Cooperative multithreading via setjmp and longjmp has been around in C since the 80s at least.
I’m not sure this is so much hacking as an accepted technique from the old-old days which has somewhat fallen out of favour, especially as C is falling a little outside of the mainstream these days.
Perhaps it’s almost becoming lost knowledge :)
One of the most surprising things I discovered a while back is that this technique not only technically works in JavaScript, it actually beats its own built-in generator syntax in performance terms even if used as an iterable object:
https://jsbenchit.org/?src=1b165435c816c6d298e6b800b4742568
https://jsbenchit.org/?src=dedb07499cfa289b94d686bde05901df
Context: JS has an iteration protocol[0] that lets you create your own custom objects to be used with syntactic sugar for iteration. The sensible expectation is that the built-in syntax for generating such functions would produce the fastest code. It clearly doesn't.
Having said that I do not recommend manually writing code this way because if this is something that you need to worry about while writing JavaScript, it's a sign that you're using the wrong tool for the job anyway.
[0] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...
"everything old is new again" is so true. I see it across IT all the time, heh.
This isn't using setjmp/longjmp
It's using Simon Tatham's method based on Duff's device (https://www.chiark.greenend.org.uk/~sgtatham/coroutines.html)