目的(purpose)

AutosarのC++ GuidelineをOS, 制御のプログラムで利用するにあたって、以下を検討する。
(1)hosted, freestandingのどちらを基本にすべきか。(2)C++2014,C++2017, C++202aのどれを用いると良いか。
(3)どの処理系を併用すると良いか。
-std=c++14, -std=c++17, -std=c++2aの3種類で、複数のコンパイラでコンパイルすることにより、誤(error)、警告(warning)、関数・変数連携(link)、出力(output)、にどのような影響があるかを確認する。
#成果(outcome)
複数の処理系の特徴が明確になる。
各標準段階の違いを明確にする。
hostedまたはfreestandingの特徴と課題を明確にする。

A27-0-2.cpp

算譜(source code)

A27-0-2.cpp

//Guidelines for the use of the C++14 language in critical and safety-related systems
const char* msg="Rule A27-0-2 (required, implementation, automated)A C-style string shall guarantee sufficient space for data and the null terminator.(169)A27-0-2.cpp";

//https://www.autosar.org/fileadmin/user_upload/standards/adaptive/17-03/AUTOSAR_RS_CPP14Guidelines.pdf
// There is no description about Autosar declear hosted or freestanding.
// If the Autosar intended both depending on the cases, autosar.h can choose one.
// Compile with -DHOSTED work as  hosted environment, -DFREESTANDING work as freestanding.

#include "autosar.h"/// @line add header file https://qiita.com/kaizen_nagoya/items/4bde8f21ab059b96cf2a

using namespace std;/// @line add using

/// @ start AUTOSAR: From here to the "///end AUTOSAR" are from the AUTOSAR code without some code having /// comment in line.
// $Id: A27-0-2.cpp 270728 2017-03-16 10:38:20Z piotr.tanski $
#include <iostream>
#include <string>
void f1() noexcept
{
  char buffer[10];
  std::cin >> buffer; // Non-compliant - this could lead to a buffer overflow
}
void f2() noexcept
{
  std::string string1;
  std::string string2;
  std::cin >> string1 >> string2; // Compliant - no buffer overflows
}
void f3(std::istream& in) noexcept
{
  char buffer[32];

  try
  {
    in.read(buffer, sizeof(buffer));
  }

  catch (std::ios_base::failure&)
  {
// Handle an error
  }

  std::string str(buffer); // Non-compliant - if ’buffer’ is not null
// terminated, then constructing std::string leads
// to undefined behavior.
}
void f4(std::istream& in) noexcept
{
  char buffer[32];

  try
  {
    in.read(buffer, sizeof(buffer));
  }

  catch (std::ios_base::failure&)
  {
// Handle an error
  }

  std::string str(buffer, in.gcount()); // Compliant
}
/// @ end AUTOSAR
int start() { /// @{} for start
  f1();
  f2();
  cout<< msg << endl;
  ShutdownOS()  EXIT_SUCCESS;
/// Autosar OS 3.1.1, 2009: 7.1.2.2 Undefined Behaviour in OSEK OS
/// OS425 If ShutdownOS is called and ShutdownHook() returns then the operating system shall disable all interrupts and enter an endless loop.
}

##編纂・実行結果(compile and go)

cpa.sh

$ ../cpa.sh a27-0-2
$ clang++ a27-0-2.cpp -I./ -std=c++14 -Wall
i
o
b
Rule A27-0-2 (required, implementation, automated)A C-style string shall guarantee sufficient space for data and the null terminator.(169)A27-0-2.cpp
$ clang++ a27-0-2.cpp  -I./ -std=c++17 -Wall
i
o
b
Rule A27-0-2 (required, implementation, automated)A C-style string shall guarantee sufficient space for data and the null terminator.(169)A27-0-2.cpp
$ clang++ a27-0-2.cpp  -I./ -std=c++2a -Wall
i
o
b
Rule A27-0-2 (required, implementation, automated)A C-style string shall guarantee sufficient space for data and the null terminator.(169)A27-0-2.cpp

$ g++-8 a27-0-2.cpp  -I./ -std=c++14  -Wall
i
o
b
Rule A27-0-2 (required, implementation, automated)A C-style string shall guarantee sufficient space for data and the null terminator.(169)A27-0-2.cpp
$ g++-8 a27-0-2.cpp  -I./ -std=c++17  -Wall
i
o
b
Rule A27-0-2 (required, implementation, automated)A C-style string shall guarantee sufficient space for data and the null terminator.(169)A27-0-2.cpp
$ g++-8 a27-0-2.cpp  -I./ -std=c++2a  -Wall
i
o
b
Rule A27-0-2 (required, implementation, automated)A C-style string shall guarantee sufficient space for data and the null terminator.(169)A27-0-2.cpp

検討事項(agenda)

1. 自律(freestanding)環境. 接待(hosted)環境

C++N4606 1.4 Implementation compliance p.4

2. 対応OSの水準、対応通信規約、応用機能による分類

freestanding用の関数、ライブラリ等
###3. C++2014, C++2017, C++202aの比較項目
本件なし
###4. clang++, g++の比較検討項目
本件なし

###5. f3(std::istream& in), f4(std::istream& in)の引数の渡し方

###6. 役立つまたは意味のある出力

参考文献(reference)

###C++N4741 2018
Working Draft, Standard for Programming Language C++
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/n4741.pdf

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

###C++N4606 2016
Working Draft, Standard for Programming Language C++
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4606.pdf

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

文書履歴(document history)

ver 0.10 初稿 20180612
ver 0.11 一覧追記 20180614

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