Exception Handling in C++
Exception matching
Catching any exception
Sometimes you want to create a handler that catches any type of exception. You do this using the ellipsis in the argument list:
catch(...) { cout << "an exception was thrown" << endl; }
Because an ellipsis catches any exception, you'll want to put it at the end of your list of handlers to avoid pre-empting any that follow it.
The ellipsis gives you no possibility to have an argument, so you can't know anything about the exception or its type. It's a "catchall." Such a catch clause is often used to clean up some resources and then rethrow the exception.