check_dev_tty - What does it do?

[John Carter]

Here is the bash-3.1 code from general.c for check_dev_tty.

It is invoked shortly after main...

void
check_dev_tty ()
{
  int tty_fd;
  char *tty;

  tty_fd = open ("/dev/tty", O_RDWR|O_NONBLOCK);

  if (tty_fd < 0)
    {
      tty = (char *)ttyname (fileno (stdin));
      if (tty == 0)
      return;
      tty_fd = open (tty, O_RDWR|O_NONBLOCK);
    }
  close (tty_fd);
}

It seems to open and close /dev/tty and return nothing.

This seems very strange to me.

Why is it doing this?



John Carter                             Phone : (64)(3) 358 6639
Tait Electronics                        Fax   : (64)(3) 359 4632
PO Box 1645 Christchurch                Email : john.carter@tait.co.nz
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Carter's Clarification of Murphy's Law.

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> From this principle, all of life and physics may be deduced.