The IDCMP gives an application convenient access to many types of user input events through the Exec message and port system. Intuition input event messages include mouse and keyboard activity as well as high level events from menus and gadgets. With the IDCMP, you specify the input events you want to know about when you open the window. The input events are specified with one or more of the IDCMP flags in <intuition/intuition.h>. Use the flags with the WA_IDCMP tag for the OpenWindowTagList() (or OpenWindowTags()) function. Or, set the flags in NewWindow.IDCMPFlags for the OpenWindow() function. If any IDCMP flags are set when the window is opened, Intuition automatically creates a message port for you to receive messages about user activity. If NULL is specified for IDCMP flags, no port is created. For more information on receiving messages from Intuition, see the IDCMP sections in the chapter "Intuition Input and Output Methods."