Disposition

A type X satisfies the disposition concept if it is nothrow default-constructible, nothrow move-constructible, nothrow move-assignable, as well as satisfying the additional requirements listed below. In the following table x denotes a glvalue of type X.

Table 12. Disposition requirements

expression	return type	assertion/note pre/post-conditions
`boost::asio::disposition_traits<X>::not_an_error(x)`	`bool`
`boost::asio::disposition_traits<X>::throw_exception(x)`		pre: `boost::asio::disposition_traits<X>::not_an_error(x)` is `false.` This function call must exit via an exception.
`boost::asio::disposition_traits<X>::to_exception_ptr(x)`	`std::exception_ptr`