From: "Berger, Daniel" <Daniel.Berger@...>
Date: 2007-12-19T00:09:15+09:00
Subject: Re: Curious warning with IO.popen on Windows

 > -----Original Message-----
> From: Nobuyoshi Nakada [mailto:nobu@ruby-lang.org] 
> Sent: Monday, December 17, 2007 7:07 PM
> To: ruby-core@ruby-lang.org
> Subject: Re: Curious warning with IO.popen on Windows
> 
> Hi,
> 
> At Tue, 18 Dec 2007 08:22:20 +0900,
> Berger, Daniel wrote in [ruby-core:14126]:
> > This code causes a "The process tried to write to a 
> nonexistent pipe."
> > warning when run with -w.
> > 
> > io =IO.popen('date /t')
> > io.close
> 
> Why curious?
> 
> That date command tries to write to the pipe, but it has been 
> closed before it.  That is the message from cmd.exe.

But I haven't closed it until after the command has finished, have I?
Also, Linux does not emit any warning using the same code (replacing
'date /t' with just 'date').
 
> > However, this code does not:
> > 
> > io = IO.popen('date /t')
> > io.gets
> > io.close
> 
> Because the output is just one line, and it is read by gets.

If io.gets works, then the date output has already been written to the
IO object in the IO.popen call, right? So, why would it complain about
the pipe being closed?

Thanks,

Dan





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