process-lock-locker

Arguments: lock

This function returns the value of the locker slot of lock, which must be a lock object (see make-process-lock). This value is usually the process holding the lock. If the value in the slot is nil, the lock is free. The following idiom is useful when a process wants to seize a lock but not block if it is already seized:

  (without-interrupts
    (if (process-lock-locker lock)
	    (...) ;; Lock not free
		  ;; do something else.

      (process-lock lock))) ;; Seize the lock. 

See process-lock, process-unlock, with-process-lock and make-process-lock.

See multiprocessing.htm for general information on multiprocessing in Allegro CL and see Process locks for more information on process locks in Allegro CL.

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This page was not revised from the 8.1 page.
Created 2010.1.21.