C++ In a Nutshell

Name

unexpected function — Handles an unexpected exception type

Synopsis

void unexpected(  )

If a function has an exception specification and throws an exception that is not listed in the exception specification, the unexpected function is called to handle the unexpected exception.

You can implement your own unexpected function. If you do so, you must ensure that unexpected does not return normally. It can terminate the program—for example, by calling terminate—or it can throw an exception.

If your unexpected function throws an exception that is not listed in the function’s exception specification, a new exception of type bad_exception is created and thrown. If the function’s exception specification does not list bad_exception, terminate is called automatically.

The default implementation of unexpected calls terminate.

In other words, if a function has an exception specification, it is guaranteed that only the specified exceptions can be thrown out of the function, or else the application will be terminated.

See Also

bad_exception class, set_unexpected function, abort in <cstdlib> , throw keyword