in reply to Re: (jptxs)Re: use _specific_ version
in thread use _specific_ version

I don't see anybody who has coded what you want. Several have given you code to check which version was called, but none to pull the version of Perl that you wanted.

If this is just for testing, then I would recommend a wrapper script that explicitly calls the wanted version of Perl. Call the wrapper script and it should just work.

(Don't forget that the wrapper may need to set environment variables, etc for your client's environment.)