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From: cnrdean@ucbtopaz.BERKELEY.EDU
Newsgroups: net.unix-wizards
Subject: cbreak problem
Message-ID: <299@ucbjade.BERKELEY.EDU>
Date: Wed, 5-Feb-86 17:26:39 EST
Article-I.D.: ucbjade.299
Posted: Wed Feb  5 17:26:39 1986
Date-Received: Sun, 9-Feb-86 04:31:44 EST
Sender: network@ucbjade.BERKELEY.EDU
Reply-To: cnrdean@ucbtopaz.BERKELEY.EDU ()
Organization: University of California, Berkeley
Lines: 27

I am porting a program on to a Berkeley 4.2  Vax, and I'm having
trouble with my cbreak mode:  I need to process characters as they come
in.  My problem is that when I try to print the characters, they don't
get printed at the point that I request them to, unless I put a fflush
in.  I thought that when I was in cbreak mode, putchar() would show up
immediately, without fflushing.

Can you help?  I've read TTY(4), and tried fooling with some of the
flushing mechanisms in there, to no avail.

Following is an example of my code:

#include <sgtty.h>
. . .
char c;
struct sgttyb
cbrmode,			/* Controlling tty cbreak mode */
cookedmode;			/* Controlling tty cooked mode */
. . .
gtty(0,&cbrmode);
cbrmode.sg_flags |= (CBREAK);
cbrmode.sg_flags &= ~(ECHO|XTABS|CRMOD);
stty(0,&cbrmode);			/* Put tty in cbreak mode */
. . .
read(0,&c,1);		/* Get a character */
c =  c & 0177;
putchar(c);