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 WM_SIZE

The WM_SIZE message is sent to a window after its size has changed.

A window receives this message through its WindowProc function.

Syntax

    WM_SIZE
        WPARAM wParam
        LPARAM lParam

Parameters

• wParam
Specifies the type of resizing requested. This parameter can be one of the following values.
• SIZE_MAXHIDE
Message is sent to all pop-up windows when some other window is maximized.
• SIZE_MAXIMIZED
The window has been maximized.
• SIZE_MAXSHOW
Message is sent to all pop-up windows when some other window has been restored to its former size.
• SIZE_MINIMIZED
The window has been minimized.
• SIZE_RESTORED
The window has been resized, but neither the SIZE_MINIMIZED nor SIZE_MAXIMIZED value applies.
• lParam
The low-order word of lParam specifies the new width of the client area. The high-order word of lParam specifies the new height of the client area.

Return Value

If an application processes this message, it should return zero.

Remarks

If the SetScrollPos or MoveWindow function is called for a child window as a result of the WM_SIZE message, the bRedraw or bRepaint parameter should be nonzero to cause the window to be repainted.

Although the width and height of a window are 32-bit values, the lParam parameter contains only the low-order 16 bits of each.

Notification Requirements

• Minimum DLL Version None
• Header Declared in Winuser.h, include Windows.h
• Minimum operating systems Windows 95, Windows NT 3.1

Prototype for Message Handler

void on_size(HWND hwnd, UINT state, int cx, int cy)
{
}

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Notebook exported on Monday, 7 July 2008, 18:56:50 PM Eastern Daylight Time