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In the queue, when the first process of the queue leaves it, it awakes the next one in line to test its condition.

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This commit is contained in:
Juan Jose Garcia Ripoll 2012-04-15 22:48:33 +02:00
parent abf312520f
commit 323822457c
1 changed files with 8 additions and 7 deletions
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15
src/c/threads/queue.d
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@ -271,13 +271,14 @@ ecl_wait_on(cl_env_ptr env, cl_object (*condition)(cl_env_ptr, cl_object), cl_ob
own_process->process.queue_record = record;
ECL_RPLACD(record, Cnil);
/* 5) We know that we are aborting when we exit this
* function with output == Cnil. In this case, if we
* got a wakeup signal, this could be lost. The safe
* thing to do is to wakeup the first process, because
* first processes are always allowed to check for the
* condition */
if (Null(output) && (firstone == record)) {
/* 5) When this process exits, it may be because it
* aborts (which we know because output == Cnil), or
* because the condition is satisfied. In both cases
* we allow the first in the queue to test again its
* condition. This is needed for objects, such as
* semaphores, where the condition may be satisfied
* more than once. */
if (/*Null(output) &&*/ (firstone == record)) {
ecl_wakeup_waiters(the_env, o, 0, ECL_WAKEUP_ONE);
}