1 @c Copyright (C) 2004, 2005
2 @c Free Software Foundation, Inc.
3 @c This is part of the GFORTRAN manual.
4 @c For copying conditions, see the file gfortran.texi.
8 Copyright @copyright{} 2004, 2005
9 Free Software Foundation, Inc.
11 Permission is granted to copy, distribute and/or modify this document
12 under the terms of the GNU Free Documentation License, Version 1.2 or
13 any later version published by the Free Software Foundation; with the
14 Invariant Sections being ``GNU General Public License'' and ``Funding
15 Free Software'', the Front-Cover texts being (a) (see below), and with
16 the Back-Cover Texts being (b) (see below). A copy of the license is
17 included in the gfdl(7) man page.
19 (a) The FSF's Front-Cover Text is:
23 (b) The FSF's Back-Cover Text is:
25 You have freedom to copy and modify this GNU Manual, like GNU
26 software. Copies published by the Free Software Foundation raise
27 funds for GNU development.
29 @c Set file name and title for the man page.
31 @settitle GNU Fortran 95 compiler.
33 gfortran [@option{-c}|@option{-S}|@option{-E}]
34 [@option{-g}] [@option{-pg}] [@option{-O}@var{level}]
35 [@option{-W}@var{warn}@dots{}] [@option{-pedantic}]
36 [@option{-I}@var{dir}@dots{}] [@option{-L}@var{dir}@dots{}]
37 [@option{-D}@var{macro}[=@var{defn}]@dots{}] [@option{-U}@var{macro}]
38 [@option{-f}@var{option}@dots{}]
39 [@option{-m}@var{machine-option}@dots{}]
40 [@option{-o} @var{outfile}] @var{infile}@dots{}
42 Only the most useful options are listed here; see below for the
46 gpl(7), gfdl(7), fsf-funding(7),
47 cpp(1), gcov(1), gcc(1), as(1), ld(1), gdb(1), adb(1), dbx(1), sdb(1)
48 and the Info entries for @file{gcc}, @file{cpp}, @file{gfortran}, @file{as},
49 @file{ld}, @file{binutils} and @file{gdb}.
52 For instructions on reporting bugs, see
53 @w{@uref{http://gcc.gnu.org/bugs.html}}.
56 See the Info entry for @command{gfortran} for contributors to GCC and
61 @node Invoking GFORTRAN
62 @chapter GNU Fortran 95 Command Options
63 @cindex GNU Fortran 95 command options
64 @cindex command options
65 @cindex options, GNU Fortran 95 command
67 @c man begin DESCRIPTION
69 The @command{gfortran} command supports all the options supported by the
70 @command{gcc} command. Only options specific to gfortran are documented here.
72 @xref{Invoking GCC,,GCC Command Options,gcc,Using the GNU Compiler
73 Collection (GCC)}, for information
74 on the non-Fortran-specific aspects of the @command{gcc} command (and,
75 therefore, the @command{gfortran} command).
77 @cindex options, negative forms
78 @cindex negative forms of options
79 All @command{gcc} and @command{gfortran} options
80 are accepted both by @command{gfortran} and by @command{gcc}
81 (as well as any other drivers built at the same time,
82 such as @command{g++}),
83 since adding @command{gfortran} to the @command{gcc} distribution
84 enables acceptance of @command{gfortran} options
85 by all of the relevant drivers.
87 In some cases, options have positive and negative forms;
88 the negative form of @option{-ffoo} would be @option{-fno-foo}.
89 This manual documents only one of these two forms, whichever
90 one is not the default.
94 * Option Summary:: Brief list of all @command{gfortran} options,
96 * Fortran Dialect Options:: Controlling the variant of Fortran language
98 * Warning Options:: How picky should the compiler be?
99 * Debugging Options:: Symbol tables, measurements, and debugging dumps.
100 * Directory Options:: Where to find module files
101 * Code Gen Options:: Specifying conventions for function calls, data layout
103 * Environment Variables:: Env vars that affect GNU Fortran.
107 @section Option Summary
111 Here is a summary of all the options specific to GNU Fortran, grouped
112 by type. Explanations are in the following sections.
115 @item Fortran Language Options
116 @xref{Fortran Dialect Options,,Options Controlling Fortran Dialect}.
118 -ffree-form -fno-fixed-form @gol
119 -fdollar-ok -fimplicit-none -fmax-identifier-length @gol
120 -std=@var{std} -fd-lines-as-code -fd-lines-as-comments @gol
121 -ffixed-line-length-@var{n} -ffixed-line-length-none @gol
122 -fdefault-double-8 -fdefault-integer-8 -fdefault-real-8 @gol
125 @item Warning Options
126 @xref{Warning Options,,Options to Request or Suppress Warnings}.
128 -fsyntax-only -pedantic -pedantic-errors @gol
129 -w -Wall -Waliasing -Wconversion @gol
130 -Wimplicit-interface -Wnonstd-intrinsics -Wsurprising -Wunderflow @gol
131 -Wunused-labels -Wline-truncation @gol
134 @item Debugging Options
135 @xref{Debugging Options,,Options for Debugging Your Program or GCC}.
137 -fdump-parse-tree -ffpe-trap=@var{list}}
139 @item Directory Options
140 @xref{Directory Options,,Options for Directory Search}.
142 -I@var{dir} -M@var{dir}}
144 @item Code Generation Options
145 @xref{Code Gen Options,,Options for Code Generation Conventions}.
147 -fno-automatic -ff2c -fno-underscoring -fsecond-underscore @gol
148 -fbounds-check -fmax-stack-var-size=@var{n} @gol
149 -fpackderived -frepack-arrays -fshort-enums}
153 * Fortran Dialect Options:: Controlling the variant of Fortran language
155 * Warning Options:: How picky should the compiler be?
156 * Debugging Options:: Symbol tables, measurements, and debugging dumps.
157 * Directory Options:: Where to find module files
158 * Code Gen Options:: Specifying conventions for function calls, data layout
162 @node Fortran Dialect Options
163 @section Options Controlling Fortran Dialect
164 @cindex dialect options
165 @cindex language, dialect options
166 @cindex options, dialect
168 The following options control the dialect of Fortran
169 that the compiler accepts:
172 @cindex -ffree-form option
173 @cindex options, -ffree-form
174 @cindex -fno-fixed-form option
175 @cindex options, -fno-fixed-form
176 @cindex source file format
180 @cindex Fortran 90, features
183 Specify the layout used by the source file. The free form layout
184 was introduced in Fortran 90. Fixed form was traditionally used in
185 older Fortran programs.
187 @cindex option, -fd-lines-as-code
188 @cindex -fd-lines-as-code, option
189 @cindex option, -fd-lines-as-comments
190 @cindex -fd-lines-as-comments, option
191 @item -fd-lines-as-code
192 @item -fd-lines-as-comment
193 Enables special treating for lines with @samp{d} or @samp{D} in fixed
194 form sources. If the @option{-fd-lines-as-code} option is given
195 they are treated as if the first column contained a blank. If the
196 @option{-fd-lines-as-comments} option is given, they are treated as
199 @cindex option, -fdefault-double-8
200 @cindex -fdefault-double-8, option
201 @item -fdefault-double-8
202 Set the "DOUBLE PRECISION" type to an 8 byte wide.
204 @cindex option, -fdefault-integer-8
205 @cindex -fdefault-integer-8, option
206 @item -fdefault-integer-8
207 Set the default integer and logical types to an 8 byte wide type.
208 Do nothing if this is already the default.
210 @cindex option, -fdefault-real-8
211 @cindex -fdefault-real-8, option
212 @item -fdefault-real-8
213 Set the default real type to an 8 byte wide type.
214 Do nothing if this is already the default.
216 @cindex -fdollar-ok option
217 @cindex options, -fdollar-ok
221 @cindex character set
222 Allow @samp{$} as a valid character in a symbol name.
224 @cindex -fno-backslash option
225 @cindex options, -fno-backslash
228 @cindex escape characters
230 Compile switch to change the interpretation of a backslash from
231 ``C''-style escape characters to a single backslash character.
233 @cindex -ffixed-line-length-@var{n} option
234 @cindex options, -ffixed-line-length-@var{n}
235 @item -ffixed-line-length-@var{n}
236 @cindex source file format
237 @cindex lines, length
238 @cindex length of source lines
240 @cindex limits, lengths of source lines
241 Set column after which characters are ignored in typical fixed-form
242 lines in the source file, and through which spaces are assumed (as
243 if padded to that length) after the ends of short fixed-form lines.
246 @cindex extended-source option
247 Popular values for @var{n} include 72 (the
248 standard and the default), 80 (card image), and 132 (corresponds
249 to ``extended-source'' options in some popular compilers).
250 @var{n} may be @samp{none}, meaning that the entire line is meaningful
251 and that continued character constants never have implicit spaces appended
252 to them to fill out the line.
253 @option{-ffixed-line-length-0} means the same thing as
254 @option{-ffixed-line-length-none}.
256 @cindex -fmax-identifier-length=@var{n} option
257 @cindex option -fmax-identifier-length=@var{n}
258 @item -fmax-identifier-length=@var{n}
259 Specify the maximum allowed identifier length. Typical values are
260 31 (Fortran 95) and 63 (Fortran 200x).
262 @cindex -fimplicit-none option
263 @cindex options, -fimplicit-none
264 @item -fimplicit-none
265 Specify that no implicit typing is allowed, unless overridden by explicit
266 @samp{IMPLICIT} statements. This is the equivalent of adding
267 @samp{implicit none} to the start of every procedure.
269 @cindex -fcray-pointer option
270 @cindex options, -fcray-pointer
272 Enables the Cray pointer extension, which provides a C-like pointer.
274 @cindex -std=@var{std} option
275 @cindex option, -std=@var{std}
277 Conform to the specified standard. Allowed values for @var{std} are
278 @samp{gnu}, @samp{f95}, @samp{f2003} and @samp{legacy}.
282 @node Warning Options
283 @section Options to Request or Suppress Warnings
284 @cindex options, warnings
285 @cindex warnings, suppressing
286 @cindex messages, warning
287 @cindex suppressing warnings
289 Warnings are diagnostic messages that report constructions which
290 are not inherently erroneous but which are risky or suggest there
291 might have been an error.
293 You can request many specific warnings with options beginning @option{-W},
294 for example @option{-Wimplicit} to request warnings on implicit
295 declarations. Each of these specific warning options also has a
296 negative form beginning @option{-Wno-} to turn off warnings;
297 for example, @option{-Wno-implicit}. This manual lists only one of the
298 two forms, whichever is not the default.
300 These options control the amount and kinds of warnings produced by GNU
304 @cindex syntax checking
305 @cindex -fsyntax-only option
306 @cindex options, -fsyntax-only
308 Check the code for syntax errors, but don't do anything beyond that.
310 @cindex -pedantic option
311 @cindex options, -pedantic
313 Issue warnings for uses of extensions to FORTRAN 95.
314 @option{-pedantic} also applies to C-language constructs where they
315 occur in GNU Fortran source files, such as use of @samp{\e} in a
316 character constant within a directive like @samp{#include}.
318 Valid FORTRAN 95 programs should compile properly with or without
320 However, without this option, certain GNU extensions and traditional
321 Fortran features are supported as well.
322 With this option, many of them are rejected.
324 Some users try to use @option{-pedantic} to check programs for conformance.
325 They soon find that it does not do quite what they want---it finds some
326 nonstandard practices, but not all.
327 However, improvements to @command{gfortran} in this area are welcome.
329 This should be used in conjunction with -std=@var{std}.
331 @cindex -pedantic-errors option
332 @cindex options, -pedantic-errors
333 @item -pedantic-errors
334 Like @option{-pedantic}, except that errors are produced rather than
340 Inhibit all warning messages.
344 @cindex options, -Wall
347 @cindex warnings, all
348 Enables commonly used warning options that which pertain to usage that
349 we recommend avoiding and that we believe is easy to avoid.
350 This currently includes @option{-Wunused-labels}, @option{-Waliasing},
351 @option{-Wsurprising}, @option{-Wnonstd-intrinsic} and
352 @option{-Wline-truncation}.
355 @cindex -Waliasing option
356 @cindex options, -Waliasing
359 Warn about possible aliasing of dummy arguments. Specifically, it warns
360 if the same actual argument is associated with a dummy argument with
361 @code{intent(in)} and a dummy argument with @code{intent(out)} in a call
362 with an explicit interface.
364 The following example will trigger the warning.
368 integer, intent(in) :: a
369 integer, intent(out) :: b
378 @cindex -Wconversion option
379 @cindex options, -Wconversion
382 Warn about implicit conversions between different types.
385 @cindex -Wimplicit-interface option
386 @cindex options, -Wimplicit-interface
387 @item -Wimplicit-interface
388 Warn about when procedure are called without an explicit interface.
389 Note this only checks that an explicit interface is present. It does not
390 check that the declared interfaces are consistent across program units.
393 @cindex -Wnonstd-intrinsic option
394 @cindex options, -Wnonstd-intrinsic
395 @item -Wnonstd-intrinsic
396 Warn if the user tries to use an intrinsic that does not belong to the
397 standard the user has chosen via the -std option.
401 @cindex options, -Wsurprising
404 Produce a warning when ``suspicious'' code constructs are encountered.
405 While technically legal these usually indicate that an error has been made.
407 This currently produces a warning under the following circumstances:
411 An INTEGER SELECT construct has a CASE that can never be matched as its
412 lower value is greater than its upper value.
415 A LOGICAL SELECT construct has three CASE statements.
419 @cindex options, -Wunderflow
422 Produce a warning when numerical constant expressions are
423 encountered, which yield an UNDERFLOW during compilation.
426 @cindex -Wunused-labels option
427 @cindex options, -Wunused-labels
428 @item -Wunused-labels
429 @cindex unused labels
430 @cindex labels, unused
431 Warn whenever a label is defined but never referenced.
435 @cindex options, -Werror
437 Turns all warnings into errors.
443 @cindex extra warnings
444 @cindex warnings, extra
445 Turns on ``extra warnings'' and, if optimization is specified
446 via @option{-O}, the @option{-Wuninitialized} option.
447 (This might change in future versions of @command{gfortran}
450 @xref{Warning Options,,Options to Request or Suppress Warnings,
451 gcc,Using the GNU Compiler Collection (GCC)}, for information on more
452 options offered by the GBE shared by @command{gfortran}, @command{gcc} and
455 Some of these have no effect when compiling programs written in Fortran.
457 @node Debugging Options
458 @section Options for Debugging Your Program or GNU Fortran
459 @cindex options, debugging
460 @cindex debugging information options
462 GNU Fortran has various special options that are used for debugging
463 either your program or @command{gfortran}
466 @cindex -fdump-parse-tree option
467 @cindex option, -fdump-parse-tree
468 @item -fdump-parse-tree
469 Output the internal parse tree before starting code generation. Only
470 really useful for debugging gfortran itself.
474 @cindex -ffpe-trap=@var{list} option
475 @cindex option, -ffpe-trap=@var{list}
476 @item -ffpe-trap=@var{list}
477 Specify a list of IEEE exceptions when a Floating Point Exception
478 (FPE) should be raised. On most systems, this will result in a SIGFPE
479 signal being sent and the program being interrupted, producing a core
480 file useful for debugging. @var{list} is a (possibly empty) comma-separated
481 list of the following IEEE exceptions: @samp{invalid} (invalid floating
482 point operation, such as @code{sqrt(-1.0)}), @samp{zero} (division by
483 zero), @samp{overflow} (overflow in a floating point operation),
484 @samp{underflow} (underflow in a floating point operation),
485 @samp{precision} (loss of precision during operation) and @samp{denormal}
486 (operation produced a denormal denormal value).
489 @xref{Debugging Options,,Options for Debugging Your Program or GCC,
490 gcc,Using the GNU Compiler Collection (GCC)}, for more information on
493 @node Directory Options
494 @section Options for Directory Search
495 @cindex directory, options
496 @cindex options, directory search
499 @cindex INCLUDE directive
500 @cindex directive, INCLUDE
501 These options affect how @command{gfortran} searches
502 for files specified by the @code{INCLUDE} directive and where it searches
503 for previously compiled modules.
505 It also affects the search paths used by @command{cpp} when used to preprocess
510 @cindex options, -Idir
512 @cindex directory, search paths for inclusion
513 @cindex inclusion, directory search paths for
514 @cindex search paths, for included files
515 @cindex paths, search
516 @cindex module search path
517 These affect interpretation of the @code{INCLUDE} directive
518 (as well as of the @code{#include} directive of the @command{cpp}
521 Also note that the general behavior of @option{-I} and
522 @code{INCLUDE} is pretty much the same as of @option{-I} with
523 @code{#include} in the @command{cpp} preprocessor, with regard to
524 looking for @file{header.gcc} files and other such things.
526 This path is also used to search for @samp{.mod} files when previously
527 compiled modules are required by a @code{USE} statement.
529 @xref{Directory Options,,Options for Directory Search,
530 gcc,Using the GNU Compiler Collection (GCC)}, for information on the
534 @cindex option, -Mdir
537 This option specifies where to put @samp{.mod} files for compiled modules.
538 It is also added to the list of directories to searched by an @code{USE}
541 The default is the current directory.
543 @option{-J} is an alias for @option{-M} to avoid conflicts with existing
547 @node Code Gen Options
548 @section Options for Code Generation Conventions
549 @cindex code generation, conventions
550 @cindex options, code generation
551 @cindex run-time, options
553 These machine-independent options control the interface conventions
554 used in code generation.
556 Most of them have both positive and negative forms; the negative form
557 of @option{-ffoo} would be @option{-fno-foo}. In the table below, only
558 one of the forms is listed---the one which is not the default. You
559 can figure out the other form by either removing @option{no-} or adding
563 @cindex @option{-fno-automatic} option
564 @cindex options, @option{-fno-automatic}
566 @cindex SAVE statement
567 @cindex statements, SAVE
568 Treat each program unit as if the @code{SAVE} statement was specified for
569 every local variable and array referenced in it. Does not affect common
570 blocks. (Some Fortran compilers provide this option under the name
573 @cindex @option{-ff2c} option
574 @cindex options, @option{-ff2c}
576 @cindex calling convention
577 @cindex @command{f2c} calling convention
578 @cindex @command{g77} calling convention
579 @cindex libf2c calling convention
580 Generate code designed to be compatible with code generated
581 by @command{g77} and @command{f2c}.
583 The calling conventions used by @command{g77} (originally implemented
584 in @command{f2c}) require functions that return type
585 default @code{REAL} to actually return the C type @code{double}, and
586 functions that return type @code{COMPLEX} to return the values via an
587 extra argument in the calling sequence that points to where to
588 store the return value. Under the default GNU calling conventions, such
589 functions simply return their results as they would in GNU
590 C -- default @code{REAL} functions return the C type @code{float}, and
591 @code{COMPLEX} functions return the GNU C type @code{complex}.
592 Additionally, this option implies the @option{-fsecond-underscore}
593 option, unless @option{-fno-second-underscore} is explicitly requested.
595 This does not affect the generation of code that interfaces with
596 the @command{libgfortran} library.
598 @emph{Caution:} It is not a good idea to mix Fortran code compiled
599 with @code{-ff2c} with code compiled with the default @code{-fno-f2c}
600 calling conventions as, calling @code{COMPLEX} or default @code{REAL}
601 functions between program parts which were compiled with different
602 calling conventions will break at execution time.
604 @emph{Caution:} This will break code which passes intrinsic functions
605 of type default @code{REAL} or @code{COMPLEX} as actual arguments, as
606 the library implementations use the @command{-fno-f2c} calling conventions.
608 @cindex @option{-fno-underscoring option}
609 @cindex options, @option{-fno-underscoring}
610 @item -fno-underscoring
612 @cindex symbol names, underscores
613 @cindex transforming symbol names
614 @cindex symbol names, transforming
615 Do not transform names of entities specified in the Fortran
616 source file by appending underscores to them.
618 With @option{-funderscoring} in effect, @command{gfortran} appends one
619 underscore to external names with no underscores. This is done to ensure
620 compatibility with code produced by many UNIX Fortran compilers.
622 @emph{Caution}: The default behavior of @command{gfortran} is
623 incompatible with @command{f2c} and @command{g77}, please use the
624 @option{-ff2c} option if you want object files compiled with
625 @option{gfortran} to be compatible with object code created with these
628 Use of @option{-fno-underscoring} is not recommended unless you are
629 experimenting with issues such as integration of (GNU) Fortran into
630 existing system environments (vis-a-vis existing libraries, tools, and
633 For example, with @option{-funderscoring}, and assuming other defaults like
634 @option{-fcase-lower} and that @samp{j()} and @samp{max_count()} are
635 external functions while @samp{my_var} and @samp{lvar} are local variables,
639 I = J() + MAX_COUNT (MY_VAR, LVAR)
643 is implemented as something akin to:
646 i = j_() + max_count__(&my_var__, &lvar);
649 With @option{-fno-underscoring}, the same statement is implemented as:
652 i = j() + max_count(&my_var, &lvar);
655 Use of @option{-fno-underscoring} allows direct specification of
656 user-defined names while debugging and when interfacing @command{gfortran}
657 code with other languages.
659 Note that just because the names match does @emph{not} mean that the
660 interface implemented by @command{gfortran} for an external name matches the
661 interface implemented by some other language for that same name.
662 That is, getting code produced by @command{gfortran} to link to code produced
663 by some other compiler using this or any other method can be only a
664 small part of the overall solution---getting the code generated by
665 both compilers to agree on issues other than naming can require
666 significant effort, and, unlike naming disagreements, linkers normally
667 cannot detect disagreements in these other areas.
669 Also, note that with @option{-fno-underscoring}, the lack of appended
670 underscores introduces the very real possibility that a user-defined
671 external name will conflict with a name in a system library, which
672 could make finding unresolved-reference bugs quite difficult in some
673 cases---they might occur at program run time, and show up only as
674 buggy behavior at run time.
676 In future versions of @command{gfortran} we hope to improve naming and linking
677 issues so that debugging always involves using the names as they appear
678 in the source, even if the names as seen by the linker are mangled to
679 prevent accidental linking between procedures with incompatible
682 @cindex @option{-fsecond-underscore option}
683 @cindex options, @option{-fsecond-underscore}
684 @item -fsecond-underscore
686 @cindex symbol names, underscores
687 @cindex transforming symbol names
688 @cindex symbol names, transforming
689 @cindex @command{f2c} calling convention
690 @cindex @command{g77} calling convention
691 @cindex libf2c calling convention
692 By default, @command{gfortran} appends an underscore to external
693 names. If this option is used @command{gfortran} appends two
694 underscores to names with underscores and one underscore to external names
695 with no underscores. (@command{gfortran} also appends two underscores to
696 internal names with underscores to avoid naming collisions with external
699 This option has no effect if @option{-fno-underscoring} is
700 in effect. It is implied by the @option{-ff2c} option.
702 Otherwise, with this option, an external name such as @samp{MAX_COUNT}
703 is implemented as a reference to the link-time external symbol
704 @samp{max_count__}, instead of @samp{max_count_}. This is required
705 for compatibility with @command{g77} and @command{f2c}, and is implied
706 by use of the @option{-ff2c} option.
709 @cindex -fbounds-check option
710 @cindex -ffortran-bounds-check option
712 @cindex bounds checking
713 @cindex range checking
714 @cindex array bounds checking
715 @cindex subscript checking
716 @cindex checking subscripts
717 Enable generation of run-time checks for array subscripts
718 and against the declared minimum and maximum values. It also
719 checks array indices for assumed and deferred
720 shape arrays against the actual allocated bounds.
722 In the future this may also include other forms of checking, eg. checking
723 substring references.
726 @cindex -fmax-stack-var-size option
727 @item -fmax-stack-var-size=@var{n}
728 This option specifies the size in bytes of the largest array that will be put
731 This option currently only affects local arrays declared with constant
732 bounds, and may not apply to all character variables.
733 Future versions of @command{gfortran} may improve this behavior.
735 The default value for @var{n} is 32768.
737 @cindex -fpackderived
739 @cindex Structure packing
740 This option tells gfortran to pack derived type members as closely as
741 possible. Code compiled with this option is likely to be incompatible
742 with code compiled without this option, and may execute slower.
744 @cindex -frepack-arrays option
745 @item -frepack-arrays
746 @cindex Repacking arrays
747 In some circumstances @command{gfortran} may pass assumed shape array
748 sections via a descriptor describing a discontiguous area of memory.
749 This option adds code to the function prologue to repack the data into
750 a contiguous block at runtime.
752 This should result in faster accesses to the array. However it can introduce
753 significant overhead to the function call, especially when the passed data
756 @cindex -fshort-enums
758 This option is provided for interoperability with C code that was
759 compiled with the @command{-fshort-enums} option. It will make
760 @command{gfortran} choose the smallest @code{INTEGER} kind a given
761 enumerator set will fit in, and give all its enumerators this kind.
764 @xref{Code Gen Options,,Options for Code Generation Conventions,
765 gcc,Using the GNU Compiler Collection (GCC)}, for information on more options
767 shared by @command{gfortran} @command{gcc} and other GNU compilers.
772 @node Environment Variables
773 @section Environment Variables Affecting GNU Fortran
774 @cindex environment variables
776 @c man begin ENVIRONMENT
778 GNU Fortran 95 currently does not make use of any environment
779 variables to control its operation above and beyond those
780 that affect the operation of @command{gcc}.
782 @xref{Environment Variables,,Environment Variables Affecting GCC,
783 gcc,Using the GNU Compiler Collection (GCC)}, for information on environment