NativeEventQueue.cpp@ 95894

Last change on this file since 95894 was 95186, checked in by vboxsync, 3 years ago
Main/glue: Updated NativeEventQueue::processEventQueue with more details on darwin and Ctrl-C. [scm] bugref:9898
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 19.7 KB

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1	/* $Id: NativeEventQueue.cpp 95186 2022-06-03 13:40:07Z vboxsync $ */
2	/** @file
3	* MS COM / XPCOM Abstraction Layer:
4	* Main event queue class declaration
5	*/
6
7	/*
8	* Copyright (C) 2006-2022 Oracle Corporation
9	*
10	* This file is part of VirtualBox Open Source Edition (OSE), as
11	* available from http://www.virtualbox.org. This file is free software;
12	* you can redistribute it and/or modify it under the terms of the GNU
13	* General Public License (GPL) as published by the Free Software
14	* Foundation, in version 2 as it comes in the "COPYING" file of the
15	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
16	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
17	*/
18
19	#include "VBox/com/NativeEventQueue.h"
20
21	#include <new> /* For bad_alloc. */
22
23	#ifdef RT_OS_DARWIN
24	# include <CoreFoundation/CFRunLoop.h>
25	#endif
26
27	#if defined(VBOX_WITH_XPCOM) && !defined(RT_OS_DARWIN) && !defined(RT_OS_OS2)
28	# define USE_XPCOM_QUEUE
29	#endif
30
31	#include <iprt/err.h>
32	#include <iprt/time.h>
33	#include <iprt/thread.h>
34	#include <iprt/log.h>
35	#ifdef USE_XPCOM_QUEUE
36	# include <errno.h>
37	#endif
38
39	namespace com
40	{
41
42	// NativeEventQueue class
43	////////////////////////////////////////////////////////////////////////////////
44
45	#ifndef VBOX_WITH_XPCOM
46
47	# define CHECK_THREAD_RET(ret) \
48	do { \
49	AssertMsg(GetCurrentThreadId() == mThreadId, ("Must be on event queue thread!")); \
50	if (GetCurrentThreadId() != mThreadId) \
51	return ret; \
52	} while (0)
53
54	/** Magic LPARAM value for the WM_USER messages that we're posting.
55	* @remarks This magic value is duplicated in
56	* vboxapi/PlatformMSCOM::interruptWaitEvents(). */
57	#define EVENTQUEUE_WIN_LPARAM_MAGIC UINT32_C(0xf241b819)
58
59
60	#else // VBOX_WITH_XPCOM
61
62	# define CHECK_THREAD_RET(ret) \
63	do { \
64	if (!mEventQ) \
65	return ret; \
66	BOOL isOnCurrentThread = FALSE; \
67	mEventQ->IsOnCurrentThread(&isOnCurrentThread); \
68	AssertMsg(isOnCurrentThread, ("Must be on event queue thread!")); \
69	if (!isOnCurrentThread) \
70	return ret; \
71	} while (0)
72
73	#endif // VBOX_WITH_XPCOM
74
75	/** Pointer to the main event queue. */
76	NativeEventQueue *NativeEventQueue::sMainQueue = NULL;
77
78
79	#ifdef VBOX_WITH_XPCOM
80
81	struct MyPLEvent : public PLEvent
82	{
83	MyPLEvent(NativeEvent *e) : event(e) {}
84	NativeEvent *event;
85	};
86
87	/* static */
88	void PR_CALLBACK com::NativeEventQueue::plEventHandler(PLEvent self)
89	{
90	NativeEvent ev = ((MyPLEvent )self)->event;
91	if (ev)
92	ev->handler();
93	else
94	{
95	NativeEventQueue eq = (NativeEventQueue )self->owner;
96	Assert(eq);
97	eq->mInterrupted = true;
98	}
99	return NULL;
100	}
101
102	/* static */
103	void PR_CALLBACK com::NativeEventQueue::plEventDestructor(PLEvent *self)
104	{
105	NativeEvent ev = ((MyPLEvent )self)->event;
106	if (ev)
107	delete ev;
108	delete self;
109	}
110
111	#endif // VBOX_WITH_XPCOM
112
113	/**
114	* Constructs an event queue for the current thread.
115	*
116	* Currently, there can be only one event queue per thread, so if an event
117	* queue for the current thread already exists, this object is simply attached
118	* to the existing event queue.
119	*/
120	NativeEventQueue::NativeEventQueue()
121	{
122	#ifndef VBOX_WITH_XPCOM
123
124	mThreadId = GetCurrentThreadId();
125	// force the system to create the message queue for the current thread
126	MSG msg;
127	PeekMessage(&msg, NULL, WM_USER, WM_USER, PM_NOREMOVE);
128
129	if (!DuplicateHandle(GetCurrentProcess(),
130	GetCurrentThread(),
131	GetCurrentProcess(),
132	&mhThread,
133	0 /dwDesiredAccess/,
134	FALSE /bInheritHandle/,
135	DUPLICATE_SAME_ACCESS))
136	mhThread = INVALID_HANDLE_VALUE;
137
138	#else // VBOX_WITH_XPCOM
139
140	mEQCreated = false;
141	mInterrupted = false;
142
143	// Here we reference the global nsIEventQueueService instance and hold it
144	// until we're destroyed. This is necessary to keep NS_ShutdownXPCOM() away
145	// from calling StopAcceptingEvents() on all event queues upon destruction of
146	// nsIEventQueueService, and makes sense when, for some reason, this happens
147	// before we're able to send a NULL event to stop our event handler thread
148	// when doing unexpected cleanup caused indirectly by NS_ShutdownXPCOM()
149	// that is performing a global cleanup of everything. A good example of such
150	// situation is when NS_ShutdownXPCOM() is called while the VirtualBox component
151	// is still alive (because it is still referenced): eventually, it results in
152	// a VirtualBox::uninit() call from where it is already not possible to post
153	// NULL to the event thread (because it stopped accepting events).
154
155	nsresult rc = NS_GetEventQueueService(getter_AddRefs(mEventQService));
156
157	if (NS_SUCCEEDED(rc))
158	{
159	rc = mEventQService->GetThreadEventQueue(NS_CURRENT_THREAD,
160	getter_AddRefs(mEventQ));
161	if (rc == NS_ERROR_NOT_AVAILABLE)
162	{
163	rc = mEventQService->CreateThreadEventQueue();
164	if (NS_SUCCEEDED(rc))
165	{
166	mEQCreated = true;
167	rc = mEventQService->GetThreadEventQueue(NS_CURRENT_THREAD,
168	getter_AddRefs(mEventQ));
169	}
170	}
171	}
172	AssertComRC(rc);
173
174	#endif // VBOX_WITH_XPCOM
175	}
176
177	NativeEventQueue::~NativeEventQueue()
178	{
179	#ifndef VBOX_WITH_XPCOM
180	if (mhThread != INVALID_HANDLE_VALUE)
181	{
182	CloseHandle(mhThread);
183	mhThread = INVALID_HANDLE_VALUE;
184	}
185	#else // VBOX_WITH_XPCOM
186	// process all pending events before destruction
187	if (mEventQ)
188	{
189	if (mEQCreated)
190	{
191	mEventQ->StopAcceptingEvents();
192	mEventQ->ProcessPendingEvents();
193	mEventQService->DestroyThreadEventQueue();
194	}
195	mEventQ = nsnull;
196	mEventQService = nsnull;
197	}
198	#endif // VBOX_WITH_XPCOM
199	}
200
201	/**
202	* Initializes the main event queue instance.
203	* @returns VBox status code.
204	*
205	* @remarks If you're using the rest of the COM/XPCOM glue library,
206	* com::Initialize() will take care of initializing and uninitializing
207	* the NativeEventQueue class. If you don't call com::Initialize, you must
208	* make sure to call this method on the same thread that did the
209	* XPCOM initialization or we'll end up using the wrong main queue.
210	*/
211	/* static */
212	int NativeEventQueue::init()
213	{
214	Assert(sMainQueue == NULL);
215	Assert(RTThreadIsMain(RTThreadSelf()));
216
217	try
218	{
219	sMainQueue = new NativeEventQueue();
220	AssertPtr(sMainQueue);
221	#ifdef VBOX_WITH_XPCOM
222	/* Check that it actually is the main event queue, i.e. that
223	we're called on the right thread. */
224	nsCOMPtr<nsIEventQueue> q;
225	nsresult rv = NS_GetMainEventQ(getter_AddRefs(q));
226	AssertComRCReturn(rv, VERR_INVALID_POINTER);
227	Assert(q == sMainQueue->mEventQ);
228
229	/* Check that it's a native queue. */
230	PRBool fIsNative = PR_FALSE;
231	rv = sMainQueue->mEventQ->IsQueueNative(&fIsNative);
232	Assert(NS_SUCCEEDED(rv) && fIsNative);
233	#endif // VBOX_WITH_XPCOM
234	}
235	catch (std::bad_alloc &ba)
236	{
237	NOREF(ba);
238	return VERR_NO_MEMORY;
239	}
240
241	return VINF_SUCCESS;
242	}
243
244	/**
245	* Uninitialize the global resources (i.e. the main event queue instance).
246	* @returns VINF_SUCCESS
247	*/
248	/* static */
249	int NativeEventQueue::uninit()
250	{
251	if (sMainQueue)
252	{
253	/* Must process all events to make sure that no NULL event is left
254	* after this point. It would need to modify the state of sMainQueue. */
255	#ifdef RT_OS_DARWIN /* Do not process the native runloop, the toolkit may not be ready for it. */
256	sMainQueue->mEventQ->ProcessPendingEvents();
257	#else
258	sMainQueue->processEventQueue(0);
259	#endif
260	delete sMainQueue;
261	sMainQueue = NULL;
262	}
263	return VINF_SUCCESS;
264	}
265
266	/**
267	* Get main event queue instance.
268	*
269	* Depends on init() being called first.
270	*/
271	/* static */
272	NativeEventQueue* NativeEventQueue::getMainEventQueue()
273	{
274	return sMainQueue;
275	}
276
277	#ifdef VBOX_WITH_XPCOM
278	# ifdef RT_OS_DARWIN
279	/**
280	* Wait for events and process them (Darwin).
281	*
282	* @retval VINF_SUCCESS
283	* @retval VERR_TIMEOUT
284	* @retval VERR_INTERRUPTED
285	*
286	* @param cMsTimeout How long to wait, or RT_INDEFINITE_WAIT.
287	*/
288	static int waitForEventsOnDarwin(RTMSINTERVAL cMsTimeout)
289	{
290	/*
291	* Wait for the requested time, if we get a hit we do a poll to process
292	* any other pending messages.
293	*
294	* Note! About 1.0e10: According to the sources anything above 3.1556952e+9
295	* means indefinite wait and 1.0e10 is what CFRunLoopRun() uses.
296	*/
297	CFTimeInterval rdTimeout = cMsTimeout == RT_INDEFINITE_WAIT ? 1e10 : (double)cMsTimeout / 1000;
298	OSStatus orc = CFRunLoopRunInMode(kCFRunLoopDefaultMode, rdTimeout, true /returnAfterSourceHandled/);
299	if (orc == kCFRunLoopRunHandledSource)
300	{
301	OSStatus orc2 = CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.0, false /returnAfterSourceHandled/);
302	if ( orc2 == kCFRunLoopRunStopped
303	\|\| orc2 == kCFRunLoopRunFinished)
304	orc = orc2;
305	}
306	if ( orc == 0 /???/
307	\|\| orc == kCFRunLoopRunHandledSource)
308	return VINF_SUCCESS;
309	if ( orc == kCFRunLoopRunStopped
310	\|\| orc == kCFRunLoopRunFinished)
311	return VERR_INTERRUPTED;
312	AssertMsg(orc == kCFRunLoopRunTimedOut, ("Unexpected status code from CFRunLoopRunInMode: %#x", orc));
313	return VERR_TIMEOUT;
314	}
315	# else // !RT_OS_DARWIN
316
317	/**
318	* Wait for events (generic XPCOM).
319	*
320	* @retval VINF_SUCCESS
321	* @retval VERR_TIMEOUT
322	* @retval VINF_INTERRUPTED
323	* @retval VERR_INTERNAL_ERROR_4
324	*
325	* @param pQueue The queue to wait on.
326	* @param cMsTimeout How long to wait, or RT_INDEFINITE_WAIT.
327	*/
328	static int waitForEventsOnXPCOM(nsIEventQueue *pQueue, RTMSINTERVAL cMsTimeout)
329	{
330	int fd = pQueue->GetEventQueueSelectFD();
331	fd_set fdsetR;
332	FD_ZERO(&fdsetR);
333	FD_SET(fd, &fdsetR);
334
335	fd_set fdsetE = fdsetR;
336
337	struct timeval tv = {0,0};
338	struct timeval *ptv;
339	if (cMsTimeout == RT_INDEFINITE_WAIT)
340	ptv = NULL;
341	else
342	{
343	tv.tv_sec = cMsTimeout / 1000;
344	tv.tv_usec = (cMsTimeout % 1000) * 1000;
345	ptv = &tv;
346	}
347
348	int rc = select(fd + 1, &fdsetR, NULL, &fdsetE, ptv);
349	if (rc > 0)
350	rc = VINF_SUCCESS;
351	else if (rc == 0)
352	rc = VERR_TIMEOUT;
353	else if (errno == EINTR)
354	rc = VINF_INTERRUPTED;
355	else
356	{
357	static uint32_t s_ErrorCount = 0;
358	if (s_ErrorCount < 500)
359	{
360	LogRel(("waitForEventsOnXPCOM rc=%d errno=%d\n", rc, errno));
361	++s_ErrorCount;
362	}
363
364	AssertMsgFailed(("rc=%d errno=%d\n", rc, errno));
365	rc = VERR_INTERNAL_ERROR_4;
366	}
367	return rc;
368	}
369
370	# endif // !RT_OS_DARWIN
371	#endif // VBOX_WITH_XPCOM
372
373	#ifndef VBOX_WITH_XPCOM
374
375	/**
376	* Dispatch a message on Windows.
377	*
378	* This will pick out our events and handle them specially.
379	*
380	* @returns @a rc or VERR_INTERRUPTED (WM_QUIT or NULL msg).
381	* @param pMsg The message to dispatch.
382	* @param rc The current status code.
383	*/
384	/static/
385	int NativeEventQueue::dispatchMessageOnWindows(MSG const *pMsg, int rc)
386	{
387	/*
388	* Check for and dispatch our events.
389	*/
390	if ( pMsg->hwnd == NULL
391	&& pMsg->message == WM_USER)
392	{
393	if (pMsg->lParam == EVENTQUEUE_WIN_LPARAM_MAGIC)
394	{
395	NativeEvent pEvent = (NativeEvent )pMsg->wParam;
396	if (pEvent)
397	{
398	pEvent->handler();
399	delete pEvent;
400	}
401	else
402	rc = VERR_INTERRUPTED;
403	return rc;
404	}
405	AssertMsgFailed(("lParam=%p wParam=%p\n", pMsg->lParam, pMsg->wParam));
406	}
407
408	/*
409	* Check for the quit message and dispatch the message the normal way.
410	*/
411	if (pMsg->message == WM_QUIT)
412	rc = VERR_INTERRUPTED;
413	TranslateMessage(pMsg);
414	DispatchMessage(pMsg);
415
416	return rc;
417	}
418
419
420	/**
421	* Process pending events (Windows).
422	*
423	* @retval VINF_SUCCESS
424	* @retval VERR_TIMEOUT
425	* @retval VERR_INTERRUPTED.
426	*/
427	static int processPendingEvents(void)
428	{
429	int rc = VERR_TIMEOUT;
430	MSG Msg;
431	if (PeekMessage(&Msg, NULL /hWnd/, 0 /wMsgFilterMin/, 0 /wMsgFilterMax/, PM_REMOVE))
432	{
433	rc = VINF_SUCCESS;
434	do
435	rc = NativeEventQueue::dispatchMessageOnWindows(&Msg, rc);
436	while (PeekMessage(&Msg, NULL /hWnd/, 0 /wMsgFilterMin/, 0 /wMsgFilterMax/, PM_REMOVE));
437	}
438	return rc;
439	}
440
441	#else // VBOX_WITH_XPCOM
442
443	/**
444	* Process pending XPCOM events.
445	* @param pQueue The queue to process events on.
446	* @retval VINF_SUCCESS
447	* @retval VERR_TIMEOUT
448	* @retval VERR_INTERRUPTED (darwin only)
449	* @retval VERR_INTERNAL_ERROR_2
450	*/
451	static int processPendingEvents(nsIEventQueue *pQueue)
452	{
453	/* ProcessPendingEvents doesn't report back what it did, so check here. */
454	PRBool fHasEvents = PR_FALSE;
455	nsresult hr = pQueue->PendingEvents(&fHasEvents);
456	if (NS_FAILED(hr))
457	return VERR_INTERNAL_ERROR_2;
458
459	/* Process pending events. */
460	int rc = VINF_SUCCESS;
461	if (fHasEvents)
462	pQueue->ProcessPendingEvents();
463	else
464	rc = VERR_TIMEOUT;
465
466	# ifdef RT_OS_DARWIN
467	/* Process pending native events. */
468	int rc2 = waitForEventsOnDarwin(0);
469	if (rc == VERR_TIMEOUT \|\| rc2 == VERR_INTERRUPTED)
470	rc = rc2;
471	# endif
472
473	return rc;
474	}
475
476	#endif // VBOX_WITH_XPCOM
477
478	/**
479	* Process events pending on this event queue, and wait up to given timeout, if
480	* nothing is available.
481	*
482	* Must be called on same thread this event queue was created on.
483	*
484	* @param cMsTimeout The timeout specified as milliseconds. Use
485	* RT_INDEFINITE_WAIT to wait till an event is posted on the
486	* queue.
487	*
488	* @returns VBox status code
489	* @retval VINF_SUCCESS if one or more messages was processed.
490	* @retval VERR_TIMEOUT if cMsTimeout expired.
491	* @retval VERR_INVALID_CONTEXT if called on the wrong thread.
492	* @retval VERR_INTERRUPTED if interruptEventQueueProcessing was called.
493	* On Windows will also be returned when WM_QUIT is encountered.
494	* On Darwin this may also be returned when the native queue is
495	* stopped or destroyed/finished.
496	* @retval VINF_INTERRUPTED if the native system call was interrupted by a
497	* an asynchronous event delivery (signal) or just felt like returning
498	* out of bounds. On darwin it will also be returned if the queue is
499	* stopped.
500	*
501	* @note On darwin this function will not return when the thread receives a
502	* signal, it will just resume the wait.
503	*/
504	int NativeEventQueue::processEventQueue(RTMSINTERVAL cMsTimeout)
505	{
506	int rc;
507	CHECK_THREAD_RET(VERR_INVALID_CONTEXT);
508
509	#ifdef VBOX_WITH_XPCOM
510	/*
511	* Process pending events, if none are available and we're not in a
512	* poll call, wait for some to appear. (We have to be a little bit
513	* careful after waiting for the events since Darwin will process
514	* them as part of the wait, while the XPCOM case will not.)
515	*
516	* Note! Unfortunately, WaitForEvent isn't interruptible with Ctrl-C,
517	* while select() is. So we cannot use it for indefinite waits.
518	*/
519	rc = processPendingEvents(mEventQ);
520	if ( rc == VERR_TIMEOUT
521	&& cMsTimeout > 0)
522	{
523	# ifdef RT_OS_DARWIN
524	/** @todo check how Ctrl-C works on Darwin.
525	* Update: It doesn't work. MACH_RCV_INTERRUPT could perhaps be returned
526	* to __CFRunLoopServiceMachPort, but neither it nor __CFRunLoopRun
527	* has any way of expressing it via their return values. So, if
528	* Ctrl-C handling is important, signal needs to be handled on
529	* a different thread or something. */
530	rc = waitForEventsOnDarwin(cMsTimeout);
531	# else // !RT_OS_DARWIN
532	rc = waitForEventsOnXPCOM(mEventQ, cMsTimeout);
533	# endif // !RT_OS_DARWIN
534	if ( RT_SUCCESS(rc)
535	\|\| rc == VERR_TIMEOUT)
536	{
537	int rc2 = processPendingEvents(mEventQ);
538	/* If the wait was successful don't fail the whole operation. */
539	if (RT_FAILURE(rc) && RT_FAILURE(rc2))
540	rc = rc2;
541	}
542	}
543
544	if ( ( RT_SUCCESS(rc)
545	\|\| rc == VERR_INTERRUPTED
546	\|\| rc == VERR_TIMEOUT)
547	&& mInterrupted)
548	{
549	mInterrupted = false;
550	rc = VERR_INTERRUPTED;
551	}
552
553	#else // !VBOX_WITH_XPCOM
554	if (cMsTimeout == RT_INDEFINITE_WAIT)
555	{
556	BOOL fRet = 0; /* Shut up MSC */
557	MSG Msg;
558	rc = VINF_SUCCESS;
559	while ( rc != VERR_INTERRUPTED
560	&& (fRet = GetMessage(&Msg, NULL /hWnd/, WM_USER, WM_USER))
561	&& fRet != -1)
562	rc = NativeEventQueue::dispatchMessageOnWindows(&Msg, rc);
563	if (fRet == 0)
564	rc = VERR_INTERRUPTED;
565	else if (fRet == -1)
566	rc = RTErrConvertFromWin32(GetLastError());
567	}
568	else
569	{
570	rc = processPendingEvents();
571	if ( rc == VERR_TIMEOUT
572	&& cMsTimeout != 0)
573	{
574	DWORD rcW = MsgWaitForMultipleObjects(1,
575	&mhThread,
576	TRUE /fWaitAll/,
577	cMsTimeout,
578	QS_ALLINPUT);
579	AssertMsgReturn(rcW == WAIT_TIMEOUT \|\| rcW == WAIT_OBJECT_0,
580	("%d\n", rcW),
581	VERR_INTERNAL_ERROR_4);
582	rc = processPendingEvents();
583	}
584	}
585	#endif // !VBOX_WITH_XPCOM
586
587	Assert(rc != VERR_TIMEOUT \|\| cMsTimeout != RT_INDEFINITE_WAIT);
588	return rc;
589	}
590
591	/**
592	* Interrupt thread waiting on event queue processing.
593	*
594	* Can be called on any thread.
595	*
596	* @returns VBox status code.
597	*/
598	int NativeEventQueue::interruptEventQueueProcessing()
599	{
600	/* Send a NULL event. This event will be picked up and handled specially
601	* both for XPCOM and Windows. It is the responsibility of the caller to
602	* take care of not running the loop again in a way which will hang. */
603	postEvent(NULL);
604	return VINF_SUCCESS;
605	}
606
607	/**
608	* Posts an event to this event loop asynchronously.
609	*
610	* @param pEvent the event to post, must be allocated using \|new\|
611	* @return @c TRUE if successful and false otherwise
612	*/
613	BOOL NativeEventQueue::postEvent(NativeEvent *pEvent)
614	{
615	#ifndef VBOX_WITH_XPCOM
616	/* Note! The event == NULL case is duplicated in vboxapi/PlatformMSCOM::interruptWaitEvents(). */
617	BOOL fRc = PostThreadMessage(mThreadId, WM_USER, (WPARAM)pEvent, EVENTQUEUE_WIN_LPARAM_MAGIC);
618	if (!fRc)
619	{
620	static int s_cBitchedAboutFullNativeEventQueue = 0;
621	if ( GetLastError() == ERROR_NOT_ENOUGH_QUOTA
622	&& s_cBitchedAboutFullNativeEventQueue < 10)
623	LogRel(("Warning: Asynchronous event queue (%p, thread %RI32) full, event (%p) not delivered (%d/10)\n",
624	this, mThreadId, pEvent, ++s_cBitchedAboutFullNativeEventQueue));
625	else
626	AssertFailed();
627	}
628	return fRc;
629	#else // VBOX_WITH_XPCOM
630	if (!mEventQ)
631	return FALSE;
632
633	try
634	{
635	MyPLEvent *pMyEvent = new MyPLEvent(pEvent);
636	mEventQ->InitEvent(pMyEvent, this, com::NativeEventQueue::plEventHandler,
637	com::NativeEventQueue::plEventDestructor);
638	HRESULT rc = mEventQ->PostEvent(pMyEvent);
639	return NS_SUCCEEDED(rc);
640	}
641	catch (std::bad_alloc &ba)
642	{
643	AssertMsgFailed(("Out of memory while allocating memory for event=%p: %s\n",
644	pEvent, ba.what()));
645	}
646
647	return FALSE;
648	#endif // VBOX_WITH_XPCOM
649	}
650
651	/**
652	* Get select()'able selector for this event queue.
653	* This will return -1 on platforms and queue variants not supporting such
654	* functionality.
655	*/
656	int NativeEventQueue::getSelectFD()
657	{
658	#ifdef VBOX_WITH_XPCOM
659	return mEventQ->GetEventQueueSelectFD();
660	#else
661	return -1;
662	#endif
663	}
664
665	}
666	/* namespace com */

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source: vbox/trunk/src/VBox/Main/glue/NativeEventQueue.cpp@ 95894

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