How do I set defines included through the toolchain?

[anthonymahshigian]

Hello! Some macros such as UINT_MAX are defined in files through the toolchain. One example of this is clang's limits.h https://clang.llvm.org/doxygen/limits_8h_source.html

How can I make DWYU aware of these? Is it possible for it to be aware of the toolchain at all? If not, a suboptimal solution could be to do something like what is done for extra_ignore_include_paths where we hardcode a list of includes available. FWIW I've been hardcoding a subset of the defines I care about via a patch and it's worked fine for my use case, but if there is a better way to do this that would be ideal. The reason defines may matter is they affect which includes are used.

Thanks!

[martis42]

It is an open TODO to incorporate the Bazel C++ toolchain as source for which headers are available to the targets.

It is hard to come with a generic solution to all potential cases involving defines without hooking into the compiler itself (which this project actively decided against for better or worse). I might introduce an interface to hard code whatever defines a user wants to be always set 🤔 Can't promise anything concrete yet though.