slist_remove_first
void *slist_remove_first (slist *);
slist_remove_first(&sl);
slist_remove_first(&sl);
slist_remove_first(&sl);
slist_remove_first(l);
slist_remove_first(&sl);
slist_remove_first(l);
while ((call = slist_remove_first(&_this->call_list)) != NULL)
session_id = (uintptr_t)slist_remove_first(
session_id = (intptr_t)slist_remove_first(