void *CtdlGetUserData(unsigned long requested_sym);
void CtdlAllocUserData(unsigned long requested_sym, size_t num_bytes);
void CtdlReallocUserData(unsigned long requested_sym, size_t num_bytes);
void *CtdlGetUserData(unsigned long requested_sym);
void CtdlAllocUserData(unsigned long requested_sym, size_t num_bytes);
void CtdlReallocUserData(unsigned long requested_sym, size_t num_bytes);