Re:Still in love with Rust
by flohofwoe on Thursday November 22, 2018 @04:38AM
(#18508951)
It depends heavily on how you're counting lines of code and what C++ features you're using.
If you include a couple of C++ stdlib headers you're already well past 45kloc per compilation unit (for instance, including <vector> pulls in about 25kloc of code). Such a file usually compiles in a second or so, but the problem in C++ projects is that each source file pulls in the same headers over and over, which explodes the line count the compiler has to crunch through (I bet that in most bigger C++ projects, the actual project code is less than 5% of what the compiler actually needs to compile).
C is much more predictable, a 45kloc C project should compile and link in under a second for a full rebuild without optimizations, and at most 2..3 seconds with optimizations. The link-step is usually the critical part, since that's hard to speed up by throwing more hardware resources at it.
If you include a couple of C++ stdlib headers you're already well past 45kloc per compilation unit (for instance, including <vector> pulls in about 25kloc of code). Such a file usually compiles in a second or so, but the problem in C++ projects is that each source file pulls in the same headers over and over, which explodes the line count the compiler has to crunch through (I bet that in most bigger C++ projects, the actual project code is less than 5% of what the compiler actually needs to compile).
C is much more predictable, a 45kloc C project should compile and link in under a second for a full rebuild without optimizations, and at most 2..3 seconds with optimizations. The link-step is usually the critical part, since that's hard to speed up by throwing more hardware resources at it.