#define SOL_CHECK_ARGUMENTS #include #include int main() { std::cout << "=== protected_functions example ===" << std::endl; sol::state lua; lua.open_libraries(sol::lib::base); // A complicated function which can error out // We define both in terms of Lua code lua.script(R"( function handler (message) return "Handled this message: " .. message end function f (a) if a < 0 then error("negative number detected") end return a + 5 end )"); // Get a protected function out of Lua sol::protected_function f = lua["f"]; // Set a non-default error handler f.error_handler = lua["handler"]; sol::protected_function_result result = f(-500); if (result.valid()) { // Call succeeded int x = result; std::cout << "call succeeded, result is " << x << std::endl; } else { // Call failed sol::error err = result; std::string what = err.what(); std::cout << "call failed, sol::error::what() is " << what << std::endl; // 'what' Should read // "Handled this message: negative number detected" } std::cout << std::endl; }