Holds a sharing lock in exclusive mode while evaluating its body, and then unlocks the lock.
A sharing lock.
The status of the process while sharing-lock is locked, as seen in the Process Browser.
The forms to execute
with-exclusive-lock is the same as with-lock, except that sharing-lock must be a "sharing" lock, that is, created with the argument sharing true in make-lock. It waits until sharing-lock is completely free, that is, not locked in a sharing mode and is not locked in exclusive mode by another thread. It then locks sharing-lock in exclusive mode, evaluates body and unlocks sharing-lock.
It is not possible to hold an exclusive lock in the scope of a sharing-lock on the same lock, and trying to do it will cause the process to hang. Whether it is possible to hold an exclusive lock inside an exclusive-lock of the same lock is determined by the recursivep argument in make-lock.
LispWorks User Guide and Reference Manual - 20 Sep 2017