posix/bits/getopt_ext.h

   1 /* Declarations for getopt (GNU extensions).
   2    Copyright (C) 1989-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library and is also part of gnulib.
   4    Patches to this file should be submitted to both projects.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #ifndef _GETOPT_EXT_H
  21 #define _GETOPT_EXT_H 1
  22
  23 /* This header should not be used directly; include getopt.h instead.
  24    Unlike most bits headers, it does not have a protective #error,
  25    because the guard macro for getopt.h in gnulib is not fixed.  */
  26
  27 __BEGIN_DECLS
  28
  29 /* Describe the long-named options requested by the application.
  30    The LONG_OPTIONS argument to getopt_long or getopt_long_only is a vector
  31    of 'struct option' terminated by an element containing a name which is
  32    zero.
  33
  34    The field 'has_arg' is:
  35    no_argument          (or 0) if the option does not take an argument,
  36    required_argument    (or 1) if the option requires an argument,
  37    optional_argument    (or 2) if the option takes an optional argument.
  38
  39    If the field 'flag' is not NULL, it points to a variable that is set
  40    to the value given in the field 'val' when the option is found, but
  41    left unchanged if the option is not found.
  42
  43    To have a long-named option do something other than set an 'int' to
  44    a compiled-in constant, such as set a value from 'optarg', set the
  45    option's 'flag' field to zero and its 'val' field to a nonzero
  46    value (the equivalent single-letter option character, if there is
  47    one).  For long options that have a zero 'flag' field, 'getopt'
  48    returns the contents of the 'val' field.  */
  49
  50 struct option
  51 {
  52   const char *name;
  53   /* has_arg can't be an enum because some compilers complain about
  54      type mismatches in all the code that assumes it is an int.  */
  55   int has_arg;
  56   int *flag;
  57   int val;
  58 };
  59
  60 /* Names for the values of the 'has_arg' field of 'struct option'.  */
  61
  62 #define no_argument             0
  63 #define required_argument       1
  64 #define optional_argument       2
  65
  66 extern int getopt_long (int ___argc, char *__getopt_argv_const *___argv,
  67                         const char *__shortopts,
  68                         const struct option *__longopts, int *__longind)
  69        __THROW __nonnull ((2, 3));
  70 extern int getopt_long_only (int ___argc, char *__getopt_argv_const *___argv,
  71                              const char *__shortopts,
  72                              const struct option *__longopts, int *__longind)
  73        __THROW __nonnull ((2, 3));
  74
  75 __END_DECLS
  76
  77 #endif /* getopt_ext.h */