Posted to a window when the cursor hovers over the nonclient area of the window for the period of time specified in a prior call to TrackMouseEvent.
A window receives this message through its WindowProc function.
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.
If an application processes this message, it should return zero.
Hover tracking stops when this message is generated. The application must call TrackMouseEvent again if it requires further tracking of mouse hover behavior.
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.
Minimum supported client
|Windows 2000 Professional [desktop apps only]|
Minimum supported server
|Windows 2000 Server [desktop apps only]|
- Mouse Input
- Other Resources