C++ Primer Plus

More Exception Features

Although the throw-catch mechanism is similar to function arguments and the function return mechanism, there are a few differences. One, which you’ve already encountered, is that a return statement in a function fun() transfers execution to the function that called fun(), but a throw transfers execution all the way up to the first function having a try-catch combination that catches the exception. For example, in Listing 15.12, when hmean() throws an exception, control passes up to means(), but when gmean() throws an exception, control passes up to main().

Another difference is that the compiler always creates a temporary copy when throwing an exception, even if the exception specifier and catch blocks specify a reference. ...