[LukeShu]

    > I don't know how many hours the author has spent/wasted
    > on this topic

The author, John Graham-Cumming, has been extremely active on the GNU Make mailing list, is the author of the "GNU Make Standard Library" of supplemental functions for Make, has written at least 2 books on GNU Make, and has developed commercial products that integrate with GNU Make (namely, "Electric Make").

That is to say: He is one of the world experts on GNU Make.

I'm confident that he did this more "for fun" than because he actually wanted to get the number of jobs.

[jgrahamc]

Yes. It was 'for fun'. Someone at CloudFlare asked me how to get the value of -j and I figured there must be some way :-)

[jordigh]

Do you know if this person hangs out in IRC? I asked this precise question 10 days ago in #emacs, and I was curious to see my precise question answered, almost the way I phrased it.

[jgrahamc]

Too funny. I think it's just random chance. Although he is an emacs user.