System, `` or exec on Windows?

ruby-talk
1

Hi all,

What is the easiest (or any) way to do the following with Ruby on
Windows:

  • execute a child process
  • get the output written to stdout and stderr (as with <command>)
  • also get the exit code ($?)
  • in a thread safe way

On unix I would probably revert to using a pipe, fork and waitpid2.
However, fork does not seem to be available (understandably) on Windows.
Any other options I missed?

Is $? thread safe?

Ronald.

2

Ronald Pijnacker wrote:

What is the easiest (or any) way to do the following with Ruby on
Windows:

  • execute a child process
  • get the output written to stdout and stderr (as with <command>)
  • also get the exit code ($?)
  • in a thread safe way

Can’t answer all your questions, but I’ll share what I got.

First, see http://ruby-talk.com/10006 for some replacement methods for
`` and system, if you’re unable to get the originals to work on Windows.
Downside as this post mentions (http://ruby-talk.com/blade/41583) is
that $? is then not set. It also doesn’t help you with stderr, although
there was a recent thread with making a popen3 for Windows, dunno what
the latest on that is. And thread-safe - dunno either.

···

–

Chris
http://clabs.org/blogki
-=-=-=-=-=-=-=-=-=-=-=-=-=-
Free solo piano album (mp3)
http://cministries.org/cstudios/blackandwhite.htm

3

Hi,

  • execute a child process
  • get the output written to stdout and stderr (as with <command>)
  • also get the exit code ($?)
  • in a thread safe way

If you run on NT,

IO.popen(“your-command 2>&1”) {|f|
output = f.read
exitcode = Process.waitpid2(f.pid)[1]
}

On unix I would probably revert to using a pipe, fork and waitpid2.
However, fork does not seem to be available (understandably) on Windows.
Any other options I missed?

I’d like to add arguments specifying redirection to system,
popen etc. for portability, but don’t have nice notation yet.

Is $? thread safe?

Yes. $? is a thread local variable.

···

At Tue, 15 Jul 2003 17:46:31 +0900, Ronald Pijnacker wrote:

–
Nobu Nakada

4

Hi,

  • execute a child process
  • get the output written to stdout and stderr (as with <command>)
  • also get the exit code ($?)
  • in a thread safe way

If you run on NT,

IO.popen(“your-command 2>&1”) {|f|
output = f.read
exitcode = Process.waitpid2(f.pid)[1]
}

On unix I would probably revert to using a pipe, fork and waitpid2.
However, fork does not seem to be available (understandably) on Windows.
Any other options I missed?

I’d like to add arguments specifying redirection to system,
popen etc. for portability, but don’t have nice notation yet.

Is $? thread safe?

Yes. $? is a thread local variable.

Thanks! This was just what I was looking for. I wonder why I missed
this in the documentation. The f.pid part supprised me a bit though…

Ronald.

···

At Tue, 15 Jul 2003 17:46:31 +0900, > Ronald Pijnacker wrote: