control

A program module or routine that enhances the functionality of a program. A control can be as small as a single button on a user interface or as large as a complicated forecasting algorithm. The term is often used with regard to user interface functions such as buttons, menus and dialog boxes. See ActiveX control, AWT, anchor and user interface control.

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(character)

control - (Or "ctrl", "^") One (or a pair) of modifier keys found on all modern keyboards. If the control key is held down while pressing and releasing certain other keys then a "control character" is generated, e.g. holding control and hitting "A" generates control-A (ASCII code 1). The ASCII code for the control character is generally 64 less than that for the unmodified character. The control key does not generate any character on its own but most modern keyboards and operating systems allow a program to tell whether each of the individual keys on the keyboard (including modifier keys) is pressed at any time. Control characters mostly have some kind of "non-printing" effect on the output such as ringing the bell (Control-G) or advancing to the next line (Control-J). Most have alternative names suggesting these functions (Bell, Line Feed, etc.). See ASCII character table.