GNU Gengetopt 2.3

April 10th, 2001

This program generate a C function that uses getopt_long function to parse
the command line options, validate them and fill a struct.

Thus your program can now handle options such as:

myprog --input foo.c -o foo.o --no-tabs -i 100 *.class

And both long options (those that start with --) and short options (start
with - and consist of only one character) can be handled. For standards
about short and long options you may want to take a look at the GNU Coding
Standards.

gengetopt is free software. Please see the file LICENSE and COPYING for
details.
Notice that: Use of gengetopt does not impose any particular license on the
generated code: the code generated is not under any license.

For documentation, please read this file.

gengetopt is perfect if you are too lazy (like me) to write all stuff
required to call getopt_long, and when you have a
program and wish it took options.

Generated code works if you use GNU Autoconf or GNU Automake.

Gengetopt has originally been written by Roberto Arturo Tena Sanchez
<arturo@directmail.org>, and currently maintained by Lorenzo Bettini
<bettini@gnu.org>.

Gengetopt is a GNU program and its main home page is at GNU site:
http://www.gnu.org/software/gengetopt/gengetopt.html,

Download

You can download it from GNU's ftp site:
ftp://ftp.gnu.org/gnu/gengetopt/ or from one of its mirrors (see
http://www.gnu.org/prep/ftp.html).

I do not distribute Windows binaries anymore; since, they can be easily
built by using Cygnus C/C++ compiler, available at http://www.cygnus.com/.
However, if you don't feel like downloading such compiler, you can request
such binaries directly to me, by e-mail (bettini@gnu.org) and I can send
them to you.

You may also want to check the md5sum of the archives, which are also
digitally signed by me (Lorenzo Bettini) with GNU gpg
(http://www.gnupg.org). My GPG public key can be found at my home page (see
at the end of this doc).

You can also get the patches, if they are available for a particular release
(see below for patching from a previous version).

Changes in this release

   * --no-handle-help and --no-handle-version option added, so that
     --help|-h and --version|-V can be explicitly handled (for instance for
     printing a copyright notice, as suggested by Vladimir Tamara
     <vtamara@gnu.org>).
   * PURPOSE added to specify in the .ggo file the purpose of the program
     (thanks to Berthold Höllmann <hoel@germanlloyd.org>).
   * generated print_version and print_help are not static so they can be
     called also in the program and they are prefixed with the name of the
     generated function, so that more than one parser can be handled.
   * test the presence of alloca function in standard library (reported by
     Aldo D. Longhi <aldo.longhi@alum.wpi.edu>).
   * test suite added (type make check, to run the tests).

Changes in release 2.2

   * scanner is simplified and now accepts arbitrary character strings
     between, thanks to nbecker@fred.net.
   * It compiles under Sun C compiler 5.1, thanks to Robert Walsh
     <Robert.J.Walsh@eng.sun.com>.
   * VERSION and PACKAGE are generated in cmdline.h instead of cmdline.c,
     thanks to Richard Heggs <richard@virtua-web.co.uk>.
   * #undef's PACKAGE and VERSION before setting them, in case they are
     defined in the .ggo file, thanks to Scott Haug <scott@id3.org>.
   * long options with no associated short options are allowed, thanks to
     damned@world.std.com.
   * fixed no_getopt_long.txt, thanks to Peter Fox
     <fox@roestock.demon.co.uk>

Changes in release 2.1

   * It is made more clear that use of gengetopt does not impose any
     particular license on the generated code.
   * A bug in the generation of code (for some new C++ compilers) was fixed,
     thanks to "James R. Van Zandt" <jrv@vanzandt.mv.com>
   * Some modifications to the man page, also due to James.
   * a directory for examples is specifically created (suggested by James).

Changes in release 2.0

This is quite a totally new release:

   * Gengetopt has become GNU software
   * it is conform to GNU coding standards, and so it uses configure script
     generated by Automake and Autoconf
   * it generates separated files: one header file with the struct used to
     store command line options information, and a C file which contains the
     function which actually uses getopt_long to parse the command line
   * 'required' option is now fully implemented

see also NEWS file and ChangeLog for the complete list of changes between
versions.

Installation

See the file INSTALL for detailed building and installation instructions;
anyway if you're used to compiling Linux software that comes with sources
you may simply follow the usual procedure:

cd <source code main directory>
./configure
make
make install

Note: unless you specify a different install directory by --prefix option of
configure (e.g. ./configure --prefix=<your home>), you must be root to 'make
install'.

You can also run some tests by issuing 'make check'.

Files will be installed in the following directories:

   * Executables          -> /prefix/bin
   * Docs                 -> /prefix/share/doc/gengetopt
   * Man pages            -> /prefix/man
   * Examples             -> /prefix/share/doc/gengetopt/examples
   * Util files           -> /prefix/share/gengetopt

Default value for prefix is /usr/local but you may change it with --prefix
option to configure (see above).

What you need to build gengetopt

Actually you need nothing more than a Unix C/C++ compiler.

getopt_long function is usually in the standard C library, but there may be
some C libraries which don't include it; in this case you have to link the
program that uses the file generated by gengetopt with the files getopt.c
and getopt1.c and include getopt.h in your project. You may also need to
link alloca.c.We obviously provide these files in the utility files
directory (/prefix/share/gengetopt). These files are part of the GNU C
library. You may want to take a look at getopt man page. Read also
no_getopt_long.txt. for instuctions on how to check if getopt_long and
alloca are part of the library and how to deal with their lacking (using
autoconf and automake).

gengetopt has been developed under Linux, using gcc, and bison (yacc) and
flex (lex), and ported under Windows with Cygnus C/C++ compiler, available
at http://www.cygnus.com/. I used the excellent GNU Autoconf and Automake. I
also used Autotools (ftp://ftp.ugcs.caltech.edu/pub/elef/autotools) which
creates a starting source tree (according to GNU standards) with autoconf,
automake starting files, and getopt_long (for command line parsing).

Actually, unless you want to develop gengetopt, you don't need all these
tools to build gengetopt because I provide generated sources; you don't need
neither bison (yacc) nor flex (lex), for the same reason. Actually programs
that use lex generated files need to link with library libfl (or libl for
lex); anyway configuration phase can discover if this library is missing and
in that case it sets the program to link with a source file I provide. This
hack works for flex: I don't know about lex generated scanners. But, again,
this is a problem only if you develop gengetopt and you use lex.

Patching from a previous version

If you downloaded a patch, say gengetopt-1.3-1.3.1-patch.gz (i.e. the patch
to go from version 1.3 to version 1.3.1), cd to the directory with sources
from the previous version (gengetopt-1.3) and type:

gunzip -cd ../gengetopt-1.3-1.3.1.patch.gz | patch -p1

and restart the compilation process (if you had already run configure a
simple make will do).

Usage (a little tutorial)

The command line options, which have to be handled by gengetopt generated
function, are specified in a file (typically with .ggo extension). This file
consist in lines of sentences with the following formats:

package <packname>
version <version>

option <long> <short> <desc> <argtype> <required>
option <long> <short> <desc> flag      <onoff>
option <long> <short> <desc> no

Where:

packname

     Double quoted string  with  upper  and  lower  case chars, digits,
     '-' and '.'.  No spaces allowed.

version

     Double  quoted  string  with  upper  and lower case chars, digits,
     '-' and '.'.  No spaces allowed.

purpose

     What the program does (even on more than one line), it will be
     printed with the help. Double  quoted  string.

long

     The long option, a double quoted string with  upper and  lower
     case  chars,  digits,  '-' and '.'.  No spaces allowed.  The name
     of the  variables  generated  to store arguments are long options
     converted to be legal C variable names.  This means, '.'  and '-'
     are  both replaced by '_'. '_arg' is appended, or '_flag' for a
     flag.

short

     The short option, a  single  upper  or  lower  case char, or a
     digit. If a '-' is specified, then no short option is considered
     for the long option (thus long options with no associated short
     options are allowed).

desc

     Double  quoted  string  with  upper  and lower case chars, digits,
     '-', '.' and spaces. First character must not be a space.

argtype

     string, int, short, long, float, double, longdouble or longlong.

required

     yes or no.

onoff

     on or off. This is the state of the flag when the program starts.
     If user specifies the option, the flag toggles.

The third type of option is used when the option does not take any argument.
It must not be required.

Comments begins with '#' in any place of the line and ends in the end of
line.

Here's an example of such a file (the file is called sample1.ggo)


  # file sample1.ggo
  option  "str-opt"         s "A string option"      string     no
  option  "int-opt"         i "A int option"         int        yes
  option  "funct-opt"       F "A function option"    no
  option  "flag-opt"        x "A flag option"        flag       off

The simplest way to use gengetopt is to pass this file as the standard
input, i.e.:

gengetopt < sample1.ggo

by default gengetopt generates cmdline.h and cmdline.c. Otherwise we can
specify these names with a command line option:

gengetopt < sample1.ggo --file-name=cmdline1

In cmdline1.h you'll find the generated C struct:

 /* cmdline1.h */

 /* File autogenerated by gengetopt version 2.3  */

 #ifndef _cmdline1_h
 #define _cmdline1_h

 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */

 /* Don't define PACKAGE and VERSION if we use automake.  */
 #if defined PACKAGE
 #  undef PACKAGE
 #endif
 #define PACKAGE "sample1"
 #if defined VERSION
 #  undef VERSION
 #endif
 #define VERSION "2.0"

 struct gengetopt_args_info {
   char * str_opt_arg;   /* A string option.  */
   int my_opt_arg;       /* Another integer option.  */
   int int_opt_arg;      /* A int option.  */
   int flag_opt_flag;    /* A flag option (default=off).  */
   long long_opt_arg;    /* A long option.  */

   int help_given ;      /* Whether help was given.  */
   int version_given ;   /* Whether version was given.  */
   int str_opt_given ;   /* Whether str-opt was given.  */
   int my_opt_given ;    /* Whether my-opt was given.  */
   int int_opt_given ;   /* Whether int-opt was given.  */
   int flag_opt_given ;  /* Whether flag-opt was given.  */
   int funct_opt_given ; /* Whether funct-opt was given.  */
   int long_opt_given ;  /* Whether long-opt was given.  */

   char **inputs ; /* unamed options */
   unsigned inputs_num ; /* unamed options number */
 } ;

 int cmdline_parser (int argc, char * const *argv, struct gengetopt_args_info *args_info);

 void cmdline_parser_print_help(void);
 void cmdline_parser_print_version(void);

 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
 #endif /* _cmdline1_h */

Notice that by default the generated function is called cmdline_parser (see
the command line options below, to override this name), and it takes the
arguments that main receives and a pointer to such a struct, that it will be
filled.
And here's how this function can be used inside the main program:

 /* main1.cc */
 /* we try to use gengetopt generated file in a C++ program */
 /* we don't use autoconf and automake vars */

 #include <iostream.h>

 #include "cmdline1.h"

 int
 main (int argc, char **argv)
 {
   gengetopt_args_info args_info;

   cout << "This one is from a C++ program" << endl ;
   cout << "Try to launch me with some options" << endl ;
   cout << "(type sample1 --help for the complete list)" << endl ;
   cout << "For example: ./sample1 *.* --funct-opt" << endl ;

   /* let's call our cmdline parser */
   if (cmdline_parser (argc, argv, &args_info) != 0)
     exit(1) ;

   cout << "Here are the options you passed..." << endl;

   for ( unsigned i = 0 ; i < args_info.inputs_num ; ++i )
     cout << "file: " << args_info.inputs[i] << endl ;

   if ( args_info.funct_opt_given )
     cout << "You chose --funct-opt or -F." << endl ;

   if ( args_info.str_opt_given )
     cout << "You inserted " << args_info.str_opt_arg << " for " <<
       "--str-opt option." << endl ;

   if ( args_info.int_opt_given )
     cout << "This is the integer you input: " <<
       args_info.int_opt_arg << "." << endl;

   cout << "The flag is " << ( args_info.flag_opt_flag ? "on" : "off" ) <<
     "." << endl ;

   cout << "Have a nice day! :-)" << endl ;

   return 0;
 }

Now you can compile main1.cc and the cmdline1.c generated by gengetopt and
link all together to obtain sample1 executable:

gcc -c cmdline1.c
g++ -c main1.cc
g++ -o sample1 cmdline1.o main1.o

(Here we assume that getopt_long is included in the standard C library; see
'What you need to build gengetopt' section).

Now let's try some tests with this program:

$ ./sample1 -s "hello" --int-opt 1234
This one is from a C++ program
Try to launch me with some options
(type sample1 --help for the complete list)
For example: ./sample1 *.* --funct-opt
Here are the options you passed...
You inserted hello for --str-opt option.
This is the integer you input: 1234.
The flag is off.
Have a nice day! :-)

You can also pass many file names to the command line (this also shows how
flags work):

$ ./sample1 *.h -i -100 -x
This one is from a C++ program
Try to launch me with some options
(type sample1 --help for the complete list)
For example: ./sample1 *.* --funct-opt
Here are the options you passed...
file: cmdline1.h
file: cmdline2.h
file: cmdline.h
file: getopt.h
This is the integer you input: -100.
The flag is on.
Have a nice day! :-)

And if we try to omit the --int-opt (or -i), which is required, we get an
error:

$ ./sample1
This one is from a C++ program
Try to launch me with some options
(type sample1 --help for the complete list)
For example: ./sample1 *.* --funct-opt
sample1: `--int-opt' (`-i') option required!

If you're curious you may want to take a look at the generated C file.

You may find other examples in /prefix/share/doc/gengetopt.

Warning for Windows users

If you run Windows, please remember that DOS shell does not translate
wildcards, and thus the previous test which uses '*.h' will not work.

Options

This is the output of gengetopt --help:

$ gengetopt --help
gengetopt 2.3

Purpose:
  This program generates a C function that uses getopt_long function
  to parse the command line options, validate them and fill a struct.

Usage: gengetopt [OPTIONS]...
   -h         --help              Print help and exit
   -V         --version           Print version and exit
   -iSTRING   --input=STRING      input file (default std input)
   -fSTRING   --func-name=STRING  name of generated function
   -FSTRING   --file-name=STRING  name of generated file (default cmdline)
   -l         --long-help         long usage line in help
   -u         --unamed-opts       accept filenames
              --no-handle-help    do not handle --help|-h automatically
              --no-handle-version do not handle --version|-V automatically

Maintained by Lorenzo Bettini <bettini@gnu.org>
Report bugs to <bug-gengetopt@gnu.org>

The options should be clear; in particular:

   * if no --func-name is given, cmdline_parser is taken by default;
   * with --long-help option, the "Usage" line reports all the options; this
     may be unpleasant if options are many;
   * with --unamed-opts we can accept also options without a name, which, in
     most case, means that we can pass many file names to the program (see
     the example above when we call sample1 *.h).
   * if --no-handle-help (--no-handle-version) is given the command line
     --help|-h (--version|-V) is not handled automatically, so the
     programmer will be able to print some other information; then the
     function for printing the standard help (version) response can be used;
     this function is called <parser-name>_print_help
     (<parser-name>_print_version), where <parser-name> is the name
     specified with ---func-name or the default cmdline_parser.

You may have already guessed it: gengetopt uses gengetopt itself for command
line options, and this is its specification file:


  purpose "This program generates a C function that uses getopt_long function
  to parse the command line options, validate them and fill a struct."

  option  "input"         i "input file. default std input"  string     no
  option  "func-name"     f "name of generated function"  string     no
  option  "file-name"     F "name of generated file. default cmdline"  string     no
  option  "long-help"     l "long usage line in help" no
  option  "unamed-opts"   u "accept filenames" no
  option  "no-handle-help"   - "do not handle --help|-h automatically" no
  option  "no-handle-version"   - "do not handle --version|-V automatically" no

In particular the command line for gengetopt itself is generated with the
following command:

gengetopt --input=cmdline.ggo --no-handle-version --no-handle-help

Indeed when --help|-h is passed on the command line, gengetopt will call
cmdline_parser_print_help() and then the lines for reporting bugs. When
--version|-V is passed, it will call cmdline_parser_print_version() and then
prints a copyright.

Credits

See THANKS file :-)

Feedback

Tell us if you like this software :-)

Actually we want to extend it, so if you have some ideas... The most import
one will be to make gengetopt more customizable :-)

Please send all bug reports by electronic mail to:
bug-gengetopt@gnu.org

Mailing Lists

The following mailing lists are available:

   * help-gengetopt@gnu.org, for generic discussions about the program and
     for asking for help about it (open mailing list),
     http://mail.gnu.org/mailman/listinfo/help-gengetopt
   * info-gengetopt@gnu.org, for receiving information about new releases
     and features (read-only mailing list),
     http://mail.gnu.org/mailman/listinfo/info-gengetopt

if you want to subscribe to a mailing list just go to the URL and follow the
instructions.

 Lorenzo Bettini                      Roberto Arturo Tena Sanchez
 http://w3.newnet.it/bettini  or      http://arturo.directmail.org
 http://infostud.dsi.unifi.it/~bettini<arturo@directmail.org>,
 (very fast if you're in University)
 <bettini@gnu.org>.

gengetopt is free software. See the file LICENSE and COPYING for copying
conditions. Anyway we won't get offended if you send us a postcard :-)

C/C++ files are formatted with GNU cpp2html
(http://www.gnu.org/software/cpp2html) by Lorenzo Bettini.

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Copyright (C) 1999 Free Software Foundation, Inc., 59 Temple Place - Suite
330, Boston, MA 02111, USA

Verbatim copying and distribution of this entire article is permitted in any
medium, provided this notice is preserved.

 Updated: 27 Mar 1999 jonas
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