Subject: Assignment mp2

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Unfortunately some (more or less) arbitrary names I picked
seem to have led some people completely off the road and into
the weeds..

I chose the name enqueue() and dequeue() ONLY because that
is what the IBM mainframe OS called the facility you are
emulating.

I should have called them alloc_resource() and free_resource()
though it should be clear that I could have also named them
mickey() and minnie() or sylvester() and tweety() without
affecting what the functions do.

Anyhow it appears that (understandably) my choice of names
has led some people to conclude that enqueue() (sylvester())
should be in the business of adding qeltypes to the qcb's queue
and the dequeue() (tweety()) should be in the business of
removing them.

Unfortunately this conclusion would be ABSOLUTELY WRONG and
will lead to a broken program.

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The reality is that qeltypes should be added (when necessary)
to the qcb's queue in SYLVESTER() before the thread waits on
the condition variable.  qeltypes should be removed from the
qcb's queue ALSO IN SYLVESTER() AFTER a thread wakes up and
realizes that its qeltype is at the head of the queue AND it
is safe for it to access the resource in the requested way
(READ or WRITE).

Any attempt to add or remove qeltypes from the qcbtype's queue
in TWEETY() is FATALLY FLAWED!

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You MUST keep the function names enqueue() and dequeue() but
if it helps you to think of them as sylvester() and tweety()
or alloc_resource() and free_resource() please do so.