Using the environment won't work.

My recommendation is to simply use files to transfer the information.

For alternative approaches, see perlipc and the discussion in your previous thread. But none of the solutions beats using files written by the children and polling for these files in the parent for simplicity. Threads::Queue comes close, but only if you can write your children as threads instead of separate processes.

Depending on the size of information, you can even get by by appending to a single file and using File::Tail in the parent.