string/envz.h

   1 /* Routines for dealing with '\0' separated environment vectors
   2    Copyright (C) 1995-2017 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _ENVZ_H
  20 #define _ENVZ_H 1
  21
  22 #include <features.h>
  23
  24 #include <errno.h>
  25
  26 /* Envz's are argz's too, and should be created etc., using the same
  27    routines.  */
  28 #include <argz.h>
  29
  30 __BEGIN_DECLS
  31
  32 /* Returns a pointer to the entry in ENVZ for NAME, or 0 if there is none.  */
  33 extern char *envz_entry (const char *__restrict __envz, size_t __envz_len,
  34                          const char *__restrict __name)
  35      __THROW __attribute_pure__;
  36
  37 /* Returns a pointer to the value portion of the entry in ENVZ for NAME, or 0
  38    if there is none.  */
  39 extern char *envz_get (const char *__restrict __envz, size_t __envz_len,
  40                        const char *__restrict __name)
  41      __THROW __attribute_pure__;
  42
  43 /* Adds an entry for NAME with value VALUE to ENVZ & ENVZ_LEN.  If an entry
  44    with the same name already exists in ENVZ, it is removed.  If VALUE is
  45    NULL, then the new entry will a special null one, for which envz_get will
  46    return NULL, although envz_entry will still return an entry; this is handy
  47    because when merging with another envz, the null entry can override an
  48    entry in the other one.  Null entries can be removed with envz_strip ().  */
  49 extern error_t envz_add (char **__restrict __envz,
  50                          size_t *__restrict __envz_len,
  51                          const char *__restrict __name,
  52                          const char *__restrict __value) __THROW;
  53
  54 /* Adds each entry in ENVZ2 to ENVZ & ENVZ_LEN, as if with envz_add().  If
  55    OVERRIDE is true, then values in ENVZ2 will supersede those with the same
  56    name in ENV, otherwise not.  */
  57 extern error_t envz_merge (char **__restrict __envz,
  58                            size_t *__restrict __envz_len,
  59                            const char *__restrict __envz2,
  60                            size_t __envz2_len, int __override) __THROW;
  61
  62 /* Remove the entry for NAME from ENVZ & ENVZ_LEN, if any.  */
  63 extern void envz_remove (char **__restrict __envz,
  64                          size_t *__restrict __envz_len,
  65                          const char *__restrict __name) __THROW;
  66
  67 /* Remove null entries.  */
  68 extern void envz_strip (char **__restrict __envz,
  69                         size_t *__restrict __envz_len) __THROW;
  70
  71 __END_DECLS
  72
  73 #endif /* envz.h */