Null characters with Pattern matching doesn't work?

[gamesthreshold]

# This one works:
my $lnbk = "\r\n";
$var =~ m{\G(.*?)$lnbk}gc

# This one fails:
my $null = chr(0);
$var =~ m{\G(.*?)$null}gc


Why won't the regex work with a Null character? But this does work...

s/(.*)$null//g


I don't want to use the replacement, but "walk" the variable as I have been doing. Can anyone help?

 

[TrojanWarBlade]

Not sure what you are trying to do or why but I wrote a little code that uses a null character field separator. I could have used "split" but I tried to stay with what you were doing.
Note that I actually embedded null bytes in the data at the end:

#!/usr/bin/perl
use warnings;
use strict;

my $count = 0;
while(<DATA>) {
    chomp;
    while(
            /                   # Start of regex
                \G              # 'pos' assertion (continue where last left off)                (               # Capture
                    [^\x{00}]*  # any NON-NULL characters (important!)
                )               # End capture
                \x{00}          # The trailing null character
            /gx                 # regex switches
        ) {
        $count++; # Counter just to prove it's going through the loop
        print "[$1] [$count]\n";
    }
}

__DATA__
one^@two^@three^@four^@
five^@six^@seven^@eight^@

Maybe that might give you some ideas....


Trojan.

 

[gamesthreshold]

lmfao I made a mistake in my code (shoulda just posted the code in the first place...)

# Incomming TCP data
sub proto_read_tcp {
   my $sock = shift;
   my $nlen = shift;
   
   return unless $nlen; # Verify new data has been added to the buffer
   
   alias $sock{$sock}->{ibfr}, my $ibfr;
   
   pos $ibfr = 0;
   WHILE:
   while (pos $ibfr < length $ibfr) {
      if ( $ibfr =~ m{\G(.*?)$pactbreak}gcso ) {
         proto_parse_packet($sock, $1);
      } else { # No more packet break's found
         substr($ibfr, 0, pos $ibfr) = '' # clear data we've processed
         print("no more packet breaks... ibfr: $ibfr\n");
         last WHILE; # Break from the loop
      }
   }
}

Well, the problem was that I forgot the "s" for the RegEx options, which makes the . match any character (as it doesn't match line breaks, nulls, etc by default) And I had a linebreak at the beginning of the test packets being sent between my sockets.

The contents of $pactbreak is a null character, so I assumed it was my problem. Didn't realise it was the linebreak at the beginning of the data that was cancelling out the (.*?) part of the search

THX FOR THE HELP THO!! Really appreciate it.