Message functions read and process Windows messages in an application's queue. Messages represent a variety of input to a Windows application. A message is a data structure that contains a message identifier and message parameters. The content of the parameters varies with the message type. The following list briefly describes each function:
| Function | Description | |
| CallWindowProc | Passes message information to the specified function. | |
| DispatchMessage | Passes a message to a window function of the specified window. | |
| GetMessage | Retrieves a message from the specified range of messages. |
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| GetMessagePos | Returns the position of the mouse at the time the last message was retrieved. | |
| GetMessageTime | Returns the time at which the last message was retrieved. |
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| InSendMessage | Determines whether the current window function is processing a message passed to it through a call to the SendMessage function. | |
| PeekMessage | Checks the application queue and places the message appropriately. | |
| PostAppMessage | Posts a message to the application. | |
| PostMessage | Places a message in the application queue. | |
| PostQuitMessage | Posts a WM_QUIT message to the application. | |
| ReplyMessage | Replies to a message. | |
| SendMessage | Sends a message to a window or windows. | |
| SetMessageQueue | Creates a new message queue of a different size. | |
| TranslateAccelerator | Processes keyboard accelerators for menu commands. | |
| Function | Description | |
| TranslateMDISysAccel | Processes multiple document interface (MDI) child window command accelerators. | |
| TranslateMessage | Translates virtual key-stroke messages into character messages. | |
| WaitMessage | Yields control to other applications. | |
| WinMain | Serves as an entry point for execution of a Windows application. |