1#include <stdlib.h>
 2#include <string.h>
 3#include <errno.h>
 4#include <unistd.h>
 5
 6static void dummy(char *old, char *new) {}
 7weak_alias(dummy, __env_rm_add);
 8
 9int 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}