Using Timer with non-dialog class

[Lost User]

Timers have nothing to do with dialogs, they operate on any Window. The issue of passing a handle to the window is so that the Windows framework knows where to post the WM_TIMER message that gets raised when the timer expires. If you do not have a Window to connect the timer to then SetWaitableTimer()[^] may be able to help you.

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[Lost User]

aangerma wrote:

so what the hWnd that I need to pass?

The one to your dialog/app window that handles WM_TIMER. As suggested you can get this handle with a FindWindow() specifying the title text. Or you can provide it form the fialog itself, I forget the func, something like GetSafeHwnd() or some such, but there is one for a dialog to get its own handle. Like I say, hunt through the win32 API. You will find what you need there.

============================== Nothing to say.

[jeron1]

In addition to what the others have suggested, maybe message only windows[^] might help.

[Albert Holguin]

No, not thread safe at all.

[Andrew Brock]

Could make it threadsafe with Mutexes[^]

[PJ Arends]

SetTimer[^] has a fourth parameter, an application defined callback function. Use that and set the HWND to NULL.

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[Lost User]

He might find that difficult to specify a class member as a call back function. But yes, it is doable (and one of the reasons I prefer C, OK, you need to be a good programmer, but you can do what you want) :)

============================== Nothing to say.

[Albert Holguin]

Yeah but consider what he wants to do... if he's already using the WinAPI, might as well use the Win timers. Otherwise we'll have to answer a bunch of questions regarding mutexes next [joke ;P ].

[Lost User]

Now why didn't I think of that; good answer.

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[Lost User]

On reflection I decided to test this and it does not work without any windows, as there is nothing to process the WM_TIMER message, which is used by the default handler to invoke the callback routine.

Unrequited desire is character building. OriginalGriff I'm sitting here giving you a standing ovation - Len Goodman

[PJ Arends]

I would be interested to see your test code. I have no problems using a timer callback procedure.

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[PJ Arends]

Looking at it further, the app does not need a window, but if there is no window then the thread needs a message loop.

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[Lost User]

PJ Arends wrote:

the thread needs a message loop.

That's the issue; even with a callback the timer signals by posting a WM_TIMER message.

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[Chuck OToole]

I have a few apps like that (mostly system services) so at the end of "main()" (or whatever you use), stick code like this:

 /\* Fall into the standard message processing loop \*/
 
 static MSG msg;
 while (GetMessage(&msg, NULL, 0, 0))		/\* wait for incoming message \*/
 {
	 TranslateMessage(&msg);		/\* translate it \*/
	 DispatchMessage(&msg);			/\* and let windows dispatch it to WinProc \*/
 }
 return(msg.wParam);				/\* done after "quit" message processed \*/

It doesn't hurt to sit in this loop while the other threads do their job and it allows them to post WM_CLOSE messages to run-down the process if necessary. Other standard messaging things works, including timers.

[aangerma]

Thanks for the reply, can you give me more details how to use it? How can I know which message I Received by msg?

[Chuck OToole]

This is the standard windows message pump, it only causes windows messages to get processed for apps that are not "dialog based". You don't modify this code in any way nor look at the message in that loop. The "dispatch" is done by windows to the proper messsage handler. If you have dialogs, windows does this for you.

[aangerma]

Can you give me exmple how to write a messsage handler , I did it only with the class wizard of mfc, and this is the first time I need to add a timer to a class that don't connected to any window, even if I creat a fictive window like dialog box the SetTimer(...) works only if the dialog is opened by DoModal. thanks