bug#2602: Emacs shell exits when executed command sets stdout and stderr to be non-blocking

bug#2602: Emacs shell exits when executed command sets stdout and stderr to be non-blocking

[William K. Foster]

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Hello,

Create an application that does the following:

  void setFdBlocking(int fd, bool block) {
    // Set an fd's blocking flag on or off.
    int flags;

    if (0 > (flags = fcntl(fd, F_GETFL, 0))) {
      throw;
    }

    if (block) {
      flags &= ~O_NONBLOCK;
    } else {
      flags |=  O_NONBLOCK;
    }

    if (0 > fcntl(fd, F_SETFL, flags)) {
      throw;
    }
  }

  // Make Stdout and Stderr be non-blocking.
  setFdBlocking(1, false);
  setFdBlocking(2, false);

If you execute the application from a shell inside emacs, the shell will
exit when the command returns.

This does not happen for a shell outside of emacs.

Thanks.

-William

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bug#2602: Emacs shell exits when executed command sets stdout and stderr to be non-blocking

[Andrew Hyatt]

I cannot reproduce this on Emacs 25.  Can you let me know if you are
still able to see this bug, otherwise I'll close this issue.

"William K. Foster" <wkf@alum.mit.edu> writes:

> Hello,
>
> Create an application that does the following:
>
> void setFdBlocking(int fd, bool block) {
> // Set an fd's blocking flag on or off.
> int flags;
>
> if (0 > (flags = fcntl(fd, F_GETFL, 0))) {
> throw;
> }
>
> if (block) {
> flags &= ~O_NONBLOCK;
> } else {
> flags |= O_NONBLOCK;
> }
>
> if (0 > fcntl(fd, F_SETFL, flags)) {
> throw;
> }
> }
>
> // Make Stdout and Stderr be non-blocking.
> setFdBlocking(1, false);
> setFdBlocking(2, false);
>
> If you execute the application from a shell inside emacs, the shell will exit when the command returns.
>
> This does not happen for a shell outside of emacs.
>
> Thanks.
>
> -William