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Mutual exclusion support
========================

This manual section was written by Moshe Zadka
<moshez@zadka.site.co.il>.
Lock and queue for mutual exclusion.

The `mutex' module defines a class that allows mutual-exclusion via
acquiring and releasing locks. It does not require (or imply) threading
or multi-tasking, though it could be useful for those purposes.

The `mutex' module defines the following class:

`mutex()'
     Create a new (unlocked) mutex.

     A mutex has two pieces of state -- a "locked" bit and a queue.
     When the mutex is not locked, the queue is empty.  Otherwise, the
     queue contains zero or more `(FUNCTION, ARGUMENT)' pairs
     representing functions (or methods) waiting to acquire the lock.
     When the mutex is unlocked while the queue is not empty, the first
     queue entry is removed and its `FUNCTION(ARGUMENT)' pair called,
     implying it now has the lock.

     Of course, no multi-threading is implied - hence the funny
     interface for `lock()', where a function is called once the lock is
     acquired.

Mutex Objects