This situation is really so commonplace you will find a features titled PostQuitMessage in order to blog post WM_Stop. PostMessage constantly works better if you want to help you simulate a demand or enter in feel from the publish WM_Command or one of the cello or mouse messages (which is always dicey, incidentally). This is true because “real” enter in occurrences usually can be found in sequences out of associated texts (such keydown/keyup pairs) along with your app might get befuddled if you try in order to techniques a special type in content in one among them sequences. Blog post works better when simulating input. Often you must use PostMessage to locate as much as an excellent quirk otherwise bug to prevent infinite recursion. Instance, imagine your own WM_SETFOCUS handler (OnSetFocus) decides the this new interest screen isn’t perfect for some cause along with adjust the main focus to another windows.
For many who phone call SetFocus from inside your own OnSetFocus handler, Window instantly directs several other WM_SETFOCUS messagea€”while you are nonetheless operating the first you to!
The result is infinite regress up to your own bunch blows up. To eliminate so it infelicity, you could blog post a contact so you can yourselfa€”MYWM_SWITCHFOCUSa€”thus OnSetFocus normally find yourself before you can process the message to change the main focus. This might be one of those instances that is simpler to see from inside the practice than just in writing. It is important to consider would be the fact Window wouldn’t enable you to SetFocus within an effective WM_SETFOCUS handler. Because the SendMessage phone calls the window proc myself, it will require a keen HWND. Exactly how else will it understand and that message proc to mention? But PostMessage adds the message towards the content queue, that is with the a thread otherwise process, maybe not a screen.
// blog post message in order to myselfPostMessage(NULL, WM_HI_THERE_Good looking, . );
Which is, it tries to end up being nice by providing for every single software a chance in order to perish gracefully, but if an application does not respond with time, ExitWindowsEx eliminates the latest app anyway
In case the HWND is actually NULL, PostMessage posts the message to the present running thread’s message queue. In practice, this feature actually poorly of use since most times we want to post a contact to some other thread (maybe that have PostThreadMessage); but you’ll find always rare facts if it is easier to create so you’re able to oneself in place of a windows. (If you think of any, excite tell me.) In the event you thought you will be begin to discover when to explore SendMessage and you will PostMessage, you can find three significantly more content-delivering characteristics you must know on: SendMessageCallback, SendNotifyMessage, and SendMessageTimeout. These types of attributes are of help in the heady arena of Win32A® and you will multithreading. Within the Win32, if you name SendMessage your own thread was blocked before the address thread process the content. If for example the target bond are by itself banned for almost all other need, SendMessage never production. Oops. SendNotifyMessage, SendMessageTimeout, and you can SendMessageCallback was designed be effective with this situation. SendNotifyMessage performs such SendMessage whether your address screen falls under (was created by the) the current https://gorgeousbrides.net/no/russiske-bruder/ thread; it really works such as for instance PostMessage should your windows belongs to a different sort of bond. SendMessageTimeout is comparable, but it allows you to establish a maximum time for you await the other bond to respond. Also crappy, thus sad. SendMessageTimeout waits, not forever. As you you’ll suppose, SendMessageCallback requires an excellent callback means. It directs the content and you may output quickly; in the event the message could have been processed, Screen phone calls their form. SendMessageCallback comes in convenient when you would want to play with PostMessage, nevertheless wish to know when the content has been treated. Look at it just like the PostMessage which have a return acknowledgment. PostMessage, SendMessageTimeout, and you will SendNotifyMessage are all good applicants to utilize if you would like in order to broadcast a message to any or all finest-level screen by using HWND_TOPMOST because HWND. It’s a bad idea to use HWND_TOPMOST which have SendMessage once the one to deceased techniques brings your own software so you’re able to a stop. Figure dos sumong the many message-giving attributes. Whew!