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#if !defined(THREADED_RTS) /* to the end */
/*
* Wait/check for external events. Periodically, the
* Scheduler checks for the completion of external operations,
* like the expiration of timers, completion of I/O requests
* issued by Haskell threads.
*
* If the Scheduler is otherwise out of work, it'll block
* herein waiting for external events to occur.
*
* This file mirrors the select()-based functionality
* for POSIX / Unix platforms in rts/Select.c, but for
* Win32.
*
*/
#include "Rts.h"
#include "Schedule.h"
#include "AwaitEvent.h"
#include <windows.h>
#include "win32/AsyncIO.h"
#include "win32/ConsoleHandler.h"
// Used to avoid calling abandonRequestWait() if we don't need to.
// Protected by sched_mutex.
static uint32_t workerWaitingForRequests = 0;
void
awaitEvent(bool wait)
{
do {
/* Try to de-queue completed IO requests
*/
workerWaitingForRequests = 1;
awaitRequests(wait);
workerWaitingForRequests = 0;
// If a signal was raised, we need to service it
// XXX the scheduler loop really should be calling
// startSignalHandlers(), but this is the way that posix/Select.c
// does it and I'm feeling too paranoid to refactor it today --SDM
if (stg_pending_events != 0) {
startSignalHandlers(&MainCapability);
return;
}
// The return value from awaitRequests() is a red herring: ignore
// it. Return to the scheduler if !wait, or
//
// - we were interrupted
// - the run-queue is now non- empty
} while (wait
&& sched_state == SCHED_RUNNING
&& emptyRunQueue(&MainCapability)
);
}
#endif
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