use strict;

my @a=qw/abc def ghi/;

sub qwe(*@) {
 my $w=shift;
 shift @$w;
}

qwe(\@a);

print @a;
[download]

The previous code is correct to delete one element of array. But you can always do some "misprints". And get just a "fake" procedure call.

use strict;

my @a=qw/abc def ghi/;

sub q(*@) {
 my $w=shift;
 shift @$w;
}

q(\@a);

print @a;
[download]

In the previous code nothing is done to @a.