Off the top of my head :

use strict on? use warnings /-w switch on? These usually help you located the "uninitialized value".

This error basically means you have assigned a variable and are trying to pass it through a CGI.pm function. The error is being thrown at you because it's saying "Hey! $variable is empty buddy! What are you trying to pull?". When you find the variable that isn't being assigned, use some debugging methods (like a whole bunch of print "Variable is here : $variable\n" to track down the problem...

Update : If you still have no luck, post your code here. Use code tags, and also use ReadMore tags. Check out Writeup Formatting Tips for explanations...

Azatoth a.k.a Captain Whiplash

Yeah, I have both use strict and the -w option at the top of my script, and CGI::Carp in case my script dies unexpectedly.

I'll start throwing in some print statements. . . I don't make a lot of calls to CGI in this particular script, so hopefully it won't take long to find.

Thanks!
MrCromeDome

it looks like the parameter name is not defined and (in my version of CGI.pm at least) this looks like a problem...

# from CGI.pm

sub parse_params {
    my($self,$tosplit) = @_;
    my(@pairs) = split(/[&;]/,$tosplit);
    my($param,$value);
    foreach (@pairs) {
    ($param,$value) = split('=',$_,2);
    $value = '' unless defined $value;
    $param = unescape($param);

# this is where the situation goes unchecked...
# CGI::Util::unescape returns undef if $param is undef
# none the wiser and no error checking!

    $value = unescape($value);
    $self->add_parameter($param);
    push (@{$self->{$param}},$value);
    }
}
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http://your.site.here/cgi-bin/script.pl?param1=value1&=value2&param3=v
+alue3
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next unless defined $param;
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hope this helps

update: if this does turn out to be the problem you may want to check if the most recent version has the same problem - if so you can email the author(s) and let him/her/them know you have discovered a bug

   larryk                                          
perl -le "s,,reverse killer,e,y,rifle,lycra,,print"

Yeah, that will always print true ;)

It's pretty much the situation that you describe above. . . just a little bit different. Instead of this:

http://cygnus/cgi-bin/view.cgi?document=12345678&=name
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I have this:

http://cygnus/cgi-bin/view.cgi?document=12345678&&tab=name
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Note the &&. If I make it a single &, it seems to work fine. Seems like I made a pretty fatal typo there. I don't know if that indicates a problem with CGI or not (my guess is not), but I do know that things work fine without the second &.

Thanks for your help :)
MrCromeDome

typo - yes
fatal - shouldn't have been (IMHO)

CGI.pm is basically doing

#!/usr/bin/perl -w
use strict;

$_ = 'test1=1&&test3=3';

for ( split '&' ) {
    my($param,$value) = split '=';
    print "param='$param'\n";
    print "value='$value'\n";
    
    # and using $param even though it is undefined the 2nd time
}
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You said that both versions of apache are the same but it looks like the two versions of CGI.pm are different - you can check ~ line 22 of CGI.pm for the version number.

if they are the same then I'm stumped - otherwise you should probably upgrade to the newer one at least as it looks like it is handling malformed URLs properly (this type anyway).

   larryk                                          
perl -le "s,,reverse killer,e,y,rifle,lycra,,print"