Function            MButtonRelease - mouse button release data

  Syntax              int MButtonRelease(int button);

  Prototype in        mousehk.h

  Remarks             determines button release information for the given
                      button, where the parameter button is 0 for the
                      left button, 1 for the right button, and 2 for the
                      middle button (Mouse Systems mouse).

                      _mouse1 is a bit field

                           xxxxxxxx xxxxxMRL

                      where

                           M = middle button released
                           R = right button released
                           L = left button released

                      _mouse2 contains the number of times the specified
                      button has been released since the last call.

                      the specified button was last released at the
                      coordinate (_mouse3,_mouse4)

  Return value        returns the number of times the button has been
                      released since the last call.

  See also            MButtonPress(), MButtonStatus()

  Example             see demomous.c