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。
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
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.
11.9.4 Initialization by inherited constructor [class.inhctor.init] C++N4910:2022 (172) p310.cpp
算譜(source code)
// 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 = "11.9.4 Initialization by inherited constructor [class.inhctor.init] C++N4910:2022 (172) p310.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>
using namespace std;
// Example 1
struct B1 {
B1(int, ...) { }
};
struct B2 {
B2(double) { }
};
int get();
struct D1 : B1 {
using B1::B1;
int x;
int y = get();
};
void test() {
D1 d(2, 3, 4);
D1 e;
struct D2 : B2 {
using B2::B2;
B1 b;
};
// inherits B1(int, ...)
// OK, B1 is initialized by calling B1(2, 3, 4),
// then d.x is default-initialized (no initialization is performed), // then d.y is initialized by calling get()
// error: D1 has a deleted default constructor
}
D2 f(1.0); // error: B1 has a deleted default constructor
struct W { W(int); };
struct X : virtual W { using W::W; X() = delete; };
struct Y : X { using X::X; };
struct Z : Y, virtual W { using Y::Y; };
Z z(0); // OK, initialization of Y does not invoke default constructor of X
template<class T> struct Log : T {
using T::T; // inherits all constructors from class T ~Log() { std::clog << "Destroying wrapper" << std::endl; }
};
// Class template Log wraps any class and forwards all of its constructors, while writing a message to the standard log whenever an object of class Log is destroyed.
// [Example 2:
struct A { A(int); };
struct B : A { using A::A; };
struct C1 : B { using B::B; };
struct C2 : B { using B::B; };
struct D1 : C1, C2 {
using C1::C1;
using C2::C2;
};
struct V1 : virtual B { using B::B; };
struct V2 : virtual B { using B::B; };
struct D2 : V1, V2 {
using V1::V1;
using V2::V2;
};
D1 d1(0);
D2 d2(0);
// error: ambiguous
// OK, initializes virtual B base class, which initializes the A base class
// then initializes the V1 and V2 base classes as if by a defaulted default constructor
struct M { M(); M(int); };
struct N : M { using M::M; };
struct O : M {};
struct P : N, O { using N::N; using O::O; };
P p(0); // OK, use M(0) to initialize N’s base class,
// use M() to initialize O’s base class
int main(){
cout << n4910 << endl;
return EXIT_SUCCESS;
}
Script
#!/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
編纂・実行結果(compile and go)
# ./clgc.sh p320
$ clang++ p320.cpp -std=c++03 -o p320l -I. -Wall
In file included from p320.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 \
^
p320.cpp:33:15: error: using declaration cannot refer to a constructor
using B1::B1;
~~~~^
p320.cpp:35:11: warning: default member initializer for non-static data member is a C++11 extension [-Wc++11-extensions]
int y = get();
^
p320.cpp:38:8: error: no matching constructor for initialization of 'D1'
D1 d(2, 3, 4);
^ ~~~~~~~
p320.cpp:32:10: note: candidate constructor (the implicit copy constructor) not viable: requires 1 argument, but 3 were provided
struct D1 : B1 {
^
p320.cpp:32:10: note: candidate constructor (the implicit default constructor) not viable: requires 0 arguments, but 3 were provided
p320.cpp:32:10: error: implicit default constructor for 'D1' must explicitly initialize the base class 'B1' which does not have a default constructor
struct D1 : B1 {
^
p320.cpp:39:4: note: in implicit default constructor for 'D1' first required here
D1 e;
^
p320.cpp:25:10: note: 'B1' declared here
struct B1 {
^
p320.cpp:41:15: error: using declaration cannot refer to a constructor
using B2::B2;
~~~~^
p320.cpp:49:1: error: unknown type name 'D2'
D2 f(1.0); // error: B1 has a deleted default constructor
^
p320.cpp:51:33: error: using declaration cannot refer to a constructor
struct X : virtual W { using W::W; X() = delete; };
~~~^
p320.cpp:51:42: warning: deleted function definitions are a C++11 extension [-Wc++11-extensions]
struct X : virtual W { using W::W; X() = delete; };
^
p320.cpp:52:25: error: using declaration cannot refer to a constructor
struct Y : X { using X::X; };
~~~^
p320.cpp:53:36: error: using declaration cannot refer to a constructor
struct Z : Y, virtual W { using Y::Y; };
~~~^
p320.cpp:54:3: error: no matching constructor for initialization of 'Z'
Z z(0); // OK, initialization of Y does not invoke default constructor of X
^ ~
p320.cpp:53:8: note: candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int' to 'const Z' for 1st argument
struct Z : Y, virtual W { using Y::Y; };
^
p320.cpp:53:8: note: candidate constructor (the implicit default constructor) not viable: requires 0 arguments, but 1 was provided
p320.cpp:61:30: error: using declaration cannot refer to a constructor
struct B : A { using A::A; };
~~~^
p320.cpp:62:31: error: using declaration cannot refer to a constructor
struct C1 : B { using B::B; };
~~~^
p320.cpp:63:31: error: using declaration cannot refer to a constructor
struct C2 : B { using B::B; };
~~~^
p320.cpp:64:13: error: redefinition of 'D1'
struct D1 : C1, C2 {
^
p320.cpp:32:10: note: previous definition is here
struct D1 : B1 {
^
p320.cpp:68:39: error: using declaration cannot refer to a constructor
struct V1 : virtual B { using B::B; };
~~~^
p320.cpp:69:39: error: using declaration cannot refer to a constructor
struct V2 : virtual B { using B::B; };
~~~^
p320.cpp:71:18: error: using declaration cannot refer to a constructor
using V1::V1;
~~~~^
p320.cpp:72:18: error: using declaration cannot refer to a constructor
using V2::V2;
~~~~^
p320.cpp:74:4: error: no matching constructor for initialization of 'D1'
D1 d1(0);
^ ~
p320.cpp:32:10: note: candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int' to 'const D1' for 1st argument
struct D1 : B1 {
^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
2 warnings and 20 errors generated.
rm: cannot remove 'p320l': No such file or directory
$ clang++ p320.cpp -std=c++2b -o p320l -I. -Wall
p320.cpp:39:4: error: call to implicitly-deleted default constructor of 'D1'
D1 e;
^
p320.cpp:32:15: note: default constructor of 'D1' is implicitly deleted because base class 'B1' has no default constructor
struct D1 : B1 {
^
p320.cpp:49:1: error: unknown type name 'D2'
D2 f(1.0); // error: B1 has a deleted default constructor
^
p320.cpp:64:13: error: redefinition of 'D1'
struct D1 : C1, C2 {
^
p320.cpp:32:10: note: previous definition is here
struct D1 : B1 {
^
3 errors generated.
$ g++ p320.cpp -std=c++03 -o p320g -I. -Wall
In file included from /usr/local/include/c++/12.1.0/atomic:38,
from p320.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 \
| ^~~~~
p320.cpp:33:15: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
33 | using B1::B1;
| ^~
p320.cpp:35:11: warning: non-static data member initializers only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
35 | int y = get();
| ^
p320.cpp: In function 'void test()':
p320.cpp:38:17: sorry, unimplemented: passing arguments to ellipsis of inherited constructor 'D1::D1(int, ...) [inherited from B1]'
38 | D1 d(2, 3, 4);
| ^
p320.cpp:33:15: note: declared here
33 | using B1::B1;
| ^~
p320.cpp: In constructor 'D1::D1()':
p320.cpp:32:10: error: no matching function for call to 'B1::B1()'
32 | struct D1 : B1 {
| ^~
p320.cpp:26:5: note: candidate: 'B1::B1(int, ...)'
26 | B1(int, ...) { }
| ^~
p320.cpp:26:5: note: candidate expects 1 argument, 0 provided
p320.cpp:25:10: note: candidate: 'B1::B1(const B1&)'
25 | struct B1 {
| ^~
p320.cpp:25:10: note: candidate expects 1 argument, 0 provided
p320.cpp: In function 'void test()':
p320.cpp:39:4: note: synthesized method 'D1::D1()' first required here
39 | D1 e;
| ^
p320.cpp:41:15: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
41 | using B2::B2;
| ^~
p320.cpp:38:8: warning: unused variable 'd' [-Wunused-variable]
38 | D1 d(2, 3, 4);
| ^
p320.cpp: At global scope:
p320.cpp:49:1: error: 'D2' does not name a type; did you mean 'D1'?
49 | D2 f(1.0); // error: B1 has a deleted default constructor
| ^~
| D1
p320.cpp:51:33: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
51 | struct X : virtual W { using W::W; X() = delete; };
| ^
p320.cpp:51:42: warning: defaulted and deleted functions only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
51 | struct X : virtual W { using W::W; X() = delete; };
| ^~~~~~
p320.cpp:52:25: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
52 | struct Y : X { using X::X; };
| ^
p320.cpp:53:36: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
53 | struct Z : Y, virtual W { using Y::Y; };
| ^
p320.cpp:56:10: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
56 | using T::T; // inherits all constructors from class T ~Log() { std::clog << "Destroying wrapper" << std::endl; }
| ^
p320.cpp:61:30: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
61 | struct B : A { using A::A; };
| ^
p320.cpp:62:31: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
62 | struct C1 : B { using B::B; };
| ^
p320.cpp:63:31: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
63 | struct C2 : B { using B::B; };
| ^
p320.cpp:64:13: error: redefinition of 'struct D1'
64 | struct D1 : C1, C2 {
| ^~
p320.cpp:32:10: note: previous definition of 'struct D1'
32 | struct D1 : B1 {
| ^~
p320.cpp:68:39: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
68 | struct V1 : virtual B { using B::B; };
| ^
p320.cpp:69:39: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
69 | struct V2 : virtual B { using B::B; };
| ^
p320.cpp:71:18: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
71 | using V1::V1;
| ^~
p320.cpp:72:18: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
72 | using V2::V2;
| ^~
p320.cpp:80:25: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
80 | struct N : M { using M::M; };
| ^
p320.cpp:82:28: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
82 | struct P : N, O { using N::N; using O::O; };
| ^
p320.cpp:82:40: warning: inheriting constructors only available with '-std=c++11' or '-std=gnu++11' [-Wc++11-extensions]
82 | struct P : N, O { using N::N; using O::O; };
| ^
rm: cannot remove 'p320g': No such file or directory
$ g++ p320.cpp -std=c++2b -o p320g -I. -Wall
p320.cpp: In function 'void test()':
p320.cpp:38:17: sorry, unimplemented: passing arguments to ellipsis of inherited constructor 'D1::D1(int, ...) [inherited from B1]'
38 | D1 d(2, 3, 4);
| ^
p320.cpp:33:15: note: declared here
33 | using B1::B1;
| ^~
p320.cpp:39:4: error: use of deleted function 'D1::D1()'
39 | D1 e;
| ^
p320.cpp:32:10: note: 'D1::D1()' is implicitly deleted because the default definition would be ill-formed:
32 | struct D1 : B1 {
| ^~
p320.cpp:32:10: error: no matching function for call to 'B1::B1()'
p320.cpp:26:5: note: candidate: 'B1::B1(int, ...)'
26 | B1(int, ...) { }
| ^~
p320.cpp:26:5: note: candidate expects 1 argument, 0 provided
p320.cpp:25:10: note: candidate: 'constexpr B1::B1(const B1&)'
25 | struct B1 {
| ^~
p320.cpp:25:10: note: candidate expects 1 argument, 0 provided
p320.cpp:25:10: note: candidate: 'constexpr B1::B1(B1&&)'
p320.cpp:25:10: note: candidate expects 1 argument, 0 provided
p320.cpp:38:8: warning: unused variable 'd' [-Wunused-variable]
38 | D1 d(2, 3, 4);
| ^
p320.cpp:39:4: warning: unused variable 'e' [-Wunused-variable]
39 | D1 e;
| ^
p320.cpp: At global scope:
p320.cpp:49:1: error: 'D2' does not name a type; did you mean 'D1'?
49 | D2 f(1.0); // error: B1 has a deleted default constructor
| ^~
| D1
p320.cpp:64:13: error: redefinition of 'struct D1'
64 | struct D1 : C1, C2 {
| ^~
p320.cpp:32:10: note: previous definition of 'struct D1'
32 | struct D1 : B1 {
| ^~
検討事項(agenda)
コンパイルエラーの理由を解説する。
<|--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
コンパイラの実装状況
typedef は C++11 ではオワコン
C99からC++14を駆け抜けるC++講座
自己参照(self reference)
C++ Error Message Collection(1)does not name a type, 11 articles
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++)
Compare the contents of C++N4910:2022, C++N4741:2018 and C++N4606:2015
C++ sample list
clang++, g++コンパイルエラー方針の違いの例
astyle 使ってみた
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
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https://qiita.com/kaizen_nagoya/items/f1a79a7cbd281607c7c9
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https://qiita.com/kaizen_nagoya/items/aa5744e0c4a8618c7671
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ver. 0.01 初稿 20220702