TTYN - determine if I/O is to terminal.

Alternate Entry Name: .TTYN

Usage:

B:
   ret = ttyn( unit );
/* C users use "istty" */

Description:

TTYN returns a non-zero value if the given "unit" is attached to a terminal, and otherwise returns zero.

See Also:

expl b lib is.default
which should be used to determine if a unit has been redirected.

Copyright © 1996, Thinkage Ltd.