There are many system-defined messages that are used to control the operations of applications and to provide input and other information for applications to process. The system sends or posts a system-defined message when it communicates with an application. An application also can send or post system-defined messages. Usually, applications use these messages to control the operation of control windows created by using preregistered window classes.
Each system message has a unique message identifier and a corresponding symbolic constant. The symbolic constant, defined in the system header files, states the purpose of the message. For example, the WM_PAINT constant represents the paint message, which requests that a window paint its contents.
The symbolic constants also specify the message category. System-defined messages can belong to several categories; the prefix identifies the type of window that can interpret and process the messages. The following table lists the prefixes and their related message categories:
旼컴컴컴컴컴컴컴쩡컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿛refix 쿘essage category � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿍KM_ 쿙otebook control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿍M_ 쿍utton control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿎BM_ 쿎ombination-box control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿎M_ 쿎ontainer control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿐M_ 쿐ntry-field control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿗M_ 쿗ist-box control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿘LM_ 쿘ultiple-line entry field control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿘M_ 쿘enu control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿞BM_ 쿞croll-bar control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿞LM_ 쿞lider control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿞M_ 쿞tatic control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿟BM_ 쿟itle-bar control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿣M_ 쿣alue set control � 쳐컴컴컴컴컴컴컴탠컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿥M_ 쿒eneral window � 읕컴컴컴컴컴컴컴좔컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴�
General window messages cover a wide range of information and requests, including: