Re: [PATCH v3 14/14] daemon: only use posix features on posix systems

From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: Oct 10, 2010, 19:40 UTC
Message-ID: <AANLkTimn3XWDXhqrZm+VS1Ouy8tzmCAVOyMN7KjQ7dFt@mail.gmail.com>
In-Reply-To: <1286716854-5744-15-git-send-email-kusmabite@gmail.com>

On Sun, Oct 10, 2010 at 13:20, Erik Faye-Lund <kusmabite@gmail.com> wrote:

> Windows does not supply the POSIX-functions fork(), setuuid(), setgid(),
> setsid() and initgroups(). Disable support for --user, --group and
> --detach on platforms lacking _POSIX_VERSION.

FWIW I checked if Perl's fork() emulation with threads on Windows could emulate this, but no:

    perl -E '
    if (my $pid = fork()) {
      say "$$: child running as $pid"
    } else {
      sleep 1;
      say "$$: running in the background"
    }'

On Unix that would detach the process from the terminal, but on Windows with threads the original process only returns after the child has finished.

I didn't expect it to act differently, but I thought I'd note it here in case anyone had it in mind to implement --detach on Windows.

> This might be a bit controversial; does anyone know of any systems that
> implements fork(), setuuid(), setgid() and setsid() but does not define
> _POSIX_VERSION? Perhaps we should have a separate makefile-switch instead?

Even if it's defined it's more self-documenting to have our own HAVE_POSIX_GOODIES (or something like that) instead.