C++N4606(273)30.4.4.2 Function call_once [thread.once.callonce]p1373
はじめに(Introduction)
C++N4606 Working Draft, Standard for Programming Language C++
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/#mailing2016-11
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4606.pdf
C++N4606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。
作業方針(sequence)
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++N4606符号断片編纂一覧(example code compile list)
C++N4606 Working Draft 2016, ISO/IEC 14882, C++ standard(1) Example code compile list
https://qiita.com/kaizen_nagoya/items/df5d62c35bd6ed1c3d43/
編纂器(Compiler)
clang++ --version
clang version 6.0.0 (tags/RELEASE_600/final)
Target: x86_64-apple-darwin17.4.0
g++-7 --version
g++-7 (Homebrew GCC 7.3.0_1) 7.3.0
Copyright (C) 2017 Free Software Foundation, Inc.
(273)30.4.4.2 Function call_once [thread.once.callonce]p1373
算譜(source code)
p1373.cpp
// C++N4606 Committee Draft, Standard for Programming Language C++
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4606.pdf
#define msg "C++N460(273)30.4.4.2 Function call_once [thread.once.callonce]p1373.cpp"
// Edited by Dr. Ogawa Kiyoshi. Compile procedure and results record.
#include <iostream>
#include <cstdlib>
#include <atomic>
#include <thread>
// global flag, regular function
void init() {};
std::once_flag flag;
void f() {
std::call_once(flag, init);
}
// function static flag, function object
struct initializer {
void operator()() {};
};
void g() {
static std::once_flag flag2;
std::call_once(flag2, initializer());
}
// object flag, member function
class information {
std::once_flag verified;
void verifier() {};
public:
void verify() {
std::call_once(verified, &information::verifier, *this);
}
};
int main()
{
init();
f();
g();
std::cout<< msg << std::endl;
return EXIT_SUCCESS;
}
編纂・実行結果(compile and go)
cppall.sh
$ ./cppall.sh p1373
$ clang++ p1373.cpp -std=c++03 -Wall
p1373.cpp:30:17: error: no matching function for call to 'call_once'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~~~~~~~
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/mutex:675:1: note: candidate function
template not viable: requires 2 arguments, but 3 were provided
call_once(once_flag& __flag, _Callable& __func)
^
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/mutex:687:1: note: candidate function
template not viable: requires 2 arguments, but 3 were provided
call_once(once_flag& __flag, const _Callable& __func)
^
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/mutex:638:9: error: no matching function
for call to object of type 'const initializer'
__f_();
^~~~
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/mutex:649:5: note: in instantiation of
member function 'std::__1::__call_once_param<const initializer>::operator()'
requested here
(*__p)();
^
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/mutex:692:45: note: in instantiation of
function template specialization 'std::__1::__call_once_proxy<const initializer>'
requested here
__call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);
^
p1373.cpp:23:6: note: in instantiation of function template specialization
'std::__1::call_once<initializer>' requested here
std::call_once(flag2, initializer());
^
p1373.cpp:19:6: note: candidate function not viable: 'this' argument has type
'const initializer', but method is not marked const
void operator()(){};
^
2 errors generated.
$ clang++ p1373.cpp -std=c++11 -Wall
C++N460(273)30.4.4.2 Function call_once [thread.once.callonce]p1373.cpp
$ clang++ p1373.cpp -std=c++17 -Wall
C++N460(273)30.4.4.2 Function call_once [thread.once.callonce]p1373.cpp
$ g++-7 p1373.cpp -std=c++03 -Wall
In file included from /usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/atomic:38:0,
from p1373.cpp:8:
/usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/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.
#error This file requires compiler and library support \
^~~~~
p1373.cpp:13:6: error: 'once_flag' in namespace 'std' does not name a type
std::once_flag flag;
^~~~~~~~~
p1373.cpp: In function 'void f()':
p1373.cpp:15:6: error: 'call_once' is not a member of 'std'
std::call_once(flag, init);
^~~~~~~~~
p1373.cpp:15:16: error: 'flag' was not declared in this scope
std::call_once(flag, init);
^~~~
p1373.cpp:15:16: note: suggested alternative: 'float'
std::call_once(flag, init);
^~~~
float
p1373.cpp: In function 'void g()':
p1373.cpp:22:13: error: 'once_flag' in namespace 'std' does not name a type
static std::once_flag flag2;
^~~~~~~~~
p1373.cpp:23:6: error: 'call_once' is not a member of 'std'
std::call_once(flag2, initializer());
^~~~~~~~~
p1373.cpp:23:16: error: 'flag2' was not declared in this scope
std::call_once(flag2, initializer());
^~~~~
p1373.cpp: At global scope:
p1373.cpp:27:6: error: 'once_flag' in namespace 'std' does not name a type
std::once_flag verified;
^~~~~~~~~
p1373.cpp: In member function 'void information::verify()':
p1373.cpp:30:22: error: 'call_once' is not a member of 'std'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~~
p1373.cpp:30:32: error: 'verified' was not declared in this scope
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~
p1373.cpp:30:32: note: suggested alternative: 'verifier'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~
verifier
$ g++-7 p1373.cpp -std=c++11 -Wall
p1373.cpp:13:6: error: 'once_flag' in namespace 'std' does not name a type
std::once_flag flag;
^~~~~~~~~
p1373.cpp: In function 'void f()':
p1373.cpp:15:6: error: 'call_once' is not a member of 'std'
std::call_once(flag, init);
^~~~~~~~~
p1373.cpp:15:16: error: 'flag' was not declared in this scope
std::call_once(flag, init);
^~~~
p1373.cpp:15:16: note: suggested alternative: 'float'
std::call_once(flag, init);
^~~~
float
p1373.cpp: In function 'void g()':
p1373.cpp:22:13: error: 'once_flag' in namespace 'std' does not name a type
static std::once_flag flag2;
^~~~~~~~~
p1373.cpp:23:6: error: 'call_once' is not a member of 'std'
std::call_once(flag2, initializer());
^~~~~~~~~
p1373.cpp:23:16: error: 'flag2' was not declared in this scope
std::call_once(flag2, initializer());
^~~~~
p1373.cpp: At global scope:
p1373.cpp:27:6: error: 'once_flag' in namespace 'std' does not name a type
std::once_flag verified;
^~~~~~~~~
p1373.cpp: In member function 'void information::verify()':
p1373.cpp:30:22: error: 'call_once' is not a member of 'std'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~~
p1373.cpp:30:32: error: 'verified' was not declared in this scope
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~
p1373.cpp:30:32: note: suggested alternative: 'verifier'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~
verifier
$ g++-7 p1373.cpp -std=c++17 -Wall
p1373.cpp:13:6: error: 'once_flag' in namespace 'std' does not name a type
std::once_flag flag;
^~~~~~~~~
p1373.cpp: In function 'void f()':
p1373.cpp:15:6: error: 'call_once' is not a member of 'std'
std::call_once(flag, init);
^~~~~~~~~
p1373.cpp:15:16: error: 'flag' was not declared in this scope
std::call_once(flag, init);
^~~~
p1373.cpp:15:16: note: suggested alternative: 'float'
std::call_once(flag, init);
^~~~
float
p1373.cpp: In function 'void g()':
p1373.cpp:22:13: error: 'once_flag' in namespace 'std' does not name a type
static std::once_flag flag2;
^~~~~~~~~
p1373.cpp:23:6: error: 'call_once' is not a member of 'std'
std::call_once(flag2, initializer());
^~~~~~~~~
p1373.cpp:23:16: error: 'flag2' was not declared in this scope
std::call_once(flag2, initializer());
^~~~~
p1373.cpp: At global scope:
p1373.cpp:27:6: error: 'once_flag' in namespace 'std' does not name a type
std::once_flag verified;
^~~~~~~~~
p1373.cpp: In member function 'void information::verify()':
p1373.cpp:30:22: error: 'call_once' is not a member of 'std'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~~
p1373.cpp:30:32: error: 'verified' was not declared in this scope
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~
p1373.cpp:30:32: note: suggested alternative: 'verifier'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~
verifier
検討事項(agenda)
// C++N4606 Committee Draft, Standard for Programming Language C++
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4606.pdf
#define msg "C++N460(273)30.4.4.2 Function call_once [thread.once.callonce]p1373.cpp"
// Edited by Dr. Ogawa Kiyoshi. Compile procedure and results record.
#include <iostream>
#include <cstdlib>
#include <atomic>
#include <thread>
// global flag, regular function
void init() {};
std::once_flag flag;
void f() {
std::call_once(flag, init);
}
// function static flag, function object
struct initializer {
void operator()() {};
};
void g() {
static std::once_flag flag2;
std::call_once(flag2, initializer());
}
// object flag, member function
class information {
std::once_flag verified;
void verifier() {};
public:
void verify() {
std::call_once(verified, &information::verifier, *this);
}
};
int main()
{
init();
f();
g();
std::cout<< msg << std::endl;
return EXIT_SUCCESS;
}
$ ./cppall.sh p1373
$ clang++ p1373.cpp -std=c++03 -Wall
p1373.cpp:30:17: error: no matching function for call to 'call_once'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~~~~~~~
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/mutex:675:1: note: candidate function
template not viable: requires 2 arguments, but 3 were provided
call_once(once_flag& __flag, _Callable& __func)
^
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/mutex:687:1: note: candidate function
template not viable: requires 2 arguments, but 3 were provided
call_once(once_flag& __flag, const _Callable& __func)
^
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/mutex:638:9: error: no matching function
for call to object of type 'const initializer'
__f_();
^~~~
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/mutex:649:5: note: in instantiation of
member function 'std::__1::__call_once_param<const initializer>::operator()'
requested here
(*__p)();
^
/usr/local/Cellar/llvm/6.0.0/include/c++/v1/mutex:692:45: note: in instantiation of
function template specialization 'std::__1::__call_once_proxy<const initializer>'
requested here
__call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);
^
p1373.cpp:23:6: note: in instantiation of function template specialization
'std::__1::call_once<initializer>' requested here
std::call_once(flag2, initializer());
^
p1373.cpp:19:6: note: candidate function not viable: 'this' argument has type
'const initializer', but method is not marked const
void operator()(){};
^
2 errors generated.
$ clang++ p1373.cpp -std=c++11 -Wall
C++N460(273)30.4.4.2 Function call_once [thread.once.callonce]p1373.cpp
$ clang++ p1373.cpp -std=c++17 -Wall
C++N460(273)30.4.4.2 Function call_once [thread.once.callonce]p1373.cpp
$ g++-7 p1373.cpp -std=c++03 -Wall
In file included from /usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/atomic:38:0,
from p1373.cpp:8:
/usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/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.
#error This file requires compiler and library support \
^~~~~
p1373.cpp:13:6: error: 'once_flag' in namespace 'std' does not name a type
std::once_flag flag;
^~~~~~~~~
p1373.cpp: In function 'void f()':
p1373.cpp:15:6: error: 'call_once' is not a member of 'std'
std::call_once(flag, init);
^~~~~~~~~
p1373.cpp:15:16: error: 'flag' was not declared in this scope
std::call_once(flag, init);
^~~~
p1373.cpp:15:16: note: suggested alternative: 'float'
std::call_once(flag, init);
^~~~
float
p1373.cpp: In function 'void g()':
p1373.cpp:22:13: error: 'once_flag' in namespace 'std' does not name a type
static std::once_flag flag2;
^~~~~~~~~
p1373.cpp:23:6: error: 'call_once' is not a member of 'std'
std::call_once(flag2, initializer());
^~~~~~~~~
p1373.cpp:23:16: error: 'flag2' was not declared in this scope
std::call_once(flag2, initializer());
^~~~~
p1373.cpp: At global scope:
p1373.cpp:27:6: error: 'once_flag' in namespace 'std' does not name a type
std::once_flag verified;
^~~~~~~~~
p1373.cpp: In member function 'void information::verify()':
p1373.cpp:30:22: error: 'call_once' is not a member of 'std'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~~
p1373.cpp:30:32: error: 'verified' was not declared in this scope
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~
p1373.cpp:30:32: note: suggested alternative: 'verifier'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~
verifier
$ g++-7 p1373.cpp -std=c++11 -Wall
p1373.cpp:13:6: error: 'once_flag' in namespace 'std' does not name a type
std::once_flag flag;
^~~~~~~~~
p1373.cpp: In function 'void f()':
p1373.cpp:15:6: error: 'call_once' is not a member of 'std'
std::call_once(flag, init);
^~~~~~~~~
p1373.cpp:15:16: error: 'flag' was not declared in this scope
std::call_once(flag, init);
^~~~
p1373.cpp:15:16: note: suggested alternative: 'float'
std::call_once(flag, init);
^~~~
float
p1373.cpp: In function 'void g()':
p1373.cpp:22:13: error: 'once_flag' in namespace 'std' does not name a type
static std::once_flag flag2;
^~~~~~~~~
p1373.cpp:23:6: error: 'call_once' is not a member of 'std'
std::call_once(flag2, initializer());
^~~~~~~~~
p1373.cpp:23:16: error: 'flag2' was not declared in this scope
std::call_once(flag2, initializer());
^~~~~
p1373.cpp: At global scope:
p1373.cpp:27:6: error: 'once_flag' in namespace 'std' does not name a type
std::once_flag verified;
^~~~~~~~~
p1373.cpp: In member function 'void information::verify()':
p1373.cpp:30:22: error: 'call_once' is not a member of 'std'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~~
p1373.cpp:30:32: error: 'verified' was not declared in this scope
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~
p1373.cpp:30:32: note: suggested alternative: 'verifier'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~
verifier
$ g++-7 p1373.cpp -std=c++17 -Wall
p1373.cpp:13:6: error: 'once_flag' in namespace 'std' does not name a type
std::once_flag flag;
^~~~~~~~~
p1373.cpp: In function 'void f()':
p1373.cpp:15:6: error: 'call_once' is not a member of 'std'
std::call_once(flag, init);
^~~~~~~~~
p1373.cpp:15:16: error: 'flag' was not declared in this scope
std::call_once(flag, init);
^~~~
p1373.cpp:15:16: note: suggested alternative: 'float'
std::call_once(flag, init);
^~~~
float
p1373.cpp: In function 'void g()':
p1373.cpp:22:13: error: 'once_flag' in namespace 'std' does not name a type
static std::once_flag flag2;
^~~~~~~~~
p1373.cpp:23:6: error: 'call_once' is not a member of 'std'
std::call_once(flag2, initializer());
^~~~~~~~~
p1373.cpp:23:16: error: 'flag2' was not declared in this scope
std::call_once(flag2, initializer());
^~~~~
p1373.cpp: At global scope:
p1373.cpp:27:6: error: 'once_flag' in namespace 'std' does not name a type
std::once_flag verified;
^~~~~~~~~
p1373.cpp: In member function 'void information::verify()':
p1373.cpp:30:22: error: 'call_once' is not a member of 'std'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~~
p1373.cpp:30:32: error: 'verified' was not declared in this scope
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~
p1373.cpp:30:32: note: suggested alternative: 'verifier'
void verify() { std::call_once(verified, &information::verifier, *this); }
^~~~~~~~
verifier
役に立つまたは意味のある出力
参考資料(reference)
docker gnu(gcc/g++) and llvm(clang/clang++)
https://qiita.com/drafts/059874ea39c4de64c0f7
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
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
文書履歴(document history)
ver. 0.10 初稿 20180502
Author And Source
この問題について(C++N4606(273)30.4.4.2 Function call_once [thread.once.callonce]p1373), 我々は、より多くの情報をここで見つけました https://qiita.com/kaizen_nagoya/items/0b1a78a34480a00d9fc0著者帰属：元の著者の情報は、元のURLに含まれています。著作権は原作者に属する。
Content is automatically searched and collected through network algorithms . If there is a violation . Please contact us . We will adjust (correct author information ,or delete content ) as soon as possible .