c++ compiler errors in include files

Question

I am trying to compile c++ program and getting errors that I have no clue what they mean. The error seems to comes from cpp_type_traits.h included in cmath

c++ -o exprtk_test exprtk_simple_example_19.cpp
In file included from /system/gnu_library/lib/gcc/i686-stratus-vos/3.4.6/../../../../include/c++/3.4.6/cmath:50, from /USERS/Dev/TumeloQ/cpp_includes/exprtk.hpp:39, from exprtk_simple_example_19.cpp:24: /system/gnu_library/lib/gcc/i686-stratus-vos/3.4.6/../../../../include/c++/3.4.6/bits/cpp_type_traits.h:75: error: template with C linkage

Answer 1

It is not very clear from your question but quite possibly you are declaring a template or a function within an extern "C" block or qualifier. That is not allowed and is treated as an error.