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 WindowProc

The WindowProc function is an application-defined function that processes messages sent to a window. The WNDPROC type defines a pointer to this callback function. WindowProc is a placeholder for the application-defined function name.

Syntax

    LRESULT CALLBACK WindowProc(  
        HWND hwnd,
        UINT uMsg,
        WPARAM wParam,
        LPARAM lParam
    );

Parameters

• hwnd
  [in] Handle to the window.
• uMsg
  [in] Specifies the message.
• wParam
  [in] Specifies additional message information. The contents of this parameter depend on the value of the uMsg parameter.
• lParam
  [in] Specifies additional message information. The contents of this parameter depend on the value of the uMsg parameter.

Return Value

The return value is the result of the message processing and depends on the message sent.

Function Information

Header Declared in Winuser.h, include Windows.h

• Import library None
• Minimum operating systems Windows 95, Windows NT 3.1

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