-@c Copyright (C) 2004, 2005, 2006, 2007, 2008
+@c Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
@c Free Software Foundation, Inc.
@c This is part of the GNU Fortran manual.
@c For copying conditions, see the file gfortran.texi.
@ignore
@c man begin COPYRIGHT
-Copyright @copyright{} 2004, 2005, 2006, 2007
+Copyright @copyright{} 2004, 2005, 2006, 2007, 2008, 2009, 2010
Free Software Foundation, Inc.
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.
-
+Invariant Sections being ``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.
+
(a) The FSF's Front-Cover Text is:
A GNU Manual
[@option{-I}@var{dir}@dots{}] [@option{-L}@var{dir}@dots{}]
[@option{-D}@var{macro}[=@var{defn}]@dots{}] [@option{-U}@var{macro}]
[@option{-f}@var{option}@dots{}]
- [@option{-m}@var{machine-option}@dots{}]
+ [@option{-m}@var{machine-option}@dots{}]
[@option{-o} @var{outfile}] @var{infile}@dots{}
Only the most useful options are listed here; see below for the
and warnings}.
@gccoptlist{-fmax-errors=@var{n} @gol
-fsyntax-only -pedantic -pedantic-errors @gol
--Wall -Waliasing -Wampersand -Wcharacter-truncation -Wconversion @gol
--Wimplicit-interface -Wline-truncation -Wnonstd-intrinsics -Wsurprising @gol
--Wno-tabs -Wunderflow -Wunused-parameter}
+-Wall -Waliasing -Wampersand -Warray-bounds -Wcharacter-truncation @gol
+-Wconversion -Wimplicit-interface -Wimplicit-procedure -Wline-truncation @gol
+-Wintrinsics-std -Wsurprising -Wno-tabs -Wunderflow -Wunused-parameter @gol
+-Wintrinsics-shadow -Wno-align-commons}
@item Debugging Options
@xref{Debugging Options,,Options for debugging your program or GNU Fortran}.
@item Directory Options
@xref{Directory Options,,Options for directory search}.
-@gccoptlist{-I@var{dir} -J@var{dir} -M@var{dir} -fintrinsic-modules-path @var{dir}}
+@gccoptlist{-I@var{dir} -J@var{dir} -M@var{dir} @gol
+-fintrinsic-modules-path @var{dir}}
@item Link Options
@xref{Link Options,,Options for influencing the linking step}.
@item Runtime Options
@xref{Runtime Options,,Options for influencing runtime behavior}.
-@gccoptlist{-fconvert=@var{conversion} -frecord-marker=@var{length} @gol
--fmax-subrecord-length=@var{length} -fsign-zero}
+@gccoptlist{-fconvert=@var{conversion} -fno-range-check
+-frecord-marker=@var{length} @gol -fmax-subrecord-length=@var{length}
+-fsign-zero}
@item Code Generation Options
@xref{Code Gen Options,,Options for code generation conventions}.
-@gccoptlist{-fno-automatic -ff2c -fno-underscoring
--fsecond-underscore @gol
--fbounds-check -fmax-stack-var-size=@var{n} @gol
+@gccoptlist{-fno-automatic -ff2c -fno-underscoring @gol
+-fwhole-file -fsecond-underscore @gol
+-fbounds-check -fcheck-array-temporaries -fmax-array-constructor =@var{n} @gol
+-fcheck=@var{<all|array-temps|bounds|do|mem|pointer|recursion>} @gol
+-fcoarray=@var{<none|single>} -fmax-stack-var-size=@var{n} @gol
-fpack-derived -frepack-arrays -fshort-enums -fexternal-blas @gol
-fblas-matmul-limit=@var{n} -frecursive -finit-local-zero @gol
--finit-integer=@var{n} -finit-real=@var{<zero|inf|-inf|nan>} @gol
--finit-logical=@var{<true|false>} -finit-character=@var{n}}
+-finit-integer=@var{n} -finit-real=@var{<zero|inf|-inf|nan|snan>} @gol
+-finit-logical=@var{<true|false>} -finit-character=@var{n} @gol
+-fno-align-commons -fno-protect-parens}
@end table
@menu
@item -fall-intrinsics
@opindex @code{fall-intrinsics}
-Accept all of the intrinsic procedures provided in libgfortran
-without regard to the setting of @option{-std}. In particular,
-this option can be quite useful with @option{-std=f95}. Additionally,
-@command{gfortran} will ignore @option{-Wnonstd-intrinsics}.
+This option causes all intrinsic procedures (including the GNU-specific
+extensions) to be accepted. This can be useful with @option{-std=f95} to
+force standard-compliance but get access to the full range of intrinsics
+available with @command{gfortran}. As a consequence, @option{-Wintrinsics-std}
+will be ignored and no user-defined procedure with the same name as any
+intrinsic will be called except when it is explicitly declared @code{EXTERNAL}.
@item -fd-lines-as-code
@item -fd-lines-as-comments
@item -fdefault-double-8
@opindex @code{fdefault-double-8}
-Set the @code{DOUBLE PRECISION} type to an 8 byte wide type.
+Set the @code{DOUBLE PRECISION} type to an 8 byte wide type. If
+@option{-fdefault-real-8} is given, @code{DOUBLE PRECISION} would
+instead be promoted to 16 bytes if possible, and @option{-fdefault-double-8}
+can be used to prevent this. The kind of real constants like @code{1.d0} will
+not be changed by @option{-fdefault-real-8} though, so also
+@option{-fdefault-double-8} does not affect it.
@item -fdefault-integer-8
@opindex @code{fdefault-integer-8}
Set the default integer and logical types to an 8 byte wide type.
-Do nothing if this is already the default.
+Do nothing if this is already the default. This option also affects
+the kind of integer constants like @code{42}.
@item -fdefault-real-8
@opindex @code{fdefault-real-8}
Set the default real type to an 8 byte wide type.
-Do nothing if this is already the default.
+Do nothing if this is already the default. This option also affects
+the kind of non-double real constants like @code{1.0}, and does promote
+the default width of @code{DOUBLE PRECISION} to 16 bytes if possible, unless
+@code{-fdefault-double-8} is given, too.
@item -fdollar-ok
@opindex @code{fdollar-ok}
@cindex $
@cindex symbol names
@cindex character set
-Allow @samp{$} as a valid character in a symbol name.
+Allow @samp{$} as a valid non-first character in a symbol name. Symbols
+that start with @samp{$} are rejected since it is unclear which rules to
+apply to implicit typing as different vendors implement different rules.
+Using @samp{$} in @code{IMPLICIT} statements is also rejected.
@item -fbackslash
@opindex @code{backslash}
in the command line, this option has no effect, since no @code{#line}
directives are emitted whatsoever.
+@item -idirafter @var{dir}
+@opindex @code{idirafter @var{dir}}
+@cindex preprocessing, include path
+Search @var{dir} for include files, but do it after all directories
+specified with @option{-I} and the standard system directories have
+been exhausted. @var{dir} is treated as a system include directory.
+If dir begins with @code{=}, then the @code{=} will be replaced by
+the sysroot prefix; see @option{--sysroot} and @option{-isysroot}.
+
@item -imultilib @var{dir}
@opindex @code{imultilib @var{dir}}
@cindex preprocessing, include path
@cindex warnings, all
Enables commonly used warning options pertaining to usage that
we recommend avoiding and that we believe are easy to avoid.
-This currently includes @option{-Waliasing},
-@option{-Wampersand}, @option{-Wsurprising}, @option{-Wnonstd-intrinsics},
-@option{-Wno-tabs}, and @option{-Wline-truncation}.
+This currently includes @option{-Waliasing}, @option{-Wampersand},
+@option{-Wconversion}, @option{-Wsurprising}, @option{-Wintrinsics-std},
+@option{-Wno-tabs}, @option{-Wintrinsic-shadow}, @option{-Wline-truncation},
+and @option{-Wunused}.
@item -Waliasing
@opindex @code{Waliasing}
at the first non-comment, non-whitespace character after the ampersand
that initiated the continuation.
+@item -Warray-temporaries
+@opindex @code{Warray-temporaries}
+@cindex warnings, array temporaries
+Warn about array temporaries generated by the compiler. The information
+generated by this warning is sometimes useful in optimization, in order to
+avoid such temporaries.
+
@item -Wcharacter-truncation
@opindex @code{Wcharacter-truncation}
@cindex warnings, character truncation
@opindex @code{Wconversion}
@cindex warnings, conversion
@cindex conversion
-Warn about implicit conversions between different types.
+Warn about implicit conversions that are likely to change the value of
+the expression after conversion. Implied by @option{-Wall}.
+
+@item -Wconversion-extra
+@opindex @code{Wconversion-extra}
+@cindex warnings, conversion
+@cindex conversion
+Warn about implicit conversions between different types and kinds.
@item -Wimplicit-interface
@opindex @code{Wimplicit-interface}
Note this only checks that an explicit interface is present. It does not
check that the declared interfaces are consistent across program units.
-@item -Wnonstd-intrinsics
-@opindex @code{Wnonstd-intrinsics}
+@item -Wimplicit-procedure
+@opindex @code{Wimplicit-procedure}
+@cindex warnings, implicit procedure
+Warn if a procedure is called that has neither an explicit interface
+nor has been declared as @code{EXTERNAL}.
+
+@item -Wintrinsics-std
+@opindex @code{Wintrinsics-std}
@cindex warnings, non-standard intrinsics
-Warn if the user tries to use an intrinsic that does not belong to the
-standard the user has chosen via the @option{-std} option.
+@cindex warnings, intrinsics of other standards
+Warn if @command{gfortran} finds a procedure named like an intrinsic not
+available in the currently selected standard (with @option{-std}) and treats
+it as @code{EXTERNAL} procedure because of this. @option{-fall-intrinsics} can
+be used to never trigger this behavior and always link to the intrinsic
+regardless of the selected standard.
@item -Wsurprising
@opindex @code{Wsurprising}
@item
A TRANSFER specifies a source that is shorter than the destination.
+
+@item
+The type of a function result is declared more than once with the same type. If
+@option{-pedantic} or standard-conforming mode is enabled, this is an error.
+
+@item
+A @code{CHARACTER} variable is declared with negative length.
@end itemize
@item -Wtabs
Produce a warning when numerical constant expressions are
encountered, which yield an UNDERFLOW during compilation.
+@item -Wintrinsic-shadow
+@opindex @code{Wintrinsic-shadow}
+@cindex warnings, intrinsic
+@cindex intrinsic
+Warn if a user-defined procedure or module procedure has the same name as an
+intrinsic; in this case, an explicit interface or @code{EXTERNAL} or
+@code{INTRINSIC} declaration might be needed to get calls later resolved to
+the desired intrinsic/procedure.
+
+@item -Wunused-dummy-argument
+@opindex @code{Wunused-dummy-argument}
+@cindex warnings, unused dummy argument
+@cindex unused dummy argument
+@cindex dummy argument, unused
+Warn about unused dummy arguments. This option is implied by @option{-Wall}.
+
@item -Wunused-parameter
@opindex @code{Wunused-parameter}
@cindex warnings, unused parameter
@cindex unused parameter
Contrary to @command{gcc}'s meaning of @option{-Wunused-parameter},
@command{gfortran}'s implementation of this option does not warn
-about unused dummy arguments, but about unused @code{PARAMETER} values.
-@option{-Wunused-parameter} is not included in @option{-Wall} but is
-implied by @option{-Wall -Wextra}.
+about unused dummy arguments (see @option{-Wunused-dummy-argument}),
+but about unused @code{PARAMETER} values. @option{-Wunused-parameter}
+is not included in @option{-Wall} but is implied by @option{-Wall -Wextra}.
+
+@item -Walign-commons
+@opindex @code{Walign-commons}
+@cindex warnings, alignment of COMMON blocks
+@cindex alignment of COMMON blocks
+By default, @command{gfortran} warns about any occasion of variables being
+padded for proper alignment inside a COMMON block. This warning can be turned
+off via @option{-Wno-align-commons}. See also @option{-falign-commons}.
@item -Werror
@opindex @code{Werror}
(operation produced a denormal value).
Some of the routines in the Fortran runtime library, like
-@samp{CPU_TIME}, are likely to to trigger floating point exceptions when
+@samp{CPU_TIME}, are likely to trigger floating point exceptions when
@code{ffpe-trap=precision} is used. For this reason, the use of
@code{ffpe-trap=precision} is not recommended.
The @code{CONVERT} specifier and the GFORTRAN_CONVERT_UNIT environment
variable override the default specified by @option{-fconvert}.}
+
+@item -fno-range-check
+@opindex @code{fno-range-check}
+Disable range checking of input values during integer @code{READ} operations.
+For example, GNU Fortran will give an error if an input value is
+outside of the relevant range of [@code{-HUGE()}:@code{HUGE()}]. In other words,
+with @code{INTEGER (kind=4) :: i} , attempting to read @math{-2147483648} will
+give an error unless @option{-fno-range-check} is given.
+
+
@item -frecord-marker=@var{length}
@opindex @code{frecord-marker=}@var{length}
Specify the length of record markers for unformatted files.
@item -fsign-zero
@opindex @code{fsign-zero}
-When writing zero values, show the negative sign if the sign bit is set.
-@code{fno-sign-zero} does not print the negative sign of zero values for
-compatibility with F77. Default behavior is to show the negative sign.
+When enabled, floating point numbers of value zero with the sign bit set
+are written as negative number in formatted output and treated as
+negative in the @code{SIGN} intrinsic. @code{fno-sign-zero} does not
+print the negative sign of zero values and regards zero as positive
+number in the @code{SIGN} intrinsic for compatibility with F77.
+Default behavior is to show the negative sign.
@end table
@node Code Gen Options
prevent accidental linking between procedures with incompatible
interfaces.
+@item -fwhole-file
+@opindex @code{fwhole-file}
+By default, GNU Fortran parses, resolves and translates each procedure
+in a file separately. Using this option modifies this such that the
+whole file is parsed and placed in a single front-end tree. During
+resolution, in addition to all the usual checks and fixups, references
+to external procedures that are in the same file effect resolution of
+that procedure, if not already done, and a check of the interfaces. The
+dependences are resolved by changing the order in which the file is
+translated into the backend tree. Thus, a procedure that is referenced
+is translated before the reference and the duplication of backend tree
+declarations eliminated.
+
@item -fsecond-underscore
@opindex @code{fsecond-underscore}
@cindex underscore
for compatibility with @command{g77} and @command{f2c}, and is implied
by use of the @option{-ff2c} option.
-@item -fbounds-check
-@opindex @code{fbounds-check}
+@item -fcoarray=@var{<keyword>}
+@opindex @code{fcoarray}
+@cindex coarrays
+
+@table @asis
+@item @samp{none}
+Disable coarray support; using coarray declarations and image-control
+statements will produce a compile-time error. (Default)
+
+@item @samp{single}
+Single-image mode, i.e. @code{num_images()} is always one.
+@end table
+
+
+@item -fcheck=@var{<keyword>}
+@opindex @code{fcheck}
@cindex array, bounds checking
@cindex bounds checking
+@cindex pointer checking
+@cindex memory checking
@cindex range checking
@cindex subscript checking
@cindex checking subscripts
+@cindex run-time checking
+@cindex checking array temporaries
+
+Enable the generation of run-time checks; the argument shall be
+a comma-delimited list of the following keywords.
+
+@table @asis
+@item @samp{all}
+Enable all run-time test of @option{-fcheck}.
+
+@item @samp{array-temps}
+Warns at run time when for passing an actual argument a temporary array
+had to be generated. The information generated by this warning is
+sometimes useful in optimization, in order to avoid such temporaries.
+
+Note: The warning is only printed once per location.
+
+@item @samp{bounds}
Enable generation of run-time checks for array subscripts
and against the declared minimum and maximum values. It also
checks array indices for assumed and deferred
-shape arrays against the actual allocated bounds.
+shape arrays against the actual allocated bounds and ensures that all string
+lengths are equal for character array constructors without an explicit
+typespec.
-Some checks require that @option{-fbounds-check} is set for
+Some checks require that @option{-fcheck=bounds} is set for
the compilation of the main program.
-In the future this may also include other forms of checking, e.g., checking
-substring references.
+Note: In the future this may also include other forms of checking, e.g.,
+checking substring references.
+
+@item @samp{do}
+Enable generation of run-time checks for invalid modification of loop
+iteration variables.
+
+@item @samp{mem}
+Enable generation of run-time checks for memory allocation.
+Note: This option does not affect explicit allocations using the
+@code{ALLOCATE} statement, which will be always checked.
+
+@item @samp{pointer}
+Enable generation of run-time checks for pointers and allocatables.
+
+@item @samp{recursion}
+Enable generation of run-time checks for recursively called subroutines and
+functions which are not marked as recursive. See also @option{-frecursive}.
+Note: This check does not work for OpenMP programs and is disabled if used
+together with @option{-frecursive} and @option{-fopenmp}.
+@end table
+
+
+@item -fbounds-check
+@opindex @code{fbounds-check}
+@c Note: This option is also referred in gcc's manpage
+Deprecated alias for @option{-fcheck=bounds}.
+
+@item -fcheck-array-temporaries
+@opindex @code{fcheck-array-temporaries}
+Deprecated alias for @option{-fcheck=array-temps}.
+
+@item -fmax-array-constructor=@var{n}
+@opindex @code{fmax-array-constructor}
+This option can be used to increase the upper limit permitted in
+array constructors. The code below requires this option to expand
+the array at compile time.
+
+@smallexample
+@code{program test}
+@code{implicit none}
+@code{integer j}
+@code{integer, parameter :: n = 100000}
+@code{integer, parameter :: i(n) = (/ (2*j, j = 1, n) /)}
+@code{print '(10(I0,1X))', i}
+@code{end program test}
+@end smallexample
+
+@emph{Caution: This option can lead to long compile times and excessively
+large object files.}
+
+The default value for @var{n} is 65535.
+
@item -fmax-stack-var-size=@var{n}
@opindex @code{fmax-stack-var-size}
@item -finit-local-zero
@item -finit-integer=@var{n}
-@item -finit-real=@var{<zero|inf|-inf|nan>}
+@item -finit-real=@var{<zero|inf|-inf|nan|snan>}
@item -finit-logical=@var{<true|false>}
@item -finit-character=@var{n}
@opindex @code{finit-local-zero}
@code{CHARACTER} variables to a string of null bytes. Finer-grained
initialization options are provided by the
@option{-finit-integer=@var{n}},
-@option{-finit-real=@var{<zero|inf|-inf|nan>}} (which also initializes
+@option{-finit-real=@var{<zero|inf|-inf|nan|snan>}} (which also initializes
the real and imaginary parts of local @code{COMPLEX} variables),
@option{-finit-logical=@var{<true|false>}}, and
@option{-finit-character=@var{n}} (where @var{n} is an ASCII character
future releases).
Note that the @option{-finit-real=nan} option initializes @code{REAL}
-and @code{COMPLEX} variables with a quiet NaN.
+and @code{COMPLEX} variables with a quiet NaN. For a signalling NaN
+use @option{-finit-real=snan}; note, however, that compile-time
+optimizations may convert them into quiet NaN and that trapping
+needs to be enabled (e.g. via @option{-ffpe-trap}).
+
+@item -falign-commons
+@opindex @code{falign-commons}
+@cindex alignment of COMMON blocks
+By default, @command{gfortran} enforces proper alignment of all variables in a
+COMMON block by padding them as needed. On certain platforms this is mandatory,
+on others it increases performance. If a COMMON block is not declared with
+consistent data types everywhere, this padding can cause trouble, and
+@option{-fno-align-commons } can be used to disable automatic alignment. The
+same form of this option should be used for all files that share a COMMON block.
+To avoid potential alignment issues in COMMON blocks, it is recommended to order
+objects from largests to smallest.
+
+@item -fno-protect-parens
+@opindex @code{fno-protect-parens}
+@cindex re-association of parenthesed expressions
+By default the parentheses in expression are honored for all optimization
+levels such that the compiler does not do any re-association. Using
+@option{-fno-protect-parens} allows the compiler to reorder REAL and
+COMPLEX expressions to produce faster code. Note that for the re-association
+optimization @option{-fno-signed-zeros} and @option{-fno-trapping-math}
+need to be in effect.
@end table
@xref{Code Gen Options,,Options for Code Generation Conventions,
OSDN Git Service
