#!/usr/bin/perl

$LOCK_SH = 1;
$LOCK_EX = 2;
$LOCK_NB = 4;
$LOCK_UN = 8;

sub lock {
	flock(MBOX, $LOCK_EX);
	# and, in case someone appended
	# while we were waiting...
	seek(MBOX, 0, 2);
}

sub unlock {
	flock(MBOX, $LOCK_UN);
}

open(MBOX, ">>/usr/spool/mail/$ENV{'USER'}")
	|| die "Can't open mailbox: $!";

&lock();
print MBOX $msg, "\n\n";
&unlock();
