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AUTOSAR CountdownAdvent Calendar 2022Day 1
この記事誰得？ 私しか得しないニッチな技術で記事投稿！
@kaizen_nagoya(Dr. Kiyoshi Ogawa)

Autosar Guidelines C++14, example code compile list(39)"Rule A5-1-5 If a lambda expression is used in the same scope

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(39)
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。

#A5-1-5.cpp
##算譜(source code)

A5-1-5.cpp
//Guidelines for the use of the C++14 language in critical and safety-related systems
const char* msg="Rule A5-1-5 (advisory, implementation, non-automated)If a lambda expression is used in the same scope in which it has been defined, the lambda should capture objects by reference.(39)A5-1-5.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: A5-1-5.cpp 272338 2017-03-28 08:15:01Z piotr.tanski $
#include <cstdint>
#include <functional>
namespace
{
  constexpr std::int32_t bufferMax = 1024;
  constexpr std::int8_t receiversMax = 10;
}
class UDPClient
{
// Implementation - size of UDPClient class exceeds 16 bytes
};
void f1() noexcept(false)
{
  UDPClient client;
  std::uint8_t buffer[bufferMax];
  auto lambda1 = [client,
                  buffer]() // Non-compliant - it is inefficient to capture
// UDPClient and buffer objects by copy in lambda
  {
// Code
  };
  lambda1(); // lambda1 used locally only

  auto lambda2 =
    [&client, &buffer]() // Compliant - be aware that this construct
// may introduce data races in parallel calls.
  {
// Code
  };
  lambda2(); // lambda2 used locally only

  std::uint32_t number1 = 10;
  std::uint32_t number2 = 20;
  auto lambda3 = [number1, number2]() // Compliant by exception - the size of
// std::uint32_t is 4 bytes (lesser or
// equal to the size of a pointer -
// depending on architecture)
  {
// Code
  };
  lambda3(); // lambda3 used locally only

  cout << "buffer[0]="<<buffer[0]<<" number1="<<number1<<" number2="<<number2<<endl; /// @ line for output
}
void f2(std::int8_t currentReceiver) noexcept(false)
{
  std::function<void()> receiver;

  if (currentReceiver < receiversMax)
  {
    UDPClient client;
    receiver =
      [&client]() // Non-compliant - lambda is not used locally, client
// object will go out of scope
    {
// Code
    };
  }

// ...
  receiver(); // Undefined behavior, client object went out of scope
}
///end AUTOSAR
int start() { /// @{} for start
  int8_t i=127;
  f1();
  f2(i);
  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 a5-1-5
$ clang++ a5-1-5.cpp -I./ -std=c++14 -Wall
a5-1-5.cpp:31:18: warning: lambda capture 'client' is not used [-Wunused-lambda-capture]
 auto lambda1 = [client,
                 ^
a5-1-5.cpp:32:2: warning: lambda capture 'buffer' is not used [-Wunused-lambda-capture]
 buffer]() // Non-compliant - it is inefficient to capture
 ^
a5-1-5.cpp:40:4: warning: lambda capture 'client' is not used [-Wunused-lambda-capture]
 [&client, &buffer]() // Compliant - be aware that this construct
   ^
a5-1-5.cpp:40:13: warning: lambda capture 'buffer' is not used [-Wunused-lambda-capture]
 [&client, &buffer]() // Compliant - be aware that this construct
            ^
a5-1-5.cpp:49:18: warning: lambda capture 'number1' is not used [-Wunused-lambda-capture]
 auto lambda3 = [number1, number2]() // Compliant by exception - the size of
                 ^
a5-1-5.cpp:49:27: warning: lambda capture 'number2' is not used [-Wunused-lambda-capture]
 auto lambda3 = [number1, number2]() // Compliant by exception - the size of
                          ^
a5-1-5.cpp:68:4: warning: lambda capture 'client' is not used [-Wunused-lambda-capture]
 [&client]() // Non-compliant - lambda is not used locally, client
   ^
7 warnings generated.
buffer[0]= number1=10 number2=20
libc++abi.dylib: terminating with uncaught exception of type std::__1::bad_function_call: std::exception
../cpa.sh: line 7: 44702 Abort trap: 6           ./$1l14 $2
$ clang++ a5-1-5.cpp  -I./ -std=c++17 -Wall
a5-1-5.cpp:31:18: warning: lambda capture 'client' is not used [-Wunused-lambda-capture]
 auto lambda1 = [client,
                 ^
a5-1-5.cpp:32:2: warning: lambda capture 'buffer' is not used [-Wunused-lambda-capture]
 buffer]() // Non-compliant - it is inefficient to capture
 ^
a5-1-5.cpp:40:4: warning: lambda capture 'client' is not used [-Wunused-lambda-capture]
 [&client, &buffer]() // Compliant - be aware that this construct
   ^
a5-1-5.cpp:40:13: warning: lambda capture 'buffer' is not used [-Wunused-lambda-capture]
 [&client, &buffer]() // Compliant - be aware that this construct
            ^
a5-1-5.cpp:49:18: warning: lambda capture 'number1' is not used [-Wunused-lambda-capture]
 auto lambda3 = [number1, number2]() // Compliant by exception - the size of
                 ^
a5-1-5.cpp:49:27: warning: lambda capture 'number2' is not used [-Wunused-lambda-capture]
 auto lambda3 = [number1, number2]() // Compliant by exception - the size of
                          ^
a5-1-5.cpp:68:4: warning: lambda capture 'client' is not used [-Wunused-lambda-capture]
 [&client]() // Non-compliant - lambda is not used locally, client
   ^
7 warnings generated.
buffer[0]= number1=10 number2=20
libc++abi.dylib: terminating with uncaught exception of type std::__1::bad_function_call: std::exception
../cpa.sh: line 13: 44707 Abort trap: 6           ./$1l17 $2
$ clang++ a5-1-5.cpp  -I./ -std=c++2a -Wall
a5-1-5.cpp:31:18: warning: lambda capture 'client' is not used [-Wunused-lambda-capture]
 auto lambda1 = [client,
                 ^
a5-1-5.cpp:32:2: warning: lambda capture 'buffer' is not used [-Wunused-lambda-capture]
 buffer]() // Non-compliant - it is inefficient to capture
 ^
a5-1-5.cpp:40:4: warning: lambda capture 'client' is not used [-Wunused-lambda-capture]
 [&client, &buffer]() // Compliant - be aware that this construct
   ^
a5-1-5.cpp:40:13: warning: lambda capture 'buffer' is not used [-Wunused-lambda-capture]
 [&client, &buffer]() // Compliant - be aware that this construct
            ^
a5-1-5.cpp:49:18: warning: lambda capture 'number1' is not used [-Wunused-lambda-capture]
 auto lambda3 = [number1, number2]() // Compliant by exception - the size of
                 ^
a5-1-5.cpp:49:27: warning: lambda capture 'number2' is not used [-Wunused-lambda-capture]
 auto lambda3 = [number1, number2]() // Compliant by exception - the size of
                          ^
a5-1-5.cpp:68:4: warning: lambda capture 'client' is not used [-Wunused-lambda-capture]
 [&client]() // Non-compliant - lambda is not used locally, client
   ^
7 warnings generated.
buffer[0]= number1=10 number2=20
libc++abi.dylib: terminating with uncaught exception of type std::__1::bad_function_call: std::exception
../cpa.sh: line 19: 44712 Abort trap: 6           ./$1l2a $2

$ g++-8 a5-1-5.cpp  -I./ -std=c++14  -Wall
a5-1-5.cpp: In function 'void f1()':
a5-1-5.cpp:36:2: warning: 'buffer' is used uninitialized in this function [-Wuninitialized]
  };
  ^
buffer[0]= number1=10 number2=20
terminate called after throwing an instance of 'std::bad_function_call'
  what():  bad_function_call
../cpa.sh: line 26: 44722 Abort trap: 6           ./$1g14 $2
$ g++-8 a5-1-5.cpp  -I./ -std=c++17  -Wall
a5-1-5.cpp: In function 'void f1()':
a5-1-5.cpp:36:2: warning: 'buffer' is used uninitialized in this function [-Wuninitialized]
  };
  ^
buffer[0]= number1=10 number2=20
terminate called after throwing an instance of 'std::bad_function_call'
  what():  bad_function_call
../cpa.sh: line 32: 44732 Abort trap: 6           ./$1g17 $2
$ g++-8 a5-1-5.cpp  -I./ -std=c++2a  -Wall
a5-1-5.cpp: In function 'void f1()':
a5-1-5.cpp:36:2: warning: 'buffer' is used uninitialized in this function [-Wuninitialized]
  };
  ^
buffer[0]= number1=10 number2=20
terminate called after throwing an instance of 'std::bad_function_call'
  what():  bad_function_call
../cpa.sh: line 38: 44742 Abort trap: 6           ./$1g2a $2

#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7、g++警告あり

###5 実行時エラーの取り方

###6 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

最後までおよみいただきありがとうございました。

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Thank you very much for reading to the last sentence.

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