You could use a file instead, but `pipe` is the most portable way to not leave clutter on the system if something goes wrong. If you need traffic in both directions, `socketpair` is useful (and I think portable across platforms that support networking as we know it).

Less-portable or less-reliable alternatives include `memfd`, a deleted-but-still-open tempfile, etc.

To avoid problems with failure after `exec`, it is very important to fork+exec the server first just to see if it actually starts. If you don't need the PID to remain the same you can actually just use that instance without the other fork or another exec (this still keeps the same PGID). Note that "failure after `exec`" can be fairly sharply divided into "error in C runtime (usually, library compatibility)" and "error in something `main` calls", which require very different approaches.

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Aside: I've had catastrophic failures using the "save after fork" approach (mentioned later in the article) when the child process crashed before the save completed, and the parent just kept trying to have the child save (I also managed to completely crash GDB while investigating this). It is very important for the parent to commit suicide if the child can't do its job, to minimize the amount of lost data.

The other thing I would recommend to anyone working with this kind of thing: use systemd and commit all the way; it will make your life 1000% easier than trying to reimplement it badly yourself.