DefMDIChildProc function user32
Provides default processing for any window message that the window procedure of a multiple-document interface (MDI) child window does not process. A window message not processed by the window procedure must be passed to the DefMDIChildProc function, not to the DefWindowProc function.
LRESULT DefMDIChildProcW(
HWND hWnd,
UINT uMsg,
WPARAM wParam,
LPARAM lParam
);
Implementation
int DefMDIChildProc(int hWnd, int uMsg, int wParam, int lParam) =>
_DefMDIChildProc(hWnd, uMsg, wParam, lParam);