signed_integral.md

signed_integral

• concepts[meta header]
• std[meta namespace]
• concept[meta id-type]
• cpp20[meta cpp]

namespace std {
  template<class T>
  concept signed_integral = integral<T> && is_signed_v<T>;
}

• integral[link /reference/concepts/integral.md]
• is_signed_v[link /reference/type_traits/is_signed.md]

概要

signed_integralは、任意の型Tが符号付き整数型であることを表すコンセプトである。

備考

charなど、符号付整数型でなくてもsigned_integralのモデルとなる型が存在する。

例

#include <iostream>
#include <concepts>
#include <cstdint>
#include <type_traits>

template<std::signed_integral T>
void f(const char* name) {
  std::cout << name << " is signed_integral" << std::endl;
}

template<typename T>
void f(const char* name) {
  std::cout << name << " is not signed_integral" << std::endl;
}


int main() {
  f<int>("int");
  f<std::int64_t>("std::int64_t");
  f<int>("char");

  std::cout << "\n";

  f<bool>("bool");
  f<std::size_t>("std::size_t");
  f<std::uint32_t>("std::uint32_t");
  f<char8_t>("char8_t");
  f<int*>("int*");
  f<int&>("int&");
  f<std::integral_constant<int, 1>>("std::integral_constant<int, 1>");
}

• std::integral[color ff0000]

出力

int is signed_integral
std::int64_t is signed_integral
char is signed_integral

bool is not signed_integral
std::size_t is not signed_integral
std::uint32_t is not signed_integral
char8_t is not signed_integral
int* is not signed_integral
int& is not signed_integral
std::integral_constant<int, 1> is not signed_integral

バージョン

言語

• C++20

処理系

• Clang: ??
• GCC: 10.1 [mark verified]
• Visual C++: 2019 Update 3 [mark verified]

関連項目

• C++20 コンセプト

参照

• P0898R3 Standard Library Concepts
• P1754R1 Rename concepts to standard_case for C++20, while we still can