unexpected

void unexpected();

The function calls the current unexpected handler, a function of type void () called when control leaves a function by a thrown exception of a type not permitted by an exception specification for the function, as in:

void f() throw()      // function may throw no exceptions
    {throw "bad"; }   // unexpected throw calls unexpected()

An unexpected handler may not return to its caller. It may terminate execution by:

• Throwing an object of a type listed in the exception specification.
• Throwing an object of type bad_exception.
• Calling terminate(), abort(), or exit(int).

At program startup, the unexpected handler is a function that calls terminate().