class class1:
public:
...
private:
class impl; //the class that i wanna hide
std::unique_ptr<impl> impl_;
//我的 doxygen 文件:
EXTRACT_ALL = 是
EXTRACT_PRIVATE = 否
EXTRACT_PACKAGE = 否
EXTRACT_STATIC = 否
EXTRACT_LOCAL_CLASSES = 是
EXTRACT_LOCAL_METHODS = 否
HIDE_UNDOC_MEMBERS = 是
HIDE_UNDOC_CLASSES = 否