Autosar Guidelines C++14, example code compile list(118)A15-0-2 At least the basic guarantee for exception safety

Guidelines for the use of the C++14 language in critical and
safety-related systems Sample code compile list(118)
https://www.autosar.org/fileadmin/user_upload/standards/adaptive/17-03/AUTOSAR_RS_CPP14Guidelines.pdf
Autosar Guidelines C++14, example code compile list will be listed.

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。

A15-0-2.cpp

算譜(source code)

A15-0-2.cpp

//Guidelines for the use of the C++14 language in critical and safety-related systems
const char* msg="Rule A15-0-2 (required, implementation, partially automated)At least the basic guarantee for exception safety shall be provided for all operations. In addition, each function may offer either the strong guarantee or the nothrow guarantee.(118)A15-0-2.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: A15-0-2.cpp 271927 2017-03-24 12:01:35Z piotr.tanski $
#include <cstdint>
#include <cstring>
class C1
{
public:
  C1(const C1& rhs)
  {
    copyBad(rhs); // Non-compliant - if an exception is thrown, an object
// will be left in an indeterminate state
    copyGood(rhs); // Compliant - full object will be properly copied or
// none of its properties will be changed
  }
  ~C1() {
    delete[] e;
  }
  void copyBad(const C1& rhs)
  {
    if (this != &rhs)
    {
      delete[] e;
      e = nullptr; // e changed before the block where an exception can
// be thrown
      s = rhs.s; // s changed before the block where an exception can be
// thrown

      if (s > 0)
      {
        e = new std::int32_t[s]; // If an exception will be thrown
// here, the
// object will be left in an indeterminate
// state
        std::memcpy(e, rhs.e, s * sizeof(std::int32_t));
      }
    }
  }
  void copyGood(const C1& rhs)
  {
    std::int32_t* eTmp = nullptr;

    if (rhs.s > 0)
    {
      eTmp = new std::int32_t[rhs.s]; // If an exception will be thrown
// here, the
// object will be left unchanged
      std::memcpy(eTmp, rhs.e, rhs.s * sizeof(std::int32_t));
    }

    delete[] e;
    e = eTmp;
    s = rhs.s;
  }

private:
  std::int32_t* e;
  std::size_t s;
};
class A
{
public:
  A() = default;
};
class C2
{
public:
  C2() : a1(new A), a2(new A) // Non-compliant - if a2 memory allocation
// fails, a1 will never be deallocated
  {
  }

private:
  A* a1;
  A* a2;
};
class C3
{
public:
  C3() : a1(nullptr), a2(nullptr) // Compliant
  {
    try
    {
      a1 = new A;
      a2 = new A; // If memory allocation for a2 fails, catch-block will
// deallocate a1
    }

    catch (...)
    {
      delete a1;
      a1 = nullptr;
      delete a2;
      a2 = nullptr;
      throw;
    }
  }

private:
  A* a1;
  A* a2;
};
/// @ end AUTOSAR
int start() { /// @{} for start
  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 a15-0-2
$ clang++ a15-0-2.cpp -I./ -std=c++14 -Wall
Rule A15-0-2 (required, implementation, partially automated)At least the basic guarantee for exception safety shall be provided for all operations. In addition, each function may offer either the strong guarantee or the nothrow guarantee.(116)A15-0-2.cpp
$ clang++ a15-0-2.cpp  -I./ -std=c++17 -Wall
Rule A15-0-2 (required, implementation, partially automated)At least the basic guarantee for exception safety shall be provided for all operations. In addition, each function may offer either the strong guarantee or the nothrow guarantee.(116)A15-0-2.cpp
$ clang++ a15-0-2.cpp  -I./ -std=c++2a -Wall
Rule A15-0-2 (required, implementation, partially automated)At least the basic guarantee for exception safety shall be provided for all operations. In addition, each function may offer either the strong guarantee or the nothrow guarantee.(116)A15-0-2.cpp

$ g++-8 a15-0-2.cpp  -I./ -std=c++14  -Wall
Rule A15-0-2 (required, implementation, partially automated)At least the basic guarantee for exception safety shall be provided for all operations. In addition, each function may offer either the strong guarantee or the nothrow guarantee.(116)A15-0-2.cpp
$ g++-8 a15-0-2.cpp  -I./ -std=c++17  -Wall
Rule A15-0-2 (required, implementation, partially automated)At least the basic guarantee for exception safety shall be provided for all operations. In addition, each function may offer either the strong guarantee or the nothrow guarantee.(116)A15-0-2.cpp
$ g++-8 a15-0-2.cpp  -I./ -std=c++2a  -Wall
Rule A15-0-2 (required, implementation, partially automated)At least the basic guarantee for exception safety shall be provided for all operations. In addition, each function may offer either the strong guarantee or the nothrow guarantee.(116)A15-0-2.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. 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/2017/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

ver 0.10 初稿 20180612