Just adding some documentation triggers recompilation: Is there a solution?

Question

Sometimes, when I look through my header files I'd like to add something little to the (doxygen) documentation. That might be a quick note about the use of some function parameter, or just fixing a little typo.

But then I think: Oh no, that'll trigger a recompile on the next make call! And for certain basic headers the whole project would recompile, which can take a long time. So, nevermind!

Is there a solution to this dilemma? Are there approaches where the functions/classes are documented not directly in the headers? Or are there (plans for) a smart make that would notice that only some comment has changed, but no recompilation is necessary?

Answer 1

You could shorten the compile times using ccache, possibly with the CCACHE_UNIFY environment option set.

ccache hashes the pre-processor output, and serves the previously compiled object if no changes were detected.

Man page section about CCACHE_UNIFY

CCACHE_UNIFY

If you set the environment variable CCACHE_UNIFY then ccache will use the C/C++ unifier when hashing the pre-processor output if -g is not used in the compile. The unifier is slower than a normal hash, so setting this environment variable loses a little bit of speed, but it means that ccache can take advantage of not recompiling when the changes to the source code consist of reformatting only. Note that using CCACHE_UNIFY changes the hash, so cached compiles with CCACHE_UNIFY set cannot be used when CCACHE_UNIFY is not set and vice versa. The reason the unifier is off by default is that it can give incorrect line number information in compiler warning messages.