Scieneer Common Lisp 1.3.9 online documentation

thread:cond-var-wait cond-var lock &optional whostate[Function]

Unlock the lock and wait for the condition variable to be signalled. The lock must be locked before calling and is reacquired upon return.

Note that on some ports, such as Redhat Linux 9.0, a lisp interrupt will not interrupt this wait so the interrupt will not be handled until the condition variable is signaled and the call returns to lisp. It may be more appropriate to use thread:cond-var-timedwait for which lisp interrupts will be handled upon a timeout and return to lisp.