WM_LBUTTONUP message (Windows)

Applies to: desktop apps only

Posted when the user releases the left mouse button while the cursor is in the client area of a window. If the mouse is not captured, the message is posted to the window beneath the cursor. Otherwise, the message is posted to the window that has captured the mouse.

A window receives this message through its WindowProc function.

#define WM_LBUTTONUP                    0x0202

Parameters

wParam

Indicates whether various virtual keys are down. This parameter can be one or more of the following values.

Value	Meaning
MK_CONTROL 0x0008	The CTRL key is down.
MK_MBUTTON 0x0010	The middle mouse button is down.
MK_RBUTTON 0x0002	The right mouse button is down.
MK_SHIFT 0x0004	The SHIFT key is down.
MK_XBUTTON1 0x0020	The first X button is down.
MK_XBUTTON2 0x0040	The second X button is down.

 

lParam

The low-order word specifies the x-coordinate of the cursor. The coordinate is relative to the upper-left corner of the client area.

The high-order word specifies the y-coordinate of the cursor. The coordinate is relative to the upper-left corner of the client area.

Return value

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

Remarks

Use the following code to obtain the horizontal and vertical position:

xPos = GET_X_LPARAM(lParam); 
yPos = GET_Y_LPARAM(lParam); 

You can also use the MAKEPOINTS macro to convert the lParam parameter to a POINTS structure.

Requirements

See also

Reference

GET_X_LPARAM

GET_Y_LPARAM

GetCapture

SetCapture

WM_LBUTTONDBLCLK

WM_LBUTTONDOWN

Conceptual

Mouse Input

Other Resources

MAKEPOINTS

POINTS

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Build date: 3/6/2012