#define SOL_CHECK_ARGUMENTS #include #include int main(int, char**) { std::cout << "=== script error handling example ===" << std::endl; sol::state lua; std::string code = R"( bad&$#*$syntax bad.code = 2 return 24 )"; /* OPTION 1 */ // Handling code like this can be robust // If you disable exceptions, then obviously you would remove // the try-catch branches, // and then rely on the `lua_atpanic` function being called // and trapping errors there before exiting the application { // default_on_error throws / panics when the code is bad: trap the error try { int value = lua.script(code, sol::default_on_error); // This will never be reached assert(false); } catch (const sol::error& err) { std::cout << "Something went horribly wrong: thrown error" << "\n\t" << err.what() << std::endl; } } /* OPTION 2 */ // Use the simple_on_error handler // this simply passes through the protected_function_result, // rather than throwing it or calling panic // This will check code validity and also whether or not it runs well { sol::protected_function_result result = lua.script(code, sol::simple_on_error); assert(!result.valid()); if (!result.valid()) { sol::error err = result; sol::call_status status = result.status(); std::cout << "Something went horribly wrong: " << sol::to_string(status) << " error" << "\n\t" << err.what() << std::endl; } } /* OPTION 3 */ // This is a lower-level, more explicit way to load code // This explicitly loads the code, giving you access to any errors // plus the load status // then, it turns the loaded code into a sol::protected_function // which is then called so that the code can run // you can then check that too, for any errors // The two previous approaches are recommended { sol::load_result loaded_chunk = lua.load(code); assert(!loaded_chunk.valid()); if (!loaded_chunk.valid()) { sol::error err = loaded_chunk; sol::load_status status = loaded_chunk.status(); std::cout << "Something went horribly wrong loading the code: " << sol::to_string(status) << " error" << "\n\t" << err.what() << std::endl; } else { // Because the syntax is bad, this will never be reached assert(false); // If there is a runtime error (lua GC memory error, nil access, etc.) // it will be caught here sol::protected_function script_func = loaded_chunk; sol::protected_function_result result = script_func(); if (!result.valid()) { sol::error err = result; sol::call_status status = result.status(); std::cout << "Something went horribly wrong running the code: " << sol::to_string(status) << " error" << "\n\t" << err.what() << std::endl; } } } return 0; }