Don't create a std::string with a nullptr
Don't create a std::string with a nullptr

dreamsxin/PHP-CPP,sjinks/PHP-CPP,CopernicaMarketingSoftware/PHP-CPP,sjinks/PHP-CPP,CopernicaMarketingSoftware/PHP-CPP-LEGACY,CopernicaMarketingSoftware/PHP-CPP,CopernicaMarketingSoftware/PHP-CPP-LEGACY,sjinks/PHP-CPP,dreamsxin/PHP-CPP,sjinks/PHP-CPP