Question

I often have a subroutine in Perl that fills an array with some information. Since I’m also used to hacking in C++, I find myself often do it like this in Perl, using references:

my @array; getInfo(\@array);  sub getInfo {    my ($arrayRef) = @_;    push @$arrayRef, 'obama';    # ... } 

instead of the more straightforward version:

my @array = getInfo();  sub getInfo {    my @array;    push @array, 'obama';    # ...    return @array; } 

The reason, of course, is that I don’t want the array to be created locally in the subroutine and then copied on return.

Is that right? Or does Perl optimize that away anyway?

Answer 1

What about returning an array reference in the first place?

sub getInfo {   my $array_ref = [];   push @$array_ref, 'foo';   # ...   return $array_ref; }  my $a_ref = getInfo(); # or if you want the array expanded my @array = @{getInfo()}; 

Edit according to dehmann’s comment:

It’s also possible to use a normal array in the function and return a reference to it.

sub getInfo {   my @array;   push @array, 'foo';   # ...   return \@array; }