|thread:make-lock &optional name &key type auto-free interruptible||[Function]|
Make a pthread-mutex based lock, returning a lisp thread:lock object encapsulating the pthread-mutex structure. The lock type may be :normal, :recursive, or :error-check. When auto-free is t, the pthread-rwlock structure will be automatically freed when the lisp object is no longer accessible, and reallocated when lisp is restarted. When auto-free is :note, the lock is noted and reallocated upon restart, but is not automatically freed.