unhandled-cpp-exceptions.md

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Learn more about: Unhandled C++ exceptions	Unhandled C++ exceptions	11/04/2016	event handlers [C++], unhandled exceptions catch keyword [C++], handler not found exceptions [C++], unhandled C++ exception handling, unhandled exceptions unhandled exceptions [C++]	13f09c53-9254-4407-9db9-14e730e047cc

Unhandled C++ exceptions

If a matching handler (or ellipsis catch handler) cannot be found for the current exception, the predefined terminate run-time function is called. (You can also explicitly call terminate in any of your handlers.) The default action of terminate is to call abort. If you want terminate to call some other function in your program before exiting the application, call the set_terminate function with the name of the function to be called as its single argument. You can call set_terminate at any point in your program. The terminate routine always calls the last function given as an argument to set_terminate.

Example

The following example throws a char * exception, but does not contain a handler designated to catch exceptions of type char *. The call to set_terminate instructs terminate to call term_func.

// exceptions_Unhandled_Exceptions.cpp// compile with: /EHsc #include<iostream>usingnamespacestd;voidterm_func() { cout << "term_func was called by terminate." << endl; exit( -1 ); } intmain() { try { set_terminate( term_func ); throw"Out of memory!"; // No catch handler for this exception } catch( int ) { cout << "Integer exception raised." << endl; } return0; }

Output

term_func was called by terminate. 

The term_func function should terminate the program or current thread, ideally by calling exit. If it doesn't, and instead returns to its caller, abort is called.

See also

Modern C++ best practices for exceptions and error handling