From: Brian Candler <B.Candler@...>
Date: 2003-05-07T21:22:27+09:00
Subject: Re: capture output

On Wed, May 07, 2003 at 08:16:44PM +0900, Simon Strandgaard wrote:
> > The problem is this: you are forking a child process, which inherits
> > stdin/stdout/stderr. It then writes to them using *Unix* write() calls, to
> > file descriptors 1 (stdout) and 2 (stderr).
> > 
> > Now, you can redirect fds 1/2 to a file before forking, in which case the
> > child will write to that file. But you cannot redirect those fds to a Ruby
> > object, because the Unix write() syscall does not call Ruby!
> 
> Im no expert on this either.. thus im asking :-)
> VIM can execute a child process and capture its output.

Yes: it opens a pipe, forks, and passes one end of the pipe as stdout
(and/or stderr) to the child. In Ruby, that's IO.popen.

> How does other applications do this redirection ?
> I cannot believe that this is NOT possible with ruby ???

I think I have answered this several times already!

The only thing is, as far as I know, IO.popen will not attach both stderr
and stdout to the same pipe. You can submit that as a feature request.

Brian.