use strict;
use warnings;

sub escaped { 
    my $string = shift;
    my $count = 0;
    $count++ if $string =~ /\\$/; 
    $count++ while $` =~ /\\$/ ;
    return ($count & 1)
}

#############################
#Aufruf:
    my $searchstring = '\#\\\#sfdgsdfgdsfg#ggg\\#';
    if ($searchstring =~ /#/ and not escaped $`)
    {
       print "# gefunden
";
    }