Cpp Coding Standards/CODEDOC/ClearBehave
Writing documentation is a tedious and - for many – unpleasant task and it takes time. To have more time for the important comments, leave out the unnecessary. A good function name often can spare many lines of documentation.
On the other hand some facts about each function have to be unambiguously clear: Preconditions, postconditions, possibly invariants, and the behaviour in error cases. If any of these stay unclear, documentation is necessary.