This example can be so commonplace there is certainly a work entitled PostQuitMessage to post WM_Quit. PostMessage constantly increases results when you want to simulate a demand or type in feel of the publish WM_Demand or one of several cello otherwise mouse texts (that is always dicey, incidentally). It holds true since «real» enter in incidents constantly have been in sequences off relevant messages (like keydown/keyup pairs) and your software might get befuddled if you try to processes a different type in message in the middle of one among them sequences. Article increases results whenever simulating type in. Either you must fool around with PostMessage to find up to a good quirk otherwise bug to get rid of unlimited recursion. Such as for example, suppose your WM_SETFOCUS handler (OnSetFocus) establishes the the focus screen isn’t perfect for certain cause and you have to switch the main focus to a different windows.

For folks who call SetFocus from within your OnSetFocus handler, Window immediately sends some other WM_SETFOCUS messagea€»while you’re however control the initial you to definitely!

The result is infinite regress up until their pile blows right up. To avoid that it infelicity, you can article a message so you’re able to yourselfa€»MYWM_SWITCHFOCUSa€»therefore OnSetFocus can also be finish one which just processes the message to switch the focus. This Oppdag her will be one of those advice that’s simpler to see when you look at the behavior than simply on paper. The main thing to remember would be the fact Window would not allow you to SetFocus within this a great WM_SETFOCUS handler. While the SendMessage phone calls the fresh new windows proc truly, it will require a keen HWND. Just how otherwise can it understand and that content proc to mention? But PostMessage contributes the message towards message waiting line, which is regarding the a bond otherwise techniques, maybe not a screen.

// blog post content to myself 
PostMessage(NULL, WM_HI_THERE_Handsome, . ); 

That is, they tries to be sweet by providing for every app a spin to die gracefully, but if a software doesn’t perform over time, ExitWindowsEx kills the brand new software anyway

Should your HWND try NULL, PostMessage posts the content to the present powering thread’s message queue. In practice, this particular feature is not poorly of good use because most minutes we wish to post a message to some other bond (maybe having PostThreadMessage); but you’ll find usually unusual things when it is convenient to share to help you on your own versus a windows. (If you were to think of every, delight tell me.) If you consider you happen to be start to see when to explore SendMessage and PostMessage, there are three a great deal more content-delivering characteristics you need to know in the: SendMessageCallback, SendNotifyMessage, and SendMessageTimeout. These qualities are of help in the heady arena of Win32A® and you will multithreading. In the Win32, if you name SendMessage their bond are banned through to the target bond processes the message. In case your target thread was by itself blocked for the majority of almost every other reason, SendMessage never ever returns. Oops. SendNotifyMessage, SendMessageTimeout, and you will SendMessageCallback had been conceived to your workplace around this situation. SendNotifyMessage works particularly SendMessage in case your target window belongs to (is made from the) the present day thread; it truly does work such as PostMessage in the event the screen is part of a unique thread. SendMessageTimeout is similar, however it enables you to indicate a max for you personally to anticipate others thread to respond. Too bad, thus sad. SendMessageTimeout waits, not permanently. Since you you’ll assume, SendMessageCallback requires a beneficial callback function. It directs the content and production instantaneously; when the message has been processed, Windows calls your setting. SendMessageCallback is available in helpful whenever you’d like to explore PostMessage, but you need to know if content has been managed. View it as the PostMessage having a return receipt. PostMessage, SendMessageTimeout, and you can SendNotifyMessage are a good applicants to make use of if you like in order to aired a message to any or all ideal-level screen that with HWND_TOPMOST once the HWND. It’s a bad idea to make use of HWND_TOPMOST which have SendMessage while the one to dry process results in their application so you’re able to a halt. Shape dos sumong various content-giving qualities. Whew!