I have a multiply nested namespace:
namespace first {namespace second {namespace third { // emacs indents three times // I want to intend h
Use an an absolute indentation column inside namespace:
(defconst my-cc-style '("gnu" (c-offsets-alist . ((innamespace . [4]))))) (c-add-style "my-cc-style" my-cc-style)
Then use c-set-style to use your own style.
Note that this only works in c++-mode, c-mode doesn't know 'innamespace'.