func (l *logger) Fatalf(format string, vals ...interface{}) {
	l.mut.Lock()
	defer l.mut.Unlock()
	s := fmt.Sprintf(format, vals...)
	l.logger.Output(2, "FATAL: "+s)
	l.callHandlers(LevelFatal, s)
	os.Exit(1)
}
func (l *logger) Fatalf(format string, vals ...interface{}) {
	l.mut.Lock()
	defer l.mut.Unlock()
	s := fmt.Sprintf(format, vals...)
	l.logger.Output(2, "FATAL: "+s)
	l.callHandlers(LevelFatal, s)
	os.Exit(1)
}
func ( l * logger ) Fatalf ( format string , vals ... interface { } ) { l . mut . Lock ( ) defer l . mut . Unlock ( ) s := fmt . Sprintf ( format , vals ... ) l . logger . Output ( 2 , " " + s ) l . callHandlers ( LevelFatal , s ) os . Exit ( 1 ) }
// Fatalf logs a formatted line with a FATAL prefix and exits the process with
// exit code 1.
Fatalf logs a formatted line with a FATAL prefix and exits the process with exit code 1 .