Retrieve hash between two subroutines

Question

I would retrieve my hash table when i pass it in argument at a function. In my case, function1 return my hash table, then i pass my hash table in argument to my function2 and in my function2 i would retrieve my hash table for browse it.

sub function1{
    my code;
    return %hash;
}

sub function2{
    my %hash=$_[0];
    my code browse my hash;
}

my %hash = function1();
function2(%hash);

I have the following error : Odd number of elements in hash assignment at

Answer 1

An alternative is to pass the hash by reference:

sub function1{
    # code here
    return \%hash;
}

sub function2{
    my $hashref = $_[0];

    #code to use the hash:
    foreach (keys %$hashref) { etc... }
}

my $hashref = function1();
function2($hashref);

my %realhash;
function2(\%realhash);

Passing by reference is a necessity when you want to pass more than one hash or array. It is also more efficient for large amounts of data, because it doesn't make a copy. However, if the function modifies a hash that was passed by reference, the original will be modified as well.