http://www.perlmonks.org?node_id=424800


in reply to Globs and globals

The easiest way might be to just localize S1 and S2 first: 

local(*S1, *S2);
...as in your first example...

[download]

OTOH, I don't think my $socket \*S1 is valid Perl--maybe there's an equal sign missing between $socket and \*S1?

=cut
--Brent Dax
There is no sig.

Replies are listed 'Best First'.
Re^2: Globs and globals
by Eyck (Priest) on Jan 25, 2005 at 13:48 UTC

    This advice is factually incorrect.

    GLOB is a glob, and local doesen't help here ( besides providing false sense of security ) 

    my $socket=\*S1;
print "Orig:",$socket,"\n";
{
local(*S1, *S2);
my $s=\*S1;
print "Local: ",$s,"\n";
}

    [download]
    Orig:GLOB(0x8160be4)
Local: GLOB(0x8160be4)
[reply]
[d/l]

      Odd--you're right, though I can't figure out why. The docs seem to say that you get a new glob when you localize:

      The construct local *name; creates a whole new symbol table entry for the glob "name" in the current package. That means that all variables in its glob slot ($name, @name, %name, &name, and the "name" filehandle) are dynamically reset.

      In any case, the following does work correctly: 

      open(S1, "/dev/null");
$a=*S1{IO};
{
    local(*S1);
    open(S1, "/dev/null");
    $b=*S1{IO};
}
print "$a $b\n";

      [download]
      IO::Handle=IO(0x101536f8) IO::Handle=IO(0x1013cdec)

      =cut
      --Brent Dax
      There is no sig.

[reply]
[d/l]
[select]

        Interesting, your code works, although I would expect it not to. I haven't seen this excerpt in documentation about local and globs so it's a bit of surprise for me, thanks.

        There must be something about dual nature of globs - whatever experiment you devise it proves your theory, even if it contradicts other experiments.

[reply]

In Section Seekers of Perl Wisdom