#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 #include "win32/AsyncIO.h" #include "win32/ConsoleHandler.h" // Used to avoid calling abandonRequestWait() if we don't need to. // Protected by sched_mutex. static nat workerWaitingForRequests = 0; void awaitEvent(rtsBool wait) { int ret; do { /* Try to de-queue completed IO requests */ workerWaitingForRequests = 1; ret = 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