getchget character procedure

Syntax   getch ( var ch : string ( 1 ) )

Description   The getch procedure is used to input a single character without waiting for the end of a line. The parameter ch is set to the next character in the keyboard buffer (the oldest not-yet-read character).

Example   This program contains a procedure called getKey which causes the program to wait until a key is pressed.

        setscreen ("graphics")
        procedure getKey
            var ch : string (1)
            getch (ch)
        end getKey
        for i : 1 .. 1000
            put i : 4, " Pause till a key is pressed"
        end for
Details   The screen should be in a "screen" or "graphics" mode. See the setscreen procedure for details. If the screen is not in one of these modes, it will automatically be set to "screen" mode.

On IBM PC's some keys, such as the left arrow key, insert key, delete key, and function keys do not produce ordinary character values. These keystrokes are returned by getch as their "scan code" with 128 added to them, unless the scan code already has a value of 128 or greater. This provides a unique value for every key on the keyboard. See Appendix D for these codes.

See also   hasch (has character) which is used to see if a character has been typed but not yet read.

See also predefined unit Input.