This message is sent during the window creation process.
A pointer to an instance of the class window_create containing the creation parameters for the window.
|0||window creation is continued.|
|1||window creation is terminated and the window is destroyed.|
The message is sent after the window is created but before it becomes visible. It is sent during the execution of the function create_window_extended; and if the window procedure returns 1, a null window handle results.