code: func ReadPidFile(name string) (pid int, err error) {
  	var file *os.File
  	if file, err = os.OpenFile(name, os.O_RDONLY, 0640); err != nil {
  		return
  	}
  	defer file.Close()
  
  	lock := &LockFile{file}
  	pid, err = lock.ReadPid()
  	return
  }
docs: // ReadPidFile reads process id from file with give name and returns pid.
  // If unable read from a file, returns error.