For What Its Worth: example of build error uc51.cc: In member function 'virtual const char* cl_51core::disass(t_addr, const char*)': uc51.cc:335:37: error: unable to find string literal operator 'operator""_A_' with 'const char [5]', 'long unsigned int' arguments sprintf(temp, "%04"_A_"x", ^~~ uc51.cc:341:37: error: unable to find string literal operator 'operator""_A_' with 'const char [5]', 'long unsigned int' arguments sprintf(temp, "%04"_A_"x", ^~~ uc51.cc:347:39: error: unable to find string literal operator 'operator""_M_' with 'const char [5]', 'long unsigned int' arguments sprintf(temp, "%02"_M_"x", rom->get(addr+1)); ^~~ uc51.cc:351:39: error: unable to find string literal operator 'operator""_M_' with 'const char [5]', 'long unsigned int' arguments sprintf(temp, "%02"_M_"x", rom->get(addr+2)); ^~~