Having transitioned to OS X Mavericks and XCode 5.0.1, I can no longer gracefully link compiled C files (output from gcc) to a C++ project (output from g++).
The off
Most probably you are a victim of Name mangling. To avoid name mangling in C++, use extern "C" around declarations, like:
extern "C"
#ifdef __cplusplus extern "C" { #endif void load_dmat(char const*); #ifdef __cplusplus } #endif