idlastro / Miscellaneous (Non-Astronomy) Procedures: READ_KEY

[Source code]

NAME
READ_KEY
PURPOSE
To read a keystroke and return its ASCII equivalent
EXPLANATION
If an ESCAPE sequence was produced and  the sequence is
recognized (e.g. up arrow), then a code is returned.
his functionality is mostly made obsolete by the addition of the
SCAPE and KEY_NAME keywords to GET_KBRD in IDL V6.2
CALLING SEQUENCE
key = READ_KEY(Wait)
INPUTS
Wait  -  The wait flag.  If non-zero, execution is halted until a
         key is struck.  If zero, execution returns immediately and
         a zero is returned if there was no keystroke waiting in the
         keyboard buffer.  If not specified, zero is assumed.
OUTPUT
Returned - The key struck.  The ASCII code for non-escape sequences.
           Escape sequence equivalents:
                Up Arrow     --  128
                Down Arrow   --  130
                Left Arrow   --  129
                Right Arrow  --  131
                Else         --    0
The return value is a byte value.
MODIFICATION HISTORY
Written by Michael R. Greason, STX, 22 June 1990.
Rewritten for a SUN workstation.  MRG, STX, 23 August 1990.
Converted to IDL V5.0   W. Landsman   September 1997