>  Docs Center  >  Libraries  >  ASTROLIB  >  READ_KEY






To read a keystroke and return its ASCII equivalent


If an ESCAPE sequence was produced and the sequence is
recognized (e.g. up arrow), then a code is returned.
      This functionality is mostly made obsolete by the addition of the
      ESCAPE and KEY_NAME keywords to GET_KBRD in IDL V6.2

Calling Sequence

key = READ_KEY(Wait)


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.


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

© 2022 Harris Geospatial Solutions, Inc. |  Legal
My Account    |    Store    |    Contact Us