signal

#signal

##Syntax A signalStatement is:

signal variableReference

##Description A signal statement is used in a concurrent program to wake up a process that is blocked (waiting on a condition variable). The statement can only be used inside a monitor (a special kind of module that handles concurrency). A signal statement operates on a condition variable (the variableReference), which is essentially a queue of sleeping processes. See condition for an example of a signal statement.

##Details A signal statement wakes up one process that is doing a wait on the specified condition queue, if such a process exists. If the condition is deferred (or timeout; see condition), the signaler continues in the monitor, and the awakened process is allowed to continue only when the monitor becomes inactive. A signal to an immediate (non-deferred) condition causes the signaled process to begin running in the monitor immediately. The signaling process waits to re-enter the monitor when the monitor becomes inactive.

##See also condition.html and wait.html. See also monitor.html and fork.html. See also empty.html. See also pause.html.