NAME

signal, signaln − signal a semaphore

SYNOPSIS

int signal(sem)
int signaln(sem, count)
int sem;
int count;

DESCRIPTION

In either form, signal signals semaphore sem and returns SYSERR if the semaphore does not exist, OK otherwise.  The form signal increments the count of sem by 1 and frees the next process if any are waiting.  The form signaln increments the semaphore by count and frees up to count processes if that many are waiting.  Note that signaln(sem, x) is equivalent to executing signal(sem) x times. 

SEE ALSO

scount(2), screate(2), sdelete(2), sreset(2), wait(2)

December 01, 1986  —  Xinu Programmer’s Manual