WM_NCMOUSEMOVE message

Posted to a window when the cursor is moved within the nonclient area of the window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted.

A window receives this message through its WindowProc function.

#define WM_NCMOUSEMOVE                  0x00A0

Parameters

wParam

The hit-test value returned by the DefWindowProc function as a result of processing the WM_NCHITTEST message. For a list of hit-test values, see WM_NCHITTEST.

lParam

A POINTS structure that contains the x- and y-coordinates of the cursor. The coordinates are relative to the upper-left corner of the screen.

Return value

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

Remarks

If it is appropriate to do so, the system sends the WM_SYSCOMMAND message to the window.

You can also use the GET_X_LPARAM and GET_Y_LPARAM macros to extract the values of the x- and y- coordinates from lParam.

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

Important

Do not use the LOWORD or HIWORD macros to extract the x- and y- coordinates of the cursor position because these macros return incorrect results on systems with multiple monitors. Systems with multiple monitors can have negative x- and y- coordinates, and LOWORD and HIWORD treat the coordinates as unsigned quantities.

Requirements

Requirement Value
Minimum supported client
Windows 2000 Professional [desktop apps only]
Minimum supported server
Windows 2000 Server [desktop apps only]
Header
Winuser.h (include Windowsx.h)

See also

Reference

DefWindowProc

GET_X_LPARAM

GET_Y_LPARAM

WM_NCHITTEST

WM_SYSCOMMAND

Conceptual

Mouse Input

Other Resources

MAKEPOINTS

POINTS