Macros to help you wrap things

wrapper.h

#define DEF_WRAPPER(ret,name,...) typedef ret (*wrapped_##name##_t)(__VA_ARGS__); \
    static wrapped_##name##_t wrapped_##name = NULL; \
    ret name(__VA_ARGS__)

#define CALL_INNER(name, ...) (wrapped_##name ? wrapped_##name : (wrapped_##name = ((wrapped_##name##_t)dlsym(RTLD_NEXT,#name))))(__VA_ARGS__)


// Example:
//
//DEF_WRAPPER(ssize_t,send,int socket, const void *buffer, size_t length, int flags)
//{
//    return CALL_INNER(send, socket, buffer, length, flags);
//}