G77(1)

NAME
g77 - GNU project F77 Compiler (v0.5.18)

SYNOPSIS
g77 [ option | filename ]...

WARNING
The information in this man page is an extract from the full documentation of the GNU Fortran compiler (version 0.5.18), and is limited to the meaning 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.

The version of GNU Fortran documented by the Info file is 0.5.20, which includes substantial improvements and changes since 0.5.18, the version documented in this man page.

If we find that the things in this man page that are out of date cause significant confusion or complaints, we will stop distributing the man page.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 0.5.18). 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 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 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 infog77 F77 source files use the suffix `.f '; F77 files to be preprocessed by cpp(1) use the suffix `.F '.

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 g77 . For full information 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 definition.

-Dmacro=defn
    Define macro macro as defn .

--driver=command
    Specifies that command, rather than `gcc', is to be invoked by `g77' to do its job. Example: Within the gcc build directory after building GNU Fortran (but without having to install it),
      ./g77 --driver=./xgcc -B./ foo.f

-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, `-g ' enables use of extra debugging 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 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.

-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 investigating 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 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. Use `--driver=true' to disable actual invocation of `gcc' (since `true' is the name of a UNIX command that simply returns success status). The command `gcc -v' is the appropriate one to determine the g77 and GCC version numbers; it will produce an irrelevant error message from `ld'.

-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.F preprocessed Fortran source file
file.fpp preprocessed Fortran source file
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/libf2c.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 0.5.18), James Craig Burley; Using and Porting GNU CC (for version 2.0), Richard M. Stallman; The C Preprocessor, Richard M. Stallman; 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, see the file DOC in the g77 distribution.

COPYING
Copyright (c) 1991, 1992, 1993, 1994, 1995, 1996 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.