--- Michael Fowler <[EMAIL PROTECTED]> wrote:
> On Tue, Jul 10, 2001 at 10:19:43AM -0700, Paul wrote:
> > open THIS, ">&THAT"
>
> This dups (see man 2 dup) fileno(THAT) and opens it with the
> filehandle THIS. The THIS and THAT filehandles now refer to the same
> file descriptor, and thus the same underlying file.
But do they get seperate buffers?
> > *THIS = *THAT
>
> This aliases all symbols named THIS to THAT. This means \$THIS eq
> \$THAT, \%THIS eq \%THAT, \@THIS eq \@THAT, etc. (yes, I meant to
> take the references to these values, in order to indicate they are
> aliases, different names for the same values) and the filehandles
> THIS and THAT go to the same file.
But in this case, it's not just that they go to the same file --
they're literally using the same "file structure pointer", to use the C
lingo, aren't they?
> > Doesn anybody know the difference?
> > Especially if you use STDERR and STDOUT instead of THIS and THAT?
>
> The primary difference is that "*THIS = *THAT" are only visible
> from Perl, they (for reasons that should be obvious if you think
> about it) don't propagate to any external processes. Meaning, if
> you want to redirect STDERR and STDOUT for a subprocess you have to
> use the dup, or the fdopen (<&=fd), form of open, or equivalent.
whoa.... are you sure about that?
I could swear I've used aliasing to redirect subprocesses....
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