sysdeps/generic/putenv.c

   1 /* Copyright (C) 1991, 1994, 1995 Free Software Foundation, Inc.
   2
   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 Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 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 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #if defined (_AIX) && !defined (__GNUC__)
  21  #pragma alloca
  22 #endif
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #if _LIBC || HAVE_STDLIB_H
  29 #include <stdlib.h>
  30 #endif
  31 #if _LIBC || HAVE_STRING_H
  32 #include <string.h>
  33 #endif
  34
  35 #if !__GNU_LIBRARY__ && !HAVE_STRCHR
  36 #define strchr index
  37 #endif
  38
  39 #ifndef _LIBC
  40 #ifdef HAVE_ALLOCA_H
  41 #include <alloca.h>
  42 #else
  43 #ifdef __GNUC__
  44 #define alloca __builtin_alloca
  45 #else
  46 extern char *alloca ();
  47 #endif /* __GNUC__ */
  48 #endif /* HAVE_ALLOCA_H */
  49 #endif /* _LIBC */
  50
  51
  52 /* Put STRING, which is of the form "NAME=VALUE", in the environment.  */
  53 int
  54 putenv (string)
  55      const char *string;
  56 {
  57   const char *const name_end = strchr (string, '=');
  58
  59   if (name_end)
  60     {
  61       char *name = alloca (name_end - string + 1);
  62       memcpy (name, string, name_end - string);
  63       name[name_end - string] = '\0';
  64       return setenv (name, name_end + 1, 1);
  65     }
  66
  67   unsetenv (string);
  68   return 0;
  69 }