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败犬日报 2024-10-19 ​

1. 编译期判断一个类型为常指针 ​

cpp
#include <type_traits>

template <typename T>
concept IsConstPointer =
    std::is_pointer_v<T> && std::is_const_v<std::remove_pointer_t<T>>;

template <typename T>
concept IsConstPointerV2 = requires {
    requires std::is_pointer_v<T>;
    requires std::is_const_v<std::remove_pointer_t<T>>;
};

// 没有 concept 可以这么写
template <typename T>
constexpr bool IsConstPointerV3 =
    std::is_pointer_v<T> && std::is_const_v<std::remove_pointer_t<T>>;

int main() {
    static_assert(IsConstPointer<const int*>);
    static_assert(!IsConstPointer<int>);
    static_assert(!IsConstPointer<const int>);
    static_assert(!IsConstPointer<int*>);
}