Xref: utzoo comp.lang.c:15290 comp.unix.wizards:13926
Path: utzoo!utgpu!attcan!uunet!ficc!peter
From: peter@ficc.uu.net (Peter da Silva)
Newsgroups: comp.lang.c,comp.unix.wizards
Subject: Re: printf, data presentation
Summary: Inkey leads to poor programming.
	 It's inherently expensive to poll or busy-wait.
Keywords: printf, terminals, fixed format screens
Message-ID: <2655@ficc.uu.net>
Date: 6 Jan 89 22:25:11 GMT
References: <19@xenlink.UUCP> <731@picuxa.UUCP> <8332@ihlpl.ATT.COM>
Organization: Xenix Support
Lines: 25

From my recollection of BASIC, INKEY$ has two main uses:

	(1) Enabling a clean abort of a running compute-bound
	    program.

	(2) Busy-waiting for a time-interval.

For case 1, UNIX provides signal handlers. For case 2, a read-with-timeout
is more useful. Luckily, UNIX provides this as well. For long timeouts, it
reduces to the case of a signal handler. For short timeouts, you need the
USG termio, and set VMIN and VTIME.

	(3) Terminal emulators.

For this case, you're better off with a multiway wait or two cooperating
processes.

Using an inkey$ type call to do this will just get you a bad name as a system
hog. We just had to rip code like this out of microEmacs last year some
time.
-- 
Peter da Silva, Xenix Support, Ferranti International Controls Corporation.
Work: uunet.uu.net!ficc!peter, peter@ficc.uu.net, +1 713 274 5180.   `-_-'
Home: bigtex!texbell!sugar!peter, peter@sugar.uu.net.                 'U`
Opinions may not represent the policies of FICC or the Xenix Support group.