use Fcntl qw(:flock SEEK_END);

# ---------------------------------------
# sub logmsg
# ---------------------------------------
sub logmsg {
  my $now = time;
  my $msec = int( ( $now - int($now) ) * 1000 );
  my ( $sec, $min, $hour, $mday, $mon, $year, $wday, $yday, $isdst ) = localtime(time);

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

  sub unlock {
    flock( LOG, LOCK_UN );
  }

  open LOG, ">> $logFilename";
  lock();
  printf LOG "%02d:%02d:%02d:%03d %s\r\n", $hour, $min, $sec, $msec, @_;
  unlock();

  close(LOG);
}

##</code><code>##

16:57:23:238    progman: sent supervisor - progman,ctrlman,set,wort_pump,off

16:57:23:240 supervisor: rcvd pidman     - pidman,webman,status,hlt_duty,0

16:57:23:239    progman: sent supervisor - progman,ctrlman,set,boil_heater,off

16:57:23:240    progman: sent supervisor - progman,ctrlman,set,hlt_heater,off

16:57:23:241    progman: sent supervisor - progman,ctrlman,set,hlt_ssr,off

16:57:23:241 supervisor: sent ctrlman    - pidman,webman,status,hlt_duty,0

16:57:23:234    ctrlman: rcvd supervisor - pidman,webman,status,hlt_duty,0

16:57:23:244 supervisor: sent progman    - pidman,webman,status,hlt_duty,0

16:57:23:245 supervisor: sent webman     - pidman,webman,status,hlt_duty,0

16:57:23:250     webman: rcvd supervisor - pidman,webman,status,hlt_duty,0
16:57:23:241    progman: sent supervisor - progman,ctrlman,set,boil_ssr,off

16:57:23:246    progman: sent supervisor - progman,webman,status,hlt_duty,0

16:57:23:246    progman: sent supervisor - progman,webman,status,hlt_setpoint,0


16:57:23:246 supervisor: rcvd progman    - progman,webman,status,step,startup

16:57:23:249 supervisor: sent webman     - progman,webman,status,step,startup

16:57:23:253     webman: rcvd supervisor - progman,webman,status,step,startup

16:57:23:250 supervisor: sent ctrlman    - progman,webman,status,step,startup

16:57:23:241    ctrlman: rcvd supervisor - progman,webman,status,step,startup

16:57:23:247    progman: sent supervisor - progman,webman,status,hlt_mode,pid

16:57:23:251    progman: sent supervisor - progman,webman,status,hlt_power,100

16:57:23:251    progman: sent supervisor - progman,webman,status,hlt_vary,1