Autosar Guidelines C++14 example code compile list(17)Rule A2-11-4 The identifier name of a non-member object

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

Autosar Guidelines C++14 example code compile list
https://qiita.com/kaizen_nagoya/items/8ccbf6675c3494d57a76

# 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。

# A2-11-4.cpp
## 算譜(source code)

```c++:A2-11-4.cpp
//Guidelines for the use of the C++14 language in critical and safety-related systemsc
const char* msg= "Rule A2-11-4 (required, implementation, automated)The identifier name of a non-member object with static storage duration or static function shall not be reused within a namespace.(17)A2-11-4.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.

/// Comment: This rule is for last section.

///start AUTOSAR: From here to the "///end AUTOSAR" is from AUTOSAR without code having /// comment in line.
//% $Id: A2-11-4.cpp 272338 2017-03-28 08:15:01Z piotr.tanski $
#include "autosar.h"/// @line add header file https://qiita.com/kaizen_nagoya/items/4bde8f21ab059b96cf2a
#include <cstdint>

using namespace std;/// @line add using

namespace ns1 { /// @ add namespace for ns1::f()
  extern void f();
}

namespace ns2 { /// @ add namespace for ns2::f()
  extern void f();
}

// f3.cpp
static std::int32_t globalvariable =
  0; // Compliant - identifier reused, but in another namespace

///end AUTOSAR
int start() { /// @{} for start
  ns1::f();
  ns2::f();
  cout << "globalvariable="<<globalvariable << endl;
  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.
}
```

```c++:a2-11-4a.cpp
#include "autosar.h"/// @line add header file https://qiita.com/kaizen_nagoya/items/4bde8f21ab059b96cf2a
#include <cstdint>

using namespace std;

// f1.cpp
namespace ns1
{
  static std::int32_t globalvariable = 0;
  void f() {/// @ add {} for output
    cout << "ns1="<<globalvariable << endl;
  }
}
```
```c++:a2-11-4b.cpp
#include "autosar.h" /// @line add header file https://qiita.com/kaizen_nagoya/items/4bde8f21ab059b96cf2a
#include <cstdint>// f2.cpp

using namespace std;

namespace ns1
{
// static std::int32_t globalvariable = 0; // Non-compliant - identifier reused
// in ns1 namespace in f1.cpp
}
namespace ns2
{
  static std::int32_t globalvariable =
    0; // Compliant - identifier reused, but in another namespace
  void f() { /// @ add {} for output
    cout << "ns2="<<globalvariable << endl;
  }
}

```
##編纂・実行結果(compile and go)

```shell-session:cpa.sh
$ ../cpa3.sh a2-11-4 a2-11-4a a2-11-4b
$ clang++ a2-11-4.cpp a2-11-4a.cpp a2-11-4b.cpp -std=c++14 -Wall
ns1=0
ns2=0
globalvariable=0
Rule A2-11-4 (required, implementation, automated)The identifier name of a non-member object with static storage duration or static function shall not be reused within a namespace.(17)A2-11-4.cpp
rm: a2-11-4l13: No such file or directory
$ clang++ a2-11-4.cpp  a2-11-4a.cpp a2-11-4b.cpp -std=c++17 -Wall
ns1=0
ns2=0
globalvariable=0
Rule A2-11-4 (required, implementation, automated)The identifier name of a non-member object with static storage duration or static function shall not be reused within a namespace.(17)A2-11-4.cpp
$ clang++ a2-11-4.cpp  a2-11-4a.cpp a2-11-4b.cpp -std=c++2a -Wall
ns1=0
ns2=0
globalvariable=0
Rule A2-11-4 (required, implementation, automated)The identifier name of a non-member object with static storage duration or static function shall not be reused within a namespace.(17)A2-11-4.cpp

$ g++-8 a2-11-4.cpp a2-11-4a.cpp a2-11-4b.cpp -std=c++14  -Wall
ns1=0
ns2=0
globalvariable=0
Rule A2-11-4 (required, implementation, automated)The identifier name of a non-member object with static storage duration or static function shall not be reused within a namespace.(17)A2-11-4.cpp
$ g++-8 a2-11-4.cpp a2-11-4a.cpp a2-11-4b.cpp -std=c++17  -Wall
ns1=0
ns2=0
globalvariable=0
Rule A2-11-4 (required, implementation, automated)The identifier name of a non-member object with static storage duration or static function shall not be reused within a namespace.(17)A2-11-4.cpp
$ g++-8 a2-11-4.cpp a2-11-4a.cpp a2-11-4b.cpp -std=c++2a  -Wall
ns1=0
ns2=0
globalvariable=0
Rule A2-11-4 (required, implementation, automated)The identifier name of a non-member object with static storage duration or static function shall not be reused within a namespace.(17)A2-11-4.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 出力のためには各ファイルにもヘッダファイルが必要。
　　また起動関数があるファイルにextern宣言のnamespaceが必要。

# 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

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 20180607
ver 0.11 一覧追記 20180613
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