with-exclusive-lock

with-exclusive-lock Macro

Summary

Holds a sharing lock in exclusive mode while evaluating its body, and then unlocks the lock.

Package

Signature

with-exclusive-lock (sharing-lock &optional whostate timeout) &body body => results

Arguments

`sharing-lock`⇩	A sharing lock.
`whostate`⇩	A string or `nil`.
`timeout`⇩	A non-negative real or `nil`.
`body`⇩	The forms to execute.

Values

results

The values returned from evaluating body.

Description

The macro 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.

If whostate is non-nil, it is used as the wait reason while waiting for sharing-lock.

timeout, if non-nil, specifies the time in seconds to wait before timing out. The default value of timeout is nil.

Notes

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.