glutDialsFunc  - sets the dial & button box dials callback
for the current window.

glutDialsFunc
	glutDialsFunc(func) -> None

void glutDialsFunc(void (*func)(int dial, int value));

func      The new dials callback function.

glutDialsFunc sets the dial & button  box  dials  callback
for  the current window. The dial & button box dials call-
back for a window is called when the  window  has  dial  &
button box input focus (normally, when the mouse is in the
window) and the user generates  dial  &  button  box  dial
changes.  The  dial  parameter  will  be  the  dial number
(starting at one). The number of available dial  &  button
box    dials    can    be    determined    with    glutDe-
viceGet(GLUT_NUM_DIALS). The value measures  the  absolute
rotation in degrees. Dial values do not ``roll over'' with
each complete rotation but continue to accumulate  degrees
(until the int dial value overflows).

Registering a dial & button box dials callback when a dial
& button box device is not available  is  ineffectual  and
not  an  error.  In  this case, no dial & button box dials
callbacks will be generated.

Passing NULL to glutDialsFunc disables the  generation  of
dial  &  button  box dials callbacks. When a new window is
created, no dial & button box dials callback is  initially
registered.

glutButtonBoxFunc, glutDeviceGet

Mark J. Kilgard (mjk@nvidia.com)