Question

What exactly does ‘use 5.014’ enable?

Please, someone copy&paste here, because i was not able find it in any perldoc. (maybe i’m blind). In the ‘perldoc feature’ are only some things for the 5.10. Or point me to some URL.

thanx.

EDIT:

Please first check, what do you reply. For example: try this:

use 5.008;
$s=1;
say "hello";

You will get error message about the “say”, because perl 5.8 doesn’t know “say”

after, try this:

use 5.014;
$s=1;
say "hello";

you will get error

Global symbol "$s" requires explicit package name 

so, the “use 5.014” enabling use strict, and use feature 'say'; – by default.

Answer 1

Besides what raj correctly said about the error messages you’d receive if using use 5.014 with an older version of Perl, you can find a list of features enabled reading the source code of feature. The relevant part is near the top:

my %feature_bundle = (
    "5.10" => [qw(switch say state)],
    "5.11" => [qw(switch say state unicode_strings)],
    "5.12" => [qw(switch say state unicode_strings)],
    "5.13" => [qw(switch say state unicode_strings)],
    "5.14" => [qw(switch say state unicode_strings)],
);

The strict bit part is buried somewhat deeper in the code for the interpreter itself. If you look into pp_ctl.c for tag v5.11.0:

/* If a version >= 5.11.0 is requested, strictures are on by default! */

if (PL_compcv && vcmp(sv, sv_2mortal(upg_version(newSVnv(5.011000), FALSE))) >= 0) {
    PL_hints |= (HINT_STRICT_REFS | HINT_STRICT_SUBS | HINT_STRICT_VARS);
}