Crash immediately after calling a function of dll successfully

Python Help
1

I can make sure this dll is accurate.
Why does the program crash immediately after successfully calling the function APlayer_Create and prompts: The process has ended and the exit code is -1073740771 (0xC000041D)

        aplayerCaller = ctypes.CDLL(application_path + '\APlayerCaller.dll')

        global CALLBACK,Callback_cfun,Callback_address,aaa
        aaa = self.OnMessage_Callback
        CALLBACK = ctypes.CFUNCTYPE(None, ctypes.c_int,ctypes.c_int,ctypes.c_int)
        Callback_cfun =CALLBACK(aaa)
        Callback_address = ctypes.cast(Callback_cfun,ctypes.c_void_p).value
        #aa = ctypes.cast(OnMessage_Callback_cfun, ctypes.c_void_p).value
        print(CALLBACK,Callback_cfun,Callback_address)
        aplayer = aplayerCaller.APlayer_Create(winID, 0, 0, self.width(), self.height(),
                                                   Callback_address, 0, 0, 0, 0, 0, 0, 0)

    def OnMessage_Callback(self,a2, a3,a4):
        qs = QMessageBox.information(self,'zzz','test',)
        print(f'a1={self},a2={a2},a3={a3},a4={a4}')

a2, a3, a4, I can get the data normally and print it out once, but then it crashes immediately and prompts an error message (-1073740771 (0xC000041D)) in pycharm. If it is normal, it should keep outputting a2, a3, a4 until my mouse stop moving

2

Beware that '\APlayerCaller.dll' is not valid in python 3.12 you need to double the \ to be \\.
Does the code wrk outside of PyCharm?

You can use the Win32 FormatError function to turn the code into text.
See FormatMessage function (winbase.h) - Win32 apps | Microsoft Learn
You often can get help on windows errors code with a web search like windows error I found that 0xC000041d.
I did that and it seems that code is I found that 0xC000041d = STATUS_FATAL_USER_CALLBACK_EXCEPTION

3

I can confirm that the dll can run normally in my code. As long as I change the callback function ‘Callback_address’ to 0, the code can run normally. Once changed to ‘Callback_address’, after calling ‘OnMessage_Callback’ and printing, the program It exited abnormally. This OnMessage_Callback should have been called multiple times in succession, but it was only called once and crashed immediately.

4

You will need to figure out what is wrong with your callback function.

5

Changing CDLL to WinDLL solved my problem!

thank you very much!

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