Your prototype definition is wrong. Your definition of (@) says that your sub takes one array or list as argument, so all arguments are flattened into one list. This is the way any "normal" subroutine without prototypes works.

However now consider this:

use Modern::Perl;

sub create_output (\@$) {
    my ($arrayref_of_lines, $entry_no_new) = @_;
    say "array:  @{$arrayref_of_lines}";
    say "scalar: $entry_no_new";
}
my @array = qw/1 2 3 4/;
create_output @array, 5;

[download]
And its output:
array:  1 2 3 4
scalar: 5

[download]

This is actually one of the few cases of a prototype being applied in a useful way.

The prototype (\@$) means the first argument to your sub MUST start with a @ (in other words, it must be an array), followed by a scalar. Due to the (\@) in the prototype, Perl actually takes a reference to the array and passes that as the first argument to your sub. So don't you forget to de-reference it in your sub!

It is this automagical referencing that allows you to pass one or more arrays to a subroutine without them all getting flattened in one big @_.

CountZero

A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James

My blog: Imperial Deltronics

In reply to Re: Passing variables into a subroutine by CountZero
in thread Passing variables into a subroutine by Freezer

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.