Autosar Guidelines C++14, example code compile list(79)Rule A9-6-1 Bit-fields shall be either unsigned integral, or enumeration 

Guidelines for the use of the C++14 language in critical and
safety-related systems Sample code compile list(79)
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。


#A9-6-1.cpp
##算譜(source code)

```c++:A9-6-1.cpp
//Guidelines for the use of the C++14 language in critical and safety-related systems
const char* msg="Rule A9-6-1 (required, implementation, automated)Bit-fields shall be either unsigned integral, or enumeration (with underlying type of unsigned integral type).(79)A9-6-1.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: A9-6-1.cpp 271715 2017-03-23 10:13:51Z piotr.tanski $
#include <cstdint>
enum class E1 : std::uint8_t
{
  E11,
  E12,
  E13
};
enum class E2 : std::int16_t
{
  E21,
  E22,
  E23
};
enum class E3
{
  E31,
  E32,
  E33
};
enum E4
{
  E41,
  E42,
  E43
};
class C
{
public:
  std::int32_t a : 2; // Non-compliant - signed integral type
  std::uint8_t b : 2U; // Compliant
  bool c : 1; // Non-compliant - it is implementation-defined whether bool is
// signed or unsigned
  char d : 2; // Non-compliant
  wchar_t e : 2; // Non-compliant
  E1 f1 : 2; // Compliant
  E2 f2 : 2; // Non-compliant - E2 enum class underlying type is signed
// int
  E3 f3 : 2; // Non-compliant - E3 enum class does not explicitly define
// underlying type
  E4 f4 : 2; // Non-compliant - E4 enum does not explicitly define underlying
// type
};
void fn() noexcept
{
  C c;
  c.f1 = E1::E11;
}
///end AUTOSAR
int start() { /// @{} for start
  fn();
  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)

```shell-session:cpa.sh
$ ../cpa.sh a9-6-1
$ clang++ a9-6-1.cpp -I./ -std=c++14 -Wall
Rule A9-6-1 (required, implementation, automated)Bit-fields shall be either unsigned integral, or enumeration (with underlying type of unsigned integral type).(79)A9-6-1.cpp
$ clang++ a9-6-1.cpp  -I./ -std=c++17 -Wall
Rule A9-6-1 (required, implementation, automated)Bit-fields shall be either unsigned integral, or enumeration (with underlying type of unsigned integral type).(79)A9-6-1.cpp
$ clang++ a9-6-1.cpp  -I./ -std=c++2a -Wall
Rule A9-6-1 (required, implementation, automated)Bit-fields shall be either unsigned integral, or enumeration (with underlying type of unsigned integral type).(79)A9-6-1.cpp

$ g++-8 a9-6-1.cpp  -I./ -std=c++14  -Wall
a9-6-1.cpp:48:10: warning: 'C::f1' is too small to hold all values of 'enum class E1'
  E1 f1 : 2; // Compliant
          ^
a9-6-1.cpp:49:10: warning: 'C::f2' is too small to hold all values of 'enum class E2'
  E2 f2 : 2; // Non-compliant - E2 enum class underlying type is signed
          ^
a9-6-1.cpp:51:10: warning: 'C::f3' is too small to hold all values of 'enum class E3'
  E3 f3 : 2; // Non-compliant - E3 enum class does not explicitly define
          ^
a9-6-1.cpp: In function 'void fn()':
a9-6-1.cpp:58:4: warning: variable 'c' set but not used [-Wunused-but-set-variable]
  C c;
    ^
Rule A9-6-1 (required, implementation, automated)Bit-fields shall be either unsigned integral, or enumeration (with underlying type of unsigned integral type).(79)A9-6-1.cpp
$ g++-8 a9-6-1.cpp  -I./ -std=c++17  -Wall
a9-6-1.cpp:48:10: warning: 'C::f1' is too small to hold all values of 'enum class E1'
  E1 f1 : 2; // Compliant
          ^
a9-6-1.cpp:49:10: warning: 'C::f2' is too small to hold all values of 'enum class E2'
  E2 f2 : 2; // Non-compliant - E2 enum class underlying type is signed
          ^
a9-6-1.cpp:51:10: warning: 'C::f3' is too small to hold all values of 'enum class E3'
  E3 f3 : 2; // Non-compliant - E3 enum class does not explicitly define
          ^
a9-6-1.cpp: In function 'void fn()':
a9-6-1.cpp:58:4: warning: variable 'c' set but not used [-Wunused-but-set-variable]
  C c;
    ^
Rule A9-6-1 (required, implementation, automated)Bit-fields shall be either unsigned integral, or enumeration (with underlying type of unsigned integral type).(79)A9-6-1.cpp
$ g++-8 a9-6-1.cpp  -I./ -std=c++2a  -Wall
a9-6-1.cpp:48:10: warning: 'C::f1' is too small to hold all values of 'enum class E1'
  E1 f1 : 2; // Compliant
          ^
a9-6-1.cpp:49:10: warning: 'C::f2' is too small to hold all values of 'enum class E2'
  E2 f2 : 2; // Non-compliant - E2 enum class underlying type is signed
          ^
a9-6-1.cpp:51:10: warning: 'C::f3' is too small to hold all values of 'enum class E3'
  E3 f3 : 2; // Non-compliant - E3 enum class does not explicitly define
          ^
a9-6-1.cpp: In function 'void fn()':
a9-6-1.cpp:58:4: warning: variable 'c' set but not used [-Wunused-but-set-variable]
  C c;
    ^
Rule A9-6-1 (required, implementation, automated)Bit-fields shall be either unsigned integral, or enumeration (with underlying type of unsigned integral type).(79)A9-6-1.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
clang++警告なし, g++警告あり

###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 20180611