Path: utzoo!utgpu!news-server.csri.toronto.edu!utcs.toronto.edu!cks
Newsgroups: comp.unix.ultrix
From: cks@hawkwind.utcs.toronto.edu (Chris Siebenmann)
Subject: ttys and the POSIXification of Ultrix (Ultrix 4.0, possibly +)
Message-ID: <1991Feb25.223042.8566@jarvis.csri.toronto.edu>
Summary: avoid -YPOSIX and -Y[SYSTEM_FIVE]
Keywords: braindamage
Organization: Ziebmef home away from home
Date: 26 Feb 91 03:30:42 GMT
Lines: 44

/*
 * A program that illustrates a problem with Ultrix POSIXification
 * incant: cc -YPOSIX tty-bug.c; stty new; stty; ./a.out /dev/tty; stty
 * to see the bug.
 * incant: cc tty-bug.c; stty new; stty; ./a.out /dev/tty; stty
 * to see the bug go away.
 * (Note: the bug also occurs if you compile for System V or if you
 *  use ./a.out `tty`.)
 *
 * The bug is that whenever a tty is opened by a program is POSIX
 * or SysV mode, the line discipline on that tty is instantly changed
 * to termios. This is braindamaged. It also seems to be deliberate;
 * see tty_def_open() in sys/sys/tty.c.
 *
 * Workaround: Never compile a program for POSIX or System V environments,
 * learn to love termios line discipline, start saying 'stty new' or
 * 'stty old' after all dubious commands, or never ever point a POSIX
 * or System V program near a terminal. In particular, don't compile
 * the 4.3BSD syslogging patches from jtkohl@MIT.EDU (John T Kohl)
 * with -YPOSIX, or your console line discipline will randomly change
 * to termios.
*/
#include	<stdio.h>
#include	<fcntl.h>

main(argc, argv)
int	argc;
char	**argv;
{
	int	fd, i;

	for (i = 1; i < argc; i++) {
		fd = open(argv[i], O_WRONLY, 0);
		if (fd < 0)
			perror(argv[i]);
		(void) close(fd);
	}
	return 0;
}

--
		 "You don't *run* programs on Ultrix." - Mark Moraes
		 "Right, you chase them." - Rayan Zachariassen
cks@hawkwind.utcs.toronto.edu	           ...!{utgpu,utzoo,watmath}!utgpu!cks


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