What are the C/C++ documentation tools that you have used? Which one would you recommend?
I have used doxygen with graphviz but it seems to have a problem with large code bases especially when generating collaboration diagrams.
I found DoxyS on the web but have not used it. Going by the documention on its homepage it looks like its worth trying out.
Doxys is based on doxygen so any problems you are having with doxygen are likely to be present also in doxys. I had asked a question a while ago about performance of doxygen here: How to get doxygen to run faster?
I have used cxref in the past. It is C-only, but I find that it is nice and simple to use. I tend to prefer doxygen nowadays.
We too experienced performance problems with Doxygen when running it on all our codebase at once. We solved the problem by running Doxygen on each module separately, and using tagfiles to link them.
Alternatively, you could try Synopsis. It seems interesting but I never tried it, as we are currently satisfied with the Doxygen-with-tagfiles solution.
I'm an old-time literate programmer. Noweb has some barely adequate indexing and cross-reference for C.
@Michael:
The code base has roughly 2500 files. It is a mix of C/C++. The problems was that doxygen would never complete when I had the configuration updated to generate collaboration diagrams.