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Ask HN: C/C++ adjusting variables at runtime

5 points by scraft ↗ HN
I recall hearing of a library that can be linked into a C/C++ program that allows you to register variables. When your application is launched, the library would start a webserver, which you can then connect to. The displayed webpage would then show you all the variables you have registered and allow you to adjust them.

In terms of games development, this would be very useful, but after spending 90 minutes searching Google, I can't find the library. Either it no longer exists, my search terms are bad, or perhaps I made up this whole idea in my head.

Can anyone help?

8 comments

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to3m
I wrote an HTTP server (https://github.com/tom-seddon/yhs) with pretty much exactly this use case in mind. (This influenced the main unusual thing about it: it doesn't use threads, the idea being that when your function is called in response to an HTTP request, you're less likely to have to do anything special before modifying values as requested.)

The code is mostly complete, and should be usable as-is, but I never ended up using it in anger. My quick and dirty stopgap solution at the time was some on-screen (on the iPhone) widgets, and people seemed to prefer that in the end, because it meant they didn't need a computer/second iPhone/etc. So I never rolled out an HTTP-based equivalent.

If I were doing it again, I probably wouldn't bother with a full(ish) HTTP implementation - I'd support only WebSockets. Then write the Javascript client code separately from the game, and store it separately in SVN or whatever. Faster iteration on the client code, and you can update the UI stuff separately from the game.

Though of course, if people preferred on-screen widgets once, they might then still prefer it a second time ;)

(As an example, a project that's on my must-take-a-closer-look list, that I believe but works in the way I suggest: https://github.com/Celtoys/Remotery)

shortoncash
Kuck and Associates had a performance tuning library with OpenMP support years ago that did this or something similar to this around 17 years ago. They got acquired by Intel. I don't know if Intel's compilers and libraries still have this feature.