From: "Berger, Daniel" <djberge@...>
Date: 2002-08-22T04:45:45+09:00
Subject: RE: select on solaris

> -----Original Message-----
> From: Jeff Putsch [mailto:putsch@mxim.com]
> Howdy,
> 
> I'm trying to use select() with Open3.popen3 on Solaris 8 
> with ruby 1.6.7.
> If it matters ruby was built on Solaris 2.6.

I *highly* recommend rebuilding Ruby on 2.8.  It's a big enough pain to get
a native build working on Solaris, much less a binary from an older kernel.
That doesn't seem to be the issue here, however.
 
> It seems that select() is claiming file descriptors are ready 
> whether or
> not they are.
> 
> The simple program I'm trying as a test is:
> 
>    #!/usr/sepp/bin/ruby
>    
>    require 'open3'
>    
>    def run_command
>      [stdin, out, err] = Open3.popen3("cat /etc/hosts")
>      while not (r=select([out,err])).nil?
>        yield r.inspect
>      end
>    end
>    

> This does not seem right. First, there is never any data on the error
> object, so why is select saying there is? Second once the end of the
> file is reached, why is select continuing to claim both descriptors
> have data? I'm sure I'm doing something wrong...

err is in IO object, it's not the data contained within the object.

To see if err contains an actual error message, just do this:

e = err.gets
if e.nil?
   # No error
else
   # kerblooey!
end

Hope that helps.

Regards,

Dan