Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

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const value_type &&assume_value() const && noexcept

Narrow contract const rvalue reference observer of any value present. NoValuePolicy::narrow_value_check() is first invoked, then the reference to the value is returned. The convention is that hard undefined behaviour occurs if no value is actually present, however NoValuePolicy::narrow_value_check() can do something to avoid that.

Note that if value_type is void, only a const overload returning void is present.

Requires: Always available.

Complexity: Depends on NoValuePolicy::narrow_value_check().

Guarantees: An exception is never thrown.

Last revised: February 12, 2019 at 16:36:24 UTC

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