带有连接消息的c ++运行时错误

Question

我想在加载包含其路径

的位图时抛出错误

ALLEGRO_BITMAP* bitmap;
bitmap_path
if(bitmap=al_load_bitmap(bitmap_path)==0){
   throw runtime_error("error loading bitmap from: '"<<bitmap_path<<"'");
};
//continue if no error

Answer 1

您无法使用<<运算符直接连接字符串。

如果bitmap_path是std:::string，请改用+运算符：

throw runtime_error("error loading bitmap from: '" + bitmap_path + "'");

如果bitmap_path是char*，请将其或第一个字符串文字投放到临时std::string，以便您可以使用+：

throw runtime_error("error loading bitmap from: '" + string(bitmap_path) + "'");

throw runtime_error(string("error loading bitmap from: '") + bitmap_path + "'");

否则，您可以使用std::ostringstream或等效值构建临时std::string值：

ostringstream oss;
oss << "error loading bitmap from: '" << bitmap_path << "'";
throw runtime_error(oss.str());