Createmediawex: The returned handle is 0, while getlasterror returns 0.

This is really strange. It is clear that createmediawex has failed, but it is followed by getlasterror but returns 0 to say it is successful. Fuck Widnows!

In fact, the window fails to be created because the registered window handler does not process messages sent to the window when several windows such as wm_create are created. In the window handler, defwindowproc () is called () done.

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Haha ~~~~~ I finally called it out to announce the correct answer !!!
It turns out that wndproc has no write pair and does not process some system messages, such as wm_create ~
As long as wndproc is correctly handled, even if defwindowproc is called ~
You can use an export function to enter the main message loop ~
It is worth learning from. When createwindow returns NULL and getlasterror is normal, this problem should be solved!