class Base { public: virtual ~Base() {} }; class D1: public Base {}; class D2: public Base {}; int main(int argc,char* argv[]); { D1 d1; D2 d2; Base* x = (argc > 2)?&d1:&d2; if (dynamic_cast<D2*>(x) == nullptr) { std::cout << “NOT A D2” << std::endl; } if (dynamic_cast<D1*>(x) == nullptr) { std::cout << “NOT … Read more
There are Python libraries that can recognize files based on their content (usually a header / magic number) and that don’t rely on the file name or extension. If you’re addressing many different file types, you can use python-magic. That’s just a Python binding for the well-established magic library. This has a good reputation and … Read more
I have just found the builtin imghdr module. From python documentation: The imghdr module determines the type of image contained in a file or byte stream. This is how it works: >>> import imghdr >>> imghdr.what(‘/tmp/bass’) ‘gif’ Using a module is much better than reimplementing similar functionality UPDATE: imghdr is deprecated as of python 3.11