Function kern_unsetenv

freebsd/kern/kern_environment.c:597–618

* Unset an environment variable string. */

 * Unset an environment variable string.
 */
int
kern_unsetenv(const char *name)
{
	char *cp, *oldenv;
	int i, j;

	KENV_CHECK;

	mtx_lock(&kenv_lock);
	cp = _getenv_dynamic(name, &i);
	if (cp != NULL) {
		oldenv = kenvp[i];
		for (j = i + 1; kenvp[j] != NULL; j++)
			kenvp[i++] = kenvp[j];
		kenvp[i] = NULL;
		mtx_unlock(&kenv_lock);
		zfree(oldenv, M_KENV);
		return (0);
	}
	mtx_unlock(&kenv_lock);
	return (-1);
}

/*
 * Return the internal kenv buffer for the variable name, if it exists.