dequeue_exn t raises if
length t = 0. The idiom for dequeueing a single element
if length t > 0 then dequeue_exn t else ...
The idiom for dequeueing until empty is:
while length t > 0 do let a = dequeue_exn t in ... done
These idioms work in the presence of threads because OCaml will not context switch
length t > 0 test and the call to
dequeue_exn. Also, if one has only
a single thread calling
dequeue_exn, then the idiom is obviously OK even in the
presence of a context switch.
The queue maintains an internal pool of unused elements, which are used by
and returned to the pool by
enqueue creates a new element if the
pool is empty. Nothing shrinks the pool automatically. One can call
clear_internal_pool to clear the pool, so that all unused elements will be reclaimed
by the garbage collector.