4 General utilities library [utilities]

4.2 Utility components [utility]

4.2.3 static_­downcast [static.downcast]

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A static_­cast that performs a downcast.
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template <class DerivedRef, class Base> constexpr DerivedRef static_downcast(Base&& base) noexcept;
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Let derived-ref be static_­cast<DerivedRef>(std​::​forward<Base>(base)).
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Constraints:
  • (3.1)
    DerivedRef is a reference type,
  • (3.2)
    std​::​remove_­cvref_­t<DerivedRef> is derived from std​::​remove_­cvref_­t<Base>, and
  • (3.3)
    derived-ref is well-formed.
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Preconditions: derived-ref has well-defined behavior.
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Returns: derived-ref.