function is the opposite of the
function in that it awakens processes that have gone to sleep using
the same condition variable. All the processes sleeping on the given
condition are awakened. If there are no processes sleeping on the
condition, then none are affected.
does not block and may be called by interrupt handlers. It is in fact
the principle means of synchronizing with interrupt events.
parameter is NULL, or there are no processes sleeping on
the call to
is a no-op.