22.11.1 Header synopsis
#include // see 17.11.1
はじめに(Introduction)
N4910 Working Draft, Standard for Programming Language C++
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。
cpprefjp - C++日本語リファレンス
コンパイラの実装状況
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
C++N4741, 2018 Standard Working Draft on ISO/IEC 14882 sample code compile list
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++
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.
22.10.19 Class template hash [unord.hash] C++N4910:2022 (629) p764.cpp
算譜(source code)
p764.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 = "22.10.19 Class template hash [unord.hash] C++N4910:2022 (629) p764.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 "N4910.h"
using namespace std;
// 22.11.1 Header <typeindex> synopsis [type.index.synopsis]
#include <compare> // see 17.11.1
namespace std {
class type_index;
template<class T> struct hash;
template<> struct hash<type_index>;
}
// 22.11.2 type_index overview [type.index.overview]
namespace std {
class type_index {
public:
type_index(const type_info& rhs) noexcept;
bool operator==(const type_index& rhs) const noexcept;
bool operator< (const type_index& rhs) const noexcept;
bool operator> (const type_index& rhs) const noexcept;
bool operator<=(const type_index& rhs) const noexcept;
bool operator>=(const type_index& rhs) const noexcept;
strong_ordering operator<=>(const type_index& rhs) const noexcept;
size_t hash_code() const noexcept;
const char* name() const noexcept;
private:
const type_info* target; // exposition only
// Note that the use of a pointer here, rather than a reference, // means that the default copy/move constructor and assignment // operators will be provided and work as expected.
}; }
// The class type_index provides a simple wrapper for type_info which can be used as an index type in associative containers (24.4) and in unordered associative containers (24.5).
// 22.11.3 type_index members [type.index.members]
type_index(const type_info& rhs) noexcept;
// Effects: Constructs a type_index object, the equivalent of target = &rhs. bool operator==(const type_index& rhs) const noexcept;
// Returns: *target == *rhs.target.
bool operator<(const type_index& rhs) const noexcept;
// Returns: target->before(*rhs.target).
bool operator>(const type_index& rhs) const noexcept;
// Returns: rhs.target->before(*target).
bool operator<=(const type_index& rhs) const noexcept;
// Returns: !rhs.target->before(*target).
bool operator>=(const type_index& rhs) const noexcept;
// Returns: !target->before(*rhs.target).
strong_ordering operator<=>(const type_index& rhs) const noexcept;
// Effects: Equivalent to:
if (*target == *rhs.target) return strong_ordering::equal;
if (target->before(*rhs.target)) return strong_ordering::less;
return strong_ordering::greater;
size_t hash_code() const noexcept;
// Returns: target->hash_code().
const char* name() const noexcept;
// Returns: target->name().
// 22.11.4 Hash support [type.index.hash]
template<> struct hash<type_index>;
// For an object index of type type_index, hash<type_index>()(index) shall evaluate to the same result as index.hash_code().
int main(){
cout << n4910 << endl;
return EXIT_SUCCESS;
}
編纂・実行結果(compile and go)
bash
$ clang++ p764.cpp -std=03 -o p764l -I. -Wall
In file included from p764.cpp:10:
In file included from ./N4910.h:11:
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 \
^
p764.cpp:25:39: error: expected ';' at end of declaration list
type_index(const type_info& rhs) noexcept;
^
;
p764.cpp:26:51: error: expected ';' at end of declaration list
bool operator==(const type_index& rhs) const noexcept;
^
;
p764.cpp:27:51: error: expected ';' at end of declaration list
bool operator< (const type_index& rhs) const noexcept;
^
;
p764.cpp:28:51: error: expected ';' at end of declaration list
bool operator> (const type_index& rhs) const noexcept;
^
;
p764.cpp:29:51: error: expected ';' at end of declaration list
bool operator<=(const type_index& rhs) const noexcept;
^
;
p764.cpp:30:51: error: expected ';' at end of declaration list
bool operator>=(const type_index& rhs) const noexcept;
^
;
p764.cpp:31:7: error: unknown type name 'strong_ordering'
strong_ordering operator<=>(const type_index& rhs) const noexcept;
^
p764.cpp:31:31: warning: '<=>' is a single token in C++20; add a space to avoid a change in behavior [-Wc++20-compat]
strong_ordering operator<=>(const type_index& rhs) const noexcept;
^
p764.cpp:31:23: error: 'operator<=' cannot be the name of a variable or data member
strong_ordering operator<=>(const type_index& rhs) const noexcept;
^
p764.cpp:31:33: error: expected ';' at end of declaration list
strong_ordering operator<=>(const type_index& rhs) const noexcept;
^
;
p764.cpp:32:31: error: expected ';' at end of declaration list
size_t hash_code() const noexcept;
^
;
p764.cpp:33:31: error: expected ';' at end of declaration list
const char* name() const noexcept;
^
;
p764.cpp:40:12: error: expected unqualified-id
type_index(const type_info& rhs) noexcept;
^
p764.cpp:40:12: error: expected ')'
p764.cpp:40:11: note: to match this '('
type_index(const type_info& rhs) noexcept;
^
p764.cpp:43:45: error: expected function body after function declarator
bool operator<(const type_index& rhs) const noexcept;
^
p764.cpp:45:45: error: expected function body after function declarator
bool operator>(const type_index& rhs) const noexcept;
^
p764.cpp:47:46: error: expected function body after function declarator
bool operator<=(const type_index& rhs) const noexcept;
^
p764.cpp:49:46: error: expected function body after function declarator
bool operator>=(const type_index& rhs) const noexcept;
^
p764.cpp:51:1: error: unknown type name 'strong_ordering'
strong_ordering operator<=>(const type_index& rhs) const noexcept;
^
p764.cpp:51:25: warning: '<=>' is a single token in C++20; add a space to avoid a change in behavior [-Wc++20-compat]
strong_ordering operator<=>(const type_index& rhs) const noexcept;
^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
2 warnings and 20 errors generated.
$ clang++ p764.cpp -std=2b -o p764l -I. -Wall
p764.cpp:40:12: error: expected unqualified-id
type_index(const type_info& rhs) noexcept;
^
p764.cpp:40:12: error: expected ')'
p764.cpp:40:11: note: to match this '('
type_index(const type_info& rhs) noexcept;
^
p764.cpp:43:39: error: non-member function cannot have 'const' qualifier
bool operator<(const type_index& rhs) const noexcept;
^~~~~~
p764.cpp:43:6: error: overloaded 'operator<' must be a binary operator (has 1 parameter)
bool operator<(const type_index& rhs) const noexcept;
^
p764.cpp:45:39: error: non-member function cannot have 'const' qualifier
bool operator>(const type_index& rhs) const noexcept;
^~~~~~
p764.cpp:45:6: error: overloaded 'operator>' must be a binary operator (has 1 parameter)
bool operator>(const type_index& rhs) const noexcept;
^
p764.cpp:47:40: error: non-member function cannot have 'const' qualifier
bool operator<=(const type_index& rhs) const noexcept;
^~~~~~
p764.cpp:47:6: error: overloaded 'operator<=' must be a binary operator (has 1 parameter)
bool operator<=(const type_index& rhs) const noexcept;
^
p764.cpp:49:40: error: non-member function cannot have 'const' qualifier
bool operator>=(const type_index& rhs) const noexcept;
^~~~~~
p764.cpp:49:6: error: overloaded 'operator>=' must be a binary operator (has 1 parameter)
bool operator>=(const type_index& rhs) const noexcept;
^
p764.cpp:51:52: error: non-member function cannot have 'const' qualifier
strong_ordering operator<=>(const type_index& rhs) const noexcept;
^~~~~~
p764.cpp:51:17: error: overloaded 'operator<=>' must be a binary operator (has 1 parameter)
strong_ordering operator<=>(const type_index& rhs) const noexcept;
^
p764.cpp:53:3: error: expected unqualified-id
if (*target == *rhs.target) return strong_ordering::equal;
^
p764.cpp:54:3: error: expected unqualified-id
if (target->before(*rhs.target)) return strong_ordering::less;
^
p764.cpp:55:3: error: expected unqualified-id
return strong_ordering::greater;
^
p764.cpp:56:20: error: non-member function cannot have 'const' qualifier
size_t hash_code() const noexcept;
^~~~~~
p764.cpp:58:20: error: non-member function cannot have 'const' qualifier
const char* name() const noexcept;
^~~~~~
17 errors generated.
$ g++ p764.cpp -std=03 -o p764g -I. -Wall
In file included from /usr/local/include/c++/12.1.0/atomic:38,
from N4910.h:11,
from p764.cpp:10:
/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 \
| ^~~~~
p764.cpp:25:40: warning: identifier 'noexcept' is a keyword in C++11 [-Wc++11-compat]
25 | type_index(const type_info& rhs) noexcept;
| ^~~~~~~~
p764.cpp:25:38: error: expected ';' at end of member declaration
25 | type_index(const type_info& rhs) noexcept;
| ^
| ;
p764.cpp:25:40: error: 'noexcept' does not name a type
25 | type_index(const type_info& rhs) noexcept;
| ^~~~~~~~
p764.cpp:25:40: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p764.cpp:26:46: error: expected ';' at end of member declaration
26 | bool operator==(const type_index& rhs) const noexcept;
| ^~~~~
| ;
p764.cpp:26:52: error: 'noexcept' does not name a type
26 | bool operator==(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:26:52: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p764.cpp:27:46: error: expected ';' at end of member declaration
27 | bool operator< (const type_index& rhs) const noexcept;
| ^~~~~
| ;
p764.cpp:27:52: error: 'noexcept' does not name a type
27 | bool operator< (const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:27:52: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p764.cpp:28:46: error: expected ';' at end of member declaration
28 | bool operator> (const type_index& rhs) const noexcept;
| ^~~~~
| ;
p764.cpp:28:52: error: 'noexcept' does not name a type
28 | bool operator> (const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:28:52: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p764.cpp:29:46: error: expected ';' at end of member declaration
29 | bool operator<=(const type_index& rhs) const noexcept;
| ^~~~~
| ;
p764.cpp:29:52: error: 'noexcept' does not name a type
29 | bool operator<=(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:29:52: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p764.cpp:30:46: error: expected ';' at end of member declaration
30 | bool operator>=(const type_index& rhs) const noexcept;
| ^~~~~
| ;
p764.cpp:30:52: error: 'noexcept' does not name a type
30 | bool operator>=(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:30:52: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p764.cpp:31:7: error: 'strong_ordering' does not name a type
31 | strong_ordering operator<=>(const type_index& rhs) const noexcept;
| ^~~~~~~~~~~~~~~
p764.cpp:32:26: error: expected ';' at end of member declaration
32 | size_t hash_code() const noexcept;
| ^~~~~
| ;
p764.cpp:32:32: error: 'noexcept' does not name a type
32 | size_t hash_code() const noexcept;
| ^~~~~~~~
p764.cpp:32:32: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p764.cpp:33:26: error: expected ';' at end of member declaration
33 | const char* name() const noexcept;
| ^~~~~
| ;
p764.cpp:33:32: error: 'noexcept' does not name a type
33 | const char* name() const noexcept;
| ^~~~~~~~
p764.cpp:33:32: note: C++11 'noexcept' only available with '-std=c++11' or '-std=gnu++11'
p764.cpp:40:12: error: expected unqualified-id before 'const'
40 | type_index(const type_info& rhs) noexcept;
| ^~~~~
p764.cpp:40:12: error: expected ')' before 'const'
40 | type_index(const type_info& rhs) noexcept;
| ~^~~~~
| )
p764.cpp:43:45: error: expected initializer before 'noexcept'
43 | bool operator<(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:45:45: error: expected initializer before 'noexcept'
45 | bool operator>(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:47:46: error: expected initializer before 'noexcept'
47 | bool operator<=(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:49:46: error: expected initializer before 'noexcept'
49 | bool operator>=(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:51:1: error: 'strong_ordering' does not name a type
51 | strong_ordering operator<=>(const type_index& rhs) const noexcept;
| ^~~~~~~~~~~~~~~
p764.cpp:53:3: error: expected unqualified-id before 'if'
53 | if (*target == *rhs.target) return strong_ordering::equal;
| ^~
p764.cpp:54:3: error: expected unqualified-id before 'if'
54 | if (target->before(*rhs.target)) return strong_ordering::less;
| ^~
p764.cpp:55:3: error: expected unqualified-id before 'return'
55 | return strong_ordering::greater;
| ^~~~~~
p764.cpp:56:26: error: expected initializer before 'noexcept'
56 | size_t hash_code() const noexcept;
| ^~~~~~~~
p764.cpp:58:26: error: expected initializer before 'noexcept'
58 | const char* name() const noexcept;
| ^~~~~~~~
p764.cpp:61:19: error: explicit specialization of 'template<class T> struct std::hash' outside its namespace must use a nested-name-specifier [-fpermissive]
61 | template<> struct hash<type_index>;
| ^~~~~~~~~~~~~~~~
$ g++ p764.cpp -std=2b -o p764g -I. -Wall
p764.cpp:40:42: error: expected constructor, destructor, or type conversion before ';' token
40 | type_index(const type_info& rhs) noexcept;
| ^
p764.cpp:43:45: error: non-member function 'bool operator<(const std::type_index&)' cannot have cv-qualifier
43 | bool operator<(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:43:6: error: 'bool operator<(const std::type_index&)' must have exactly two arguments
43 | bool operator<(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:45:45: error: non-member function 'bool operator>(const std::type_index&)' cannot have cv-qualifier
45 | bool operator>(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:45:6: error: 'bool operator>(const std::type_index&)' must have exactly two arguments
45 | bool operator>(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:47:46: error: non-member function 'bool operator<=(const std::type_index&)' cannot have cv-qualifier
47 | bool operator<=(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:47:6: error: 'bool operator<=(const std::type_index&)' must have exactly two arguments
47 | bool operator<=(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:49:46: error: non-member function 'bool operator>=(const std::type_index&)' cannot have cv-qualifier
49 | bool operator>=(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:49:6: error: 'bool operator>=(const std::type_index&)' must have exactly two arguments
49 | bool operator>=(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:51:58: error: non-member function 'std::strong_ordering operator<=>(const std::type_index&)' cannot have cv-qualifier
51 | strong_ordering operator<=>(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:51:17: error: 'std::strong_ordering operator<=>(const std::type_index&)' must have exactly two arguments
51 | strong_ordering operator<=>(const type_index& rhs) const noexcept;
| ^~~~~~~~
p764.cpp:53:3: error: expected unqualified-id before 'if'
53 | if (*target == *rhs.target) return strong_ordering::equal;
| ^~
p764.cpp:54:3: error: expected unqualified-id before 'if'
54 | if (target->before(*rhs.target)) return strong_ordering::less;
| ^~
p764.cpp:55:3: error: expected unqualified-id before 'return'
55 | return strong_ordering::greater;
| ^~~~~~
p764.cpp:56:26: error: non-member function 'size_t hash_code()' cannot have cv-qualifier
56 | size_t hash_code() const noexcept;
| ^~~~~~~~
p764.cpp:58:26: error: non-member function 'const char* name()' cannot have cv-qualifier
58 | const char* name() const noexcept;
| ^~~~~~~~
p764.cpp:61:19: error: explicit specialization of 'template<class _Tp> struct std::hash' outside its namespace must use a nested-name-specifier [-fpermissive]
61 | template<> struct hash<type_index>;
| ^~~~~~~~~~~~~~~~
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。
参考資料(reference)
関連する自己参照以外は、こちらの先頭に移転。
C言語（C++)に対する誤解、曲解、無理解、爽快。
#include "N4910.h"
C++N4910資料の改善点
dockerにclang
docker gnu(gcc/g++) and llvm(clang/clang++)
コンパイル用shell script C版(clangとgcc)とC++版(clang++とg++)
C++N4910:2022 tag follower 300人超えました。ありがとうございます。
astyle 使ってみた
DoCAP（ドゥーキャップ）って何ですか？
小川メソッド 覚え（書きかけ）
＜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 20220731