-@c Copyright (C) 2004, 2005, 2006
+@c Copyright (C) 2004, 2005, 2006, 2007
@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
+Copyright @copyright{} 2004, 2005, 2006, 2007
Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
therefore, the @command{gfortran} command).
@cindex options, negative forms
-@cindex negative forms of options
All GCC and GNU Fortran options
are accepted both by @command{gfortran} and by @command{gcc}
(as well as any other drivers built at the same time,
* Error and Warning Options:: How picky should the compiler be?
* Debugging Options:: Symbol tables, measurements, and debugging dumps.
* Directory Options:: Where to find module files
+* Link Options :: Influencing the linking step
* Runtime Options:: Influencing runtime behavior
* Code Gen Options:: Specifying conventions for function calls, data layout
and register usage.
-* Environment Variables:: Env vars that affect @command{gfortran}.
+* Environment Variables:: Environment variables that affect @command{gfortran}.
@end menu
@node Option Summary
-@section Option Summary
+@section Option summary
@c man begin OPTIONS
@table @emph
@item Fortran Language Options
-@xref{Fortran Dialect Options,,Options Controlling Fortran Dialect}.
+@xref{Fortran Dialect Options,,Options controlling Fortran dialect}.
@gccoptlist{-fall-intrinsics -ffree-form -fno-fixed-form @gol
-fdollar-ok -fimplicit-none -fmax-identifier-length @gol
-std=@var{std} -fd-lines-as-code -fd-lines-as-comments @gol
-ffixed-line-length-@var{n} -ffixed-line-length-none @gol
-ffree-line-length-@var{n} -ffree-line-length-none @gol
-fdefault-double-8 -fdefault-integer-8 -fdefault-real-8 @gol
--fcray-pointer -fopenmp -frange-check }
+-fcray-pointer -fopenmp -frange-check -fno-backslash }
@item Error and Warning Options
-@xref{Error and Warning Options,,Options to Request or Suppress Errors
-and Warnings}.
+@xref{Error and Warning Options,,Options to request or suppress errors
+and warnings}.
@gccoptlist{-fmax-errors=@var{n} @gol
-fsyntax-only -pedantic -pedantic-errors @gol
--w -Wall -Waliasing -Wampersand -Wconversion -Wimplicit-interface @gol
--Wtabs -Wnonstd-intrinsics -Wsurprising -Wunderflow @gol
--Wline-truncation -W}
+-Wall -Waliasing -Wampersand -Wcharacter-truncation -Wconversion @gol
+-Wimplicit-interface -Wline-truncation -Wnonstd-intrinsics -Wsurprising @gol
+-Wno-tabs -Wunderflow}
@item Debugging Options
-@xref{Debugging Options,,Options for Debugging Your Program or GCC}.
-@gccoptlist{-fdump-parse-tree -ffpe-trap=@var{list}}
+@xref{Debugging Options,,Options for debugging your program or GNU Fortran}.
+@gccoptlist{-fdump-parse-tree -ffpe-trap=@var{list} @gol
+-fdump-core -fbacktrace}
@item Directory Options
-@xref{Directory Options,,Options for Directory Search}.
-@gccoptlist{-I@var{dir} -M@var{dir}}
+@xref{Directory Options,,Options for directory search}.
+@gccoptlist{-I@var{dir} -J@var{dir} -M@var{dir} -fintrinsic-modules-path @var{dir}}
+
+@item Link Options
+@xref{Link Options,,Options for influencing the linking step}.
+@gccoptlist{-static-libgfortran}
@item Runtime Options
@xref{Runtime Options,,Options for influencing runtime behavior}.
-@gccoptlist{-fconvert=@var{conversion} -frecord-marker=@var{length}}
+@gccoptlist{-fconvert=@var{conversion} -frecord-marker=@var{length} @gol
+-fmax-subrecord-length=@var{length}}
@item Code Generation Options
-@xref{Code Gen Options,,Options for Code Generation Conventions}.
+@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
* Error and Warning Options:: How picky should the compiler be?
* Debugging Options:: Symbol tables, measurements, and debugging dumps.
* Directory Options:: Where to find module files
+* Link Options :: Influencing the linking step
* Runtime Options:: Influencing runtime behavior
* Code Gen Options:: Specifying conventions for function calls, data layout
and register usage.
@end menu
@node Fortran Dialect Options
-@section Options Controlling Fortran Dialect
+@section Options controlling Fortran dialect
@cindex dialect options
@cindex language, dialect options
@cindex options, dialect
accepted by the compiler:
@table @gcctabopt
-@cindex -ffree-form option
-@cindex options, -ffree-form
-@cindex -fno-fixed-form option
-@cindex options, -fno-fixed-form
-@cindex source file format
-@cindex free form
-@cindex fixed form
-@cindex Source Form
-@cindex Fortran 90, features
@item -ffree-form
@item -ffixed-form
+@opindex @code{ffree-form}
+@opindex @code{fno-fixed-form}
+@cindex options, fortran dialect
+@cindex file format, free
+@cindex file format, fixed
Specify the layout used by the source file. The free form layout
was introduced in Fortran 90. Fixed form was traditionally used in
older Fortran programs. When neither option is specified, the source
form is determined by the file extension.
-@cindex -fall-intrinsics
@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}.
-@cindex option, -fd-lines-as-code
-@cindex -fd-lines-as-code, option
-@cindex option, -fd-lines-as-comments
-@cindex -fd-lines-as-comments, option
@item -fd-lines-as-code
-@item -fd-lines-as-comment
-Enable special treatment for lines beginning with @samp{d} or @samp{D}
+@item -fd-lines-as-comments
+@opindex @code{fd-lines-as-code}
+@opindex @code{fd-lines-as-comments}
+Enable special treatment for lines beginning with @code{d} or @code{D}
in fixed form sources. If the @option{-fd-lines-as-code} option is
given they are treated as if the first column contained a blank. If the
@option{-fd-lines-as-comments} option is given, they are treated as
comment lines.
-@cindex option, -fdefault-double-8
-@cindex -fdefault-double-8, option
@item -fdefault-double-8
+@opindex @code{fdefault-double-8}
Set the @code{DOUBLE PRECISION} type to an 8 byte wide type.
-@cindex option, -fdefault-integer-8
-@cindex -fdefault-integer-8, option
@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.
-@cindex option, -fdefault-real-8
-@cindex -fdefault-real-8, option
@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.
-@cindex -fdollar-ok option
-@cindex options, -fdollar-ok
@item -fdollar-ok
-@cindex dollar sign
+@opindex @code{fdollar-ok}
+@cindex $
@cindex symbol names
@cindex character set
Allow @samp{$} as a valid character in a symbol name.
-@cindex -fno-backslash option
-@cindex options, -fno-backslash
@item -fno-backslash
+@opindex @code{fno-backslash}
@cindex backslash
@cindex escape characters
Change the interpretation of backslashes in string literals from
``C-style'' escape characters to a single backslash character.
-@cindex -ffixed-line-length-@var{n} option
-@cindex options, -ffixed-line-length-@var{n}
@item -ffixed-line-length-@var{n}
-@cindex source file format
-@cindex lines, length
-@cindex length of source lines
-@cindex fixed form
-@cindex limits, lengths of source lines
+@opindex @code{ffixed-line-length-}@var{n}
+@cindex file format, fixed
Set column after which characters are ignored in typical fixed-form
lines in the source file, and through which spaces are assumed (as
if padded to that length) after the ends of short fixed-form lines.
-@cindex card image
-@cindex extended-source option
Popular values for @var{n} include 72 (the
standard and the default), 80 (card image), and 132 (corresponding
to ``extended-source'' options in some popular compilers).
@option{-ffixed-line-length-0} means the same thing as
@option{-ffixed-line-length-none}.
-@cindex -ffree-line-length-@var{n} option
-@cindex options, -ffree-line-length-@var{n}
@item -ffree-line-length-@var{n}
-@cindex source file format
-@cindex lines, length
-@cindex length of source lines
-@cindex free form
-@cindex limits, lengths of source lines
+@opindex @code{ffree-line-length-}@var{n}
+@cindex file format, free
Set column after which characters are ignored in typical free-form
lines in the source file. The default value is 132.
@var{n} may be @samp{none}, meaning that the entire line is meaningful.
@option{-ffree-line-length-0} means the same thing as
@option{-ffree-line-length-none}.
-@cindex -fmax-identifier-length=@var{n} option
-@cindex option -fmax-identifier-length=@var{n}
@item -fmax-identifier-length=@var{n}
+@opindex @code{fmax-identifier-length=}@var{n}
Specify the maximum allowed identifier length. Typical values are
31 (Fortran 95) and 63 (Fortran 2003).
-@cindex -fimplicit-none option
-@cindex options, -fimplicit-none
@item -fimplicit-none
+@opindex @code{fimplicit-none}
Specify that no implicit typing is allowed, unless overridden by explicit
-@samp{IMPLICIT} statements. This is the equivalent of adding
-@samp{implicit none} to the start of every procedure.
+@code{IMPLICIT} statements. This is the equivalent of adding
+@code{implicit none} to the start of every procedure.
-@cindex -fcray-pointer option
-@cindex options, -fcray-pointer
@item -fcray-pointer
+@opindex @code{fcray-pointer}
Enable the Cray pointer extension, which provides C-like pointer
functionality.
-@cindex -fopenmp
-@cindex options, -fopenmp
@item -fopenmp
+@opindex @code{fopenmp}
+@cindex OpenMP
Enable the OpenMP extensions. This includes OpenMP @code{!$omp} directives
in free form
and @code{c$omp}, @code{*$omp} and @code{!$omp} directives in fixed form,
and when linking arranges for the OpenMP runtime library to be linked
in.
-@cindex -frange-check
-@cindex options, -frange-check
@item -frange-check
-Enable range checking on results of simplification of constant expressions
-during compilation. For example, by default, GNU Fortran will give
-an overflow error at compile time when simplifying @code{a = EXP(1000)}.
-With @samp{-fno-range-check}, no error will be given and the variable @code{a}
-will be assigned the value @code{+Infinity}. Similarly,
-@code{DATA i/Z'FFFFFFFF'/} will result in an integer overflow on most systems,
-but with @samp{-fno-range-check} the value will ``wrap around'' and @code{i}
-will be initialized to @math{-1} instead.
-
-@cindex -std=@var{std} option
-@cindex option, -std=@var{std}
+@opindex @code{frange-check}
+Enable range checking on results of simplification of constant
+expressions during compilation. For example, by default, GNU Fortran
+will give an overflow error at compile time when simplifying @code{a =
+EXP(1000)}. With @option{-fno-range-check}, no error will be given and
+the variable @code{a} will be assigned the value @code{+Infinity}.
+Similarly, @code{DATA i/Z'FFFFFFFF'/} will result in an integer overflow
+on most systems, but with @option{-fno-range-check} the value will
+``wrap around'' and @code{i} will be initialized to @math{-1} instead.
+
@item -std=@var{std}
-Conform to the specified standard. The default value for @var{std} is
-@samp{gnu}; a superset of the Fortran 95 standard which includes all
-of the GNU extensions recommended for use in new code. The @samp{legacy}
-value also includes obsolete extensions that may be required for old
-non-standard programs. Strict conformance to the Fortran 95 and Fortran 2003
-standards is specified by @samp{f95} and @samp{f2003}, respectively.
+@opindex @code{std=}@var{std} option
+Specify the standard to which the program is expected to conform, which
+may be one of @samp{f95}, @samp{f2003}, @samp{gnu}, or @samp{legacy}.
+The default value for @var{std} is @samp{gnu}, which specifies a
+superset of the Fortran 95 standard that includes all of the extensions
+supported by GNU Fortran, although warnings will be given for obsolete
+extensions not recommended for use in new code. The @samp{legacy} value
+is equivalent but without the warnings for obsolete extensions, and may
+be useful for old non-standard programs. The @samp{f95} and
+@samp{f2003} values specify strict conformance to the Fortran 95 and
+Fortran 2003 standards, respectively; errors are given for all
+extensions beyond the relevant language standard, and warnings are given
+for the Fortran 77 features that are permitted but obsolescent in later
+standards.
@end table
@node Error and Warning Options
-@section Options to Request or Suppress Errors and Warnings
+@section Options to request or suppress errors and warnings
@cindex options, warnings
@cindex options, errors
@cindex warnings, suppressing
Warnings are diagnostic messages that report constructions which
are not inherently erroneous but which are risky or suggest there is
-likely to be a bug in the program. Unless @option{-Werrors} is specified,
+likely to be a bug in the program. Unless @option{-Werror} is specified,
they do not prevent compilation of the program.
You can request many specific warnings with options beginning @option{-W},
by GNU Fortran:
@table @gcctabopt
-@cindex errors, limiting
-@cindex -fmax-errors-@var{n} option
-@cindex options, -fmax-errors-@var{n}
@item -fmax-errors-@var{n}
+@opindex @code{fmax-errors-}@var{n}
+@cindex errors, limiting
Limits the maximum number of error messages to @var{n}, at which point
GNU Fortran bails out rather than attempting to continue processing the
source code. If @var{n} is 0, there is no limit on the number of error
messages produced.
-@cindex syntax checking
-@cindex -fsyntax-only option
-@cindex options, -fsyntax-only
@item -fsyntax-only
+@opindex @code{fsyntax-only}
+@cindex syntax checking
Check the code for syntax errors, but don't do anything beyond that.
-@cindex -pedantic option
-@cindex options, -pedantic
@item -pedantic
+@opindex @code{pedantic}
Issue warnings for uses of extensions to Fortran 95.
@option{-pedantic} also applies to C-language constructs where they
occur in GNU Fortran source files, such as use of @samp{\e} in a
-character constant within a directive like @samp{#include}.
+character constant within a directive like @code{#include}.
Valid Fortran 95 programs should compile properly with or without
this option.
nonstandard practices, but not all.
However, improvements to GNU Fortran in this area are welcome.
-This should be used in conjunction with -std=@var{std}.
+This should be used in conjunction with @option{-std=f95} or
+@option{-std=f2003}.
-@cindex -pedantic-errors option
-@cindex options, -pedantic-errors
@item -pedantic-errors
+@opindex @code{pedantic-errors}
Like @option{-pedantic}, except that errors are produced rather than
warnings.
-@cindex -w option
-@cindex options, -w
-@item -w
-Inhibit all warning messages.
-
-
-@cindex -Wall option
-@cindex options, -Wall
@item -Wall
+@opindex @code{Wall}
@cindex all warnings
@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-intrinsic},
+@option{-Wampersand}, @option{-Wsurprising}, @option{-Wnonstd-intrinsics},
@option{-Wno-tabs}, and @option{-Wline-truncation}.
-
-@cindex -Waliasing option
-@cindex options, -Waliasing
@item -Waliasing
+@opindex @code{Waliasing}
@cindex aliasing
+@cindex warnings, aliasing
Warn about possible aliasing of dummy arguments. Specifically, it warns
if the same actual argument is associated with a dummy argument with
-@code{intent(in)} and a dummy argument with @code{intent(out)} in a call
+@code{INTENT(IN)} and a dummy argument with @code{INTENT(OUT)} in a call
with an explicit interface.
The following example will trigger the warning.
call bar(a,a)
@end smallexample
-
-@cindex -Wampersand option
-@cindex options, -Wampersand
@item -Wampersand
-@cindex ampersand
+@opindex @code{Wampersand}
+@cindex warnings, ampersand
+@cindex &
Warn about missing ampersand in continued character constants. The warning is
given with @option{-Wampersand}, @option{-pedantic}, @option{-std=f95}, and
@option{-std=f2003}. Note: With no ampersand given in a continued character
constant, GNU Fortran assumes continuation at the first non-comment,
non-whitespace character after the ampersand that initiated the continuation.
+@item -Wcharacter-truncation
+@opindex @code{Wcharacter-truncation}
+@cindex warnings, character truncation
+Warn when a character assignment will truncate the assigned string.
-@cindex -Wconversion option
-@cindex options, -Wconversion
@item -Wconversion
+@opindex @code{Wconversion}
+@cindex warnings, conversion
@cindex conversion
Warn about implicit conversions between different types.
-
-@cindex -Wimplicit-interface option
-@cindex options, -Wimplicit-interface
@item -Wimplicit-interface
+@opindex @code{Wimplicit-interface}
+@cindex warnings, implicit interface
Warn if a procedure is called without an explicit interface.
Note this only checks that an explicit interface is present. It does not
check that the declared interfaces are consistent across program units.
-
-@cindex -Wnonstd-intrinsic option
-@cindex options, -Wnonstd-intrinsic
-@item -Wnonstd-intrinsic
+@item -Wnonstd-intrinsics
+@opindex @code{Wnonstd-intrinsics}
+@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 -std option.
-
+standard the user has chosen via the @option{-std} option.
-@cindex -Wsurprising
-@cindex options, -Wsurprising
@item -Wsurprising
-@cindex Suspicious
+@opindex @code{Wsurprising}
+@cindex warnings, suspicious code
Produce a warning when ``suspicious'' code constructs are encountered.
While technically legal these usually indicate that an error has been made.
A LOGICAL SELECT construct has three CASE statements.
@end itemize
-
-@cindex -Wtabs
-@cindex options, -Wtabs
@item -Wtabs
-@cindex Tabs
+@opindex @code{Wtabs}
+@cindex warnings, tabs
+@cindex tabulators
By default, tabs are accepted as whitespace, but tabs are not members
of the Fortran Character Set. @option{-Wno-tabs} will cause a warning
to be issued if a tab is encountered. Note, @option{-Wno-tabs} is active
-for @option{-pedantic}, @option{-std=f95}, and @option{-Wall}.
-
+for @option{-pedantic}, @option{-std=f95}, @option{-std=f2003}, and
+@option{-Wall}.
-@cindex -Wunderflow
-@cindex options, -Wunderflow
@item -Wunderflow
-@cindex UNDERFLOW
+@opindex @code{Wunderflow}
+@cindex warnings, underflow
+@cindex underflow
Produce a warning when numerical constant expressions are
encountered, which yield an UNDERFLOW during compilation.
-
-@cindex -Werror
-@cindex options, -Werror
@item -Werror
+@opindex @code{Werror}
+@cindex warnings, to errors
Turns all warnings into errors.
-
-
-@cindex -W option
-@cindex options, -W
-@item -W
-@cindex extra warnings
-@cindex warnings, extra
-Turns on ``extra warnings'' and, if optimization is specified
-via @option{-O}, the @option{-Wuninitialized} option.
-(This might change in future versions of GNU Fortran.)
@end table
@xref{Error and Warning Options,,Options to Request or Suppress Errors and
Some of these have no effect when compiling programs written in Fortran.
@node Debugging Options
-@section Options for Debugging Your Program or GNU Fortran
+@section Options for debugging your program or GNU Fortran
@cindex options, debugging
@cindex debugging information options
either your program or the GNU Fortran compiler.
@table @gcctabopt
-@cindex -fdump-parse-tree option
-@cindex option, -fdump-parse-tree
@item -fdump-parse-tree
+@opindex @code{fdump-parse-tree}
Output the internal parse tree before starting code generation. Only
really useful for debugging the GNU Fortran compiler itself.
-@end table
-@table @gcctabopt
-@cindex -ffpe-trap=@var{list} option
-@cindex option, -ffpe-trap=@var{list}
@item -ffpe-trap=@var{list}
+@opindex @code{ffpe-trap=}@var{list}
Specify a list of IEEE exceptions when a Floating Point Exception
(FPE) should be raised. On most systems, this will result in a SIGFPE
signal being sent and the program being interrupted, producing a core
file useful for debugging. @var{list} is a (possibly empty) comma-separated
list of the following IEEE exceptions: @samp{invalid} (invalid floating
-point operation, such as @code{sqrt(-1.0)}), @samp{zero} (division by
+point operation, such as @code{SQRT(-1.0)}), @samp{zero} (division by
zero), @samp{overflow} (overflow in a floating point operation),
@samp{underflow} (underflow in a floating point operation),
@samp{precision} (loss of precision during operation) and @samp{denormal}
(operation produced a denormal value).
+
+@item -fbacktrace
+@opindex @code{fbacktrace}
+@cindex backtrace
+@cindex trace
+Specify that, when a runtime error is encountered, the Fortran runtime
+library should output a backtrace of the error. This option
+only has influence for compilation of the Fortran main program.
+
+@item -fdump-core
+@cindex core, dump
+@opindex @code{fdump-core}
+Request that a core-dump file is written to disk when a runtime error
+is encountered on systems that support core dumps. This option is
+only effective for the compilation of the Fortran main program.
@end table
@xref{Debugging Options,,Options for Debugging Your Program or GCC,
debugging options.
@node Directory Options
-@section Options for Directory Search
+@section Options for directory search
@cindex directory, options
@cindex options, directory search
@cindex search path
-
@cindex INCLUDE directive
@cindex directive, INCLUDE
These options affect how GNU Fortran searches
Fortran source.
@table @gcctabopt
-@cindex -Idir option
-@cindex options, -Idir
@item -I@var{dir}
+@opindex @code{I}@var{dir}
@cindex directory, search paths for inclusion
@cindex inclusion, directory search paths for
@cindex search paths, for included files
@code{#include} in the @command{cpp} preprocessor, with regard to
looking for @file{header.gcc} files and other such things.
-This path is also used to search for @samp{.mod} files when previously
+This path is also used to search for @file{.mod} files when previously
compiled modules are required by a @code{USE} statement.
@xref{Directory Options,,Options for Directory Search,
gcc,Using the GNU Compiler Collection (GCC)}, for information on the
@option{-I} option.
-@cindex -Mdir option
-@cindex option, -Mdir
@item -M@var{dir}
@item -J@var{dir}
-This option specifies where to put @samp{.mod} files for compiled modules.
+@opindex @code{M}@var{dir}
+@opindex @code{J}@var{dir}
+@cindex paths, search
+@cindex module search path
+This option specifies where to put @file{.mod} files for compiled modules.
It is also added to the list of directories to searched by an @code{USE}
statement.
@option{-J} is an alias for @option{-M} to avoid conflicts with existing
GCC options.
+
+@item -fintrinsic-modules-path @var{dir}
+@opindex @code{fintrinsic-modules-path} @var{dir}
+@cindex paths, search
+@cindex module search path
+This option specifies the location of pre-compiled intrinsic modules, if
+they are not in the default location expected by the compiler.
@end table
+@node Link Options
+@section Influencing the linking step
+@cindex options, linking
+@cindex linking, static
+
+These options come into play when the compiler links object files into an
+executable output file. They are meaningless if the compiler is not doing
+a link step.
+
+@table @gcctabopt
+@item -static-libgfortran
+@opindex @code{static-libgfortran}
+On systems that provide @file{libgfortran} as a shared and a static
+library, this option forces the use of the static version. If no
+shared version of @file{libgfortran} was built when the compiler was
+configured, this option has no effect.
+@end table
+
+
@node Runtime Options
@section Influencing runtime behavior
-@cindex runtime, options
+@cindex options, runtime
These options affect the runtime behavior of programs compiled with GNU Fortran.
@table @gcctabopt
-@cindex -fconvert=@var{conversion} option
@item -fconvert=@var{conversion}
+@opindex @code{fconvert=}@var{conversion}
Specify the representation of data for unformatted files. Valid
values for conversion are: @samp{native}, the default; @samp{swap},
swap between big- and little-endian; @samp{big-endian}, use big-endian
@emph{This option has an effect only when used in the main program.
The @code{CONVERT} specifier and the GFORTRAN_CONVERT_UNIT environment
-variable override the default specified by -fconvert.}
+variable override the default specified by @option{-fconvert}.}
-@cindex -frecord-marker=@var{length}
@item -frecord-marker=@var{length}
+@opindex @code{frecord-marker=}@var{length}
Specify the length of record markers for unformatted files.
Valid values for @var{length} are 4 and 8. Default is 4.
-@emph{This is different from previous versions of gfortran},
+@emph{This is different from previous versions of @command{gfortran}},
which specified a default record marker length of 8 on most
systems. If you want to read or write files compatible
-with earlier versions of gfortran, use @samp{-frecord-marker=8}.
+with earlier versions of @command{gfortran}, use @option{-frecord-marker=8}.
-@cindex -fmax-subrecord-length=@var{length}
@item -fmax-subrecord-length=@var{length}
+@opindex @code{fmax-subrecord-length=}@var{length}
Specify the maximum length for a subrecord. The maximum permitted
value for length is 2147483639, which is also the default. Only
really useful for use by the gfortran testsuite.
@end table
@node Code Gen Options
-@section Options for Code Generation Conventions
+@section Options for code generation conventions
@cindex code generation, conventions
@cindex options, code generation
-@cindex run-time, options
+@cindex options, run-time
These machine-independent options control the interface conventions
used in code generation.
it.
@table @gcctabopt
-@cindex @option{-fno-automatic} option
-@cindex options, @option{-fno-automatic}
@item -fno-automatic
-@cindex SAVE statement
-@cindex statements, SAVE
+@opindex @code{fno-automatic}
+@cindex @code{SAVE} statement
+@cindex statement, @code{SAVE}
Treat each program unit as if the @code{SAVE} statement was specified for
every local variable and array referenced in it. Does not affect common
blocks. (Some Fortran compilers provide this option under the name
@option{-static}.)
-@cindex @option{-ff2c} option
-@cindex options, @option{-ff2c}
@item -ff2c
+@opindex ff2c
@cindex calling convention
@cindex @command{f2c} calling convention
@cindex @command{g77} calling convention
This does not affect the generation of code that interfaces with
the @command{libgfortran} library.
-@emph{Caution:} It is not a good idea to mix Fortran code compiled
-with @code{-ff2c} with code compiled with the default @code{-fno-f2c}
+@emph{Caution:} It is not a good idea to mix Fortran code compiled with
+@option{-ff2c} with code compiled with the default @option{-fno-f2c}
calling conventions as, calling @code{COMPLEX} or default @code{REAL}
functions between program parts which were compiled with different
calling conventions will break at execution time.
@emph{Caution:} This will break code which passes intrinsic functions
of type default @code{REAL} or @code{COMPLEX} as actual arguments, as
-the library implementations use the @command{-fno-f2c} calling conventions.
+the library implementations use the @option{-fno-f2c} calling conventions.
-@cindex @option{-fno-underscoring option}
-@cindex options, @option{-fno-underscoring}
@item -fno-underscoring
+@opindex @code{fno-underscoring}
@cindex underscore
@cindex symbol names, underscores
@cindex transforming symbol names
so on).
For example, with @option{-funderscoring}, and assuming other defaults like
-@option{-fcase-lower} and that @samp{j()} and @samp{max_count()} are
-external functions while @samp{my_var} and @samp{lvar} are local variables,
+@option{-fcase-lower} and that @code{j()} and @code{max_count()} are
+external functions while @code{my_var} and @code{lvar} are local variables,
a statement like
-
@smallexample
I = J() + MAX_COUNT (MY_VAR, LVAR)
@end smallexample
-
@noindent
is implemented as something akin to:
-
@smallexample
i = j_() + max_count__(&my_var__, &lvar);
@end smallexample
prevent accidental linking between procedures with incompatible
interfaces.
-@cindex @option{-fsecond-underscore option}
-@cindex options, @option{-fsecond-underscore}
@item -fsecond-underscore
+@opindex @code{fsecond-underscore}
@cindex underscore
@cindex symbol names, underscores
@cindex transforming symbol names
This option has no effect if @option{-fno-underscoring} is
in effect. It is implied by the @option{-ff2c} option.
-Otherwise, with this option, an external name such as @samp{MAX_COUNT}
+Otherwise, with this option, an external name such as @code{MAX_COUNT}
is implemented as a reference to the link-time external symbol
-@samp{max_count__}, instead of @samp{max_count_}. This is required
+@code{max_count__}, instead of @code{max_count_}. This is required
for compatibility with @command{g77} and @command{f2c}, and is implied
by use of the @option{-ff2c} option.
-
-@cindex -fbounds-check option
-@cindex -ffortran-bounds-check option
@item -fbounds-check
+@opindex @code{fbounds-check}
+@cindex array, bounds checking
@cindex bounds checking
@cindex range checking
-@cindex array bounds checking
@cindex subscript checking
@cindex checking subscripts
Enable generation of run-time checks for array subscripts
checks array indices for assumed and deferred
shape arrays against the actual allocated bounds.
-In the future this may also include other forms of checking, eg. checking
-substring references.
+Some checks require that @option{-fbounds-check} is set for
+the compilation of the main probram.
+In the future this may also include other forms of checking, e.g., checking
+substring references.
-@cindex -fmax-stack-var-size option
@item -fmax-stack-var-size=@var{n}
+@opindex @code{fmax-stack-var-size}
This option specifies the size in bytes of the largest array that will be put
on the stack.
The default value for @var{n} is 32768.
-@cindex -fpack-derived
@item -fpack-derived
-@cindex Structure packing
+@opindex @code{fpack-derived}
+@cindex structure packing
This option tells GNU Fortran to pack derived type members as closely as
possible. Code compiled with this option is likely to be incompatible
with code compiled without this option, and may execute slower.
-@cindex -frepack-arrays option
@item -frepack-arrays
-@cindex Repacking arrays
+@opindex @code{frepack-arrays}
+@cindex repacking arrays
In some circumstances GNU Fortran may pass assumed shape array
sections via a descriptor describing a noncontiguous area of memory.
This option adds code to the function prologue to repack the data into
significant overhead to the function call, especially when the passed data
is noncontiguous.
-@cindex -fshort-enums
@item -fshort-enums
+@opindex @code{fshort-enums}
This option is provided for interoperability with C code that was
-compiled with the @command{-fshort-enums} option. It will make
+compiled with the @option{-fshort-enums} option. It will make
GNU Fortran choose the smallest @code{INTEGER} kind a given
enumerator set will fit in, and give all its enumerators this kind.
-@cindex -fexternal-blas
@item -fexternal-blas
-This option will make gfortran generate calls to BLAS functions for some
-matrix operations like @code{MATMUL}, instead of using our own
+@opindex @code{fexternal-blas}
+This option will make @command{gfortran} generate calls to BLAS functions
+for some matrix operations like @code{MATMUL}, instead of using our own
algorithms, if the size of the matrices involved is larger than a given
-limit (see @command{-fblas-matmul-limit}). This may be profitable if an
+limit (see @option{-fblas-matmul-limit}). This may be profitable if an
optimized vendor BLAS library is available. The BLAS library will have
to be specified at link time.
-@cindex -fblas-matmul-limit
@item -fblas-matmul-limit=@var{n}
-Only significant when @command{-fexternal-blas} is in effect.
+@opindex @code{fblas-matmul-limit}
+Only significant when @option{-fexternal-blas} is in effect.
Matrix multiplication of matrices with size larger than (or equal to) @var{n}
will be performed by calls to BLAS functions, while others will be
handled by @command{gfortran} internal algorithms. If the matrices
@c man end
@node Environment Variables
-@section Environment Variables Affecting @command{gfortran}
-@cindex environment variables
+@section Environment variables affecting @command{gfortran}
+@cindex environment variable
@c man begin ENVIRONMENT
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