gnu/dist/gettext/djgpp/unsetenv.c

   1 /*
   2    libc of DJGPP 2.03 does not offer function unsetenv,
   3    so this version from DJGPP 2.04 CVS tree is supplied.
   4    This file will become superflous and will be removed
   5    from the  distribution as soon as DJGPP 2.04 has been
   6    released.
   7 */
   8
   9 /* Copyright (C) 2001 DJ Delorie, see COPYING.DJ for details */
  10
  11 #include <libc/stubs.h>
  12 #include <libc/unconst.h>
  13 #include <errno.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16
  17 extern char **environ;
  18
  19 int
  20 unsetenv(const char *name)
  21 {
  22   /* No environment == success */
  23   if (environ == 0)
  24     return 0;
  25
  26   /* Check for the failure conditions */
  27   if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
  28   {
  29     errno = EINVAL;
  30     return -1;
  31   }
  32
  33   /* Let putenv() do the work
  34    * Note that we can just pass name directly as our putenv() treats
  35    * this the same as passing 'name='. */
  36   /* The cast is needed because POSIX specifies putenv() to take a non-const
  37    * parameter.  Our putenv is well-behaved, so this is OK.  */
  38   putenv (unconst (name, char*));
  39
  40   return 0;
  41 }