libc-top-half/musl/src/env/unsetenv.c

   1 #include <stdlib.h>
   2 #include <string.h>
   3 #include <errno.h>
   4 #include <unistd.h>
   5
   6 static void dummy(char *old, char *new) {}
   7 weak_alias(dummy, __env_rm_add);
   8
   9 int unsetenv(const char *name)
  10 {
  11         size_t l = __strchrnul(name, '=') - name;
  12         if (!l || name[l]) {
  13                 errno = EINVAL;
  14                 return -1;
  15         }
  16         if (__environ) {
  17                 char **e = __environ, **eo = e;
  18                 for (; *e; e++)
  19                         if (!strncmp(name, *e, l) && l[*e] == '=')
  20                                 __env_rm_add(*e, 0);
  21                         else if (eo != e)
  22                                 *eo++ = *e;
  23                         else
  24                                 eo++;
  25                 if (eo != e) *eo = 0;
  26         }
  27         return 0;
  28 }