IPC::Shm implements shared memory Perl variables as follows:

use IPC::Shm;
our %variable1 : shm;

The variable by that name in that package will always have the same
contents in any process, and will persist beyond the processes'
lifetimes.

Lexicals are supported, but since they are by definition unlocatable
without being supplied a reference, they will be garbage collected
when the program exits unless another shared memory variable has
a reference to it. (TODO).

Currently, scalars and hashes are supported, with arrays to follow.