 1
    if (float(i) /= 1.) call abort
end program test_float
@end smallexample

@item @emph{See also}:
@ref{DBLE}, @ref{DFLOAT}, @ref{REAL}
@end table



@node FGET
@section @code{FGET} --- Read a single character in stream mode from stdin 
@findex @code{FGET} intrinsic
@cindex file operations
@cindex stream operations

@table @asis
@item @emph{Description}:
Read a single character in stream mode from stdin by bypassing normal 
formatted output. Stream I/O should not be mixed with normal record-oriented 
(formatted or unformatted) I/O on the same unit; the results are unpredictable.

This intrinsic routine is provided for backwards compatibility with 
@command{g77}.  GNU Fortran provides the Fortran 2003 Stream facility.
Programmers should consider the use of new stream IO feature in new code 
for future portability. See also @ref{Fortran 2003 status}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Non-elemental subroutine

@item @emph{Syntax}:
@code{CALL fget(C[,STATUS])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{C}      @tab The type shall be @code{CHARACTER}.
@item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER}. Returns 0 on success,
                        -1 on end-of-file and a system specific positive error code otherwise.
@end multitable

@item @emph{Example}:
@smallexample
PROGRAM test_fget
  INTEGER, PARAMETER :: strlen = 100
  INTEGER :: status, i = 1
  CHARACTER(len=strlen) :: str = ""

  WRITE (*,*) 'Enter text:'
  DO
    CALL fget(str(i:i), status)
    if (status /= 0 .OR. i > strlen) exit
    i = i + 1
  END DO
  WRITE (*,*) TRIM(str)
END PROGRAM
@end smallexample

@item @emph{See also}:
@ref{FGETC}, @ref{FPUT}, @ref{FPUTC}
@end table


@node FGETC
@section @code{FGETC} --- Read a single character in stream mode
@findex @code{FGETC} intrinsic
@cindex file operations
@cindex stream operations

@table @asis
@item @emph{Description}:
Read a single character in stream mode by bypassing normal formatted output. 
Stream I/O should not be mixed with normal record-oriented (formatted or 
unformatted) I/O on the same unit; the results are unpredictable.

This intrinsic routine is provided for backwards compatibility with 
@command{g77}.  GNU Fortran provides the Fortran 2003 Stream facility.
Programmers should consider the use of new stream IO feature in new code 
for future portability. See also @ref{Fortran 2003 status}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Non-elemental subroutine

@item @emph{Syntax}:
@code{CALL fgetc(UNIT,C[,STATUS])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{UNIT}   @tab The type shall be @code{INTEGER}.
@item @var{C}      @tab The type shall be @code{CHARACTER}.
@item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER}. Returns 0 on success,
                        -1 on end-of-file and a system specific positive error code otherwise.
@end multitable

@item @emph{Example}:
@smallexample
PROGRAM test_fgetc
  INTEGER :: fd = 42, status
  CHARACTER :: c

  OPEN(UNIT=fd, FILE="/etc/passwd", ACTION="READ", STATUS = "OLD")
  DO
    CALL fgetc(fd, c, status)
    IF (status /= 0) EXIT
    call fput(c)
  END DO
  CLOSE(UNIT=fd)
END PROGRAM
@end smallexample

@item @emph{See also}:
@ref{FGET}, @ref{FPUT}, @ref{FPUTC}
@end table



@node FLOOR
@section @code{FLOOR} --- Integer floor function
@findex @code{FLOOR} intrinsic
@cindex floor

@table @asis
@item @emph{Description}:
@code{FLOOR(X)} returns the greatest integer less than or equal to @var{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{I = FLOOR(X[,KIND])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}.
@item @var{KIND} @tab Optional scaler integer initialization expression.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER(KIND)}

@item @emph{Example}:
@smallexample
program test_floor
    real :: x = 63.29
    real :: y = -63.59
    print *, floor(x) ! returns 63
    print *, floor(y) ! returns -64
end program test_floor
@end smallexample

@item @emph{See also}:
@ref{CEILING}, @ref{NINT}

@end table



@node FLUSH
@section @code{FLUSH} --- Flush I/O unit(s)
@findex @code{FLUSH}
@cindex flush

@table @asis
@item @emph{Description}:
Flushes Fortran unit(s) currently open for output. Without the optional
argument, all units are flushed, otherwise just the unit specified.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
non-elemental subroutine

@item @emph{Syntax}:
@code{CALL FLUSH(UNIT)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{UNIT} @tab (Optional) The type shall be @code{INTEGER}.
@end multitable

@item @emph{Note}:
Beginning with the Fortran 2003 standard, there is a @code{FLUSH}
statement that should be preferred over the @code{FLUSH} intrinsic.

@end table



@node FNUM
@section @code{FNUM} --- File number function
@findex @code{FNUM} intrinsic
@cindex fnum

@table @asis
@item @emph{Description}:
@code{FNUM(UNIT)} returns the POSIX file descriptor number corresponding to the
open Fortran I/O unit @code{UNIT}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
non-elemental function

@item @emph{Syntax}:
@code{I = FNUM(UNIT)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{UNIT} @tab The type shall be @code{INTEGER}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER}

@item @emph{Example}:
@smallexample
program test_fnum
  integer :: i
  open (unit=10, status = "scratch")
  i = fnum(10)
  print *, i
  close (10)
end program test_fnum
@end smallexample
@end table



@node FPUT
@section @code{FPUT} --- Write a single character in stream mode to stdout 
@findex @code{FPUT} intrinsic
@cindex file operations
@cindex stream operations

@table @asis
@item @emph{Description}:
Write a single character in stream mode to stdout by bypassing normal 
formatted output. Stream I/O should not be mixed with normal record-oriented 
(formatted or unformatted) I/O on the same unit; the results are unpredictable.

This intrinsic routine is provided for backwards compatibility with 
@command{g77}.  GNU Fortran provides the Fortran 2003 Stream facility.
Programmers should consider the use of new stream IO feature in new code 
for future portability. See also @ref{Fortran 2003 status}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Non-elemental subroutine

@item @emph{Syntax}:
@code{CALL fput(C[,STATUS])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{C}      @tab The type shall be @code{CHARACTER}.
@item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER}. Returns 0 on success,
                        -1 on end-of-file and a system specific positive error code otherwise.
@end multitable

@item @emph{Example}:
@smallexample
PROGRAM test_fput
  CHARACTER(len=*) :: str = "gfortran"
  INTEGER :: i
  DO i = 1, len_trim(str)
    CALL fput(str(i:i))
  END DO
END PROGRAM
@end smallexample

@item @emph{See also}:
@ref{FPUTC}, @ref{FGET}, @ref{FGETC}
@end table



@node FPUTC
@section @code{FPUTC} --- Write a single character in stream mode
@findex @code{FPUTC} intrinsic
@cindex file operations
@cindex stream operations

@table @asis
@item @emph{Description}:
Write a single character in stream mode by bypassing normal formatted 
output. Stream I/O should not be mixed with normal record-oriented 
(formatted or unformatted) I/O on the same unit; the results are unpredictable.

This intrinsic routine is provided for backwards compatibility with 
@command{g77}.  GNU Fortran provides the Fortran 2003 Stream facility.
Programmers should consider the use of new stream IO feature in new code 
for future portability. See also @ref{Fortran 2003 status}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Non-elemental subroutine

@item @emph{Syntax}:
@code{CALL fputc(UNIT,C[,STATUS])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{UNIT}   @tab The type shall be @code{INTEGER}.
@item @var{C}      @tab The type shall be @code{CHARACTER}.
@item @var{STATUS} @tab (Optional) status flag of type @code{INTEGER}. Returns 0 on success,
                        -1 on end-of-file and a system specific positive error code otherwise.
@end multitable

@item @emph{Example}:
@smallexample
PROGRAM test_fputc
  CHARACTER(len=*) :: str = "gfortran"
  INTEGER :: fd = 42, i

  OPEN(UNIT = fd, FILE = "out", ACTION = "WRITE", STATUS="NEW")
  DO i = 1, len_trim(str)
    CALL fputc(fd, str(i:i))
  END DO
  CLOSE(fd)
END PROGRAM
@end smallexample

@item @emph{See also}:
@ref{FPUT}, @ref{FGET}, @ref{FGETC}
@end table



@node FRACTION
@section @code{FRACTION} --- Fractional part of the model representation
@findex @code{FRACTION} intrinsic
@cindex fractional part

@table @asis
@item @emph{Description}:
@code{FRACTION(X)} returns the fractional part of the model
representation of @code{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{Y = FRACTION(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type of the argument shall be a @code{REAL}.
@end multitable

@item @emph{Return value}:
The return value is of the same type and kind as the argument.
The fractional part of the model representation of @code{X} is returned;
it is @code{X * RADIX(X)**(-EXPONENT(X))}.

@item @emph{Example}:
@smallexample
program test_fraction
  real :: x
  x = 178.1387e-4
  print *, fraction(x), x * radix(x)**(-exponent(x))
end program test_fraction
@end smallexample

@end table



@node FREE
@section @code{FREE} --- Frees memory
@findex @code{FREE} intrinsic
@cindex FREE

@table @asis
@item @emph{Description}:
Frees memory previously allocated by @code{MALLOC()}. The @code{FREE}
intrinsic is an extension intended to be used with Cray pointers, and is
provided in GNU Fortran to allow user to compile legacy code. For
new code using Fortran 95 pointers, the memory de-allocation intrinsic is
@code{DEALLOCATE}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@code{FREE(PTR)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{PTR} @tab The type shall be @code{INTEGER}. It represents the
location of the memory that should be de-allocated.
@end multitable

@item @emph{Return value}:
None

@item @emph{Example}:
See @code{MALLOC} for an example.

@item @emph{See also}:
@ref{MALLOC}
@end table




@node FSTAT
@section @code{FSTAT} --- Get file status
@findex @code{FSTAT} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
GNU extension

@item @emph{Standard}:
@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@end table



@node FSEEK
@section @code{FSEEK} --- Low level file positioning subroutine
@findex @code{FSEEK} 
@cindex file system functions

Not yet implemented in GNU Fortran.

@table @asis
@item @emph{Description}:

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@uref{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19292, g77 features lacking in gfortran}

@end table



@node FTELL
@section @code{FTELL} --- Current stream position
@findex @code{FTELL} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@end table



@node GETARG
@section @code{GETARG} --- Get command line arguments
@findex @code{GETARG} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{IARGC}, @ref{GET_COMMAND}, @ref{GET_COMMAND_ARGUMENT}
@end table



@node GET_COMMAND
@section @code{GET_COMMAND} --- Subroutine to retrieve the entire command line
@findex @code{GET_COMMAND} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F2003

@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@end table



@node GET_COMMAND_ARGUMENT
@section @code{GET_COMMAND_ARGUMENT} --- Subroutine to retrieve a command argument
@findex @code{GET_COMMAND_ARGUMENT} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F2003

@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@ref{COMMAND_ARGUMENT_COUNT}
@end table



@node GETCWD
@section @code{GETCWD} --- Get current working directory
@findex @code{GETCWD} intrinsic
@cindex file system functions

@table @asis
@item @emph{Description}:
Get current working directory.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Non-elemental subroutine.

@item @emph{Syntax}:
@code{CALL getcwd(CWD[,STATUS])}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{CWD}    @tab The type shall be @code{CHARACTER(*)}.
@item @var{STATUS} @tab (Optional) status flag. Returns 0 on success, 
                        a system specific and non-zero error code otherwise.
@end multitable

@item @emph{Example}:
@smallexample
PROGRAM test_getcwd
  CHARACTER(len=255) :: cwd
  CALL getcwd(cwd)
  WRITE(*,*) TRIM(cwd)
END PROGRAM
@end smallexample

@item @emph{See also}:
@ref{CHDIR}
@end table



@node GETENV
@section @code{GETENV} --- Get an environmental variable
@findex @code{GETENV} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@ref{GET_ENVIRONMENT_VARIABLE}
@end table



@node GET_ENVIRONMENT_VARIABLE
@section @code{GET_ENVIRONMENT_VARIABLE} --- Get an environmental variable
@findex @code{GET_ENVIRONMENT_VARIABLE} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F2003

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@end table



@node GETGID
@section @code{GETGID} --- Group ID function
@findex @code{GETGID} intrinsic
@cindex GETGID

@table @asis
@item @emph{Description}:
Returns the numerical group ID of the current process.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
function

@item @emph{Syntax}:
@code{I = GETGID()}

@item @emph{Return value}:
The return value of @code{GETGID} is an @code{INTEGER} of the default
kind.


@item @emph{Example}:
See @code{GETPID} for an example.

@item @emph{See also}:
@ref{GETPID}
@end table



@node GETLOG
@section @code{GETLOG} --- Get login name
@findex @code{GETLOG} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@end table




@node GETPID
@section @code{GETPID} --- Process ID function
@findex @code{GETPID} intrinsic
@cindex GETPID

@table @asis
@item @emph{Description}:
Returns the numerical process identifier of the current process.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
function

@item @emph{Syntax}:
@code{I = GETPID()}

@item @emph{Return value}:
The return value of @code{GETPID} is an @code{INTEGER} of the default
kind.


@item @emph{Example}:
@smallexample
program info
  print *, "The current process ID is ", getpid()
  print *, "Your numerical user ID is ", getuid()
  print *, "Your numerical group ID is ", getgid()
end program info
@end smallexample

@end table



@node GETUID
@section @code{GETUID} --- User ID function
@findex @code{GETUID} intrinsic
@cindex GETUID

@table @asis
@item @emph{Description}:
Returns the numerical user ID of the current process.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
function

@item @emph{Syntax}:
@code{GETUID()}

@item @emph{Return value}:
The return value of @code{GETUID} is an @code{INTEGER} of the default
kind.


@item @emph{Example}:
See @code{GETPID} for an example.

@item @emph{See also}:
@ref{GETPID}
@end table



@node GMTIME
@section @code{GMTIME} --- Convert time to GMT info
@findex @code{GMTIME} 
@cindex time function

Not yet implemented in GNU Fortran.

@table @asis
@item @emph{Description}:

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@uref{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19292, g77 features lacking in gfortran}

@end table



@node HOSTNM
@section @code{HOSTNM} --- Get system host name
@findex @code{HOSTNM} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@end table



@node HUGE
@section @code{HUGE} --- Largest number of a kind
@findex @code{HUGE} intrinsic
@cindex huge

@table @asis
@item @emph{Description}:
@code{HUGE(X)} returns the largest number that is not an infinity in
the model of the type of @code{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{Y = HUGE(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab shall be of type @code{REAL} or @code{INTEGER}.
@end multitable

@item @emph{Return value}:
The return value is of the same type and kind as @var{X}

@item @emph{Example}:
@smallexample
program test_huge_tiny
  print *, huge(0), huge(0.0), huge(0.0d0)
  print *, tiny(0.0), tiny(0.0d0)
end program test_huge_tiny
@end smallexample
@end table



@node IACHAR
@section @code{IACHAR} --- Code in @acronym{ASCII} collating sequence 
@findex @code{IACHAR} intrinsic
@cindex @acronym{ASCII} collating sequence
@cindex conversion function (character)

@table @asis
@item @emph{Description}:
@code{IACHAR(C)} returns the code for the @acronym{ASCII} character
in the first character position of @code{C}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{I = IACHAR(C)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{C} @tab Shall be a scalar @code{CHARACTER}, with @code{INTENT(IN)}
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER} and of the default integer
kind.

@item @emph{Example}:
@smallexample
program test_iachar
  integer i
  i = iachar(' ')
end program test_iachar
@end smallexample

@item @emph{See also}:
@ref{CHAR},@ref{ICHAR}

@end table


@node IAND
@section @code{IAND} --- Bitwise logical and
@findex @code{IAND} intrinsic
@cindex bit operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{IOR}, @ref{IEOR}, @ref{IBITS}, @ref{IBSET}, @ref{IBCLR},
@end table




@node IARGC
@section @code{IARGC} --- Get number of command line arguments
@findex @code{IARGC} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@ref{GETARG}, @ref{GET_COMMAND}, @ref{COMMAND_ARGUMENT_COUNT}, @ref{GET_COMMAND_ARGUMENT}

@end table




@node IBCLR
@section @code{IBCLR} --- Clear bit
@findex @code{IBCLR} intrinsic
@cindex bit operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{IBITS}, @ref{IBSET}, @ref{IAND}, @ref{IOR}, @ref{IEOR}
@end table




@node IBITS
@section @code{IBITS} --- Bit extraction
@findex @code{IBITS} intrinsic
@cindex bit operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@ref{IBCLR}, @ref{IBSET}, @ref{IAND}, @ref{IOR}, @ref{IEOR}

@end table




@node IBSET
@section @code{IBSET} --- Set bit
@findex @code{IBSET} intrinsic
@cindex bit operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{IBCLR}, @ref{IBITS}, @ref{IAND}, @ref{IOR}, @ref{IEOR}

@end table



@node ICHAR
@section @code{ICHAR} --- Character-to-integer conversion function
@findex @code{ICHAR} intrinsic
@cindex conversion function (character)

@table @asis
@item @emph{Description}:
@code{ICHAR(C)} returns the code for the character in the first character
position of @code{C} in the system's native character set.
The correspondence between characters and their codes is not necessarily
the same across different GNU Fortran implementations.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{I = ICHAR(C)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{C} @tab Shall be a scalar @code{CHARACTER}, with @code{INTENT(IN)}
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER} and of the default integer
kind.

@item @emph{Example}:
@smallexample
program test_ichar
  integer i
  i = ichar(' ')
end program test_ichar
@end smallexample

@item @emph{Note}:
No intrinsic exists to convert a printable character string to a numerical
value. For example, there is no intrinsic that, given the @code{CHARACTER}
value 154, returns an @code{INTEGER} or @code{REAL} value with the
value 154.

Instead, you can use internal-file I/O to do this kind of conversion. For
example:
@smallexample
program read_val
  integer value
  character(len=10) string

  string = '154'
  read (string,'(I10)') value
  print *, value
end program read_val
@end smallexample
@end table

@node IDATE
@section @code{IDATE} --- Get current local time subroutine (day/month/year) 
@findex @code{IDATE} intrinsic

@table @asis
@item @emph{Description}:
@code{IDATE(TARRAY)} Fills @var{TARRAY} with the numerical values at the  
current local time. The day (in the range 1-31), month (in the range 1-12), 
and year appear in elements 1, 2, and 3 of @var{TARRAY}, respectively. 
The year has four significant digits.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@code{CALL IDATE(TARRAY)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{TARRAY} @tab The type shall be @code{INTEGER, DIMENSION(3)} and
the kind shall be the default integer kind.
@end multitable

@item @emph{Return value}:
Does not return.

@item @emph{Example}:
@smallexample
program test_idate
  integer, dimension(3) :: tarray
  call idate(tarray)
  print *, tarray(1)
  print *, tarray(2)
  print *, tarray(3)
end program test_idate
@end smallexample
@end table



@node IEOR
@section @code{IEOR} --- Bitwise logical exclusive or
@findex @code{IEOR} intrinsic
@cindex bit operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{IOR}, @ref{IAND}, @ref{IBITS}, @ref{IBSET}, @ref{IBCLR},
@end table




@node IERRNO
@section @code{IERRNO} --- Get the last system error number
@findex @code{IERRNO} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:

@item @emph{See also}:
@ref{PERROR}
@end table




@node INDEX
@section @code{INDEX} --- Position of a substring within a string
@findex @code{INDEX} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@end table




@node INT
@section @code{INT} --- Convert to integer type
@findex @code{INT} intrinsic
@findex @code{IFIX} intrinsic
@findex @code{IDINT} intrinsic
@cindex conversion function (integer)

@table @asis
@item @emph{Description}:
Convert to integer type

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@multitable @columnfractions .30 .80
@item @code{X = INT(X)}
@item @code{X = INT(X, KIND)}
@end multitable

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab shall be of type @code{INTEGER(*)}, @code{REAL(*)} or @code{COMPLEX(*)}
@item @var{KIND}  @tab (Optional) @var{KIND} shall be a scalar integer.
@end multitable

@item @emph{Return value}:
These functions return a @code{INTEGER(*)} variable or array under 
the following rules: 

@table @asis
@item (A)
If @var{X} is of type @code{INTEGER(*)}, @code{INT(X) = X} 
@item (B)
If @var{X} is of type @code{REAL(*)} and @math{|X| < 1} @code{INT(X)} equals @var{0}. 
If @math{|X| \geq 1}, then @code{INT(X)} equals the largest integer that does not exceed 
the range of @var{X} and whose sign is the same as the sign of @var{X}.
@item (C)
If @var{X} is of type @code{COMPLEX(*)}, rule B is applied to the real part of X.
@end table

@item @emph{Example}:
@smallexample
program test_int
  integer :: i = 42
  complex :: z = (-3.7, 1.0)
  print *, int(i)
  print *, int(z), int(z,8)
end program
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name             @tab Argument            @tab Return type       @tab Standard
@item @code{IFIX(X)}   @tab @code{REAL(4) X}    @tab @code{INTEGER}    @tab F77 and later
@item @code{IDINT(X)}  @tab @code{REAL(8) X}    @tab @code{INTEGER}    @tab F77 and later
@end multitable

@comment @item @emph{See also}:
@end table




@node IOR
@section @code{IOR} --- Bitwise logical or
@findex @code{IOR} intrinsic
@cindex bit operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{IEOR}, @ref{IAND}, @ref{IBITS}, @ref{IBSET}, @ref{IBCLR},
@end table




@node IRAND
@section @code{IRAND} --- Integer pseudo-random number
@findex @code{IRAND} intrinsic
@cindex random number

@table @asis
@item @emph{Description}:
@code{IRAND(FLAG)} returns a pseudo-random number from a uniform
distribution between 0 and a system-dependent limit (which is in most
cases 2147483647). If @var{FLAG} is 0, the next number
in the current sequence is returned; if @var{FLAG} is 1, the generator
is restarted by @code{CALL SRAND(0)}; if @var{FLAG} has any other value,
it is used as a new seed with @code{SRAND}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
non-elemental function

@item @emph{Syntax}:
@code{I = IRAND(FLAG)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{FLAG} @tab shall be a scalar @code{INTEGER} of kind 4.
@end multitable

@item @emph{Return value}:
The return value is of @code{INTEGER(kind=4)} type.

@item @emph{Example}:
@smallexample
program test_irand
  integer,parameter :: seed = 86456
  
  call srand(seed)
  print *, irand(), irand(), irand(), irand()
  print *, irand(seed), irand(), irand(), irand()
end program test_irand
@end smallexample

@end table



@node ISHFT
@section @code{ISHFT} --- Shift bits
@findex @code{ISHFT} intrinsic
@cindex bit manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{ISHFTC}
@end table




@node ISHFTC
@section @code{ISHFTC} --- Shift bits circularly
@findex @code{ISHFTC} intrinsic
@cindex bit manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{ISHFT}
@end table



@node ITIME
@section @code{ITIME} --- Get current local time subroutine (hour/minutes/seconds) 
@findex @code{ITIME} intrinsic

@table @asis
@item @emph{Description}:
@code{IDATE(TARRAY)} Fills @var{TARRAY} with the numerical values at the  
current local time. The hour (in the range 1-24), minute (in the range 1-60), 
and seconds (in the range 1-60) appear in elements 1, 2, and 3 of @var{TARRAY}, 
respectively.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@code{CALL ITIME(TARRAY)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{TARRAY} @tab The type shall be @code{INTEGER, DIMENSION(3)}
and the kind shall be the default integer kind.
@end multitable

@item @emph{Return value}:
Does not return.


@item @emph{Example}:
@smallexample
program test_itime
  integer, dimension(3) :: tarray
  call itime(tarray)
  print *, tarray(1)
  print *, tarray(2)
  print *, tarray(3)
end program test_itime
@end smallexample
@end table



@node KILL
@section @code{KILL} --- Send a signal to a process
@findex @code{KILL} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{ABORT}, @ref{EXIT}
@end table



@node KIND
@section @code{KIND} --- Kind of an entity
@findex @code{KIND} intrinsic

@table @asis
@item @emph{Description}:
@code{KIND(X)} returns the kind value of the entity @var{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{K = KIND(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab Shall be of type @code{LOGICAL}, @code{INTEGER},
@code{REAL}, @code{COMPLEX} or @code{CHARACTER}.
@end multitable

@item @emph{Return value}:
The return value is a scalar of type @code{INTEGER} and of the default
integer kind.

@item @emph{Example}:
@smallexample
program test_kind
  integer,parameter :: kc = kind(' ')
  integer,parameter :: kl = kind(.true.)

  print *, "The default character kind is ", kc
  print *, "The default logical kind is ", kl
end program test_kind
@end smallexample

@end table



@node LBOUND
@section @code{LBOUND} --- Lower dimension bounds of an array
@findex @code{LBOUND} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@ref{UBOUND}
@end table




@node LEN
@section @code{LEN} --- Length of a character entity
@findex @code{LEN} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{LEN_TRIM}, @ref{ADJUSTL}, @ref{ADJUSTR}
@end table




@node LEN_TRIM
@section @code{LEN_TRIM} --- Length of a character entity without trailing blank characters
@findex @code{LEN_TRIM} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:

@item @emph{See also}:
@ref{LEN}, @ref{ADJUSTL}, @ref{ADJUSTR}
@end table




@node LGE
@section @code{LGE} --- Lexical greater than or equal
@findex @code{LGE} intrinsic
@cindex comparison (lexical)

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:

@item @emph{See also}:
@ref{LGT}, @ref{LLE}, @ref{LLT}
@end table




@node LGT
@section @code{LGT} --- Lexical greater than
@findex @code{LGT} intrinsic
@cindex comparison (lexical)

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:

@item @emph{See also}:
@ref{LGE}, @ref{LLE}, @ref{LLT}
@end table




@node LINK
@section @code{LINK} --- Create a hard link
@findex @code{LINK} intrinsic
@cindex file system operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{UNLINK}
@end table




@node LLE
@section @code{LLE} --- Lexical less than or equal
@findex @code{LLE} intrinsic
@cindex comparison (lexical)

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:

@item @emph{See also}:
@ref{LGE}, @ref{LGT}, @ref{LLT}
@end table




@node LLT
@section @code{LLT} --- Lexical less than
@findex @code{LLT} intrinsic
@cindex comparison (lexical)

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:

@item @emph{See also}:
@ref{LGE}, @ref{LGT}, @ref{LLE}
@end table




@node LNBLNK
@section @code{LNBLNK} --- Index of the last non-blank character in a string
@findex @code{LNBLNK} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{INDEX}
@end table




@node LOC
@section @code{LOC} --- Returns the address of a variable
@findex @code{LOC} intrinsic
@cindex loc

@table @asis
@item @emph{Description}:
@code{LOC(X)} returns the address of @var{X} as an integer.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{I = LOC(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab Variable of any type.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER(n)}, where @code{n} is the
size (in bytes) of a memory address on the target machine.

@item @emph{Example}:
@smallexample
program test_loc
  integer :: i
  real :: r
  i = loc(r)
  print *, i
end program test_loc
@end smallexample
@end table

@node LOG
@section @code{LOG} --- Logarithm function
@findex @code{LOG} intrinsic
@findex @code{ALOG} intrinsic
@findex @code{DLOG} intrinsic
@findex @code{CLOG} intrinsic
@findex @code{ZLOG} intrinsic
@findex @code{CDLOG} intrinsic
@cindex logarithm

@table @asis
@item @emph{Description}:
@code{LOG(X)} computes the logarithm of @var{X}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = LOG(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)} or
@code{COMPLEX(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} or @code{COMPLEX(*)}.
The kind type parameter is the same as @var{X}.

@item @emph{Example}:
@smallexample
program test_log
  real(8) :: x = 1.0_8
  complex :: z = (1.0, 2.0)
  x = log(x)
  z = log(z)
end program test_log
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{ALOG(X)}  @tab @code{REAL(4) X}  @tab @code{REAL(4)}    @tab f95, gnu
@item @code{DLOG(X)}  @tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab f95, gnu
@item @code{CLOG(X)}  @tab @code{COMPLEX(4) X}  @tab @code{COMPLEX(4)}    @tab f95, gnu
@item @code{ZLOG(X)}  @tab @code{COMPLEX(8) X}  @tab @code{COMPLEX(8)}    @tab f95, gnu
@item @code{CDLOG(X)} @tab @code{COMPLEX(8) X}  @tab @code{COMPLEX(8)}    @tab f95, gnu
@end multitable
@end table



@node LOG10
@section @code{LOG10} --- Base 10 logarithm function
@findex @code{LOG10} intrinsic
@findex @code{ALOG10} intrinsic
@findex @code{DLOG10} intrinsic
@cindex logarithm

@table @asis
@item @emph{Description}:
@code{LOG10(X)} computes the base 10 logarithm of @var{X}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = LOG10(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)} or
@code{COMPLEX(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} or @code{COMPLEX(*)}.
The kind type parameter is the same as @var{X}.

@item @emph{Example}:
@smallexample
program test_log10
  real(8) :: x = 10.0_8
  x = log10(x)
end program test_log10
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{ALOG10(X)}  @tab @code{REAL(4) X}  @tab @code{REAL(4)}    @tab F95 and later
@item @code{DLOG10(X)}  @tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab F95 and later
@end multitable
@end table


@node LOGICAL
@section @code{LOGICAL} --- Convert to logical type
@findex @code{LOGICAL} intrinsic
@cindex conversion function (logical)

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@end table




@node LSHIFT
@section @code{LSHIFT} --- Left shift bits
@findex @code{LSHIFT} 
@cindex bit manipulation

Not yet implemented in GNU Fortran.

@table @asis
@item @emph{Description}:

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@uref{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19292, g77 features lacking in gfortran}

@end table



@node LTIME
@section @code{LTIME} --- Convert time to local time info
@findex @code{LTIME} 
@cindex time function

Not yet implemented in GNU Fortran.

@table @asis
@item @emph{Description}:

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@uref{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19292, g77 features lacking in gfortran}

@end table



@node MALLOC
@section @code{MALLOC} --- Allocate dynamic memory
@findex @code{MALLOC} intrinsic
@cindex MALLOC

@table @asis
@item @emph{Description}:
@code{MALLOC(SIZE)} allocates @var{SIZE} bytes of dynamic memory and
returns the address of the allocated memory. The @code{MALLOC} intrinsic
is an extension intended to be used with Cray pointers, and is provided
in GNU Fortran to allow the user to compile legacy code. For new code
using Fortran 95 pointers, the memory allocation intrinsic is
@code{ALLOCATE}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
non-elemental function

@item @emph{Syntax}:
@code{PTR = MALLOC(SIZE)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{SIZE} @tab The type shall be @code{INTEGER(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER(K)}, with @var{K} such that
variables of type @code{INTEGER(K)} have the same size as
C pointers (@code{sizeof(void *)}).

@item @emph{Example}:
The following example demonstrates the use of @code{MALLOC} and
@code{FREE} with Cray pointers. This example is intended to run on
32-bit systems, where the default integer kind is suitable to store
pointers; on 64-bit systems, ptr_x would need to be declared as
@code{integer(kind=8)}.

@smallexample
program test_malloc
  integer i
  integer ptr_x
  real*8 x(*), z
  pointer(ptr_x,x)

  ptr_x = malloc(20*8)
  do i = 1, 20
    x(i) = sqrt(1.0d0 / i)
  end do
  z = 0
  do i = 1, 20
    z = z + x(i)
    print *, z
  end do
  call free(ptr_x)
end program test_malloc
@end smallexample

@item @emph{See also}:
@ref{FREE}
@end table


@node MATMUL
@section @code{MATMUL} --- matrix multiplication
@findex @code{MATMUL} intrinsic
@cindex matrix operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table


@node MAX
@section @code{MAX} --- Maximum value of an argument list
@findex @code{MAX} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name             @tab Argument            @tab Return type         @tab Standard
@item @code{MAX0(I)}   @tab @code{INTEGER(4) I} @tab @code{INTEGER(4)}   @tab F77 and later
@item @code{AMAX0(I)}  @tab @code{INTEGER(4) I} @tab @code{REAL(MAX(X))} @tab F77 and later
@item @code{MAX1(X)}   @tab @code{REAL(*) X}    @tab @code{INT(MAX(X))}  @tab F77 and later
@item @code{AMAX1(X)}  @tab @code{REAL(4)    X} @tab @code{REAL(4)}      @tab F77 and later
@item @code{DMAX1(X)}  @tab @code{REAL(8)    X} @tab @code{REAL(8)}      @tab F77 and later
@end multitable

@item @emph{See also}:
@ref{MAXLOC} @ref{MAXVAL}
@end table


@node MAXEXPONENT
@section @code{MAXEXPONENT} --- Maximum exponent of a real kind
@findex @code{MAXEXPONENT} intrinsic
@cindex MAXEXPONENT

@table @asis
@item @emph{Description}:
@code{MAXEXPONENT(X)} returns the maximum exponent in the model of the
type of @code{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{I = MAXEXPONENT(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab shall be of type @code{REAL}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER} and of the default integer
kind.

@item @emph{Example}:
@smallexample
program exponents
  real(kind=4) :: x
  real(kind=8) :: y

  print *, minexponent(x), maxexponent(x)
  print *, minexponent(y), maxexponent(y)
end program exponents
@end smallexample
@end table


@node MAXLOC
@section @code{MAXLOC} --- Location of the maximum value within an array
@findex @code{MAXLOC} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@ref{MAX}, @ref{MAXVAL}
@end table



@node MAXVAL
@section @code{MAXVAL} --- Maximum value of an array
@findex @code{MAXVAL} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:


@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{MAX}, @ref{MAXLOC}
@end table




@node MERGE
@section @code{MERGE} --- Merge arrays
@findex @code{MERGE} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@end table


@node MIN
@section @code{MIN} --- Minimum value of an argument list
@findex @code{MIN} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name             @tab Argument            @tab Return type         @tab Standard
@item @code{MIN0(I)}   @tab @code{INTEGER(4) I} @tab @code{INTEGER(4)}   @tab F77 and later
@item @code{AMIN0(I)}  @tab @code{INTEGER(4) I} @tab @code{REAL(MIN(X))} @tab F77 and later
@item @code{MIN1(X)}   @tab @code{REAL(*) X}    @tab @code{INT(MIN(X))}  @tab F77 and later
@item @code{AMIN1(X)}  @tab @code{REAL(4)    X} @tab @code{REAL(4)}      @tab F77 and later
@item @code{DMIN1(X)}  @tab @code{REAL(8)    X} @tab @code{REAL(8)}      @tab F77 and later
@end multitable

@item @emph{See also}:
@ref{MINLOC}, @ref{MINVAL}
@end table

@node MINEXPONENT
@section @code{MINEXPONENT} --- Minimum exponent of a real kind
@findex @code{MINEXPONENT} intrinsic
@cindex MINEXPONENT

@table @asis
@item @emph{Description}:
@code{MINEXPONENT(X)} returns the minimum exponent in the model of the
type of @code{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{I = MINEXPONENT(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab shall be of type @code{REAL}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER} and of the default integer
kind.

@item @emph{Example}:
See @code{MAXEXPONENT} for an example.
@end table


@node MINLOC
@section @code{MINLOC} --- Location of the minimum value within an array
@findex @code{MINLOC} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:

@item @emph{See also}:
@ref{MIN}, @ref{MINVAL}

@end table


@node MINVAL
@section @code{MINVAL} --- Minimum value of an array
@findex @code{MINVAL} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:

@item @emph{See also}:
@ref{MIN}, @ref{MINLOC}
@end table




@node MOD
@section @code{MOD} --- Remainder function
@findex @code{MOD} intrinsic
@findex @code{AMOD} intrinsic
@findex @code{DMOD} intrinsic
@cindex remainder

@table @asis
@item @emph{Description}:
@code{MOD(A,P)} computes the remainder of the division of A by P. It is
calculated as @code{A - (INT(A/P) * P)}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = MOD(A,P)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{A} @tab shall be a scalar of type @code{INTEGER} or @code{REAL}
@item @var{P} @tab shall be a scalar of the same type as @var{A} and not
equal to zero
@end multitable

@item @emph{Return value}:
The kind of the return value is the result of cross-promoting
the kinds of the arguments.

@item @emph{Example}:
@smallexample
program test_mod
  print *, mod(17,3)
  print *, mod(17.5,5.5)
  print *, mod(17.5d0,5.5)
  print *, mod(17.5,5.5d0)

  print *, mod(-17,3)
  print *, mod(-17.5,5.5)
  print *, mod(-17.5d0,5.5)
  print *, mod(-17.5,5.5d0)

  print *, mod(17,-3)
  print *, mod(17.5,-5.5)
  print *, mod(17.5d0,-5.5)
  print *, mod(17.5,-5.5d0)
end program test_mod
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name             @tab Arguments      @tab Return type    @tab Standard
@item @code{AMOD(A,P)} @tab @code{REAL(4)} @tab @code{REAL(4)} @tab F95 and later
@item @code{DMOD(A,P)} @tab @code{REAL(8)} @tab @code{REAL(8)} @tab F95 and later
@end multitable
@end table



@node MODULO
@section @code{MODULO} --- Modulo function
@findex @code{MODULO} intrinsic
@cindex modulo

@table @asis
@item @emph{Description}:
@code{MODULO(A,P)} computes the @var{A} modulo @var{P}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = MODULO(A,P)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{A} @tab shall be a scalar of type @code{INTEGER} or @code{REAL}
@item @var{P} @tab shall be a scalar of the same type and kind as @var{A}
@end multitable

@item @emph{Return value}:
The type and kind of the result are those of the arguments.
@table @asis
@item If @var{A} and @var{P} are of type @code{INTEGER}:
@code{MODULO(A,P)} has the value @var{R} such that @code{A=Q*P+R}, where
@var{Q} is an integer and @var{R} is between 0 (inclusive) and @var{P}
(exclusive).
@item If @var{A} and @var{P} are of type @code{REAL}:
@code{MODULO(A,P)} has the value of @code{A - FLOOR (A / P) * P}.
@end table
In all cases, if @var{P} is zero the result is processor-dependent.

@item @emph{Example}:
@smallexample
program test_modulo
  print *, modulo(17,3)
  print *, modulo(17.5,5.5)

  print *, modulo(-17,3)
  print *, modulo(-17.5,5.5)

  print *, modulo(17,-3)
  print *, modulo(17.5,-5.5)
end program test_mod
@end smallexample

@end table



@node MVBITS
@section @code{MVBITS} --- Move bits from one integer to another
@findex @code{MVBITS} intrinsic
@cindex bit operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node NEAREST
@section @code{NEAREST} --- Nearest representable number
@findex @code{NEAREST} intrinsic
@cindex processor-representable number

@table @asis
@item @emph{Description}:
@code{NEAREST(X, S)} returns the processor-representable number nearest
to @code{X} in the direction indicated by the sign of @code{S}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{Y = NEAREST(X, S)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab shall be of type @code{REAL}.
@item @var{S} @tab (Optional) shall be of type @code{REAL} and
not equal to zero.
@end multitable

@item @emph{Return value}:
The return value is of the same type as @code{X}. If @code{S} is
positive, @code{NEAREST} returns the processor-representable number
greater than @code{X} and nearest to it. If @code{S} is negative,
@code{NEAREST} returns the processor-representable number smaller than
@code{X} and nearest to it.

@item @emph{Example}:
@smallexample
program test_nearest
  real :: x, y
  x = nearest(42.0, 1.0)
  y = nearest(42.0, -1.0)
  write (*,"(3(G20.15))") x, y, x - y
end program test_nearest
@end smallexample
@end table



@node NINT
@section @code{NINT} --- Nearest whole number
@findex @code{NINT} intrinsic
@findex @code{IDNINT} intrinsic
@cindex whole number

@table @asis
@item @emph{Description}:
@code{NINT(X)} rounds its argument to the nearest whole number.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = NINT(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X}    @tab The type of the argument shall be @code{REAL}.
@end multitable

@item @emph{Return value}:
Returns @var{A} with the fractional portion of its magnitude eliminated by
rounding to the nearest whole number and with its sign preserved,
converted to an @code{INTEGER} of the default kind.

@item @emph{Example}:
@smallexample
program test_nint
  real(4) x4
  real(8) x8
  x4 = 1.234E0_4
  x8 = 4.321_8
  print *, nint(x4), idnint(x8)
end program test_nint
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .33 .33 .33
@item Name             @tab Argument         @tab Standard
@item @code{IDNINT(X)} @tab @code{REAL(8)}   @tab F95 and later
@end multitable

@item @emph{See also}:
@ref{CEILING}, @ref{FLOOR}

@end table


@node NOT
@section @code{NOT} --- Logical negation
@findex @code{NOT} intrinsic
@cindex logical operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node NULL
@section @code{NULL} --- Function that returns an disassociated pointer
@findex @code{NULL} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@ref{ASSOCIATED}
@end table




@node OR
@section @code{OR} --- Bitwise logical OR
@findex @code{OR} intrinsic
@cindex bit operations

@table @asis
@item @emph{Description}:
Bitwise logical @code{OR}.

This intrinsic routine is provided for backwards compatibility with 
GNU Fortran 77.  For integer arguments, programmers should consider
the use of the @ref{IOR} intrinsic defined by the Fortran standard.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Non-elemental function

@item @emph{Syntax}:
@code{RESULT = OR(X, Y)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be either @code{INTEGER(*)} or @code{LOGICAL}.
@item @var{Y} @tab The type shall be either @code{INTEGER(*)} or @code{LOGICAL}.
@end multitable

@item @emph{Return value}:
The return type is either @code{INTEGER(*)} or @code{LOGICAL} 
after cross-promotion of the arguments.

@item @emph{Example}:
@smallexample
PROGRAM test_or
  LOGICAL :: T = .TRUE., F = ..FALSE.
  INTEGER :: a, b
  DATA a / Z'F' /, b / Z'3' /

  WRITE (*,*) OR(T, T), OR(T, F), OR(F, T), OR(F, F)
  WRITE (*,*) OR(a, b)
END PROGRAM
@end smallexample

@item @emph{See also}:
F95 elemental function: @ref{IOR}
@end table




@node PACK
@section @code{PACK} --- Pack an array into an array of rank one
@findex @code{PACK} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@ref{UNPACK}
@end table




@node PERROR
@section @code{PERROR} --- Print system error message
@findex @code{PERROR} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@ref{IERRNO}
@end table




@node PRECISION
@section @code{PRECISION} --- Decimal precision of a real kind
@findex @code{PRECISION} intrinsic
@cindex PRECISION

@table @asis
@item @emph{Description}:
@code{PRECISION(X)} returns the decimal precision in the model of the
type of @code{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{I = PRECISION(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab shall be of type @code{REAL} or @code{COMPLEX}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER} and of the default integer
kind.

@item @emph{Example}:
@smallexample
program prec_and_range
  real(kind=4) :: x(2)
  complex(kind=8) :: y

  print *, precision(x), range(x)
  print *, precision(y), range(y)
end program prec_and_range
@end smallexample
@end table



@node PRESENT
@section @code{PRESENT} --- Determine whether an optional argument is specified
@findex @code{PRESENT} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node PRODUCT
@section @code{PRODUCT} --- Product of array elements
@findex @code{PRODUCT} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@ref{SUM}
@end table




@node RADIX
@section @code{RADIX} --- Base of a model number
@findex @code{RADIX} intrinsic
@cindex base

@table @asis
@item @emph{Description}:
@code{RADIX(X)} returns the base of the model representing the entity @var{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{R = RADIX(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab Shall be of type @code{INTEGER} or @code{REAL}
@end multitable

@item @emph{Return value}:
The return value is a scalar of type @code{INTEGER} and of the default
integer kind.

@item @emph{Example}:
@smallexample
program test_radix
  print *, "The radix for the default integer kind is", radix(0)
  print *, "The radix for the default real kind is", radix(0.0)
end program test_radix
@end smallexample

@end table



@node RANDOM_NUMBER
@section @code{RANDOM_NUMBER} --- Pseudo-random number
@findex @code{RANDOM_NUMBER} intrinsic
@cindex random numbers

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@ref{RANDOM_SEED}
@end table




@node RANDOM_SEED
@section @code{RANDOM_SEED} --- Initialize a pseudo-random number sequence
@findex @code{RANDOM_SEED} intrinsic
@cindex random numbers

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@ref{RANDOM_NUMBER}
@end table




@node RAND
@section @code{RAND} --- Real pseudo-random number
@findex @code{RAND} intrinsic
@findex @code{RAN} intrinsic
@cindex random number

@table @asis
@item @emph{Description}:
@code{RAND(FLAG)} returns a pseudo-random number from a uniform
distribution between 0 and 1. If @var{FLAG} is 0, the next number
in the current sequence is returned; if @var{FLAG} is 1, the generator
is restarted by @code{CALL SRAND(0)}; if @var{FLAG} has any other value,
it is used as a new seed with @code{SRAND}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
non-elemental function

@item @emph{Syntax}:
@code{X = RAND(FLAG)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{FLAG} @tab shall be a scalar @code{INTEGER} of kind 4.
@end multitable

@item @emph{Return value}:
The return value is of @code{REAL} type and the default kind.

@item @emph{Example}:
@smallexample
program test_rand
  integer,parameter :: seed = 86456
  
  call srand(seed)
  print *, rand(), rand(), rand(), rand()
  print *, rand(seed), rand(), rand(), rand()
end program test_rand
@end smallexample

@item @emph{Note}:
For compatibility with HP FORTRAN 77/iX, the @code{RAN} intrinsic is
provided as an alias for @code{RAND}.

@item @emph{See also}:
@ref{SRAND}, @ref{RANDOM_NUMBER}

@end table



@node RANGE
@section @code{RANGE} --- Decimal exponent range of a real kind
@findex @code{RANGE} intrinsic
@cindex RANGE

@table @asis
@item @emph{Description}:
@code{RANGE(X)} returns the decimal exponent range in the model of the
type of @code{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@code{I = RANGE(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab shall be of type @code{REAL} or @code{COMPLEX}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{INTEGER} and of the default integer
kind.

@item @emph{Example}:
See @code{PRECISION} for an example.
@end table



@node RAN
@section @code{RAN} --- Real pseudo-random number
@findex @code{RAN} intrinsic
@cindex random number

@table @asis
@item @emph{Standard}:
GNU extension

@item @emph{See also}:
@ref{RAND}, @ref{RANDOM_NUMBER}
@end table



@node REAL
@section @code{REAL} --- Convert to real type 
@findex @code{REAL} intrinsic
@findex @code{REALPART} intrinsic
@cindex true values

@table @asis
@item @emph{Description}:
@code{REAL(X [, KIND])} converts its argument @var{X} to a real type.  The
@code{REALPART(X)} function is provided for compatibility with @command{g77},
and its use is strongly discouraged.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@multitable @columnfractions .30 .80
@item @code{X = REAL(X)}
@item @code{X = REAL(X, KIND)}
@item @code{X = REALPART(Z)}
@end multitable

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab shall be @code{INTEGER(*)}, @code{REAL(*)}, or  
@code{COMPLEX(*)}.
@item @var{KIND}  @tab (Optional) @var{KIND} shall be a scalar integer.
@end multitable

@item @emph{Return value}:
These functions return a @code{REAL(*)} variable or array under
the following rules: 

@table @asis
@item (A)
@code{REAL(X)} is converted to a default real type if @var{X} is an 
integer or real variable.
@item (B)
@code{REAL(X)} is converted to a real type with the kind type parameter
of @var{X} if @var{X} is a complex variable.
@item (C)
@code{REAL(X, KIND)} is converted to a real type with kind type
parameter @var{KIND} if @var{X} is a complex, integer, or real
variable.
@end table

@item @emph{Example}:
@smallexample
program test_real
  complex :: x = (1.0, 2.0)
  print *, real(x), real(x,8), realpart(x)
end program test_real
@end smallexample

@item @emph{See also}:
@ref{DBLE}, @ref{DFLOAT}, @ref{FLOAT}

@end table


@node RENAME
@section @code{RENAME} --- Rename a file
@findex @code{RENAME} intrinsic
@cindex file system operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node REPEAT
@section @code{REPEAT} --- Repeated string concatenation 
@findex @code{REPEAT} intrinsic
@cindex string manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node RESHAPE
@section @code{RESHAPE} --- Function to reshape an array
@findex @code{RESHAPE} intrinsic
@cindex array manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@ref{SHAPE}
@end table



@node RRSPACING
@section @code{RRSPACING} --- Reciprocal of the relative spacing
@findex @code{RRSPACING} intrinsic

@table @asis
@item @emph{Description}:
@code{RRSPACING(X)} returns the  reciprocal of the relative spacing of
model numbers near @var{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{Y = RRSPACING(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab shall be of type @code{REAL}.
@end multitable

@item @emph{Return value}:
The return value is of the same type and kind as @var{X}.
The value returned is equal to
@code{ABS(FRACTION(X)) * FLOAT(RADIX(X))**DIGITS(X)}.

@end table



@node RSHIFT
@section @code{RSHIFT} --- Right shift bits
@findex @code{RSHIFT} 
@cindex bit manipulation

Not yet implemented in GNU Fortran.

@table @asis
@item @emph{Description}:

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@uref{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19292, g77 features lacking in gfortran}

@end table



@node SCALE
@section @code{SCALE} --- Scale a real value
@findex @code{SCALE} intrinsic

@table @asis
@item @emph{Description}:
@code{SCALE(X,I)} returns @code{X * RADIX(X)**I}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{Y = SCALE(X, I)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type of the argument shall be a @code{REAL}.
@item @var{I} @tab The type of the argument shall be a @code{INTEGER}.
@end multitable

@item @emph{Return value}:
The return value is of the same type and kind as @var{X}.
Its value is @code{X * RADIX(X)**I}.

@item @emph{Example}:
@smallexample
program test_scale
  real :: x = 178.1387e-4
  integer :: i = 5
  print *, scale(x,i), x*radix(x)**i
end program test_scale
@end smallexample

@end table


@node SCAN
@section @code{SCAN} --- Scan a string for the presence of a set of characters
@findex @code{SCAN} intrinsic
@cindex string manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node SECNDS
@section @code{SECNDS} --- Time function
@findex @code{SECNDS} intrinsic
@cindex SECNDS

@table @asis
@item @emph{Description}:
@code{SECNDS(X)} gets the time in seconds from the real-time system clock.
@var{X} is a reference time, also in seconds. If this is zero, the time in
seconds from midnight is returned. This function is non-standard and its
use is discouraged.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
function

@item @emph{Syntax}:
@code{T = SECNDS (X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item Name        @tab Type
@item @var{T}     @tab REAL(4)
@item @var{X}     @tab REAL(4)
@end multitable

@item @emph{Return value}:
None

@item @emph{Example}:
@smallexample
program test_secnds
    real(4) :: t1, t2
    print *, secnds (0.0)   ! seconds since midnight
    t1 = secnds (0.0)       ! reference time
    do i = 1, 10000000      ! do something
    end do
    t2 = secnds (t1)        ! elapsed time
    print *, "Something took ", t2, " seconds."
end program test_secnds
@end smallexample
@end table



@node SELECTED_INT_KIND
@section @code{SELECTED_INT_KIND} --- Choose integer kind
@findex @code{SELECTED_INT_KIND} intrinsic
@cindex integer kind

@table @asis
@item @emph{Description}:
@code{SELECTED_INT_KIND(I)} return the kind value of the smallest integer
type that can represent all values ranging from @math{-10^I} (exclusive)
to @math{10^I} (exclusive). If there is no integer kind that accommodates
this range, @code{SELECTED_INT_KIND} returns @math{-1}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@multitable @columnfractions .30 .80
@item @code{J = SELECTED_INT_KIND(I)}
@end multitable

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{I} @tab shall be a scalar and of type @code{INTEGER}.
@end multitable

@item @emph{Example}:
@smallexample
program large_integers
  integer,parameter :: k5 = selected_int_kind(5)
  integer,parameter :: k15 = selected_int_kind(15)
  integer(kind=k5) :: i5
  integer(kind=k15) :: i15

  print *, huge(i5), huge(i15)

  ! The following inequalities are always true
  print *, huge(i5) >= 10_k5**5-1
  print *, huge(i15) >= 10_k15**15-1
end program large_integers
@end smallexample
@end table



@node SELECTED_REAL_KIND
@section @code{SELECTED_REAL_KIND} --- Choose real kind
@findex @code{SELECTED_REAL_KIND} intrinsic
@cindex real kind

@table @asis
@item @emph{Description}:
@code{SELECTED_REAL_KIND(P,R)} return the kind value of a real data type
with decimal precision greater of at least @code{P} digits and exponent
range greater at least @code{R}. 

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@multitable @columnfractions .30 .80
@item @code{I = SELECTED_REAL_KIND(P,R)}
@end multitable

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{P} @tab (Optional) shall be a scalar and of type @code{INTEGER}.
@item @var{R} @tab (Optional) shall be a scalar and of type @code{INTEGER}.
@end multitable
At least one argument shall be present.

@item @emph{Return value}:

@code{SELECTED_REAL_KIND} returns the value of the kind type parameter of
a real data type with decimal precision of at least @code{P} digits and a
decimal exponent range of at least @code{R}. If more than one real data
type meet the criteria, the kind of the data type with the smallest
decimal precision is returned. If no real data type matches the criteria,
the result is
@table @asis
@item -1 if the processor does not support a real data type with a
precision greater than or equal to @code{P}
@item -2 if the processor does not support a real type with an exponent
range greater than or equal to @code{R}
@item -3 if neither is supported.
@end table

@item @emph{Example}:
@smallexample
program real_kinds
  integer,parameter :: p6 = selected_real_kind(6)
  integer,parameter :: p10r100 = selected_real_kind(10,100)
  integer,parameter :: r400 = selected_real_kind(r=400)
  real(kind=p6) :: x
  real(kind=p10r100) :: y
  real(kind=r400) :: z

  print *, precision(x), range(x)
  print *, precision(y), range(y)
  print *, precision(z), range(z)
end program real_kinds
@end smallexample
@end table



@node SET_EXPONENT
@section @code{SET_EXPONENT} --- Set the exponent of the model
@findex @code{SET_EXPONENT} intrinsic
@cindex exponent

@table @asis
@item @emph{Description}:
@code{SET_EXPONENT(X, I)} returns the real number whose fractional part
is that that of @var{X} and whose exponent part if @var{I}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{Y = SET_EXPONENT(X, I)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab shall be of type @code{REAL}.
@item @var{I} @tab shall be of type @code{INTEGER}.
@end multitable

@item @emph{Return value}:
The return value is of the same type and kind as @var{X}.
The real number whose fractional part
is that that of @var{X} and whose exponent part if @var{I} is returned;
it is @code{FRACTION(X) * RADIX(X)**I}.

@item @emph{Example}:
@smallexample
program test_setexp
  real :: x = 178.1387e-4
  integer :: i = 17
  print *, set_exponent(x), fraction(x) * radix(x)**i
end program test_setexp
@end smallexample

@end table



@node SHAPE
@section @code{SHAPE} --- Determine the shape of an array
@findex @code{SHAPE} intrinsic
@cindex array manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@ref{RESHAPE}
@end table




@node SIGN
@section @code{SIGN} --- Sign copying function
@findex @code{SIGN} intrinsic
@findex @code{ISIGN} intrinsic
@findex @code{DSIGN} intrinsic
@cindex sign copying

@table @asis
@item @emph{Description}:
@code{SIGN(A,B)} returns the value of @var{A} with the sign of @var{B}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = SIGN(A,B)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{A} @tab shall be a scalar of type @code{INTEGER} or @code{REAL}
@item @var{B} @tab shall be a scalar of the same type and kind as @var{A}
@end multitable

@item @emph{Return value}:
The kind of the return value is that of @var{A} and @var{B}.
If @math{B\ge 0} then the result is @code{ABS(A)}, else
it is @code{-ABS(A)}.

@item @emph{Example}:
@smallexample
program test_sign
  print *, sign(-12,1)
  print *, sign(-12,0)
  print *, sign(-12,-1)

  print *, sign(-12.,1.)
  print *, sign(-12.,0.)
  print *, sign(-12.,-1.)
end program test_sign
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name              @tab Arguments      @tab Return type    @tab Standard
@item @code{ISIGN(A,P)} @tab @code{INTEGER(4)} @tab @code{INTEGER(4)} @tab f95, gnu
@item @code{DSIGN(A,P)} @tab @code{REAL(8)} @tab @code{REAL(8)} @tab f95, gnu
@end multitable
@end table



@node SIGNAL
@section @code{SIGNAL} --- Signal handling subroutine (or function)
@findex @code{SIGNAL} intrinsic
@cindex SIGNAL subroutine 

@table @asis
@item @emph{Description}:
@code{SIGNAL(NUMBER, HANDLER [, STATUS])} causes external subroutine
@var{HANDLER} to be executed with a single integer argument when signal
@var{NUMBER} occurs.  If @var{HANDLER} is an integer, it can be used to
turn off handling of signal @var{NUMBER} or revert to its default
action.  See @code{signal(2)}.

If @code{SIGNAL} is called as a subroutine and the @var{STATUS} argument
is supplied, it is set to the value returned by @code{signal(2)}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
subroutine, non-elemental function

@item @emph{Syntax}:
@multitable @columnfractions .30 .80
@item @code{CALL ALARM(NUMBER, HANDLER)}
@item @code{CALL ALARM(NUMBER, HANDLER, STATUS)}
@item @code{STATUS = ALARM(NUMBER, HANDLER)}
@end multitable

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{NUMBER} @tab shall be a scalar integer, with @code{INTENT(IN)}
@item @var{HANDLER}@tab Signal handler (@code{INTEGER FUNCTION} or
@code{SUBROUTINE}) or dummy/global @code{INTEGER} scalar.
@code{INTEGER}. It is @code{INTENT(IN)}.
@item @var{STATUS} @tab (Optional) @var{STATUS} shall be a scalar
integer. It has @code{INTENT(OUT)}.
@end multitable

@item @emph{Return value}:
The @code{SIGNAL} functions returns the value returned by @code{signal(2)}.

@item @emph{Example}:
@smallexample
program test_signal
  intrinsic signal
  external handler_print

  call signal (12, handler_print)
  call signal (10, 1)

  call sleep (30)
end program test_signal
@end smallexample
@end table




@node SIN
@section @code{SIN} --- Sine function 
@findex @code{SIN} intrinsic
@findex @code{DSIN} intrinsic
@findex @code{ZSIN} intrinsic
@findex @code{CDSIN} intrinsic
@cindex trigonometric functions

@table @asis
@item @emph{Description}:
@code{SIN(X)} computes the sine of @var{X}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = SIN(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)} or
@code{COMPLEX(*)}.
@end multitable

@item @emph{Return value}:
The return value has same type and kind as @var{X}.

@item @emph{Example}:
@smallexample
program test_sin
  real :: x = 0.0
  x = sin(x)
end program test_sin
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DSIN(X)}  @tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab f95, gnu
@item @code{CSIN(X)}  @tab @code{COMPLEX(4) X}  @tab @code{COMPLEX(4)}    @tab f95, gnu
@item @code{ZSIN(X)}  @tab @code{COMPLEX(8) X}  @tab @code{COMPLEX(8)}    @tab f95, gnu
@item @code{CDSIN(X)} @tab @code{COMPLEX(8) X}  @tab @code{COMPLEX(8)}    @tab f95, gnu
@end multitable

@item @emph{See also}:
@ref{ASIN}
@end table



@node SINH
@section @code{SINH} --- Hyperbolic sine function 
@findex @code{SINH} intrinsic
@findex @code{DSINH} intrinsic
@cindex hyperbolic sine

@table @asis
@item @emph{Description}:
@code{SINH(X)} computes the hyperbolic sine of @var{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = SINH(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)}.

@item @emph{Example}:
@smallexample
program test_sinh
  real(8) :: x = - 1.0_8
  x = sinh(x)
end program test_sinh
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DSINH(X)} @tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab F95 and later
@end multitable

@item @emph{See also}:
@ref{ASINH}
@end table



@node SIZE
@section @code{SIZE} --- Determine the size of an array
@findex @code{SIZE} intrinsic
@cindex array manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table



@node SNGL
@section @code{SNGL} --- Convert double precision real to default real
@findex @code{SNGL} intrinsic
@cindex conversion function (real)

@table @asis
@item @emph{Description}:
@code{SNGL(A)} converts the double precision real @var{A}
to a default real value. This is an archaic form of @code{REAL}
that is specific to one type for @var{A}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
function

@item @emph{Syntax}:
@code{X = SNGL(A)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{A} @tab The type shall be a double precision @code{REAL}.
@end multitable

@item @emph{Return value}:
The return value is of type default @code{REAL}.

@item @emph{See also}:
@ref{DBLE}
@end table



@node SPACING
@section @code{SPACING} --- Smallest distance between two numbers of a given type
@findex @code{SPACING} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node SPREAD
@section @code{SPREAD} --- Add a dimension to an array
@findex @code{SPREAD} intrinsic
@cindex array manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node SQRT
@section @code{SQRT} --- Square-root function
@findex @code{SQRT} intrinsic
@findex @code{DSQRT} intrinsic
@findex @code{CSQRT} intrinsic
@findex @code{ZSQRT} intrinsic
@findex @code{CDSQRT} intrinsic
@cindex square-root

@table @asis
@item @emph{Description}:
@code{SQRT(X)} computes the square root of @var{X}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = SQRT(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)} or
@code{COMPLEX(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} or @code{COMPLEX(*)}.
The kind type parameter is the same as @var{X}.

@item @emph{Example}:
@smallexample
program test_sqrt
  real(8) :: x = 2.0_8
  complex :: z = (1.0, 2.0)
  x = sqrt(x)
  z = sqrt(z)
end program test_sqrt
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name             @tab Argument             @tab Return type          @tab Standard
@item @code{DSQRT(X)}  @tab @code{REAL(8) X}     @tab @code{REAL(8)}       @tab F95 and later
@item @code{CSQRT(X)}  @tab @code{COMPLEX(4) X}  @tab @code{COMPLEX(4)}    @tab F95 and later
@item @code{ZSQRT(X)}  @tab @code{COMPLEX(8) X}  @tab @code{COMPLEX(8)}    @tab GNU extension
@item @code{CDSQRT(X)} @tab @code{COMPLEX(8) X}  @tab @code{COMPLEX(8)}    @tab GNU extension
@end multitable
@end table



@node SRAND
@section @code{SRAND} --- Reinitialize the random number generator
@findex @code{SRAND} intrinsic
@cindex random number

@table @asis
@item @emph{Description}:
@code{SRAND} reinitializes the pseudo-random number generator
called by @code{RAND} and @code{IRAND}. The new seed used by the
generator is specified by the required argument @var{SEED}.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
non-elemental subroutine

@item @emph{Syntax}:
@code{CALL SRAND(SEED)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{SEED} @tab shall be a scalar @code{INTEGER(kind=4)}.
@end multitable

@item @emph{Return value}:
Does not return.

@item @emph{Example}:
See @code{RAND} and @code{IRAND} for examples.

@item @emph{Notes}:
The Fortran 2003 standard specifies the intrinsic @code{RANDOM_SEED} to
initialize the pseudo-random numbers generator and @code{RANDOM_NUMBER}
to generate pseudo-random numbers. Please note that in
GNU Fortran, these two sets of intrinsics (@code{RAND},
@code{IRAND} and @code{SRAND} on the one hand, @code{RANDOM_NUMBER} and
@code{RANDOM_SEED} on the other hand) access two independent
pseudo-random number generators.

@item @emph{See also}:
@ref{RAND}, @ref{RANDOM_SEED}, @ref{RANDOM_NUMBER}

@end table


@node STAT
@section @code{STAT} --- Get file status
@findex @code{STAT} intrinsic
@cindex file system operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@ref{FSTAT}
@end table




@node SUM
@section @code{SUM} --- Sum of array elements
@findex @code{SUM} intrinsic
@cindex array manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@ref{PRODUCT}
@end table




@node SYMLNK
@section @code{SYMLNK} --- Create a symbolic link
@findex @code{SYMLNK} intrinsic
@cindex file system operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
@item @emph{Class}:
GNU extension

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node SYSTEM
@section @code{SYSTEM} --- Execute a shell command
@findex @code{SYSTEM} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node SYSTEM_CLOCK
@section @code{SYSTEM_CLOCK} --- Time function
@findex @code{SYSTEM_CLOCK} intrinsic
@cindex time functions

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table



@node TAN
@section @code{TAN} --- Tangent function
@findex @code{TAN} intrinsic
@findex @code{DTAN} intrinsic
@cindex trigonometric functions

@table @asis
@item @emph{Description}:
@code{TAN(X)} computes the tangent of @var{X}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = TAN(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)}.  The kind type parameter is
the same as @var{X}.

@item @emph{Example}:
@smallexample
program test_tan
  real(8) :: x = 0.165_8
  x = tan(x)
end program test_tan
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DTAN(X)}  @tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab F95 and later
@end multitable

@item @emph{See also}:
@ref{ATAN}
@end table



@node TANH
@section @code{TANH} --- Hyperbolic tangent function 
@findex @code{TANH} intrinsic
@findex @code{DTANH} intrinsic
@cindex hyperbolic tangent

@table @asis
@item @emph{Description}:
@code{TANH(X)} computes the hyperbolic tangent of @var{X}.

@item @emph{Standard}:
F77 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{X = TANH(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be @code{REAL(*)}.
@end multitable

@item @emph{Return value}:
The return value is of type @code{REAL(*)} and lies in the range
@math{ - 1 \leq tanh(x) \leq 1 }.

@item @emph{Example}:
@smallexample
program test_tanh
  real(8) :: x = 2.1_8
  x = tanh(x)
end program test_tanh
@end smallexample

@item @emph{Specific names}:
@multitable @columnfractions .20 .20 .20 .40
@item Name            @tab Argument          @tab Return type       @tab Standard
@item @code{DTANH(X)} @tab @code{REAL(8) X}  @tab @code{REAL(8)}    @tab F95 and later
@end multitable

@item @emph{See also}:
@ref{ATANH}
@end table



@node TIME
@section @code{TIME} --- Time function
@findex @code{TIME} intrinsic
@cindex time functions

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Non-elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table



@node TINY
@section @code{TINY} --- Smallest positive number of a real kind
@findex @code{TINY} intrinsic
@cindex tiny

@table @asis
@item @emph{Description}:
@code{TINY(X)} returns the smallest positive (non zero) number
in the model of the type of @code{X}.

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@code{Y = TINY(X)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab shall be of type @code{REAL}.
@end multitable

@item @emph{Return value}:
The return value is of the same type and kind as @var{X}

@item @emph{Example}:
See @code{HUGE} for an example.
@end table



@node TRANSFER
@section @code{TRANSFER} --- Transfer bit patterns
@findex @code{TRANSFER} intrinsic
@cindex bit manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node TRANSPOSE
@section @code{TRANSPOSE} --- Transpose an array of rank two
@findex @code{TRANSPOSE} intrinsic
@cindex matrix manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node TRIM
@section @code{TRIM} --- Function to remove trailing blank characters of a string
@findex @code{TRIM} intrinsic
@cindex string manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{See also}:
@end table




@node UBOUND
@section @code{UBOUND} --- Upper dimension bounds of an array
@findex @code{UBOUND} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:

@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Inquiry function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:

@item @emph{See also}:
@ref{LBOUND}
@end table




@node UMASK
@section @code{UMASK} --- Set the file creation mask
@findex @code{UMASK} intrinsic
@cindex file system operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@end table




@node UNLINK
@section @code{UNLINK} --- Remove a file from the file system
@findex @code{UNLINK} intrinsic
@cindex file system operations

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Subroutine

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:

@item @emph{See also}:
@ref{LINK}
@end table




@node UNMASK
@section @code{UNMASK} --- (?)
@findex @code{UNMASK} intrinsic
@cindex undocumented intrinsic 

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
@item @emph{Class}:
@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@end table




@node UNPACK
@section @code{UNPACK} --- Unpack an array of rank one into an array
@findex @code{UNPACK} intrinsic
@cindex array manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Transformational function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:

@item @emph{See also}:
@ref{PACK}
@end table




@node VERIFY
@section @code{VERIFY} --- Scan a string for the absence of a set of characters
@findex @code{VERIFY} intrinsic
@cindex string manipulation

Intrinsic implemented, documentation pending.

@table @asis
@item @emph{Description}:
@item @emph{Standard}:
F95 and later

@item @emph{Class}:
Elemental function

@item @emph{Syntax}:
@item @emph{Arguments}:
@item @emph{Return value}:
@item @emph{Example}:
@item @emph{Specific names}:
@item @emph{See also}:
@end table


@node XOR
@section @code{XOR} --- Bitwise logical exclusive OR
@findex @code{XOR} intrinsic
@cindex bit operations

@table @asis
@item @emph{Description}:
Bitwise logical exclusive or. 

This intrinsic routine is provided for backwards compatibility with 
GNU Fortran 77.  For integer arguments, programmers should consider
the use of the @ref{IEOR} intrinsic defined by the Fortran standard.

@item @emph{Standard}:
GNU extension

@item @emph{Class}:
Non-elemental function

@item @emph{Syntax}:
@code{RESULT = XOR(X, Y)}

@item @emph{Arguments}:
@multitable @columnfractions .15 .80
@item @var{X} @tab The type shall be either @code{INTEGER(*)} or @code{LOGICAL}.
@item @var{Y} @tab The type shall be either @code{INTEGER(*)} or @code{LOGICAL}.
@end multitable

@item @emph{Return value}:
The return type is either @code{INTEGER(*)} or @code{LOGICAL}
after cross-promotion of the arguments.

@item @emph{Example}:
@smallexample
PROGRAM test_xor
  LOGICAL :: T = .TRUE., F = .FALSE.
  INTEGER :: a, b
  DATA a / Z,'F' /, b / Z'3' /

  WRITE (*,*) XOR(T, T), XOR(T, F), XOR(F, T), XOR(F, F)
  WRITE (*,*) XOR(a, b)
END PROGRAM
@end smallexample

@item @emph{See also}:
F95 elemental function: @ref{IEOR}
@end table