Crit.pl is one thread program. It may be called simultaneously, as you mentioned I need to serialize access.

Example:
Call1 to crit.pl - running 
Call2 - waiting for lock
Call3 - waiting for lock
..

[download]

In this case call2 should execute after call1 completes, followed by call3.

Can you please explain more on how shared variable can be used for this?

In reply to Re^2: Critical section FCFS by Anonymous Monk
in thread Critical section FCFS by aj7700

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