$12.$ Consider the following code. Note the first line in the main function that says $"|/$ what should X be$?"$ sem$\_$t s;void $*$child $($void $*$arg$)$ i printf $("$child

$")$;sem$\_$post $($&s$)$; $//$ signal here: child is done return NULL;int main $($int argc, char targvil$)$ tsem$\_$init $($&s$,0,$ X$)$; $//$ what should X be$?$ printf $("$parent: begin

$")$; pthread$\_$t c;Pthread$\_$create $($&c$,$ NULL, child, NULL$)$ ; sem$\_$wait $($&s$)$; $//$ wait here for chila printf $("$parent: end

$")$ ; return $0$;i$)$ What considerations go into determining the appropriate initial value of a semaphore?