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SendAsyncProc callback function

An application-defined callback function used with the SendMessageCallback function. The system passes the message to the callback function after passing the message to the destination window procedure. The SENDASYNCPROC type defines a pointer to this callback function. SendAsyncProc is a placeholder for the application-defined function name.

Syntax


VOID CALLBACK SendAsyncProc(
  _In_  HWND hwnd,
  _In_  UINT uMsg,
  _In_  ULONG_PTR dwData,
  _In_  LRESULT lResult
);

Parameters

hwnd [in]

Type: HWND

A handle to the window whose window procedure received the message.

If the SendMessageCallback function was called with its hwnd parameter set to HWND_BROADCAST, the system calls the SendAsyncProc function once for each top-level window.

uMsg [in]

Type: UINT

The message.

dwData [in]

Type: ULONG_PTR

An application-defined value sent from the SendMessageCallback function.

lResult [in]

Type: LRESULT

The result of the message processing. This value depends on the message.

Return value

This callback function does not return a value.

Remarks

You install a SendAsyncProc application-defined callback function by passing a SENDASYNCPROC pointer to the SendMessageCallback function.

The callback function is only called when the thread that called SendMessageCallback calls GetMessage, PeekMessage, or WaitMessage.

Requirements

Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]

Header

Winuser.h (include Windows.h)

See also

Reference
GetMessage
PeekMessage
SendMessageCallback
WaitMessage
Conceptual
Messages and Message Queues

 

 

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