Why does Perl complain “Use of implicit split to @_ is deprecated”?

Question

This code triggers the complaint below:

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

my $s = \"aaa bbb\";
my $num_of_item = split(/\\s+/, $s) ;
print $num_of_         


        

Answer 1

Let diagnostics provide more information:

use strict;
use warnings;
use diagnostics; # comment this out when you are done debugging

my $s = "aaa bbb";
my $num_of_item = split(/\s+/, $s) ;
print $num_of_item;

Use of implicit split to @_ is deprecated

(D deprecated, W syntax) It makes a lot of work for the compiler when you clobber a subroutine's argument list, so it's better if you assign the results of a split() explicitly to an array (or list).

A better way to get diagnostic info is from the command line:

perl -Mdiagnostics my_program.pl