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From: chris@mimsy.umd.edu (Chris Torek)
Newsgroups: comp.lang.c
Subject: Re: How to test if a key has been hit w/o waiting for a key ?
Keywords: kbhit, stdin, getchar
Message-ID: <24113@mimsy.umd.edu>
Date: 2 May 90 09:36:27 GMT
References: <1990Apr24.000717.7882@cunixf.cc.columbia.edu> <8281@cognos.UUCP>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 23

>In article <1990Apr24.000717.7882@cunixf.cc.columbia.edu>
>gm@cunixd.cc.columbia.edu (Gary Mathews) writes:
>>I want to do some computation and be able to stop by a key pressed by the
>>user.

(As I said already, this cannot be done *portably*.  Given a definition
for `key pressed' and `user', it can usually be done; and it can usually
be done without resorting to writing assembly code, as I once did on VMS
so as to bypass the Pascal runtime library....)

In article <8281@cognos.UUCP> jimp@cognos.UUCP (Jim Patterson) writes:
>        ioctl( stdin->_file, FIONREAD, &count );
>        count += stdin->_cnt;

Be *very* careful with this:
  a. FIONREAD does not exist on all Unix systems, and on some of those
     on which it does exist, it does not quite work right;
  b. stdin probably does not have a _file and/or _cnt structure member
     on some machines.  (If you disagree, try porting to 4.4BSD when
     it comes out.  You may be unpleasantly surprised.)
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@cs.umd.edu	Path:	uunet!mimsy!chris