code: func LogErrorAndExit(err error, opts ...int) {
  	var rc int
  	if len(opts) > 0 {
  		rc = opts[0]
  	}
  	if gLogLevel <= LError {
  		logMessage("ERROR - ", err.Error())
  	}
  	os.Exit(rc)
  }
docs: // LogErrorAndExit logs an error and exit with an optional return code