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AUTOSAR CountdownAdvent Calendar 2022Day 21
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@kaizen_nagoya(Dr. Kiyoshi Ogawa)

Autosar Guidelines C++14, example code compile list(34)A5-0-3 The declaration of objects

Last updated at Posted at 2018-06-10

Guidelines for the use of the C++14 language in critical and
safety-related systems Sample code compile list(34)
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。

#A5-0-3.cpp
##算譜(source code)

A5-0-3.cpp
//Guidelines for the use of the C++14 language in critical and safety-related systems
const char* msg="Rule A5-0-3 (required, implementation, automated) The declaration of objects shall contain no more than two levels of pointer indirection.(34)A5-0-3.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: A5-0-3.cpp 271687 2017-03-23 08:57:35Z piotr.tanski $
#include <cstdint>
using IntPtr = std::int8_t*;
struct S
{
  std::int8_t* s1; // Compliant
  std::int8_t** s2; // Compliant
  std::int8_t*** s3; // Non-compliant
};
S* ps1; // Compliant
S** ps2; // Compliant
S*** ps3; // Non-compliant

std::int8_t** (*pfunc1)(); // Compliant
std::int8_t** (**pfunc2)(); // Compliant
std::int8_t** (***pfunc3)(); // Non-compliant
std::int8_t*** (**pfunc4)(); // Non-compliant

void fn(std::int8_t* par1, // Compliant
        std::int8_t** par2, // Compliant
        std::int8_t*** par3, // Non-compliant
        IntPtr* par4, // Compliant
        IntPtr* const* const par5, // Non-compliant
        std::int8_t* par6[], // Compliant
        std::int8_t** par7[]) // Non-compliant
{
  std::int8_t* ptr1=par1; // Compliant
  std::int8_t** ptr2=par2; // Compliant
  std::int8_t*** ptr3=par3; // Non-compliant
  IntPtr* ptr4=par4; // Compliant
  IntPtr* const* const ptr5 = nullptr; // Non-compliant
  std::int8_t* ptr6[10]; // Compliant
  std::int8_t** ptr7[10]; // Compliant
  cout <<"ptr1="<<ptr1 <<" ptr2="<<ptr2<<" ptr3="<<ptr3<<" ptr4="<<ptr4<<" &ptr5="<<&ptr5<<" ptr6="<<ptr6<<" ptr7="<<ptr7<<endl;
}
// Explanation of types
// 1) par1 and ptr1 are of type pointer to std::int8_t.
// 2) par2 and ptr2 are of type pointer to pointer to std::int8_t.
// 3) par3 and ptr3 are of type pointer to a pointer to a pointer
// to std::int8_t.
// This is three levels and is non-compliant.
// 4) par4 and ptr4 are expanded to a type of pointer to a pointer to
// std::int8_t.
// 5) par5 and ptr5 are expanded to a type of const pointer to a const
// pointer
// to a pointer to std::int8_t. This is three levels and is non-compliant.
// 6) par6 is of type pointer to pointer to std::int8_t because arrays
// are converted
// to a pointer to the initial element of the array.
// 7) ptr6 is of type pointer to array of std::int8_t.
// 8) par7 is of type pointer to pointer to pointer to
// std::int8_t because arrays are
// converted to a pointer to the initial element of the array. This is
// three
// levels and is non-compliant.
// 9) ptr7 is of type array of pointer to pointer to std::int8_t. This
// is compliant.
///end AUTOSAR
int start() { /// @{} for start
  int8_t i=127;
  int8_t* par1=&i; // Compliant
  int8_t** par2=&par1; // Compliant
  int8_t*** par3=&par2; // Non-compliant
  IntPtr* par4=par2;  // Compliant
  IntPtr* const* const par5=&par2; // Non-compliant
  int8_t* par6[]= {par1,*par2,*par4}; // Compliant
  int8_t** par7[]= {par2,*par3,par4};
  fn(par1,par2,par3,par4,par5,par6,par7);
  cout <<"par1="<<par1 <<" par2="<<par2<<" par3="<<par3<<" par4="<<par4<<" &par5="<<&par5<<" par6="<<par6<<" par7="<<par7<<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.
}

##編纂・実行結果(compile and go)

cpa.sh
$ ../cpa2.sh a5-0-2 a5-0-2a 
$ clang++ a5-0-2.cpp a5-0-2a.cpp  -std=c++14 -Wall
ip=0x10a0c9100
Rule A5-0-2 (required, implementation, automated)The condition of an if-statement and the condition of an iteration statementshall have type bool.(32)A5-0-2.cpp
rm: a5-0-2l13: No such file or directory
$ clang++ a5-0-2.cpp  a5-0-2a.cpp  -std=c++17 -Wall
ip=0x10c0e3100
Rule A5-0-2 (required, implementation, automated)The condition of an if-statement and the condition of an iteration statementshall have type bool.(32)A5-0-2.cpp
$ clang++ a5-0-2.cpp  a5-0-2a.cpp  -std=c++2a -Wall
ip=0x1072c1100
Rule A5-0-2 (required, implementation, automated)The condition of an if-statement and the condition of an iteration statementshall have type bool.(32)A5-0-2.cpp

$ g++-8 a5-0-2.cpp a5-0-2a.cpp  -std=c++14  -Wall
a5-0-2.cpp: In function 'void f()':
a5-0-2.cpp:50:22: warning: unused variable 'length' [-Wunused-variable]
  while (std::int32_t length = fn2()) // Compliant by exception
                      ^~~~~~
a5-0-2.cpp:55:14: warning: unused variable 'flag' [-Wunused-variable]
  while (bool flag = fn3()) // Compliant
              ^~~~
a5-0-2.cpp:60:20: warning: unused variable 'ptr' [-Wunused-variable]
  if (std::int32_t* ptr = fn())
                    ^~~
a5-0-2.cpp:63:19: warning: unused variable 'length' [-Wunused-variable]
  if (std::int32_t length = fn2())
                   ^~~~~~
a5-0-2.cpp:66:11: warning: unused variable 'flag' [-Wunused-variable]
  if (bool flag = fn3())
           ^~~~
ip=0x10b088130
Rule A5-0-2 (required, implementation, automated)The condition of an if-statement and the condition of an iteration statementshall have type bool.(32)A5-0-2.cpp
$ g++-8 a5-0-2.cpp a5-0-2a.cppp -std=c++17  -Wall
a5-0-2.cpp: In function 'void f()':
a5-0-2.cpp:50:22: warning: unused variable 'length' [-Wunused-variable]
  while (std::int32_t length = fn2()) // Compliant by exception
                      ^~~~~~
a5-0-2.cpp:55:14: warning: unused variable 'flag' [-Wunused-variable]
  while (bool flag = fn3()) // Compliant
              ^~~~
a5-0-2.cpp:60:20: warning: unused variable 'ptr' [-Wunused-variable]
  if (std::int32_t* ptr = fn())
                    ^~~
a5-0-2.cpp:63:19: warning: unused variable 'length' [-Wunused-variable]
  if (std::int32_t length = fn2())
                   ^~~~~~
a5-0-2.cpp:66:11: warning: unused variable 'flag' [-Wunused-variable]
  if (bool flag = fn3())
           ^~~~
ip=0x10e199130
Rule A5-0-2 (required, implementation, automated)The condition of an if-statement and the condition of an iteration statementshall have type bool.(32)A5-0-2.cpp
$ g++-8 a5-0-2.cpp a5-0-2a.cppp -std=c++2a  -Wall
a5-0-2.cpp: In function 'void f()':
a5-0-2.cpp:50:22: warning: unused variable 'length' [-Wunused-variable]
  while (std::int32_t length = fn2()) // Compliant by exception
                      ^~~~~~
a5-0-2.cpp:55:14: warning: unused variable 'flag' [-Wunused-variable]
  while (bool flag = fn3()) // Compliant
              ^~~~
a5-0-2.cpp:60:20: warning: unused variable 'ptr' [-Wunused-variable]
  if (std::int32_t* ptr = fn())
                    ^~~
a5-0-2.cpp:63:19: warning: unused variable 'length' [-Wunused-variable]
  if (std::int32_t length = fn2())
                   ^~~~~~
a5-0-2.cpp:66:11: warning: unused variable 'flag' [-Wunused-variable]
  if (bool flag = fn3())
           ^~~~
ip=0x103d4b130
Rule A5-0-2 (required, implementation, automated)The condition of an if-statement and the condition of an iteration statementshall have type bool.(32)A5-0-2.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
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)

###プログラミング言語教育のXYZ
https://qiita.com/kaizen_nagoya/items/1950c5810fb5c0b07be4
プログラミング言語教育のXYZ(youtube)
https://www.youtube.com/watch?v=He1_tg4px-w&t=486s

###C++N4741 2018
Working Draft, Standard for Programming Language C++
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/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/

###　CEDD(Compile Error Driven Design)
初めての　CEDD(Compile Error Driven Design) ８回直してコンパイル。
https://qiita.com/kaizen_nagoya/items/9494236aa1753f3fd1e1

コンパイルエラーを記録するとよい理由7つ
https://qiita.com/kaizen_nagoya/items/85c0e92b206883140e89

C Puzzle Bookの有り難み5つ、C言語規格及びCコンパイラの特性を認識
https://qiita.com/kaizen_nagoya/items/d89a48c1536a02ecdec9

C言語（C++)に対する誤解、曲解、無理解、爽快。
https://qiita.com/kaizen_nagoya/items/3f3992c9722c1cee2e3a

Qiitaに投稿するCのStyle例(暫定)
https://qiita.com/kaizen_nagoya/items/946df1528a6a1ef2bc0d

C++N4606 Working Draft 2016, ISO/IEC 14882, C++ standardのコード断片をコンパイルするためにしていること
https://qiita.com/kaizen_nagoya/items/a8d7ee2f2e29e76c19c1

コンパイル用shell script C版(clangとgcc)とC++版(clang++とg++)
https://qiita.com/kaizen_nagoya/items/74220c0577a512c2d7da

[C][C++]の国際規格案の例題をコンパイルするときの課題７つ。
https://qiita.com/kaizen_nagoya/items/5f4b155030259497c4de

docker gnu(gcc/g++) and llvm(clang/clang++)
https://qiita.com/drafts/059874ea39c4de64c0f7

#文書履歴(document history)
ver 0.10 初稿 20180610
ver 0.11 一覧追記 参考文献欄追記 20180616

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Thank you very much for reading to the last sentence.

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