C++ get description of an exception caught in catch(...) block

Question

can I get description of an exception caught by

catch(...) 

block? something like .what() of std::exception.

Answer 1

There is one trick you might be able to use:

catch(...) {     handle_exception(); }  void handle_exception() {     try {         throw;     } catch (const std::exception &e) {         std::cout << e.what() << "\n";     } catch (const int i) {         std::cout << i << "\n";     } catch (const long l) {         std::cout << l << "\n";     } catch (const char *p) {         std::cout << p << "\n";     } catch (...) {         std::cout << "nope, sorry, I really have no clue what that is\n";     } } 

and so on, for as many different types as you think might be thrown. If you really know nothing about what might be thrown then even that second-to-last one is wrong, because somebody might throw a char* that doesn't point to a nul-terminated string.

It's generally a bad idea to throw anything that isn't a std::exception or derived class. The reason std::exception exists is to allow everybody to throw and catch objects that they can do something useful with. In a toy program where you just want to get out of there and can't even be bothered to include a standard header, OK, maybe throw an int or a string literal. I don't think I'd make that part of a formal interface. Any exceptions you throw are part of your formal interface, even if you somehow forgot to document them.

Answer 2

That block might catch an int, or a const char*, or anything. How can the compiler possibly know how to describe something when it knows nothing about it? If you want to get information off an exception, you must know the type.