20.3.2.2.1 General [util.smartptr.shared.general] C++N4910:2022 (456) p604.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.

# 20.3.2.2.1 General [util.smartptr.shared.general] C++N4910:2022 (456) p604.cpp

## 算譜(source code)

```c++:p604.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 = "20.3.2.2.1 General [util.smartptr.shared.general] C++N4910:2022 (456) p604.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 <typeinfo>

using namespace std;

// Example 1
namespace std {
template<class T> class shared_ptr {
public:
    using element_type = remove_extent_t<T>;
    using weak_type    = weak_ptr<T>;
// 20.3.2.2.2, constructors
    constexpr shared_ptr() noexcept;
    constexpr shared_ptr(nullptr_t) noexcept : shared_ptr() { } template<class Y>
    explicit shared_ptr(Y* p);
    template<class Y, class D>
    shared_ptr(Y* p, D d);
    template<class Y, class D, class A>
    shared_ptr(Y* p, D d, A a);
    template<class D>
    shared_ptr(nullptr_t p, D d);
    template<class D, class A>
    shared_ptr(nullptr_t p, D d, A a);
    template<class Y>
    shared_ptr(const shared_ptr<Y>& r, element_type* p) noexcept;
    template<class Y>
    shared_ptr(shared_ptr<Y>&& r, element_type* p) noexcept;
    shared_ptr(const shared_ptr& r) noexcept;
    template<class Y>
    shared_ptr(const shared_ptr<Y>& r) noexcept;
    shared_ptr(shared_ptr&& r) noexcept;
    template<class Y>
    shared_ptr(shared_ptr<Y>&& r) noexcept;
    template<class Y>
    explicit shared_ptr(const weak_ptr<Y>& r);
    template<class Y, class D>
    shared_ptr(unique_ptr<Y, D>&& r);
// 20.3.2.2.3, destructor ~shared_ptr();
// 20.3.2.2.4, assignment
    shared_ptr& operator=(const shared_ptr& r) noexcept;
    template<class Y>
    shared_ptr& operator=(const shared_ptr<Y>& r) noexcept;
    shared_ptr& operator=(shared_ptr&& r) noexcept;
    template<class Y>
    shared_ptr& operator=(shared_ptr<Y>&& r) noexcept;
    template<class Y, class D>
    shared_ptr& operator=(unique_ptr<Y, D>&& r);
// 20.3.2.2.5, modifiers
    void swap(shared_ptr& r) noexcept;
    void reset() noexcept;
    template<class Y>
    void reset(Y* p);
    template<class Y, class D>
    void reset(Y* p, D d);
    template<class Y, class D, class A>
    void reset(Y* p, D d, A a);
// 20.3.2.2.6, observers
    element_type* get() const noexcept;
    T& operator*() const noexcept;
    T* operator->() const noexcept;
// Constraints: When T is an array type, the expression delete[] p is well-formed and either T is U[N] and Y(*)[N] is convertible to T*, or T is U[] and Y(*)[] is convertible to T*. When T is not an array type, the expression delete p is well-formed and Y* is convertible to T*.
// Mandates: Y is a complete type.
// Preconditions: The expression delete[] p, when T is an array type, or delete p, when T is not an array type, has well-defined behavior, and does not throw exceptions.
// Effects: When T is not an array type, constructs a shared_ptr object that owns the pointer p. Otherwise, constructs a shared_ptr that owns p and a deleter of an unspecified type that calls delete[] p. When T is not an array type, enables shared_from_this with p. If an exception is thrown, delete p is called when T is not an array type, delete[] p otherwise.
    element_type& operator[](ptrdiff_t i) const;
    long use_count() const noexcept;
    explicit operator bool() const noexcept;
    template<class U>
    bool owner_before(const shared_ptr<U>& b) const noexcept;
    template<class U>
    bool owner_before(const weak_ptr<U>& b) const noexcept;
};
template<class T>
shared_ptr(weak_ptr<T>) -> shared_ptr<T>;
template<class T, class D>
shared_ptr(unique_ptr<T, D>) -> shared_ptr<T>;
}
//  Specializations of shared_ptr shall be Cpp17CopyConstructible, Cpp17CopyAssignable, and Cpp17LessThan- Comparable, allowing their use in standard containers. Specializations of shared_ptr shall be contextually convertible to bool, allowing their use in boolean expressions and declarations in conditions.
//  The template parameter T of shared_ptr may be an incomplete type.
// [Note 1: T can be a function type.
//  [Example 1 :
int main() {
    if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
    }
// int main(){
    cout  <<  n4910 << endl;
    return EXIT_SUCCESS;
}
```

## 編纂・実行結果(compile and go)

```ubuntu:bash
$ clang++ p604.cpp -std=c++03 -o p604l -I. -Wall
In file included from p604.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 \
 ^
p604.cpp:29:28: warning: alias declarations are a C++11 extension [-Wc++11-extensions]
      using element_type = remove_extent_t<T>;
                           ^
p604.cpp:29:28: error: no template named 'remove_extent_t'
p604.cpp:30:28: warning: alias declarations are a C++11 extension [-Wc++11-extensions]
      using weak_type    = weak_ptr<T>;
                           ^
p604.cpp:30:28: error: no template named 'weak_ptr'
p604.cpp:32:1: error: unknown type name 'constexpr'
constexpr shared_ptr() noexcept;
^
p604.cpp:32:11: error: constructor cannot have a return type
constexpr shared_ptr() noexcept;
          ^~~~~~~~~~
p604.cpp:32:23: error: expected ';' at end of declaration list
constexpr shared_ptr() noexcept;
                      ^
                      ;
p604.cpp:33:1: error: unknown type name 'constexpr'
constexpr shared_ptr(nullptr_t) noexcept : shared_ptr() { } template<class Y>
^
p604.cpp:33:22: error: unknown type name 'nullptr_t'
constexpr shared_ptr(nullptr_t) noexcept : shared_ptr() { } template<class Y>
                     ^
p604.cpp:33:11: error: constructor cannot have a return type
constexpr shared_ptr(nullptr_t) noexcept : shared_ptr() { } template<class Y>
          ^~~~~~~~~~
p604.cpp:33:32: error: expected ';' at end of declaration list
constexpr shared_ptr(nullptr_t) noexcept : shared_ptr() { } template<class Y>
                               ^
                               ;
p604.cpp:40:20: error: unknown type name 'nullptr_t'
        shared_ptr(nullptr_t p, D d);
                   ^
p604.cpp:42:20: error: unknown type name 'nullptr_t'
        shared_ptr(nullptr_t p, D d, A a);
                   ^
p604.cpp:44:44: error: unknown type name 'element_type'
        shared_ptr(const shared_ptr<Y>& r, element_type* p) noexcept;
                                           ^
p604.cpp:44:60: error: expected ';' at end of declaration list
        shared_ptr(const shared_ptr<Y>& r, element_type* p) noexcept;
                                                           ^
                                                           ;
p604.cpp:46:33: warning: rvalue references are a C++11 extension [-Wc++11-extensions]
        shared_ptr(shared_ptr<Y>&& r, element_type* p) noexcept;
                                ^
p604.cpp:46:39: error: unknown type name 'element_type'
        shared_ptr(shared_ptr<Y>&& r, element_type* p) noexcept;
                                      ^
p604.cpp:46:55: error: expected ';' at end of declaration list
        shared_ptr(shared_ptr<Y>&& r, element_type* p) noexcept;
                                                      ^
                                                      ;
p604.cpp:47:38: error: expected ';' at end of declaration list
      shared_ptr(const shared_ptr& r) noexcept;
                                     ^
                                     ;
p604.cpp:49:43: error: expected ';' at end of declaration list
        shared_ptr(const shared_ptr<Y>& r) noexcept;
                                          ^
                                          ;
p604.cpp:50:28: warning: rvalue references are a C++11 extension [-Wc++11-extensions]
      shared_ptr(shared_ptr&& r) noexcept;
                           ^
p604.cpp:50:33: error: expected ';' at end of declaration list
      shared_ptr(shared_ptr&& r) noexcept;
                                ^
                                ;
p604.cpp:52:33: warning: rvalue references are a C++11 extension [-Wc++11-extensions]
        shared_ptr(shared_ptr<Y>&& r) noexcept;
                                ^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
5 warnings and 20 errors generated.
rm: cannot remove 'p604l': No such file or directory
$ clang++ p604.cpp -std=c++2b -o p604l -I. -Wall
p604.cpp:30:28: error: no template named 'weak_ptr'
      using weak_type    = weak_ptr<T>;
                           ^
p604.cpp:54:35: error: no template named 'weak_ptr'
        explicit shared_ptr(const weak_ptr<Y>& r);
                                  ^
p604.cpp:56:36: error: expected ')'
        shared_ptr(unique_ptr<Y, D>&& r);
                                   ^
p604.cpp:56:19: note: to match this '('
        shared_ptr(unique_ptr<Y, D>&& r);
                  ^
p604.cpp:56:20: error: member 'unique_ptr' declared as a template
        shared_ptr(unique_ptr<Y, D>&& r);
                   ^
p604.cpp:65:31: error: no template named 'unique_ptr'
        shared_ptr& operator=(unique_ptr<Y, D>&& r);
                              ^
p604.cpp:86:36: error: no template named 'weak_ptr'
           bool owner_before(const weak_ptr<U>& b) const noexcept;
                                   ^
p604.cpp:89:20: error: cannot use parentheses when declaring variable with deduced class template specialization type
         shared_ptr(weak_ptr<T>) -> shared_ptr<T>;
                   ^
p604.cpp:89:21: error: no variable template matches partial specialization
         shared_ptr(weak_ptr<T>) -> shared_ptr<T>;
                    ^
p604.cpp:89:33: error: expected ';' at end of declaration
         shared_ptr(weak_ptr<T>) -> shared_ptr<T>;
                                ^
                                ;
p604.cpp:89:34: error: cannot use arrow operator on a type
         shared_ptr(weak_ptr<T>) -> shared_ptr<T>;
                                 ^
p604.cpp:91:20: error: cannot use parentheses when declaring variable with deduced class template specialization type
         shared_ptr(unique_ptr<T, D>) -> shared_ptr<T>;
                   ^
p604.cpp:91:21: error: no variable template matches partial specialization
         shared_ptr(unique_ptr<T, D>) -> shared_ptr<T>;
                    ^
p604.cpp:91:38: error: expected ';' at end of declaration
         shared_ptr(unique_ptr<T, D>) -> shared_ptr<T>;
                                     ^
                                     ;
p604.cpp:91:39: error: cannot use arrow operator on a type
         shared_ptr(unique_ptr<T, D>) -> shared_ptr<T>;
                                      ^
p604.cpp:98:16: error: use of undeclared identifier 'X'
if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
               ^
p604.cpp:98:45: error: use of undeclared identifier 'X'
if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
                                            ^
p604.cpp:98:48: error: use of undeclared identifier 'py'
if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
                                               ^
17 errors generated.

$ g++ p604.cpp -std=c++03 -o p604g -I. -Wall
In file included from /usr/local/include/c++/12.1.0/atomic:38,
                 from p604.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 \
      |  ^~~~~
p604.cpp:32:1: warning: identifier 'constexpr' is a keyword in C++11 [-Wc++11-compat]
   32 | constexpr shared_ptr() noexcept;
      | ^~~~~~~~~
p604.cpp:32:24: warning: identifier 'noexcept' is a keyword in C++11 [-Wc++11-compat]
   32 | constexpr shared_ptr() noexcept;
      |                        ^~~~~~~~
p604.cpp:29:13: error: expected nested-name-specifier before 'element_type'
   29 |       using element_type = remove_extent_t<T>;
      |             ^~~~~~~~~~~~
p604.cpp:30:13: error: expected nested-name-specifier before 'weak_type'
   30 |       using weak_type    = weak_ptr<T>;
      |             ^~~~~~~~~
p604.cpp:32:1: error: 'constexpr' does not name a type
   32 | constexpr shared_ptr() noexcept;
      | ^~~~~~~~~
p604.cpp:32:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p604.cpp:33:1: error: 'constexpr' does not name a type
   33 | constexpr shared_ptr(nullptr_t) noexcept : shared_ptr() { } template<class Y>
      | ^~~~~~~~~
p604.cpp:33:1: note: C++11 'constexpr' only available with '-std=c++11' or '-std=gnu++11'
p604.cpp:40:29: error: expected ')' before 'p'
   40 |         shared_ptr(nullptr_t p, D d);
      |                   ~         ^~
      |                             )
p604.cpp:42:29: error: expected ')' before 'p'
   42 |         shared_ptr(nullptr_t p, D d, A a);
      |                   ~         ^~
      |                             )
p604.cpp:44:44: error: 'element_type' has not been declared
   44 |         shared_ptr(const shared_ptr<Y>& r, element_type* p) noexcept;
      |                                            ^~~~~~~~~~~~
p604.cpp:44:61: error: expected initializer before 'noexcept'
   44 |         shared_ptr(const shared_ptr<Y>& r, element_type* p) noexcept;
      |                                                             ^~~~~~~~
p604.cpp:46:33: error: expected ',' or '...' before '&&' token
   46 |         shared_ptr(shared_ptr<Y>&& r, element_type* p) noexcept;
      |                                 ^~
p604.cpp:46:56: error: expected initializer before 'noexcept'
   46 |         shared_ptr(shared_ptr<Y>&& r, element_type* p) noexcept;
      |                                                        ^~~~~~~~
p604.cpp:47:37: error: expected ';' at end of member declaration
   47 |       shared_ptr(const shared_ptr& r) noexcept;
      |                                     ^
      |                                      ;
p604.cpp:47:39: error: 'noexcept' does not name a type
   47 |       shared_ptr(const shared_ptr& r) noexcept;
      |                                       ^~~~~~~~
p604.cpp:47:39: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p604.cpp:49:44: error: expected initializer before 'noexcept'
   49 |         shared_ptr(const shared_ptr<Y>& r) noexcept;
      |                                            ^~~~~~~~
p604.cpp:50:28: error: expected ',' or '...' before '&&' token
   50 |       shared_ptr(shared_ptr&& r) noexcept;
      |                            ^~
p604.cpp:50:7: error: invalid constructor; you probably meant 'std::shared_ptr<T> (const std::shared_ptr<T>&)'
   50 |       shared_ptr(shared_ptr&& r) noexcept;
      |       ^~~~~~~~~~
p604.cpp:50:32: error: expected ';' at end of member declaration
   50 |       shared_ptr(shared_ptr&& r) noexcept;
      |                                ^
      |                                 ;
p604.cpp:50:34: error: 'noexcept' does not name a type
   50 |       shared_ptr(shared_ptr&& r) noexcept;
      |                                  ^~~~~~~~
p604.cpp:50:34: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p604.cpp:52:33: error: expected ',' or '...' before '&&' token
   52 |         shared_ptr(shared_ptr<Y>&& r) noexcept;
      |                                 ^~
p604.cpp:52:39: error: expected initializer before 'noexcept'
   52 |         shared_ptr(shared_ptr<Y>&& r) noexcept;
      |                                       ^~~~~~~~
p604.cpp:54:35: error: 'weak_ptr' does not name a type
   54 |         explicit shared_ptr(const weak_ptr<Y>& r);
      |                                   ^~~~~~~~
p604.cpp:54:43: error: expected ',' or '...' before '<' token
   54 |         explicit shared_ptr(const weak_ptr<Y>& r);
      |                                           ^
p604.cpp:56:30: error: expected ')' before '<' token
   56 |         shared_ptr(unique_ptr<Y, D>&& r);
      |                   ~          ^
      |                              )
p604.cpp:59:42: error: expected ';' at end of member declaration
   59 | shared_ptr& operator=(const shared_ptr& r) noexcept; template<class Y>
      |                                          ^
      |                                           ;
p604.cpp:59:44: error: 'noexcept' does not name a type
   59 | shared_ptr& operator=(const shared_ptr& r) noexcept; template<class Y>
      |                                            ^~~~~~~~
p604.cpp:59:44: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p604.cpp:60:55: error: expected initializer before 'noexcept'
   60 |         shared_ptr& operator=(const shared_ptr<Y>& r) noexcept;
      |                                                       ^~~~~~~~
p604.cpp:61:39: error: expected ',' or '...' before '&&' token
   61 |       shared_ptr& operator=(shared_ptr&& r) noexcept;
      |                                       ^~
p604.cpp:61:43: error: expected ';' at end of member declaration
   61 |       shared_ptr& operator=(shared_ptr&& r) noexcept;
      |                                           ^
      |                                            ;
p604.cpp:61:45: error: 'noexcept' does not name a type
   61 |       shared_ptr& operator=(shared_ptr&& r) noexcept;
      |                                             ^~~~~~~~
p604.cpp:61:45: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p604.cpp:63:44: error: expected ',' or '...' before '&&' token
   63 |         shared_ptr& operator=(shared_ptr<Y>&& r) noexcept;
      |                                            ^~
p604.cpp:63:50: error: expected initializer before 'noexcept'
   63 |         shared_ptr& operator=(shared_ptr<Y>&& r) noexcept;
      |                                                  ^~~~~~~~
p604.cpp:65:31: error: 'unique_ptr' has not been declared
   65 |         shared_ptr& operator=(unique_ptr<Y, D>&& r);
      |                               ^~~~~~~~~~
p604.cpp:65:41: error: expected ',' or '...' before '<' token
   65 |         shared_ptr& operator=(unique_ptr<Y, D>&& r);
      |                                         ^
p604.cpp:67:24: error: expected ';' at end of member declaration
   67 | void swap(shared_ptr& r) noexcept; void reset() noexcept; template<class Y>
      |                        ^
      |                         ;
p604.cpp:67:26: error: 'noexcept' does not name a type
   67 | void swap(shared_ptr& r) noexcept; void reset() noexcept; template<class Y>
      |                          ^~~~~~~~
p604.cpp:67:26: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p604.cpp:67:47: error: expected ';' at end of member declaration
   67 | void swap(shared_ptr& r) noexcept; void reset() noexcept; template<class Y>
      |                                               ^
      |                                                ;
p604.cpp:67:49: error: 'noexcept' does not name a type
   67 | void swap(shared_ptr& r) noexcept; void reset() noexcept; template<class Y>
      |                                                 ^~~~~~~~
p604.cpp:67:49: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p604.cpp:74:1: error: 'element_type' does not name a type
   74 | element_type* get() const noexcept; T& operator*() const noexcept;
      | ^~~~~~~~~~~~
p604.cpp:74:52: error: expected ';' at end of member declaration
   74 | element_type* get() const noexcept; T& operator*() const noexcept;
      |                                                    ^~~~~
      |                                                         ;
p604.cpp:74:58: error: 'noexcept' does not name a type
   74 | element_type* get() const noexcept; T& operator*() const noexcept;
      |                                                          ^~~~~~~~
p604.cpp:74:58: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p604.cpp:75:17: error: expected ';' at end of member declaration
   75 | T* operator->() const noexcept;
      |                 ^~~~~
      |                      ;
p604.cpp:75:23: error: 'noexcept' does not name a type
   75 | T* operator->() const noexcept;
      |                       ^~~~~~~~
p604.cpp:75:23: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p604.cpp:80:10: error: 'element_type' does not name a type
   80 |          element_type& operator[](ptrdiff_t i) const;
      |          ^~~~~~~~~~~~
p604.cpp:81:27: error: expected ';' at end of member declaration
   81 |          long use_count() const noexcept;
      |                           ^~~~~
      |                                ;
p604.cpp:81:33: error: 'noexcept' does not name a type
   81 |          long use_count() const noexcept;
      |                                 ^~~~~~~~
p604.cpp:81:33: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p604.cpp:82:35: warning: explicit conversion operators only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
   82 |          explicit operator bool() const noexcept;
      |                                   ^~~~~
p604.cpp:82:35: error: expected ';' at end of member declaration
   82 |          explicit operator bool() const noexcept;
      |                                   ^~~~~
      |                                        ;
p604.cpp:82:41: error: 'noexcept' does not name a type
   82 |          explicit operator bool() const noexcept;
      |                                         ^~~~~~~~
p604.cpp:82:41: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p604.cpp:84:60: error: expected initializer before 'noexcept'
   84 |            bool owner_before(const shared_ptr<U>& b) const noexcept;
      |                                                            ^~~~~~~~
p604.cpp:86:36: error: 'weak_ptr' does not name a type
   86 |            bool owner_before(const weak_ptr<U>& b) const noexcept;
      |                                    ^~~~~~~~
p604.cpp:86:44: error: expected ',' or '...' before '<' token
   86 |            bool owner_before(const weak_ptr<U>& b) const noexcept;
      |                                            ^
p604.cpp:86:58: error: expected initializer before 'noexcept'
   86 |            bool owner_before(const weak_ptr<U>& b) const noexcept;
      |                                                          ^~~~~~~~
p604.cpp:89:20: error: expected constructor, destructor, or type conversion before '(' token
   89 |          shared_ptr(weak_ptr<T>) -> shared_ptr<T>;
      |                    ^
p604.cpp:91:20: error: expected constructor, destructor, or type conversion before '(' token
   91 |          shared_ptr(unique_ptr<T, D>) -> shared_ptr<T>;
      |                    ^
p604.cpp: In function 'int main()':
p604.cpp:98:16: error: 'X' was not declared in this scope
   98 | if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
      |                ^
p604.cpp:98:17: error: template argument 1 is invalid
   98 | if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
      |                 ^
p604.cpp:98:24: error: 'dynamic_pointer_cast' was not declared in this scope
   98 | if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
      |                        ^~~~~~~~~~~~~~~~~~~~
p604.cpp:98:48: error: 'py' was not declared in this scope; did you mean 'px'?
   98 | if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
      |                                                ^~
      |                                                px
p604.cpp:98:19: warning: unused variable 'px' [-Wunused-variable]
   98 | if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
      |                   ^~
rm: cannot remove 'p604g': No such file or directory

$ g++ p604.cpp -std=c++2b -o p604g -I. -Wall
p604.cpp:30:28: error: 'weak_ptr' does not name a type
   30 |       using weak_type    = weak_ptr<T>;
      |                            ^~~~~~~~
p604.cpp:54:35: error: 'weak_ptr' does not name a type
   54 |         explicit shared_ptr(const weak_ptr<Y>& r);
      |                                   ^~~~~~~~
p604.cpp:54:43: error: expected ',' or '...' before '<' token
   54 |         explicit shared_ptr(const weak_ptr<Y>& r);
      |                                           ^
p604.cpp:56:30: error: expected ')' before '<' token
   56 |         shared_ptr(unique_ptr<Y, D>&& r);
      |                   ~          ^
      |                              )
p604.cpp:65:31: error: 'unique_ptr' has not been declared
   65 |         shared_ptr& operator=(unique_ptr<Y, D>&& r);
      |                               ^~~~~~~~~~
p604.cpp:65:41: error: expected ',' or '...' before '<' token
   65 |         shared_ptr& operator=(unique_ptr<Y, D>&& r);
      |                                         ^
p604.cpp:86:36: error: 'weak_ptr' does not name a type
   86 |            bool owner_before(const weak_ptr<U>& b) const noexcept;
      |                                    ^~~~~~~~
p604.cpp:86:44: error: expected ',' or '...' before '<' token
   86 |            bool owner_before(const weak_ptr<U>& b) const noexcept;
      |                                            ^
p604.cpp:89:29: error: expected ')' before '<' token
   89 |          shared_ptr(weak_ptr<T>) -> shared_ptr<T>;
      |                    ~        ^
      |                             )
p604.cpp:91:31: error: expected ')' before '<' token
   91 |          shared_ptr(unique_ptr<T, D>) -> shared_ptr<T>;
      |                    ~          ^
      |                               )
p604.cpp: In function 'int main()':
p604.cpp:98:16: error: 'X' was not declared in this scope
   98 | if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
      |                ^
p604.cpp:98:17: error: template argument 1 is invalid
   98 | if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
      |                 ^
p604.cpp:98:48: error: 'py' was not declared in this scope; did you mean 'px'?
   98 | if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
      |                                                ^~
      |                                                px
p604.cpp:98:24: error: 'dynamic_pointer_cast' was not declared in this scope
   98 | if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
      |                        ^~~~~~~~~~~~~~~~~~~~~~~
p604.cpp:98:19: warning: unused variable 'px' [-Wunused-variable]
   98 | if (shared_ptr<X> px = dynamic_pointer_cast<X>(py)) { // do something with px
      |                   ^~

```

## 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。-->

## Script

```bash:clgc.sh
#!/bin/sh
rm $1l
rm $1g
echo "$ clang++ $1.cpp -std=03 -o $1l -I. -Wall" 
clang++ $1.cpp -std=c++03 -o $1l -I. -Wall
if [  -e $1l ]; then
./$1l 
fi
rm $1l
echo "$ clang++ $1.cpp -std=2b -o $1l -I. -Wall"
clang++ $1.cpp -std=c++2b -o $1l -I. -Wall
if [  -e $1l ]; then
./$1l
fi
echo "\r"
echo "$ g++ $1.cpp -std=03 -o $1g -I. -Wall"
g++ $1.cpp -std=c++03 -o $1g -I. -Wall
if [ -e $1g ]; then
./$1g
fi
rm $1g
echo "\r"
echo "$ g++ $1.cpp -std=2b -o $1g -I. -Wall"
g++ $1.cpp -std=c++2b -o $1g -I. -Wall
if [ -e $1g ]; then
./$1g 
fi
```

# 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)

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

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

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


 ＜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 　20220719