code: func isCloseOnExec(fd uintptr) (bool, error) {
  	flags, err := getFdFlags(fd)
  	if err != nil {
  		return false, err
  	}
  	return flags&unix.FD_CLOEXEC != 0, nil
  }
docs: // isCloseOnExec checks the provided file descriptor to see if the CLOEXEC flag
  // is set.