DispatchMessageW function (winuser.h)

Article
02/22/2024

Dispatches a message to a window procedure. It is typically used to dispatch a message retrieved by the GetMessage function.

Syntax

LRESULT DispatchMessageW(
  [in] const MSG *lpMsg
);

Parameters

[in] lpMsg

Type: const MSG*

A pointer to a structure that contains the message.

Return value

Type: LRESULT

The return value specifies the value returned by the window procedure. Although its meaning depends on the message being dispatched, the return value generally is ignored.

Remarks

The MSG structure must contain valid message values. If the lpmsg parameter points to a WM_TIMER message and the lParam parameter of the WM_TIMER message is not NULL, lParam points to a function that is called instead of the window procedure.

Note that the application is responsible for retrieving and dispatching input messages to the dialog box. Most applications use the main message loop for this. However, to permit the user to move to and to select controls by using the keyboard, the application must call IsDialogMessage. For more information, see Dialog Box Keyboard Interface.

Examples

For an example, see Creating a Message Loop.

Note

The winuser.h header defines DispatchMessage as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	winuser.h (include Windows.h)
Library	User32.lib
DLL	User32.dll
API set	ext-ms-win-ntuser-message-l1-1-0 (introduced in Windows 8)