WM_SYSCOMMAND

This message is sent when the user selects a command from the System menu, when the user selects the minimize or maximize box, or when the screen saver is preparing to blank the screen.

Parameters

WORD wParam

Specifies the type of system command. Windows defines a series of system-command types. The Multimedia extensions add the following system-command type:

SC_SCREENSAVE

Screen saver will be invoked. Return a nonzero value to prevent the screen saver from being invoked; otherwise, pass the message to DefWindowProc.

DWORD lParam

Not used with the SC_SCREENSAVE command.

Return Value

Depends on system-command type.

Comments

Refer to the Windows SDK documentation for a description of the other WM_SYSCOMMAND command types.