man pages for g77
Online Manual
GNU Tools Last change: 1999-02-14
NAME
g77 - GNU project Fortran Compiler (v0.5.24)
SYNOPSIS
g77 [option | filename ]...
WARNING
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If we find that the things in this man page that are out of
date cause significant confusion or complaints, we will stop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 `g77' or the manual Using and Porting GNU Fortran (for
version 0.5.24). Both are made from the Texinfo source file
g77.texi.
If your system has the `info' command installed, the command
`info g77' should work, unless g77 has not been properly
installed. If your system lacks `info', or you wish to
avoid using it for now, the command `more
/usr/info/g77.info*' 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 adminis-
trator, 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 For-
tran (ANSI FORTRAN 77, also called F77). gcc processes
input files through one or more of four stages: preprocess-
ing, compilation, assembly, and linking. This man page con-
tains 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 `info g77'.
F77 source files use the suffix `.f', `.for', or `.FOR'; F77
files to be preprocessed by cpp(1) use the suffix `.F',
`.fpp', or `.FPP'; Ratfor source files use the suffix `.r'
(though ratfor itself is not supplied as part of g77).
OPTIONS
There are many command-line options, including options to
control details of optimization, warnings, and code genera-
tion, which are common to both gcc and g77. For full infor-
mation on all options, see gcc(1).
Options must be separate: `-dr' is quite different from `-d
-r '.
Most `-f' and `-W' options have two contrary forms: -fname
and -fno-name (or -Wname and -Wno-name). 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.
-Dmacro
Define macro macro with the string `1' as its defini-
tion.
-Dmacro=defn
Define macro macro as defn.
-E Stop after the preprocessing stage; do not run the com-
piler 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, `-g' enables use of extra debug-
ging information that only GDB can use.
Unlike most other Fortran compilers, GNU Fortran allows
you to use `-g' with `-O'. 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 dif-
ferent places because they were moved out of loops.
Nevertheless it proves possible to debug optimized out-
put. This makes it reasonable to use the optimizer for
programs that might have bugs.
-Idir
Append directory dir to the list of directories
searched for include files.
-Ldir
Add directory dir to the list of directories to be
searched for `-l'.
-llibrary
Use the library named library 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 investigat-
ing for typical numerical Fortran programs.
-o file
Place output in file file.
-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.
-Umacro
Undefine macro macro.
-v Print (on standard error output) the commands executed
to run the stages of compilation. Also print the ver-
sion 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/machine/version.
TMPDIR comes from the environment variable TMPDIR (default
/usr/tmp if available, else /tmp).
SEE ALSO
gcc(1), cpp(1), as(1), ld(1), gdb(1), adb(1), dbx(1),
sdb(1).
`g77', `gcc', `cpp `as', `ld', and `gdb' entries in info.
Using and Porting GNU Fortran (for version 0.5.24), James
Craig Burley; Using and Porting GNU CC (for version 2.0),
Richard M. Stallman; The C Preprocessor, Richard M. Stall-
man; Debugging with GDB: the GNU Source-Level Debugger,
Richard M. Stallman and Roland H. Pesch; Using as: the GNU
Assembler, Dean Elsner, Jay Fenlason & friends; gld: the GNU
linker, Steve Chamberlain and Roland Pesch.
BUGS
For instructions on how to report bugs, type `info g77 -n
Bugs'.
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 per-
mission notice are preserved on all copies.
Permission is granted to copy and distribute modified ver-
sions 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 condi-
tions 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 online GNU Fortran Manual for the contributors to GNU Fortran.