getopt.h

/* Declarations for getopt.
   Copyright (C) 1989,90,91,92,93,94,96,97 Free Software Foundation, Inc.

   This file is part of the GNU C Library.  Its master source is NOT part of
   the C library, however.  The master source lives in /gd/gnu/lib.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#ifndef _GETOPT_H
#define _GETOPT_H 1

#ifdef  __cplusplus
extern "C"
{
#endif

/* For communication from `getopt' to the caller.
   When `getopt' finds an option that takes an argument,
   the argument value is returned here.
   Also, when `ordering' is RETURN_IN_ORDER,
   each non-option ARGV-element is returned here.  */

        extern char *optarg;

/* Index in ARGV of the next element to be scanned.
   This is used for communication to and from the caller
   and for communication between successive calls to `getopt'.

   On entry to `getopt', zero means this is the first call; initialize.

   When `getopt' returns -1, this is the index of the first of the
   non-option elements that the caller should itself scan.

   Otherwise, `optind' communicates from one call to the next
   how much of ARGV has been scanned so far.  */

        extern int optind;

/* Callers store zero here to inhibit the error message `getopt' prints
   for unrecognized options.  */

        extern int opterr;

/* Set to an option character which was unrecognized.  */

        extern int optopt;

/* Describe the long-named options requested by the application.
   The LONG_OPTIONS argument to getopt_long or getopt_long_only is a vector
   of `struct option' terminated by an element containing a name which is
   zero.

   The field `has_arg' is:
   no_argument          (or 0) if the option does not take an argument,
   required_argument    (or 1) if the option requires an argument,
   optional_argument    (or 2) if the option takes an optional argument.

   If the field `flag' is not NULL, it points to a variable that is set
   to the value given in the field `val' when the option is found, but
   left unchanged if the option is not found.

   To have a long-named option do something other than set an `int' to
   a compiled-in constant, such as set a value from `optarg', set the
   option's `flag' field to zero and its `val' field to a nonzero
   value (the equivalent single-letter option character, if there is
   one).  For long options that have a zero `flag' field, `getopt'
   returns the contents of the `val' field.  */

        struct option
        {
#if defined (__STDC__) && __STDC__
                const char *name;
#else
                char *name;
#endif
                /* has_arg can't be an enum because some compilers complain about
                   type mismatches in all the code that assumes it is an int.  */
                int has_arg;
                int *flag;
                int val;
        };

/* Names for the values of the `has_arg' field of `struct option'.  */

#define no_argument             0
#define required_argument       1
#define optional_argument       2

#if defined (__STDC__) && __STDC__
#ifdef __GNU_LIBRARY__
/* Many other libraries have conflicting prototypes for getopt, with
   differences in the consts, in stdlib.h.  To avoid compilation
   errors, only prototype getopt for the GNU C library.  */
        extern int getopt(int argc, char *const *argv, const char *shortopts);
#else                           /* not __GNU_LIBRARY__ */
        extern int getopt();
#endif                          /* __GNU_LIBRARY__ */
        extern int getopt_long(int argc, char *const *argv, const char *shortopts,
                               const struct option *longopts, int *longind);
        extern int getopt_long_only(int argc, char *const *argv,
                                    const char *shortopts,
                               const struct option *longopts, int *longind);

/* Internal only.  Users should not call this directly.  */
        extern int _getopt_internal(int argc, char *const *argv,
                                    const char *shortopts,
                                const struct option *longopts, int *longind,
                                    int long_only);
#else                           /* not __STDC__ */
        extern int getopt();
        extern int getopt_long();
        extern int getopt_long_only();

        extern int _getopt_internal();
#endif                          /* __STDC__ */

#ifdef  __cplusplus
}
#endif

#endif                          /* _GETOPT_H */

---