Compiling an XCode project for IOS using Apple LLVM 3.1 (so clang).

arm_neon.h is choking on float32_t not being defined (even tho the typedef clearly is there).

It cannot find "cerrno" for include, can be fixed with a better define guard for that. Then it cannot find cstdlib and so on.

Macros.h
line 188 dies on "Unknown type name 'namespace' meaing something above is causing some weird error.

There is a ton of other C++ stuff compiling in this project with no issues, using a bunch of tr1 c++11x stuff as well. As soon as I include Eigen it barfs.

I've used Eigen a ton in the past on Windows, Linux and Android without issues.

Any tips?

If I force #define EIGEN_NO_DEBUG then the only error remaining is the missing cerrno. In fact it appears all the cXXX libs are missing (cstdlib for example). Yet they work if I include them outside of Eigen.

The file I'm including some C++ files from (which include Eigen) is an .mm file so I assume it would be using clang++.

Under "SupportingFiles" was main.m. This means clang was being used to compile main.m which included the files and eventually lead to Eigen being compiled with the wrong compiler. I am surprised there was not a million more errors.

Rename main.m to main.mm, problems solved.