http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54112
--- Comment #2 from Marc Glisse <glisse at gcc dot gnu.org> 2012-07-28 10:26:42 UTC --- (In reply to comment #1) > Why it happens only in C++03 mode? Because the complex.h wrapper distributed with libstdc++ does: #ifdef __GXX_EXPERIMENTAL_CXX0X__ # include <ccomplex> #else # if _GLIBCXX_HAVE_COMPLEX_H # include_next <complex.h> # endif #endif That's what I meant by "hijack", the system's complex.h can never be included in C++11. > I'm asking because if the issue isn't a > regression and we are sure that it doesn't happen in C++11 mode, I don't think > it can be considered high priority. I am not saying it is high priority (on the other hand, it is rather easy). Note that there are 2 issues (I should have been clearer): 1) we can't include both complex.h and complex in C++03 mode. The fix is trivial, #undef complex after the #include_next quoted above. The other headers all have a long list of #undef, that's just one more. 2) In C++11, there is no way to have cacos declared. A solution would be to move the _GLIBCXX_HAVE_COMPLEX_H block outside of the __GXX_EXPERIMENTAL_CXX0X__ condition.
