+static int
+unsetenv (const char *name)
+{
+ size_t len;
+ char **ep;
+
+ if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
+ {
+ __set_errno (EINVAL);
+ return -1;
+ }
+
+ len = strlen (name);
+
+ LOCK;
+
+ ep = environ;
+ while (*ep != NULL)
+ if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
+ {
+ /* Found it. Remove this pointer by moving later ones back. */
+ char **dp = ep;
+
+ do
+ dp[0] = dp[1];
+ while (*dp++);
+ /* Continue the loop in case NAME appears again. */
+ }
+ else
+ ++ep;
+
+ UNLOCK;
+
+ return 0;
+}
+