Ranges
The ranges library are a great addition to the C++ standard. However they can increase compilation times; especially when used in template headers which are included by other translation units. It also caused the following error: 'error C1128: number of sections exceeded object file format limit: compile with /bigobj'.
The specific use case was a template class which used the range library in two ways:
- use of ranges functions; e.g. std::ranges::adjacent_find(...)
- use of a view; e.g. std::ranges::binary_search(std::views::keys(deq), h);
It turned out that especially the view was heavy for the compiler. Leaving out the range in the code improved compile times with 30% for a piece of code and 10% overall in a large application. The numbers can o.f.c. vary per use case.
Conclusion
If compile times are paramount and you have a header which is included a lot and uses the range library you could measure its impact on compilation times. if it contributes too much replace it with pre range constructs.
