> I would prefer to only use platform specific code when the platform provides something like pidfd: I understand that Linux, FreeBSD, OpenBSD, NetBSD, and Illumos are concerned. I mean reuse an exisiting solution, rather than writing our own "workaround" (solution?).

By the way, I suggest to stick to the initial problem in this issue. If someone is intersted to explore the pidfd idea, I recommend to open a different issue ;-)