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From: pem@frankland-river.aaii.oz.au (Paul E. Maisano)
Newsgroups: comp.lang.perl
Subject: Strange behavior with "local"
Keywords: local bug
Message-ID: <1363@frankland-river.aaii.oz.au>
Date: 18 Mar 90 09:36:37 GMT
Organization: Australian AI Institute
Lines: 42

Maybe I'm missing something but this seems like strange behaviour to me.

----------cut-here---------
#!/usr/bin/perl

$buf = "original value";

&buggy($buf);
print "buf=$buf\n";

sub buggy {
    local($buf) = "new value";
    print "buf=$buf\n";
    $_[0] = $buf;
}
----------cut-here---------

Running this produces:
    buf=new value
    buf=original value

It looks like the global $buf does not get changed. It should, since scalars
are passed by reference and the last line in &buggy refers to the global
variable.

If I change the name of the local variable in &buggy, everything works as
expected; the global $buf gets changed.

It seems that the value of the $buf variable is being restored before the
subroutine is exited. 

I hope this is a bug, otherwise I have to be very careful about naming my
local variables.

I'm using perl 3.0 pl15 on a SUN3/60 and sparcstation-1.

------------------
Paul E. Maisano
Australian Artificial Intelligence Institute
1 Grattan St. Carlton, Vic. 3053, Australia
Ph: +613 663-7922  Fax: +613 663-7937
Email: pem@aaii.oz.au   UUCP: {uunet,mcsun,ukc,nttlab}!munnari!aaii.oz.au!pem