4 ms·

Does anyone using C++ for a real project actually enjoy 3-second compile times? It wasn't a great example to make their case (except in a narrow comparison to C

Does anyone using C++ for a real project actually enjoy 3-second compile times? It wasn't a great example to make their case (except in a narrow comparison to C), but it doesn't make for a very realistic counter-point much either. Compile times are definitely a headache for me.

FpUser 5y ago
I have decent size project and when I change something here and there it takes about that long to recompile and run. Full rebuild goes for longer but it is parallelized and is stile very reasonable.
TaylorPhebillo 5y ago
Do you mean as high as 3 seconds, or as low as 3 seconds? C++ compile times on a template heavy project I used recently were in the hours- you'd basically compile overnight and before you went to lunch.
- ncmncm 5y ago
  Only if you are too masochistic to fix up your build.
  - maccard 5y ago
    I'm sure projects like chromium and llvm would love for you to just fix their build times.
    - tom_ 5y ago
      And Unreal Engine too, please.
      - maccard 5y ago
        I used to work for Epic, and I did a good chunk of work on the game projects build times with reasonable success. Unfortunately I couldn't really change too much inside the engine because of backwards compatibility. Removing headers from other public interface headers has the possibility of breaking users code, which is a no-no so their hands are pretty tied. There are definitely some big wins to be had if they're willing to break back compat though!
        usefulcat 5y ago
        Even without that restriction it's not that easy. It generally comes down to a choice between: a) #include <vector> -- Lots of dependencies, but I know it works and I don't want to reinvent the wheel b) #include <my_vector.h> -- Ok, I'm going to reinvent the wheel, but at least my wheel might have slightly fewer dependencies. c) //#include <vector> // I'll just do without the wheel entirely
        maccard 5y ago
        With ue4 that's not really the problem, it mostly falls under category b). The problem is that a bunch of stuff has unneeded module dependencies that hide the real dependency tree. Say a.h includes b.h but doesn't use anything from module B, but b.h includes SomeFundamentalHeader.h which a does need. The choice here is leave it alone or fix the dependency but break any user code that relies on the same behaviour. I did just that in a few modules that were new and off by default but good luck making a change like that in any commonly used modules.

FpUser 5y ago

I have decent size project and when I change something here and there it takes about that long to recompile and run. Full rebuild goes for longer but it is parallelized and is stile very reasonable.

TaylorPhebillo 5y ago

Do you mean as high as 3 seconds, or as low as 3 seconds? C++ compile times on a template heavy project I used recently were in the hours- you'd basically compile overnight and before you went to lunch.

ncmncm 5y ago
Only if you are too masochistic to fix up your build.
- maccard 5y ago
  I'm sure projects like chromium and llvm would love for you to just fix their build times.
  - tom_ 5y ago
    And Unreal Engine too, please.
    - maccard 5y ago
      I used to work for Epic, and I did a good chunk of work on the game projects build times with reasonable success. Unfortunately I couldn't really change too much inside the engine because of backwards compatibility. Removing headers from other public interface headers has the possibility of breaking users code, which is a no-no so their hands are pretty tied. There are definitely some big wins to be had if they're willing to break back compat though!
      - usefulcat 5y ago
        Even without that restriction it's not that easy. It generally comes down to a choice between: a) #include <vector> -- Lots of dependencies, but I know it works and I don't want to reinvent the wheel b) #include <my_vector.h> -- Ok, I'm going to reinvent the wheel, but at least my wheel might have slightly fewer dependencies. c) //#include <vector> // I'll just do without the wheel entirely
        maccard 5y ago
        With ue4 that's not really the problem, it mostly falls under category b). The problem is that a bunch of stuff has unneeded module dependencies that hide the real dependency tree. Say a.h includes b.h but doesn't use anything from module B, but b.h includes SomeFundamentalHeader.h which a does need. The choice here is leave it alone or fix the dependency but break any user code that relies on the same behaviour. I did just that in a few modules that were new and off by default but good luck making a change like that in any commonly used modules.