The information in this man page is an extract from the full
documentation of the GNU Fortran compiler (version 0.5.24),
and is limited to the meaning of some of the options.
This man page is not up to date, since no volunteers want to
maintain it. If you find a discrepancy between the man page and the
software, please check the Info file, which is the authoritative
documentation.
If we find that the things in this man page that are out of date cause
significant confusion or complaints, we will stop distributing the man
page. The alternative, updating the man page when we update the Info
file, is impractical because the rest of the work of maintaining GNU Fortran
leaves us no time for that. The GNU project regards man pages as
obsolete and should not let them take time away from other things.
For complete and current documentation, refer to the Info file `c
g77c ' or the manual
Using and Porting GNU Fortran (for version 0.5.24)c
. Both are made from the Texinfo source file
g77.texi .
If your system has the `c
infoc ' command installed, the command `c
info g77c ' should work, unless
g77 has not been properly installed.
If your system lacks `c
infoc ', or you wish to avoid using it for now,
the command `c
more /usr/info/g77.info*c ' should work, unless
g77 has not been properly installed.
If
g77 has not been properly installed, so that you
cannot easily access the Info file for it,
ask your system administrator, or the installer
of
g77 (if you know who that is) to fix the problem.
DESCRIPTION
The C and F77 compilers are integrated;
g77 is a program to call
gcc with options to recognize programs written in Fortran (ANSI FORTRAN 77,
also called F77).
gcc processes input files
through one or more of four stages: preprocessing, compilation,
assembly, and linking. This man page contains full descriptions for
only F77-specific aspects of the compiler, though it also contains
summaries of some general-purpose options. For a fuller explanation
of the compiler, see
gcc ( 1 ).
For complete documentation on GNU Fortran, type `c
info g77c '.
F77 source files use the suffix `c
.fc ', `c
.forc ', or `c
.FORc '; F77 files to be preprocessed by
cpp ( 1 ) use the suffix `c
.Fc ', `c
.fppc ', or `c
.FPPc '; Ratfor source files use the suffix `c
.rc ' (though
ratfor itself is not supplied as part of
g77c ).
OPTIONS
There are many command-line options, including options to control
details of optimization, warnings, and code generation, which are
common to both
gcc and
g77c . For full information on all options, see
gcc ( 1 ).
Options must be separate: `c
-drc ' is quite different from `c
-d -r '.
Most `c
-fc ' and `c
-Wc ' options have two contrary forms:
-f name and
-fno- namec (or
-W name and
-Wno- namec ). Only the non-default forms are shown here.
-c
Compile or assemble the source files, but do not link. The compiler
output is an object file corresponding to each source file.
-D macro
Define macro c
macroc with the string `c
1c ' as its definition.
-D macro = defn
Define macro c
macroc as c
defnc .
-E
Stop after the preprocessing stage; do not run the compiler proper. The
output is preprocessed source code, which is sent to the
standard output.
-g
Produce debugging information in the operating system's native format
(for DBX or SDB or DWARF). GDB also can work with this debugging
information. On most systems that use DBX format, `c
-gc ' enables use
of extra debugging information that only GDB can use.
Unlike most other Fortran compilers, GNU Fortran allows you to use `c
-gc ' with
`c
-Oc '. The shortcuts taken by optimized code may occasionally
produce surprising results: some variables you declared may not exist
at all; flow of control may briefly move where you did not expect it;
some statements may not be executed because they compute constant
results or their values were already at hand; some statements may
execute in different places because they were moved out of loops.
Nevertheless it proves possible to debug optimized output. This makes
it reasonable to use the optimizer for programs that might have bugs.
-I dirc
Append directory c
dirc to the list of directories searched for include files.
-L dirc
Add directory c
dirc to the list of directories to be searched
for `c
-lc '.
-l libraryc
Use the library named c
libraryc when linking.
-nostdinc
Do not search the standard system directories for header files. Only
the directories you have specified with
-I options (and the current directory, if appropriate) are searched.
-O
Optimize. Optimizing compilation takes somewhat more time, and a lot
more memory for a large function. See the GCC documentation for
further optimisation options. Loop unrolling, in particular, may be
worth investigating for typical numerical Fortran programs.
-o filec
Place output in file c
filec .
-S
Stop after the stage of compilation proper; do not assemble. The output
is an assembler code file for each non-assembler input
file specified.
-U macro
Undefine macro c
macroc .
-v
Print (on standard error output) the commands executed to run the
stages of compilation. Also print the version number of the compiler
driver program and of the preprocessor and the compiler proper. The
version numbers of g77 itself and the GCC distribution on which it is
based are distinct.
-Wall
Issue warnings for conditions which pertain to usage that we recommend
avoiding and that we believe is easy to avoid, even in conjunction
with macros.
FILES
file.h C header (preprocessor) file
file.f Fortran source file
file.for Fortran source file
file.FOR Fortran source file
file.F preprocessed Fortran source file
file.fpp preprocessed Fortran source file
file.FPP preprocessed Fortran source file
file.r Ratfor source file (ratfor not included)
file.s assembly language file
file.o object file
a.out link edited output
TMPDIR/cc(** temporary files
LIBDIR/cpp preprocessor
LIBDIR/f771 compiler
LIBDIR/libg2c.a Fortran run-time library
LIBDIR/libgcc.a GCC subroutine library
/lib/crt[01n].o start-up routine
/lib/libc.a standard C library, see
intro(3) /usr/include standard directory for
#include files
LIBDIR/include standard gcc directory for
#include files.
LIBDIR is usually
/usr/local/lib/c machine / version .
TMPDIR comes from the environment variable
TMPDIR (default
/usr/tmp if available, else
/tmpc ).
SEE ALSO
gcc(1) , cpp(1) , as(1) , ld(1) , gdb(1) , adb(1) , dbx(1) , sdb(1) .
and
entries in
infoc .
Using and Porting GNU Fortran (for version 0.5.24)c
, James Craig Burley;
Using and Porting GNU CC (for version 2.0)c
, Richard M. Stallman;
The C Preprocessorc
, Richard M. Stallman;
Debugging with GDB: the GNU Source-Level Debuggerc
, Richard M. Stallman and Roland H. Pesch;
Using as: the GNU Assemblerc
, Dean Elsner, Jay Fenlason & friends;
gld: the GNU linkerc
, Steve Chamberlain and Roland Pesch.
BUGS
For instructions on how to report bugs, type `c
info g77 -n Bugsc '.
COPYING
Copyright (c) 1991-1998 Free Software Foundation, Inc.
Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
are preserved on all copies.
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.
Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that this permission notice may be included in
translations approved by the Free Software Foundation instead of in
the original English.
AUTHORS
See the GNU CC Manual for the contributors to GNU CC.
See the GNU Fortran Manual for the contributors to
GNU Fortran.
