# Win32 window messaging **URL:** \ **Category:** questions\ **Tags:** winapi\ **Created:** [December 6, 2023, 11:50am UTC](https://clarionhub.com/t/win32-window-messaging/6831 "2023-12-06T11:50:26Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Bostjan\_Laba](https://clarionhub.com/user_avatar/clarionhub.com/bostjan_laba/32/2498_2.png) [@Bostjan\_Laba](https://clarionhub.com/u/Bostjan_Laba)\ **Post date:** [December 6, 2023, 11:50am UTC](https://clarionhub.com/t/win32-window-messaging/6831/1 "2023-12-06T11:50:27Z")
Hi guys, I need to catch some messaging from a windows application made in c++. So the developer of that app (he's no longer developing it) sent me this info: > I sent a string to a hidden window class for the RDF plugin which at the > time maintained backwards compatibility with them I think.. > > If you create a window you will receive a string.. The window has to > present as > > int hWnd = getWindowId("RDFHiddenWindowClass", "RDFHiddenWindow"); > result = sendWindowsStringMessage(hWnd, 0, callsignsString); > > you will then receive a string separated by colons as follows > > windowMessaging.SendReceivingCallsigns(string.Join(":", > e.ReceivingCallsigns)); > > if there are no receivingcallsigns at the time you will get a blank string > as such > > windowMessaging.SendReceivingCallsigns(""); So how do I create such "window" in CW and get that message I want? Thank you all Bostjan ---
**Author:** ![Mike\_Duglas](https://clarionhub.com/user_avatar/clarionhub.com/mike_duglas/32/1061_2.png) [@Mike\_Duglas](https://clarionhub.com/u/Mike_Duglas)\ **Post date:** [December 6, 2023, 4:28pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/2 "2023-12-06T16:28:07Z")
I suspect that getWindowId(“RDFHiddenWindowClass”, “RDFHiddenWindow”) finds the window with class name “RDFHiddenWindowClass” **OR** window text (title) “RDFHiddenWindow”, so you could create plain Clarion (hidden) window and inspect the messages receiving by this window. ---
**Author:** ![Bostjan\_Laba](https://clarionhub.com/user_avatar/clarionhub.com/bostjan_laba/32/2498_2.png) [@Bostjan\_Laba](https://clarionhub.com/u/Bostjan_Laba)\ **Post date:** [December 6, 2023, 5:10pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/3 "2023-12-06T17:10:26Z")
Ok. But how do we do “getMessages” in cw window procedure that Windows are holding a messaging queue for? ---
**Author:** ![AbdullahAkilah](https://clarionhub.com/user_avatar/clarionhub.com/abdullahakilah/32/4818_2.png) [@AbdullahAkilah](https://clarionhub.com/u/AbdullahAkilah)\ **Post date:** [December 6, 2023, 5:16pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/4 "2023-12-06T17:16:10Z")
Subclass it. I’ve always used SetWindowLong API call w/ GWL\_WndProc parameter but newer version of Clarion may have a property to that kind of thing now. Then you need a 2nd procedure to catch all the window messages before the CW runtime does. ---
**Author:** ![Rick\_UpperPark](https://clarionhub.com/user_avatar/clarionhub.com/rick_upperpark/32/346_2.png) [@Rick\_UpperPark](https://clarionhub.com/u/Rick_UpperPark)\ **Post date:** [December 6, 2023, 5:35pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/5 "2023-12-06T17:35:16Z")
Search here on ClarionHub for subclass or prop:wndproc and you’ll find some examples. ---
**Author:** ![Mike\_Duglas](https://clarionhub.com/user_avatar/clarionhub.com/mike_duglas/32/1061_2.png) [@Mike\_Duglas](https://clarionhub.com/u/Mike_Duglas)\ **Post date:** [December 6, 2023, 8:39pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/6 "2023-12-06T20:39:00Z")
Most of my gdiplus examples use the subclassing. ---
**Author:** ![Bostjan\_Laba](https://clarionhub.com/user_avatar/clarionhub.com/bostjan_laba/32/2498_2.png) [@Bostjan\_Laba](https://clarionhub.com/u/Bostjan_Laba)\ **Post date:** [December 6, 2023, 9:13pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/7 "2023-12-06T21:13:04Z")
Great! I will check it out to see if I understand the code. ---
**Author:** ![Mike\_Duglas](https://clarionhub.com/user_avatar/clarionhub.com/mike_duglas/32/1061_2.png) [@Mike\_Duglas](https://clarionhub.com/u/Mike_Duglas)\ **Post date:** [December 6, 2023, 9:30pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/8 "2023-12-06T21:30:55Z")
Just checked: all examples use inherited from TCWnd class. This is a “client” window (prop:ClientHandle). In your case you must use host window (prop:Handle, TWnd class) as only the host window has the title (window text). ---
**Author:** ![Bostjan\_Laba](https://clarionhub.com/user_avatar/clarionhub.com/bostjan_laba/32/2498_2.png) [@Bostjan\_Laba](https://clarionhub.com/u/Bostjan_Laba)\ **Post date:** [December 7, 2023, 4:49pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/9 "2023-12-07T16:49:15Z")
How do I set windowclass to a window? I think I got messaging subclass ready but I don’t know how to set window class. CW seems to set it as ClaWin01000000H\_2 In c++, this is the code: RegisterClass(&this-\>windowClass); ``` this->hiddenWindow = CreateWindow( "RDFHiddenWindowClass", "RDFHiddenWindow", NULL, 0, 0, 0, 0, NULL, NULL, GetModuleHandle(NULL), reinterpret_cast(this) ); ``` Bostjan ---
**Author:** ![Mike\_Duglas](https://clarionhub.com/user_avatar/clarionhub.com/mike_duglas/32/1061_2.png) [@Mike\_Duglas](https://clarionhub.com/u/Mike_Duglas)\ **Post date:** [December 7, 2023, 5:15pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/10 "2023-12-07T17:15:11Z")
Reread my reply, (probably) window title 'RDFHiddenWindow" is enough. ---
**Author:** ![Bostjan\_Laba](https://clarionhub.com/user_avatar/clarionhub.com/bostjan_laba/32/2498_2.png) [@Bostjan\_Laba](https://clarionhub.com/u/Bostjan_Laba)\ **Post date:** [December 7, 2023, 5:21pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/11 "2023-12-07T17:21:13Z")
I did. I changed the working c++ code where I change the class only hoping it would work with Windows name but it does not ☹ And this is the definition prior to CreateWindow in c++: WNDCLASS windowClass = { NULL, HiddenWindow, NULL, NULL, GetModuleHandle(NULL), NULL, NULL, NULL, NULL, “ADFHiddenWindowClass” }; ---
**Author:** ![Mike\_Duglas](https://clarionhub.com/user_avatar/clarionhub.com/mike_duglas/32/1061_2.png) [@Mike\_Duglas](https://clarionhub.com/u/Mike_Duglas)\ **Post date:** [December 7, 2023, 5:57pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/12 "2023-12-07T17:57:13Z")
If you have an access to c++ code, then change getWindowId function to ignore window class. ---
**Author:** ![Bostjan\_Laba](https://clarionhub.com/user_avatar/clarionhub.com/bostjan_laba/32/2498_2.png) [@Bostjan\_Laba](https://clarionhub.com/u/Bostjan_Laba)\ **Post date:** [December 7, 2023, 8:10pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/13 "2023-12-07T20:10:36Z")
I have access to a cpp plugin dll code which is a target for something else, so i can use it for testing I don’t have any code from the app that send messages unfortunately. ---
**Author:** ![Mike\_Duglas](https://clarionhub.com/user_avatar/clarionhub.com/mike_duglas/32/1061_2.png) [@Mike\_Duglas](https://clarionhub.com/u/Mike_Duglas)\ **Post date:** [December 7, 2023, 8:38pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/14 "2023-12-07T20:38:53Z")
Ah I see, then you can play with CreateWindow api. ---
**Author:** ![Bostjan\_Laba](https://clarionhub.com/user_avatar/clarionhub.com/bostjan_laba/32/2498_2.png) [@Bostjan\_Laba](https://clarionhub.com/u/Bostjan_Laba)\ **Post date:** [December 7, 2023, 9:31pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/15 "2023-12-07T21:31:42Z")
Haha, for you this is something to play with, for me it’s hard work with no certain results 🙂 ---
**Author:** ![Mike\_Duglas](https://clarionhub.com/user_avatar/clarionhub.com/mike_duglas/32/1061_2.png) [@Mike\_Duglas](https://clarionhub.com/u/Mike_Duglas)\ **Post date:** [December 7, 2023, 10:02pm UTC](https://clarionhub.com/t/win32-window-messaging/6831/16 "2023-12-07T22:02:10Z")
Yup, hard work must be done by someone else 🙂 ---
**Author:** ![Bostjan\_Laba](https://clarionhub.com/user_avatar/clarionhub.com/bostjan_laba/32/2498_2.png) [@Bostjan\_Laba](https://clarionhub.com/u/Bostjan_Laba)\ **Post date:** [December 8, 2023, 7:56am UTC](https://clarionhub.com/t/win32-window-messaging/6831/17 "2023-12-08T07:56:40Z")
That’s where the money comes in and levels it out 😁😅