    inline void srand(const cimg_uint64 seed) {
      cimg::mutex(4);
      cimg::rng() = seed;
      cimg::mutex(4,0);
    }
    inline void srand(const cimg_uint64 seed) {
      cimg::mutex(4);
      cimg::rng() = seed;
      cimg::mutex(4,0);
    }