glutDialsFunc
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## Name

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

## C Specification

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

## Python Specification

``glutDialsFunc`` | `(` | ``func`) → `None``

## Parameters

`func`
  The new dials callback function.

## Description

`glutDialsFunc` sets the dial & button box dials callback for the current window. The dial & button box dials callback 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 `glutDeviceGet(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.

## See Also

glutButtonBoxFunc, glutDeviceGet

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