The WM_SIZING message is sent to a window that the user is resizing. By processing this message, an application can monitor the size and position of the drag rectangle and, if needed, change its size or position.
fwSide = wParam; // edge of window being sized
lprc = (LPRECT) lParam; // screen coordinates of drag rectangle
Parameters
fwSide
Value of wParam. Indicates which edge of the window is being sized. This parameter can be a combination of the following values:
| Value | Meaning |
| WMSZ_BOTTOM | Bottom edge |
| WMSZ_BOTTOMLEFT | Bottom-left corner |
| WMSZ_BOTTOMRIGHT | Bottom-right corner |
| WMSZ_LEFT | Left edge |
| WMSZ_RIGHT | Right edge |
| WMSZ_TOP | Top edge |
| WMSZ_TOPLEFT | Top-left corner |
| WMSZ_TOPRIGHT | Top-right corner |
lprc
Address of a RECT structure with the screen coordinates of the drag rectangle. To change the size or position of the drag rectangle, an application must change the members of this structure.
Return Values
An application should return TRUE if it processes this message.
See Also