From: Guillaume Marcais <guslist@...>
Date: 2005-07-27T08:32:28+09:00
Subject: Re: redirecting stdout in an extension

On Wed, 2005-07-27 at 08:15 +0900, Mark Probert wrote:
> Hi ..
> 
> Any ideas on how to redirect stdout in an extension and then revert it
> back to its default behaviour?  freopen() redirects, though I am not
> sure of returning to normal programming.
> 
> So,
> 

Just a guess. I don't know how well it will play with the Ruby
interpreter. Error checking might also be a good idea:

> VALUE rb_dump(VALUE self, VALUE o_name)
> {
>     VALUE   rval;       /* our result */
>     VALUE   fname;      /* holds the filename */
      int     old_stdout;
>     
>     fname = StringValue(o_name);
>     
>     /* redirect stdout */
      old_stdout = dup(1);
>     freopen("a.xml", "w+", stdout);
>     if (foo_dump(STR2CSTR(fname)) == -1) {
>         rval = Qnil;
>     } else {
>         rval = Qtrue;
>     }
>     fclose(stdout);  /* bad!!! want to go back to fd 1 */
      dup2(old_stdout, 1);
      close(old_stdout);
>     return rval;
> }
> 
> BTW, I have no way of modifying the call to foo_dump() to take a file
> handle.  It just splurts out to stdout.
> 
> Many thanks, 
> 

Guillaume.