Autosar Guidelines C++14, example code compile list(25)Rule A3-3-1 Objects or functions with external linkage

Guidelines for the use of the C++14 language in critical and
safety-related systems Sample code compile list(25)
https://www.autosar.org/fileadmin/user_upload/standards/adaptive/17-03/AUTOSAR_RS_CPP14Guidelines.pdf

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。

A3-3-1.cpp

算譜(source code)

A3-3-1.cpp

//Guidelines for the use of the C++14 language in critical and safety-related systems
const char* msg="Rule A3-3-1 (required, implementation, automated)Objects or functions with external linkage (including members of named namespaces) shall be declared in a header file.(25)A3-3-1.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
#include <cstdint>

using namespace std;/// @line add using

///start AUTOSAR: From here to the "///end AUTOSAR" is from AUTOSAR without code having /// comment in line.

//% $Id: A3-3-1.cpp 271715 2017-03-23 10:13:51Z piotr.tanski $
#include "A3-3-1.hpp"
std::int32_t a1 = 0; // Compliant, external linkage
std::int32_t a2 = 0; // Non-compliant, static keyword not used
static std::int32_t a3 = 0; // Compliant, internal linkage
namespace
{
  std::int32_t a4 = 0; // Compliant by exception
  void f1() // Compliant by exception
  {
  }
}
namespace n
{
  void f2() // Compliant, external linkage
  {
  }
  std::int32_t a6 = 0; // Non-compliant, external linkage
}
extern std::int32_t a7; // Non-compliant, extern object declared in .cpp file
static void f3() // Compliant, static keyword used
{
}
void f4() // Compliant, external linkage
{
  a1 = 1;
  a2 = 1;
  a3 = 1;
  a4 = 1;
  n::a5 = 1;
  n::a6 = 1;
  a7 = 1;
}
void f5() // Non-compliant, static keyword not used
{
  a1 = 2;
  a2 = 2;
  a3 = 2;
  a4 = 2;
  n::a5 = 2;
  n::a6 = 2;
  a7 = 2;
}
int main(int, char**) // Compliant by exception
{
  f1();
  n::f2();
  f3();
  f4();
  f5();

///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.
}

A3-3-1.hpp

//% $Id: A3-3-1.hpp 271715 2017-03-23 10:13:51Z piotr.tanski $
#include <cstdint>
extern std::int32_t a1;
extern void f4();
namespace n
{
  void f2();
  std::int32_t a5; // Compliant, external linkage
}
std::int32_t a7; /// @ line add declaration

編纂・実行結果(compile and go)

cpa.sh

$ ../cpa.sh a3-3-1
$ clang++ a3-3-1.cpp -I./ -std=c++14 -Wall
Rule A3-3-1 (required, implementation, automated)Objects or functions with external linkage (including members of named namespaces) shall be declared in a header file.(24)A3-3-1.cpp
$ clang++ a3-3-1.cpp  -I./ -std=c++17 -Wall
Rule A3-3-1 (required, implementation, automated)Objects or functions with external linkage (including members of named namespaces) shall be declared in a header file.(24)A3-3-1.cpp
$ clang++ a3-3-1.cpp  -I./ -std=c++2a -Wall
Rule A3-3-1 (required, implementation, automated)Objects or functions with external linkage (including members of named namespaces) shall be declared in a header file.(24)A3-3-1.cpp

$ g++-8 a3-3-1.cpp  -I./ -std=c++14  -Wall
Rule A3-3-1 (required, implementation, automated)Objects or functions with external linkage (including members of named namespaces) shall be declared in a header file.(24)A3-3-1.cpp
$ g++-8 a3-3-1.cpp  -I./ -std=c++17  -Wall
Rule A3-3-1 (required, implementation, automated)Objects or functions with external linkage (including members of named namespaces) shall be declared in a header file.(24)A3-3-1.cpp
$ g++-8 a3-3-1.cpp  -I./ -std=c++2a  -Wall
Rule A3-3-1 (required, implementation, automated)Objects or functions with external linkage (including members of named namespaces) shall be declared in a header file.(24)A3-3-1.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 ヘッダ

宣言漏れ。

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 20180609