Elements of @_ are aliased to EXISTING/DEFINED elements of the passed parameter.
Not necessarily. 
perl -MData::Dump::Streamer -le '@ary = (); x($ary[5],"foo"); sub x { 
+$_[0] = $_[1] }; Dump(\@ary)'
$ARRAY1 = [
            ( undef ) x 5,
            'foo'
          ];
perl -MData::Dump::Streamer -le '@ary = (); x($ary[5],"foo"); sub x { 
+$_[0] }; Dump(\@ary)'
$ARRAY1 = [];

[download]

As you can see, the element at index 5 is not created merely by passing its alias to the sub. It doesn't exist and isn't defined, and may remain so after the sub has been called.

--shmem 

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

In reply to Re^4: perlsub question.. by shmem
in thread perlsub question.. by Anonymous Monk

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