Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!ulysses!cjc
From: cjc@ulysses.homer.nj.att.com (Chris Calabrese)
Newsgroups: comp.windows.news
Subject: Re: Has anyone figured out how to ring the bell?
Summary: a better bell ringer without forkunix
Keywords: bell ^G
Message-ID: <12305@ulysses.homer.nj.att.com>
Date: 20 Oct 89 19:29:10 GMT
References: <18083@ppgbms.UUCP>
Distribution: na
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 162

In article <18083@ppgbms.UUCP>, paul@ppgbms (Paul Evan Matz) writes:
> I'm sorry if this has been covered before, but I can't seem to remember
> if there's a way to ring the audible bell from the NeWS server side.  I
> suppose one could forkunix an executable to do it.  Is there a better way?

Yes, it can be done!!!
I wrote this code to get the new psterm from the grasshopper group to
ring the bell (VisibleBell() is a function in the npsterm code):

P.S. no flames about using goto!  If you can't figure what's going on
in the function it's in (which is the only function in the source
file), get your brain checked...

/*
 * @(#)ringbell.c	1.1 10/20/89
 * bell ringing routines on a Sun workstation
 * for the npsterm terminal emulator running NeWS
 *
 * Christopher Calabrese
 * AT&T Bell Laboratories
 * Murray Hill, NJ
 * cjc@ulysses.att.com
 */
#ifdef sun
#	include <sys/types.h>
#	include <sundev/kbd.h>
#	include <sundev/kbio.h>
#endif
#include	"tcap.h"

#ifndef lint
	static char *sccsid="@(#)ringbell.c	1.1 10/20/89 cjc@ulysses.att.com";
#endif

RingBell()
	{
#	ifdef sun
	static int kbdfd = -1;	/* File descriptor for the keyboard.
				 * -1 means the file's never been
				 * opened and/or we're not running
				 * with the NeWS machine as the
				 * local machine
				 */
	if(kbdfd == -1 && newsislocal())
		{
		kbdfd = open("/dev/kbd", 0);
		}
	/*
	 * we need this second test if the open failed
	 * or we're not local
	 */
	if(kbdfd != -1)
		{
		int x;
		x = KBD_CMD_BELL;
		ioctl(kbdfd, KIOCCMD, &x);
		usleep(250000);
		x = KBD_CMD_NOBELL;
		ioctl(kbdfd, KIOCCMD, &x);
		}
#	endif
	VisibleBell();
	}

/*
 * @(#)newsislocal.c	1.1 10/20/89
 * checks if the NEWSSERVER variable is the same as the
 * local host
 *
 * Christopher Calabrese
 * AT&T Bell Laboratories
 * Murray Hill, NJ
 * cjc@ulysses.att.com
 */

#ifndef lint
	static char *sccsid="@(#)newsislocal.c	1.1 10/20/89 cjc@ulysses.att.com";
#endif

#include <stdio.h>
#include <netdb.h>
#include <sys/param.h>
#ifndef MAXHOSTNAMELEN
#	define	MAXHOSTNAMELEN 64
#endif

newsislocal()
	{
	/*
	 * code is our return code, -1 means we don't know
	 */
	static int code = -1;
	char *ptr;
	long atol();
	unsigned long ntohl();
	char buffer[256];
	char myhostname[MAXHOSTNAMELEN + 1];
	char *strchr(), *getenv(), strncpy();
	char *gethostname();
	struct hostent *gethostbyname();
	struct hostent *hp;
	if(code != -1)
		goto end_of_function;
	if(!(ptr=getenv("NEWSSERVER")))
		{
		/* oops, it's undefined, assume non-local */
		code = 0;
		goto end_of_function;
		}
	(void) strncpy(buffer, ptr, 256);
	buffer[255]='\0';
	/*
	 * Buffer now contains the NEWSSERVER environment variable.
	 * The format is host_id.port:host_name.
	 * To do what we want, we must find the '.' and 
	 * extract the host_id
	 */
	if(!(ptr = strchr(buffer, '.')))
		{
		/* oops, it's the wrong format, assume non-local */
		code = 0;
		goto end_of_function;
		}
	*ptr = '\0';
	/*
	 * O.k., we know the id of the news host, now let's get
	 * our own id and compare them.
	 * We'll use gethostname() to find the name of the current
	 * machine and then do a gethostbyname() to get it's net
	 * addresses.  If we want to do this right in BSD 4.3 or
	 * SunOS 4.0 we should check against all the entries for the
	 * current host, but since setnewshost(1) only looks at the primary
	 * host id and since BSD 4.2 and SunOS 3.0 only know about
	 * the primary id, we'll only use that.
	 */
	if(gethostname(myhostname, MAXHOSTNAMELEN))
		{
		/* oops, a serious error getting the host name */
		(void) perror("gethostname");
		code = 0;
		goto end_of_function;
		}
	myhostname[MAXHOSTNAMELEN] = '\0';
	if(!(hp = gethostbyname(myhostname)))
		{
		(void) perror(myhostname);
		code = 0;
		goto end_of_function;
        	}
	if((unsigned) atol(buffer) == ntohl(*(u_long *)hp->h_addr))
		{
		code = 1;
		}
	else	code = 0;
end_of_function:
	return code;
	}
-- 
Name:			Christopher J. Calabrese
Brain loaned to:	AT&T Bell Laboratories, Murray Hill, NJ
att!ulysses!cjc		cjc@ulysses.att.com
Obligatory Quote:	``Anyone who would tell you that would also try and sell you the Brooklyn Bridge.''