use strict;

my $patt1 = '!!';
my $patt2 = '++';

my $string = 'hello!!there++everyone!!in the web';

if ( $string =~ m{$patt1} ) {
    print "Matches patt1\n";
}
if ( $string =~ m{\Q $patt2 \E}x ) {
    print "Matches patt2 with /x\n";
}
if ( $string =~ m{\Q$patt2\E} ) {
    print "Matches patt2\n";
}