The function condition-variable-signal wakes exactly one thread waiting on the condition variable condvar. In most uses of condition variables, the caller should be holding the lock that the waiter used when calling condition-variable-wait for this condition variable, but this is not required. When using the lock, you may prefer to use lock-and-condition-variable-signal.
The return value signaledp is non-nil if a process was signaled, or nil if there were no processes waiting.
condition-variable-wait
make-condition-variable
lock-and-condition-variable-signal
lock-and-condition-variable-wait
simple-lock-and-condition-variable-wait
lock-and-condition-variable-broadcast
condition-variable-broadcast
LispWorks User Guide and Reference Manual - 13 Feb 2015