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 |
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See also
- Reference
- GetMessage
- PeekMessage
- SendMessageCallback
- WaitMessage
- Conceptual
- Messages and Message Queues