this is the public C interface to the ODE library.
all these files should be includable from C, i.e. they should not use any
C++ features. everything should be protected with
#ifdef __cplusplus
extern "C" {
#endif
...
#ifdef __cplusplus
}
#endif
the only exceptions are the odecpp.h and odecpp_collisioh.h files, which define a C++ wrapper for
the C interface. remember to keep this in sync!