lastSnew

#! /usr/bin/perl

use IPC::SysV qw(IPC_PRIVATE IPC_CREAT S_IRWXU S_IRWXG S_IRWXO);
use IPC::Msg;

@cams = ( 1, 2, 3, 4, 5, 6 );

$now = time;
$me = $$;
$| = 1;
$SIG{ALARM} = \&goaway;
alarm 10;

$msgIn = new IPC::Msg( $me, IPC_CREAT|S_IRWXU|S_IRWXG|S_IRWXO);
die "recvmsg create: $!\n" if !defined $msgIn;

$which = $cams[0];
$msgOut = new IPC::Msg( $which, IPC_CREAT|S_IRWXU|S_IRWXG|S_IRWXO);
die "sendmsg create: $!\n" if !defined $msgOut;
$msgOut->snd( 1, pack( "L a*", $me, "status" ) );

while(1) {
	$in = $msgIn->rcv( $buf, 256 );
	($code, $resp) = unpack( "L a*", $buf );
	#print "$which: $resp\n";
	$interval = $1 if $resp =~ /frameInterval: (\S+) /;
	last unless $in == 3;
} 
print "Interval: $interval\n";
print "Time: $now\n";

$count=0;

foreach $which (@cams) {
	$msgOut = new IPC::Msg( $which, IPC_CREAT|S_IRWXU|S_IRWXG|S_IRWXO);
	die "sendmsg create: $!\n" if !defined $msgOut;

	$msgOut->snd( 1, pack( "L a*", $me, "lastSeen" ) );

	$count++;

}

	while($count) {
		$in = $msgIn->rcv( $buf, 256 );
		($code, $resp) = unpack( "L a*", $buf );
		print "$resp\n";
		$ans{$count} = $resp;
		$count--;
}


$msgIn->remove;

alarm 0;

$minw = 999999999999990; $maxw = 0;
$tref = 0; # reference time is LAST arriving

foreach $i ( sort keys %ans ) { # in array in reverse order of arrival

	@w = split(' ', $ans{$i} );

	$t = $w[1] + $w[2]/1000000;
	$tref = $t if $tref == 0;

	do {
		$t += $interval;
	} if $t < ($tref-($interval/2));
	
	$minw = $t if( $t<$minw );
	$maxw = $t if( $t>$maxw );

}

$diff = $maxw - $minw;
printf "Max: %.6f Min: %.6f Diff: %.6f ", $maxw, $minw, $diff;
printf "ALARM! \007 \007" if $diff > .080000;
print "\n";

exit;

sub goaway {
	print "dies due to alarm\n";
	$msgIn->remove;
	exit;
}