abort, terminate or exit?

Question

What\'s the difference between those three, and how shall I end program in case of exception which I can\'t handle properly?

Answer 1

std::abort and std::exit (and more: std::_Exit, std::quick_exit) are just lower level functions. You use them to tell the program what you want it to do exactly: what destructors (and if) to call, what other clean-up functions to call, what value to return, etc.

std::terminate is a higher level abstraction: it is called (by either run-time or you) to indicate that an error in the program occurred and that for some reason it is not possible to handle by throwing an exception. The necessity for that typically occurs when error occurs in the exception mechanism itself, but you can use it any time when you do not want your program to continue beyond the given error. I compiled the full list of situations when std::terminate is called in my post. It is not specified what std::terminate does, because you are in control of it. You can configure the behavior by registering any functions. The limitations you have are that the function cannot return back to the error site and it cannot exit via an exception, but technically you can even start your message pump inside. For the list of useful things that you can do inside, see my other post.

In particular, note that std::terminate is considered an exception handler in contexts where std::terminate is called due to a thrown exception that could not be handled, and you can check what the exception was and inspect it by using C++11 using std::rethrow_exception and std::current_exception. It is all in my post.