The WM_CREATE message is sent when an application requests that a window be created by calling the CreateWindowEx or CreateWindow function. The window procedure of the new window receives this message after the window is created, but before the window becomes visible. The message is sent before the CreateWindowEx or CreateWindow function returns.
WM_CREATE
lpcs = (LPCREATESTRUCT) lParam; // structure with creation data
If an application processes this message, it should return 0 to continue creation of the window. If the application returns –1, the window is destroyed and the CreateWindowEx or CreateWindow function returns a NULL handle.
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Requires version 1.0 or later.
Header: Declared in winuser.h.
Windows Overview, Window Messages, CreateWindow, CreateWindowEx, CREATESTRUCT, WM_NCCREATE