Maybe you shouldn't prejudge the quality of developers on a project you know nothing about

you should probably become more experienced in c/c++ development before sharing your opinion

You should see how quick C++ compilation times can be a competent organization like Google before dismissing that opinion.

Are you talking about clean builds or incremental builds?

They usually do incremental builds. And a lot of work goes into reproducible builds so that incremental builds can be trusted. But even clean builds are typically minutes of wall-clock time. Not hours.

Of course part of the trick is that work has been distributed across a cluster, so a lot longer was spent compiling than that...

How long should a giant C++ code base take to compile?

How giant is giant?

I've seen tens of thousands of lines of code compile in 30 minutes.

I've seen a hundred thousand lines of code compile in 2 minutes.

It really depends on how the project is laid out. If you're using lots of header-only libraries and try to compile monolithically (like soooooo many C++ applications do these days), you're going to have a bad (compile) time.

tens of thousands? that's small. we're talking MLOCs here.

With a good CMake configuration and Ninja and ccache, a minute or two max.

Your CMake makes incremental builds safe, and the ccache saves you when switching between branches.

CMake helps a good bit, ccache goes further, and ninja helps a bit too. But none of them can help templated header-only libraries with complex interdependencies. It gets particularly bad when the developer #includes a convenience header to bring in _everything_ in the library instead of just what they need.

Agreed. Good use of PImpl when you have large external header-only libraries is also generally recommended to keep the dependency graph nicer.

Also from what I've seen, large header-only codebases tend to be external and thus generally don't change that much, so if you can limit your own internal dependency tree ccache can still save you.