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std::any_cast

性病：任何[医]铸造

template ValueType any_cast(const any& operand(1)(since C++17)
template<class ValueType> ValueType any_cast(any& operand(2)(since C++17)
template<class ValueType> ValueType any_cast(any&& operand(3)(since C++17)
template<class ValueType> const ValueType* any_cast(const any* operand(4)(since C++17)
template<class ValueType> ValueType* any_cast(any* operand(5)(since C++17)

执行对所包含对象的类型安全访问。

让U成std::remove_cv_t<std::remove_reference_t<ValueType>>...

1%29该项目的格式不正确，如果is_constructible_v<ValueType, const U&>不是true...

2%29该项目的格式不正确，如果is_constructible_v<ValueType, U&>不是true...

3%29该项目的格式不正确，如果is_constructible_v<ValueType, U>不是true...

参数

operand-target any object

返回值

1-2%29static_cast<ValueType>(*std::any_cast<U>(&operand))

3%29static_cast<ValueType>(std::move(*std::any_cast<U>(&operand)))...

4-5%29operand不是空指针，而typeid所要求的ValueType的内容与operand，指向操作数包含的值的指针，否则为空指针。

例外

1-3%29投std::bad_any_cast如果typeid所要求的ValueType的内容不匹配。operand...

4-5%29

noexcept规格：

noexcept

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