Guidelines for the use of the C++14 language in critical and
safety-related systems Sample code compile list(55)
https://www.autosar.org/fileadmin/user_upload/standards/adaptive/17-03/AUTOSAR_RS_CPP14Guidelines.pdf
Autosar Guidelines C++14, example code compile list(

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、(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を検討するため、-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とともに、各標準段階, hosted, freestandingの特徴と課題を明確にする。

A6-6-1.cpp

算譜(source code)

A6-6-1.cpp

//Guidelines for the use of the C++14 language in critical and safety-related systems
const char* msg="Rule A6-6-1 (required, implementation, automated)The goto statement shall not be used.(55)A6-6-1.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" is from AUTOSAR without code having /// comment in line.
// $Id: A6-6-1.cpp 271715 2017-03-23 10:13:51Z piotr.tanski $
# include <cstdint>
namespace
{
  constexpr std::int32_t loopLimit = 100;
}
void f1(std::int32_t n) noexcept
{
  if (n < 0)
  {
//goto exit; // Non-compliant - jumping to exit from here crosses ptr
// pointer initialization, compilation
// error
  }

  std::int32_t* ptr = new std::int32_t(n);
// ...
exit:
  delete ptr;
}
void f2() noexcept
{
// ...
  goto error; // Non-compliant
// ...
error:; // Error handling and cleanup
}
void f3() noexcept
{
  for (std::int32_t i = 0; i < loopLimit; ++i)
  {
    for (std::int32_t j = 0; j < loopLimit; ++j)
    {
      for (std::int32_t k = 0; k < loopLimit; ++k)
      {
        if ((i == j) && (j == k))
        {
// ...
          cout <<"i="<<i<<" j="<<j<<" k="<<k<<endl;/// @ line for output
          goto loop_break; // Non-compliant
        }
      }
    }
  }

loop_break:; // ...
}
///end AUTOSAR
int start() { /// @{} for start
  int32_t i=2048;
  f1(i);
  f2();
  f3();
  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 a6-6-1
$ clang++ a6-6-1.cpp -I./ -std=c++14 -Wall
a6-6-1.cpp:30:2: warning: unused label 'exit' [-Wunused-label]
 exit:
 ^~~~~
1 warning generated.
i=0 j=0 k=0
Rule A6-6-1 (required, implementation, automated)The goto statement shall not be used.(55)A6-6-1.cpp
$ clang++ a6-6-1.cpp  -I./ -std=c++17 -Wall
a6-6-1.cpp:30:2: warning: unused label 'exit' [-Wunused-label]
 exit:
 ^~~~~
1 warning generated.
i=0 j=0 k=0
Rule A6-6-1 (required, implementation, automated)The goto statement shall not be used.(55)A6-6-1.cpp
$ clang++ a6-6-1.cpp  -I./ -std=c++2a -Wall
a6-6-1.cpp:30:2: warning: unused label 'exit' [-Wunused-label]
 exit:
 ^~~~~
1 warning generated.
i=0 j=0 k=0
Rule A6-6-1 (required, implementation, automated)The goto statement shall not be used.(55)A6-6-1.cpp

$ g++-8 a6-6-1.cpp  -I./ -std=c++14  -Wall
a6-6-1.cpp: In function 'void f1(int32_t)':
a6-6-1.cpp:30:2: warning: label 'exit' defined but not used [-Wunused-label]
  exit:
  ^~~~
i=0 j=0 k=0
Rule A6-6-1 (required, implementation, automated)The goto statement shall not be used.(55)A6-6-1.cpp
$ g++-8 a6-6-1.cpp  -I./ -std=c++17  -Wall
a6-6-1.cpp: In function 'void f1(int32_t)':
a6-6-1.cpp:30:2: warning: label 'exit' defined but not used [-Wunused-label]
  exit:
  ^~~~
i=0 j=0 k=0
Rule A6-6-1 (required, implementation, automated)The goto statement shall not be used.(55)A6-6-1.cpp
$ g++-8 a6-6-1.cpp  -I./ -std=c++2a  -Wall
a6-6-1.cpp: In function 'void f1(int32_t)':
a6-6-1.cpp:30:2: warning: label 'exit' defined but not used [-Wunused-label]
  exit:
  ^~~~
i=0 j=0 k=0
Rule A6-6-1 (required, implementation, automated)The goto statement shall not be used.(55)A6-6-1.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 20180610