Re: [PATCH] Provide posix_spawn implementation

[Jeff Johnston <jjohnstn at redhat dot com>]

On 09/16/2013 04:07 PM, Petr Hosek wrote:
> I have ported over posix_spawn implementation from FreeBSD to newlib.
> It implements posix_spawn interface in terms of existing POSIX
> interfaces, in particular vfork and exec.
>
> This should make it easier to port existing code which uses
> posix_spawn, which is already supported by glibc as well as all BSD
> variants. In the longer term, posix_spawn could be also interesting to
> Cygwin as the interface is more akin to CreateProcess provided by
> Windows so the applications using posix_spawn instead of fork/vfork
> would get performance improvement compared to the current fork
> emulation.

Some comments.

1. posix_spawn should be listed as an EL/IX 4 source since it is not
   specified in the EL/IX standard (as opposed to a general source in
   Makefile.am)

2. some of the posix routines are protected by #ifndef _NO_xxxxx
   This is needed for this code (#ifndef _NO_POSIX_SPAWN)

3. execvpe is a gnu extension starting in glibc
   2.11.  It appears to be only supported by
   Cygwin in newlib.  I can't speak for RTEMS and powerpcle which are
   users of the posix dir, but you will have to set _NO_POSIX_SPAWN for
   x86-linux which don't supply this unless you can replace
   the code or shield it with a Cygwin check.  The changes go in
   configure.host.  You should turn it off for RTEMS and powerpcle
   until they confirm one way or another.

4. Other posix code there such as popen and opendir adds a check for
   HAVE_FCNTL before using it.

5. Please add documentation similar to what is found in popen.c

-- Jeff J.