22.4.3 Class template tuple [tuple.tuple] C++N4910:2022 (534) p676.cpp

# はじめに(Introduction)

N4910  Working Draft, Standard for Programming Language C++

http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/n4910.pdf

n4910は、ISO/IEC JTC1 SC22 WG21の作業原案(Working Draft)です。
公式のISO/IEC 14882原本ではありません。
ISO/IEC JTC1 SC22 WG21では、可能な限り作業文書を公開し、幅広い意見を求めています。
一連の記事はコード断片をコンパイルできる形にする方法を検討してコンパイル、リンク、実行して、規格案の原文と処理系(g++, Clang++)との違いを確認し、技術内容を検討し、ISO/IEC JTC1 SC22 WG21にフィードバックするために用います。
また、CERT C++, MISRA C++等のコーディング標準のコード断片をコンパイルする際の参考にさせていただこうと考えています。CERT C++, MISRA C++が標準化の動きとの時間的なずれがあれば確認できれば幸いです。また、boostライブラリとの関連、Linux OS, TOPPERSカーネル、g++(GCC), clang++(LLVM）との関係も調査中です。
何か、抜け漏れ、耳より情報がありましたらおしらせくださると幸いです。

 <この項は書きかけです。順次追記します。>

## 背景(back ground)
C/C++でコンパイルエラーが出ると、途方にくれることがしばしばあります。
何回かに１回は、該当するエラーが検索できます。
ただ、条件が違っていて、そこでの修正方法では目的を達成しないこともしばしばです。いろいろな条件のコンパイルエラーとその対応方法について、広く記録することによって、いつか同じエラーに遭遇した時にやくに立つことを目指しています。

この半年の間で、三度、自分のネットでの記録に助けられたことがあります。
また過去に解決できなかった記録を１０種類以上、最近になって解決できたことがあります。それは、主に次の３つの情報に基づいています。

https://stackoverflow.com
https://cpprefjp.github.io
http://ja.cppreference.com/

また
https://researchmap.jp/joub9b3my-1797580/#_1797580
に記載したサイトのお世話になっています。

## 作業方針(sequence)
Clang++では-std=c++03, C++2bの2種類
g++では-std=c++03, c++2bの２種類
でコンパイルし、

１）コンパイルエラーを収集する。
２）コンパイルエラーをなくす方法を検討する。
コンパイルエラーになる例を示すだけが目的のコードは、コンパイルエラーをなくすのではなく、コンパイルエラーの種類を収集するだけにする。
文法を示すのが目的のコード場合に、コンパイルエラーをなくすのに手間がかかる場合は、順次作業します。
３）リンクエラーをなくす方法を検討する。
文法を示すのが目的のコード場合に、リンクエラーをなくすのに手間がかかる場合は、順次作業します。
４）意味のある出力を作る。
コンパイル、リンクが通っても、意味のある出力を示そうとすると、コンパイル・リンクエラーが出て収拾できそうにない場合がある。順次作業します。

１）だけのものから４）まで進んだものと色々ある状態です。一歩でも前に進むご助言をお待ちしています。「検討事項」の欄に現状を記録するようにしています。

### C++N4910:2022 Standard Working Draft on ISO/IEC 14882(0) sample code compile list  

https://qiita.com/kaizen_nagoya/items/fc957ddddd402004bb91

### C++N4741, 2018 Standard Working Draft on ISO/IEC 14882 sample code compile list
https://qiita.com/kaizen_nagoya/items/3294c014044550896010

### C++N4606, 2016符号断片編纂一覧(example code compile list)
C++N4606, 2016 Working Draft 2016, ISO/IEC 14882, C++ standard(1) Example code compile list
https://qiita.com/kaizen_nagoya/items/df5d62c35bd6ed1c3d43/

### C++N3242, 2011 sample code compile list on clang++ and g++
https://qiita.com/kaizen_nagoya/items/685b5c1a2c17c1bf1318

## 編纂器(Compiler)
### clang++ --version
> Debian clang version 14.0.5-++20220610033153+c12386ae247c-1~exp1~20220610153237.151
Target: x86_64-pc-linux-gnu, Thread model: posix, InstalledDir: /usr/bin

### g++- --version
> g++ (GCC) 12.1.0  Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

# 22.4.3 Class template tuple [tuple.tuple] C++N4910:2022 (534) p676.cpp

## 算譜(source code)

```c++:p676.cpp
// C++N4910 Committee Draft, Standard for Programming Language C++
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/n4910.pdf
const char * n4910 = "22.4.3 Class template tuple [tuple.tuple] C++N4910:2022 (534) p676.cpp";
// Debian clang version 14.0.5-++20220610033153+c12386ae247c-
// g++ (GCC) 12.1.0 Copyright (C) 2022 Free Software Foundation, Inc.
// Edited by Dr. OGAWA Kiyoshi. Compile procedure and results record.
// C++N4910:2022 Standard Working Draft on ISO/IEC 14882(0) sample code compile list
// https://qiita.com/kaizen_nagoya/items/fc957ddddd402004bb91

#include <iostream>
#include <cstdio>
#include <cstdlib> 
#include <cstring>
#include <cassert>
#include <coroutine>
#include <vector>
#include <complex>
#include <map>
#include <atomic>
#include <unordered_map>
#include <memory>
#include <typeinfo>

using namespace std;

// Example 1  
namespace std {
    template<class... Types>
    class tuple {
    public:
// 22.4.3.1, tuple construction
constexpr explicit(see below) tuple();
constexpr explicit(see below ) tuple(const Types&...); template<class... UTypes>
constexpr explicit(see below ) tuple(UTypes&&...); tuple(const tuple&) = default;
      tuple(tuple&&) = default;
template<class... UTypes>
constexpr explicit(see below) tuple(tuple<UTypes...>&);
[tuple.tuple]
// only if sizeof...(Types) >= 1
// only if sizeof...(Types) >= 1
template<class... UTypes>
constexpr explicit(see below) tuple(const tuple<UTypes...>&);
template<class... UTypes>
constexpr explicit(see below) tuple(tuple<UTypes...>&&);
template<class... UTypes>
constexpr explicit(see below) tuple(const tuple<UTypes...>&&);
template<class U1, class U2>
constexpr explicit(see below ) tuple(pair<U1, U2>&);
template<class U1, class U2>
constexpr explicit(see below ) tuple(const pair<U1, U2>&);
template<class U1, class U2>
constexpr explicit(see below ) tuple(pair<U1, U2>&&);
template<class U1, class U2>
constexpr explicit(see below ) tuple(const pair<U1, U2>&&);
// only if sizeof...(Types) == 2
// only if sizeof...(Types) == 2
// only if sizeof...(Types) == 2
// only if sizeof...(Types) == 2
// allocator-extended constructors
template<class Alloc>
constexpr explicit(see below)
    tuple(allocator_arg_t, const Alloc& a);
template<class Alloc>
constexpr explicit(see below)
tuple(allocator_arg_t, const Alloc& a, const Types&...);
template<class Alloc, class... UTypes> constexpr explicit(see below)
    tuple(allocator_arg_t, const Alloc& a, UTypes&&...);
template<class Alloc>
  constexpr tuple(allocator_arg_t, const Alloc& a, const tuple&);
template<class Alloc>
  constexpr tuple(allocator_arg_t, const Alloc& a, tuple&&);
template<class Alloc, class... UTypes>
constexpr explicit(see below)
tuple(allocator_arg_t, const Alloc& a, tuple<UTypes...>&);
template<class Alloc, class... UTypes> constexpr explicit(see below)
    tuple(allocator_arg_t, const Alloc& a, const tuple<UTypes...>&);
template<class Alloc, class... UTypes>
constexpr explicit(see below)
tuple(allocator_arg_t, const Alloc& a, tuple<UTypes...>&&);
template<class Alloc, class... UTypes> constexpr explicit(see below)
    tuple(allocator_arg_t, const Alloc& a, const tuple<UTypes...>&&);
template<class Alloc, class U1, class U2>
constexpr explicit(see below)
tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&);
template<class Alloc, class U1, class U2> constexpr explicit(see below)
    tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&);
template<class Alloc, class U1, class U2>
constexpr explicit(see below)
tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&&);
template<class Alloc, class U1, class U2> constexpr explicit(see below)
    tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&&);
// 22.4.3.2, tuple assignment
constexpr tuple& operator=(const tuple&);
constexpr const tuple& operator=(const tuple&) const; constexpr tuple& operator=(tuple&&) noexcept(see below); constexpr const tuple& operator=(tuple&&) const;
template<class... UTypes>
  constexpr tuple& operator=(const tuple<UTypes...>&);
template<class... UTypes>
  constexpr const tuple& operator=(const tuple<UTypes...>&) const;
template<class... UTypes>
  constexpr tuple& operator=(tuple<UTypes...>&&);
template<class... UTypes>
  constexpr const tuple& operator=(tuple<UTypes...>&&) const;
template<class U1, class U2>
constexpr tuple& operator=(const pair<U1, U2>&); // only
template<class U1, class U2>
  constexpr const tuple& operator=(const pair<U1, U2>&) const;
template<class U1, class U2>
  constexpr tuple& operator=(pair<U1, U2>&&);
template<class U1, class U2>
  constexpr const tuple& operator=(pair<U1, U2>&&) const;
// only // only // only
if sizeof...(Types) == 2 if sizeof...(Types) == 2
if sizeof...(Types) == 2 if sizeof...(Types) == 2
// 22.4.3.3, tuple swap
constexpr void swap(tuple&) noexcept(see below);
constexpr void swap(const tuple&) const noexcept(see below);
};
  template<class... UTypes>
    tuple(UTypes...) -> tuple<UTypes...>;
  template<class T1, class T2>
    tuple(pair<T1, T2>) -> tuple<T1, T2>;
  template<class Alloc, class... UTypes>
    tuple(allocator_arg_t, Alloc, UTypes...) -> tuple<UTypes...>;
  template<class Alloc, class T1, class T2>
    tuple(allocator_arg_t, Alloc, pair<T1, T2>) -> tuple<T1, T2>;
  template<class Alloc, class... UTypes>
    tuple(allocator_arg_t, Alloc, tuple<UTypes...>) -> tuple<UTypes...>;
}
int main(){
  cout  <<  n4910 << endl;
  return EXIT_SUCCESS;
}
```

## 編纂・実行結果(compile and go)

```ubuntu:bash
$ clang++ p676.cpp -std=03 -o p676l -I. -Wall
In file included from p676.cpp:19:
In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/atomic:38:
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/bits/c++0x_warning.h:32:2: error: This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
#error This file requires compiler and library support \
 ^
p676.cpp:28:19: warning: variadic templates are a C++11 extension [-Wc++11-extensions]
    template<class... Types>
                  ^
p676.cpp:32:1: error: unknown type name 'constexpr'
constexpr explicit(see below) tuple();
^
p676.cpp:32:19: warning: explicit(bool) is a C++20 extension [-Wc++20-extensions]
constexpr explicit(see below) tuple();
                  ^
p676.cpp:32:20: error: use of undeclared identifier 'see'
constexpr explicit(see below) tuple();
                   ^
p676.cpp:32:31: error: constructor cannot have a return type
constexpr explicit(see below) tuple();
                              ^~~~~
p676.cpp:33:1: error: unknown type name 'constexpr'
constexpr explicit(see below ) tuple(const Types&...); template<class... UTypes>
^
p676.cpp:33:19: warning: explicit(bool) is a C++20 extension [-Wc++20-extensions]
constexpr explicit(see below ) tuple(const Types&...); template<class... UTypes>
                  ^
p676.cpp:33:20: error: use of undeclared identifier 'see'
constexpr explicit(see below ) tuple(const Types&...); template<class... UTypes>
                   ^
p676.cpp:33:32: error: constructor cannot have a return type
constexpr explicit(see below ) tuple(const Types&...); template<class... UTypes>
                               ^~~~~
p676.cpp:33:70: warning: variadic templates are a C++11 extension [-Wc++11-extensions]
constexpr explicit(see below ) tuple(const Types&...); template<class... UTypes>
                                                                     ^
p676.cpp:34:1: error: unknown type name 'constexpr'
constexpr explicit(see below ) tuple(UTypes&&...); tuple(const tuple&) = default;
^
p676.cpp:34:19: warning: explicit(bool) is a C++20 extension [-Wc++20-extensions]
constexpr explicit(see below ) tuple(UTypes&&...); tuple(const tuple&) = default;
                  ^
p676.cpp:34:20: error: use of undeclared identifier 'see'
constexpr explicit(see below ) tuple(UTypes&&...); tuple(const tuple&) = default;
                   ^
p676.cpp:34:44: warning: rvalue references are a C++11 extension [-Wc++11-extensions]
constexpr explicit(see below ) tuple(UTypes&&...); tuple(const tuple&) = default;
                                           ^
p676.cpp:34:32: error: constructor cannot have a return type
constexpr explicit(see below ) tuple(UTypes&&...); tuple(const tuple&) = default;
                               ^~~~~
p676.cpp:34:74: warning: defaulted function definitions are a C++11 extension [-Wc++11-extensions]
constexpr explicit(see below ) tuple(UTypes&&...); tuple(const tuple&) = default;
                                                                         ^
p676.cpp:35:18: warning: rvalue references are a C++11 extension [-Wc++11-extensions]
      tuple(tuple&&) = default;
                 ^
p676.cpp:35:24: warning: defaulted function definitions are a C++11 extension [-Wc++11-extensions]
      tuple(tuple&&) = default;
                       ^
p676.cpp:36:15: warning: variadic templates are a C++11 extension [-Wc++11-extensions]
template<class... UTypes>
              ^
p676.cpp:37:1: error: unknown type name 'constexpr'
constexpr explicit(see below) tuple(tuple<UTypes...>&);
^
p676.cpp:37:19: warning: explicit(bool) is a C++20 extension [-Wc++20-extensions]
constexpr explicit(see below) tuple(tuple<UTypes...>&);
                  ^
p676.cpp:37:20: error: use of undeclared identifier 'see'
constexpr explicit(see below) tuple(tuple<UTypes...>&);
                   ^
p676.cpp:37:31: error: constructor cannot have a return type
constexpr explicit(see below) tuple(tuple<UTypes...>&);
                              ^~~~~
p676.cpp:38:2: error: 'tuple' does not refer to a value
[tuple.tuple]
 ^
p676.cpp:29:11: note: declared here
    class tuple {
          ^
p676.cpp:41:1: error: expected member name or ';' after declaration specifiers
template<class... UTypes>
^
p676.cpp:43:15: warning: variadic templates are a C++11 extension [-Wc++11-extensions]
template<class... UTypes>
              ^
p676.cpp:44:1: error: unknown type name 'constexpr'
constexpr explicit(see below) tuple(tuple<UTypes...>&&);
^
p676.cpp:44:19: warning: explicit(bool) is a C++20 extension [-Wc++20-extensions]
constexpr explicit(see below) tuple(tuple<UTypes...>&&);
                  ^
p676.cpp:44:20: error: use of undeclared identifier 'see'
constexpr explicit(see below) tuple(tuple<UTypes...>&&);
                   ^
p676.cpp:44:53: warning: rvalue references are a C++11 extension [-Wc++11-extensions]
constexpr explicit(see below) tuple(tuple<UTypes...>&&);
                                                    ^
p676.cpp:44:31: error: constructor cannot have a return type
constexpr explicit(see below) tuple(tuple<UTypes...>&&);
                              ^~~~~
p676.cpp:45:15: warning: variadic templates are a C++11 extension [-Wc++11-extensions]
template<class... UTypes>
              ^
p676.cpp:46:1: error: unknown type name 'constexpr'
constexpr explicit(see below) tuple(const tuple<UTypes...>&&);
^
p676.cpp:46:19: warning: explicit(bool) is a C++20 extension [-Wc++20-extensions]
constexpr explicit(see below) tuple(const tuple<UTypes...>&&);
                  ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
16 warnings and 20 errors generated.
$ clang++ p676.cpp -std=2b -o p676l -I. -Wall
p676.cpp:29:11: error: redefinition of 'tuple'
    class tuple {
          ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/tuple:516:11: note: previous definition is here
    class tuple : public _Tuple_impl<0, _Elements...>
          ^
p676.cpp:119:5: error: redeclaration of deduction guide
    tuple(UTypes...) -> tuple<UTypes...>;
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/tuple:855:5: note: previous declaration is here
    tuple(_UTypes...) -> tuple<_UTypes...>;
    ^
p676.cpp:121:5: error: redeclaration of deduction guide
    tuple(pair<T1, T2>) -> tuple<T1, T2>;
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/tuple:857:5: note: previous declaration is here
    tuple(pair<_T1, _T2>) -> tuple<_T1, _T2>;
    ^
p676.cpp:123:5: error: redeclaration of deduction guide
    tuple(allocator_arg_t, Alloc, UTypes...) -> tuple<UTypes...>;
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/tuple:859:5: note: previous declaration is here
    tuple(allocator_arg_t, _Alloc, _UTypes...) -> tuple<_UTypes...>;
    ^
p676.cpp:125:5: error: redeclaration of deduction guide
    tuple(allocator_arg_t, Alloc, pair<T1, T2>) -> tuple<T1, T2>;
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/tuple:861:5: note: previous declaration is here
    tuple(allocator_arg_t, _Alloc, pair<_T1, _T2>) -> tuple<_T1, _T2>;
    ^
p676.cpp:127:5: error: redeclaration of deduction guide
    tuple(allocator_arg_t, Alloc, tuple<UTypes...>) -> tuple<UTypes...>;
    ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/tuple:863:5: note: previous declaration is here
    tuple(allocator_arg_t, _Alloc, tuple<_UTypes...>) -> tuple<_UTypes...>;
    ^
6 errors generated.

$ g++ p676.cpp -std=03 -o p676g -I. -Wall
In file included from /usr/local/include/c++/12.1.0/atomic:38,
                 from p676.cpp:19:
/usr/local/include/c++/12.1.0/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
   32 | #error This file requires compiler and library support \
      |  ^~~~~
p676.cpp:32:1: warning: identifier 'constexpr' is a keyword in C++11 [-Wc++11-compat]
   32 | constexpr explicit(see below) tuple();
      | ^~~~~~~~~
p676.cpp:94:91: warning: identifier 'noexcept' is a keyword in C++11 [-Wc++11-compat]
   94 | xpr const tuple& operator=(const tuple&) const; constexpr tuple& operator=(tuple&&) noexcept(see below); constexpr const tuple& operator=(tuple&&) const;
      |                                                                                     ^~~~~~~~

p676.cpp:28:19: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   28 |     template<class... Types>
      |                   ^~~
p676.cpp:32:1: error: 'constexpr' does not name a type
   32 | constexpr explicit(see below) tuple();
      | ^~~~~~~~~
p676.cpp:32:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:33:1: error: 'constexpr' does not name a type
   33 | constexpr explicit(see below ) tuple(const Types&...); template<class... UTypes>
      | ^~~~~~~~~
p676.cpp:33:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:33:70: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   33 | constexpr explicit(see below ) tuple(const Types&...); template<class... UTypes>
      |                                                                      ^~~
p676.cpp:34:1: error: 'constexpr' does not name a type
   34 | constexpr explicit(see below ) tuple(UTypes&&...); tuple(const tuple&) = default;
      | ^~~~~~~~~
p676.cpp:34:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:34:74: warning: defaulted and deleted functions only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   34 | constexpr explicit(see below ) tuple(UTypes&&...); tuple(const tuple&) = default;
      |                                                                          ^~~~~~~
p676.cpp:35:18: error: expected ',' or '...' before '&&' token
   35 |       tuple(tuple&&) = default;
      |                  ^~
p676.cpp:35:24: warning: defaulted and deleted functions only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   35 |       tuple(tuple&&) = default;
      |                        ^~~~~~~
p676.cpp:35:7: error: invalid constructor; you probably meant 'std::tuple<Types> (const std::tuple<Types>&)'
   35 |       tuple(tuple&&) = default;
      |       ^~~~~
p676.cpp:36:15: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   36 | template<class... UTypes>
      |               ^~~
p676.cpp:37:1: error: 'constexpr' does not name a type
   37 | constexpr explicit(see below) tuple(tuple<UTypes...>&);
      | ^~~~~~~~~
p676.cpp:37:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:38:1: error: expected unqualified-id before '[' token
   38 | [tuple.tuple]
      | ^
p676.cpp:43:15: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   43 | template<class... UTypes>
      |               ^~~
p676.cpp:44:1: error: 'constexpr' does not name a type
   44 | constexpr explicit(see below) tuple(tuple<UTypes...>&&);
      | ^~~~~~~~~
p676.cpp:44:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:45:15: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   45 | template<class... UTypes>
      |               ^~~
p676.cpp:46:1: error: 'constexpr' does not name a type
   46 | constexpr explicit(see below) tuple(const tuple<UTypes...>&&);
      | ^~~~~~~~~
p676.cpp:46:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:48:1: error: 'constexpr' does not name a type
   48 | constexpr explicit(see below ) tuple(pair<U1, U2>&);
      | ^~~~~~~~~
p676.cpp:48:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:50:1: error: 'constexpr' does not name a type
   50 | constexpr explicit(see below ) tuple(const pair<U1, U2>&);
      | ^~~~~~~~~
p676.cpp:50:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:52:1: error: 'constexpr' does not name a type
   52 | constexpr explicit(see below ) tuple(pair<U1, U2>&&);
      | ^~~~~~~~~
p676.cpp:52:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:54:1: error: 'constexpr' does not name a type
   54 | constexpr explicit(see below ) tuple(const pair<U1, U2>&&);
      | ^~~~~~~~~
p676.cpp:54:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:61:1: error: 'constexpr' does not name a type
   61 | constexpr explicit(see below)
      | ^~~~~~~~~
p676.cpp:61:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:64:1: error: 'constexpr' does not name a type
   64 | constexpr explicit(see below)
      | ^~~~~~~~~
p676.cpp:64:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:66:28: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   66 | template<class Alloc, class... UTypes> constexpr explicit(see below)
      |                            ^~~
p676.cpp:66:40: error: 'constexpr' does not name a type
   66 | template<class Alloc, class... UTypes> constexpr explicit(see below)
      |                                        ^~~~~~~~~
p676.cpp:66:40: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:69:3: error: 'constexpr' does not name a type
   69 |   constexpr tuple(allocator_arg_t, const Alloc& a, const tuple&);
      |   ^~~~~~~~~
p676.cpp:69:3: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:71:3: error: 'constexpr' does not name a type
   71 |   constexpr tuple(allocator_arg_t, const Alloc& a, tuple&&);
      |   ^~~~~~~~~
p676.cpp:71:3: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:72:28: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   72 | template<class Alloc, class... UTypes>
      |                            ^~~
p676.cpp:73:1: error: 'constexpr' does not name a type
   73 | constexpr explicit(see below)
      | ^~~~~~~~~
p676.cpp:73:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:75:28: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   75 | template<class Alloc, class... UTypes> constexpr explicit(see below)
      |                            ^~~
p676.cpp:75:40: error: 'constexpr' does not name a type
   75 | template<class Alloc, class... UTypes> constexpr explicit(see below)
      |                                        ^~~~~~~~~
p676.cpp:75:40: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:77:28: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   77 | template<class Alloc, class... UTypes>
      |                            ^~~
p676.cpp:78:1: error: 'constexpr' does not name a type
   78 | constexpr explicit(see below)
      | ^~~~~~~~~
p676.cpp:78:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:80:28: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   80 | template<class Alloc, class... UTypes> constexpr explicit(see below)
      |                            ^~~
p676.cpp:80:40: error: 'constexpr' does not name a type
   80 | template<class Alloc, class... UTypes> constexpr explicit(see below)
      |                                        ^~~~~~~~~
p676.cpp:80:40: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:83:1: error: 'constexpr' does not name a type
   83 | constexpr explicit(see below)
      | ^~~~~~~~~
p676.cpp:83:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:85:43: error: 'constexpr' does not name a type
   85 | template<class Alloc, class U1, class U2> constexpr explicit(see below)
      |                                           ^~~~~~~~~
p676.cpp:85:43: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:88:1: error: 'constexpr' does not name a type
   88 | constexpr explicit(see below)
      | ^~~~~~~~~
p676.cpp:88:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:90:43: error: 'constexpr' does not name a type
   90 | template<class Alloc, class U1, class U2> constexpr explicit(see below)
      |                                           ^~~~~~~~~
p676.cpp:90:43: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:93:1: error: 'constexpr' does not name a type
   93 | constexpr tuple& operator=(const tuple&);
      | ^~~~~~~~~
p676.cpp:93:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:94:1: error: 'constexpr' does not name a type
   94 | constexpr const tuple& operator=(const tuple&) const; constexpr tuple& operator=(tuple&&) noexcept(see below); constexpr const tuple& operator=(tuple&&) const;
      | ^~~~~~~~~
p676.cpp:94:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:94:55: error: 'constexpr' does not name a type
   94 | constexpr const tuple& operator=(const tuple&) const; constexpr tuple& operator=(tuple&&) noexcept(see below); constexpr const tuple& operator=(tuple&&) const;
      |                                                       ^~~~~~~~~
p676.cpp:94:55: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:94:112: error: 'constexpr' does not name a type
   94 | ator=(const tuple&) const; constexpr tuple& operator=(tuple&&) noexcept(see below); constexpr const tuple& operator=(tuple&&) const;
      |                                                                                     ^~~~~~~~~

p676.cpp:94:112: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:95:15: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   95 | template<class... UTypes>
      |               ^~~
p676.cpp:96:3: error: 'constexpr' does not name a type
   96 |   constexpr tuple& operator=(const tuple<UTypes...>&);
      |   ^~~~~~~~~
p676.cpp:96:3: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:97:15: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   97 | template<class... UTypes>
      |               ^~~
p676.cpp:98:3: error: 'constexpr' does not name a type
   98 |   constexpr const tuple& operator=(const tuple<UTypes...>&) const;
      |   ^~~~~~~~~
p676.cpp:98:3: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:99:15: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   99 | template<class... UTypes>
      |               ^~~
p676.cpp:100:3: error: 'constexpr' does not name a type
  100 |   constexpr tuple& operator=(tuple<UTypes...>&&);
      |   ^~~~~~~~~
p676.cpp:100:3: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:101:15: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
  101 | template<class... UTypes>
      |               ^~~
p676.cpp:102:3: error: 'constexpr' does not name a type
  102 |   constexpr const tuple& operator=(tuple<UTypes...>&&) const;
      |   ^~~~~~~~~
p676.cpp:102:3: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:104:1: error: 'constexpr' does not name a type
  104 | constexpr tuple& operator=(const pair<U1, U2>&); // only
      | ^~~~~~~~~
p676.cpp:104:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:106:3: error: 'constexpr' does not name a type
  106 |   constexpr const tuple& operator=(const pair<U1, U2>&) const;
      |   ^~~~~~~~~
p676.cpp:106:3: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:108:3: error: 'constexpr' does not name a type
  108 |   constexpr tuple& operator=(pair<U1, U2>&&);
      |   ^~~~~~~~~
p676.cpp:108:3: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:110:3: error: 'constexpr' does not name a type
  110 |   constexpr const tuple& operator=(pair<U1, U2>&&) const;
      |   ^~~~~~~~~
p676.cpp:110:3: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:112:1: error: expected unqualified-id before 'if'
  112 | if sizeof...(Types) == 2 if sizeof...(Types) == 2
      | ^~
p676.cpp:116:1: error: 'constexpr' does not name a type
  116 | constexpr void swap(const tuple&) const noexcept(see below);
      | ^~~~~~~~~
p676.cpp:116:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p676.cpp:118:17: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
  118 |   template<class... UTypes>
      |                 ^~~
p676.cpp:119:17: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
  119 |     tuple(UTypes...) -> tuple<UTypes...>;
      |                 ^~~
p676.cpp:119:41: error: expected constructor, destructor, or type conversion before ';' token
  119 |     tuple(UTypes...) -> tuple<UTypes...>;
      |                                         ^
p676.cpp:121:41: error: expected constructor, destructor, or type conversion before ';' token
  121 |     tuple(pair<T1, T2>) -> tuple<T1, T2>;
      |                                         ^
p676.cpp:122:30: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
  122 |   template<class Alloc, class... UTypes>
      |                              ^~~
p676.cpp:123:10: error: expected constructor, destructor, or type conversion before '(' token
  123 |     tuple(allocator_arg_t, Alloc, UTypes...) -> tuple<UTypes...>;
      |          ^
p676.cpp:125:10: error: expected constructor, destructor, or type conversion before '(' token
  125 |     tuple(allocator_arg_t, Alloc, pair<T1, T2>) -> tuple<T1, T2>;
      |          ^
p676.cpp:126:30: warning: variadic templates only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
  126 |   template<class Alloc, class... UTypes>
      |                              ^~~
p676.cpp:127:10: error: expected constructor, destructor, or type conversion before '(' token
  127 |     tuple(allocator_arg_t, Alloc, tuple<UTypes...>) -> tuple<UTypes...>;
      |          ^

$ g++ p676.cpp -std=2b -o p676g -I. -Wall
p676.cpp:29:11: error: redefinition of 'class std::tuple< <template-parameter-1-1> >'
   29 |     class tuple {
      |           ^~~~~
In file included from /usr/local/include/c++/12.1.0/bits/stl_map.h:63,
                 from /usr/local/include/c++/12.1.0/map:61,
                 from p676.cpp:18:
/usr/local/include/c++/12.1.0/tuple:609:11: note: previous definition of 'class std::tuple< <template-parameter-1-1> >'
  609 |     class tuple : public _Tuple_impl<0, _Elements...>
      |           ^~~~~
p676.cpp:119:5: error: deduction guide 'template<class ... UTypes> std::tuple(UTypes ...)-> tuple<_Args1 ...>' redeclared
  119 |     tuple(UTypes...) -> tuple<UTypes...>;
      |     ^~~~~
/usr/local/include/c++/12.1.0/tuple:948:5: note: 'template<class ... _UTypes> std::tuple(_UTypes ...)-> tuple<_Args1 ...>' previously declared here
  948 |     tuple(_UTypes...) -> tuple<_UTypes...>;
      |     ^~~~~
p676.cpp:121:5: error: deduction guide 'template<class T1, class T2> std::tuple(pair<_T1, _T2>)-> tuple<_T1, _T2>' redeclared
  121 |     tuple(pair<T1, T2>) -> tuple<T1, T2>;
      |     ^~~~~
/usr/local/include/c++/12.1.0/tuple:950:5: note: 'template<class _T1, class _T2> std::tuple(pair<_T1, _T2>)-> tuple<_T1, _T2>' previously declared here
  950 |     tuple(pair<_T1, _T2>) -> tuple<_T1, _T2>;
      |     ^~~~~
p676.cpp:123:5: error: deduction guide 'template<class Alloc, class ... UTypes> std::tuple(allocator_arg_t, Alloc, UTypes ...)-> tuple<_Args2 ...>' redeclared
  123 |     tuple(allocator_arg_t, Alloc, UTypes...) -> tuple<UTypes...>;
      |     ^~~~~
/usr/local/include/c++/12.1.0/tuple:952:5: note: 'template<class _Alloc, class ... _UTypes> std::tuple(allocator_arg_t, _Alloc, _UTypes ...)-> tuple<_Args2 ...>' previously declared here
  952 |     tuple(allocator_arg_t, _Alloc, _UTypes...) -> tuple<_UTypes...>;
      |     ^~~~~
p676.cpp:125:5: error: deduction guide 'template<class Alloc, class T1, class T2> std::tuple(allocator_arg_t, Alloc, pair<_Tp1, _Tp2>)-> tuple<_T1, _T2>' redeclared
  125 |     tuple(allocator_arg_t, Alloc, pair<T1, T2>) -> tuple<T1, T2>;
      |     ^~~~~
/usr/local/include/c++/12.1.0/tuple:954:5: note: 'template<class _Alloc, class _T1, class _T2> std::tuple(allocator_arg_t, _Alloc, pair<_Tp1, _Tp2>)-> tuple<_T1, _T2>' previously declared here
  954 |     tuple(allocator_arg_t, _Alloc, pair<_T1, _T2>) -> tuple<_T1, _T2>;
      |     ^~~~~
p676.cpp:127:5: error: deduction guide 'template<class Alloc, class ... UTypes> std::tuple(allocator_arg_t, Alloc, tuple<_Args2 ...>)-> tuple<_Args2 ...>' redeclared
  127 |     tuple(allocator_arg_t, Alloc, tuple<UTypes...>) -> tuple<UTypes...>;
      |     ^~~~~
/usr/local/include/c++/12.1.0/tuple:956:5: note: 'template<class _Alloc, class ... _UTypes> std::tuple(allocator_arg_t, _Alloc, tuple<_Args2 ...>)-> tuple<_Args2 ...>' previously declared here
  956 |     tuple(allocator_arg_t, _Alloc, tuple<_UTypes...>) -> tuple<_UTypes...>;
      |     ^~~~~
```

## 検討事項(agenda)
コンパイルエラーを取るか、コンパイルエラーの理由を解説する。

<!-- リンクエラーの解説をする。clang++とg++の比較。意味のある出力。
コンパイルエラーを取るか、コンパイルエラーの理由を解説する。-->

# 参考資料(reference)

cpprefjp - C++日本語リファレンス

https://cpprefjp.github.io/

コンパイラの実装状況

https://cpprefjp.github.io/implementation-status.html


typedef は C++11 ではオワコン

https://qiita.com/Linda_pp/items/44a67c64c14cba00eef1

C99からC++14を駆け抜けるC++講座

https://qiita.com/yumetodo/items/e49a673afd9a3ecb81a8


@kazuo_reve 私が効果を確認した「小川メソッド」

https://qiita.com/kazuo_reve/items/a3ea1d9171deeccc04da

## 自己参照(self reference)

ockerにclang

https://qiita.com/kaizen_nagoya/items/8829ffeee397eda50e80

docker gnu(gcc/g++) and llvm(clang/clang++)

https://qiita.com/drafts/059874ea39c4de64c0f7

コンパイル用shell script C版(clangとgcc)とC++版(clang++とg++)

https://qiita.com/kaizen_nagoya/items/74220c0577a512c2d7da

C++N4910:2022 tag follower 200人超えました。ありがとうございます。

https://qiita.com/kaizen_nagoya/items/a63fb96d351ac5c16ff7

C++N4910:2022 tag follower 200人超えました。ありがとうございます。

https://qiita.com/kaizen_nagoya/items/a63fb96d351ac5c16ff7

コピペコンパイルエラーあるある

https://qiita.com/kaizen_nagoya/items/29c832de9d762aed2761

C++ Error Message Collection(1)does not name a type, 11 articles

https://qiita.com/kaizen_nagoya/items/acb9f1a9b5aad6df06bd

dockerにclang

https://qiita.com/kaizen_nagoya/items/8829ffeee397eda50e80

docker gnu(gcc/g++) and llvm(clang/clang++)

https://qiita.com/drafts/059874ea39c4de64c0f7

コンパイル用shell script C版(clangとgcc)とC++版(clang++とg++)

https://qiita.com/kaizen_nagoya/items/74220c0577a512c2d7da

Compare the contents of C++N4910:2022, C++N4741:2018 and C++N4606:2015

https://qiita.com/kaizen_nagoya/items/483246d40f98abff7ded

C++ sample list

https://qiita.com/kaizen_nagoya/items/54ad75b73825b7c04f86

clang++, g++コンパイルエラー方針の違いの例

https://qiita.com/kaizen_nagoya/items/ea6e5009fe126d270a82

astyle 使ってみた

https://qiita.com/kaizen_nagoya/items/3c9a87a781d53a1a23f3

C++N4606 Working Draft 2016, ISO/IEC 14882, C++ standardのコード断片をコンパイルするためにしていること
https://qiita.com/kaizen_nagoya/items/a8d7ee2f2e29e76c19c1

コンパイル用shell script C版(clangとgcc)とC++版(clang++とg++)
https://qiita.com/kaizen_nagoya/items/74220c0577a512c2d7da

Clang/Clang++(LLVM) gcc/g++(GNU) コンパイラ警告等比較
https://qiita.com/kaizen_nagoya/items/9a82b958cc3aeef0403f

C++2003とC++2017でコンパイルエラーになるならない事例集
https://qiita.com/kaizen_nagoya/items/a13ea3823441c430edff

Qiitaに投稿するCのStyle例(暫定)
https://qiita.com/kaizen_nagoya/items/946df1528a6a1ef2bc0d

cpprefjpのdecltypeをコンパイル試験
https://qiita.com/kaizen_nagoya/items/090909af702f0d5d8a67

MISRA C++ 5-0-16
https://qiita.com/kaizen_nagoya/items/7df2d4e05db724752a74

C++ Templates Part1 BASICS Chapter 3. Class Templates 3.2 Use of Class Template Stack stack1test.cpp
https://qiita.com/kaizen_nagoya/items/cd5fc49106fad5a4e9ed

ISO/IEC TS 17961:2013 C Secure Coding Rules(1) All list(to be confirmed)
https://qiita.com/kaizen_nagoya/items/54e056195c4f11b850a1

C言語（C++)に対する誤解、曲解、無理解、爽快。
https://qiita.com/kaizen_nagoya/items/3f3992c9722c1cee2e3a

C Puzzle Bookの有り難み5つ、C言語規格及びCコンパイラの特性を認識
https://qiita.com/kaizen_nagoya/items/d89a48c1536a02ecdec9

'wchar.h' file not found で困った clang++ macOS
https://qiita.com/kaizen_nagoya/items/de15cd46d657517fac11

Open POSIX Test Suiteの使い方を調べはじめました
https://qiita.com/kaizen_nagoya/items/644d5e407f5faf96e6dc

MISRA-C 2012 Referenceに掲載している文献の入手可能性を確認
https://qiita.com/kaizen_nagoya/items/96dc8b125e462d5575bb

どうやって MISRA Example Suiteをコンパイルするか
https://qiita.com/kaizen_nagoya/items/fbdbff5ff696e2ca7f00

MISRA C まとめ #include <misra_c.h>
https://qiita.com/kaizen_nagoya/items/f1a79a7cbd281607c7c9

「C++完全理解ガイド」の同意できること上位10
https://qiita.com/kaizen_nagoya/items/aa5744e0c4a8618c7671

DoCAP（ドゥーキャップ）って何ですか？

https://qiita.com/kaizen_nagoya/items/47e0e6509ab792c43327

小川メソッド　覚え（書きかけ）

https://qiita.com/kaizen_nagoya/items/3593d72eca551742df68


 ＜この記事は個人の過去の経験に基づく個人の感想です。現在所属する組織、業務とは関係がありません。＞

# 文書履歴(document history)
ver. 0.01 初稿 　20220724