Guidelines for the use of the C++14 language in critical and
safety-related systems Sample code compile list(117)
https://www.autosar.org/fileadmin/user_upload/standards/adaptive/17-03/AUTOSAR_RS_CPP14Guidelines.pdf
Autosar Guidelines C++14, example code compile list will be listed.
#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、以下を検討する。
(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。
-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。
各標準段階の違いを明確にする。
hostedまたはfreestandingの特徴と課題を明確にする。
#A15-0-1.cpp
##算譜(source code)
//Guidelines for the use of the C++14 language in critical and safety-related systems
const char* msg="Rule A15-0-1 (required, implementation, non-automated)A function shall not exit with an exception if it is able to complete its task.(117)A15-0-1.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" are from the AUTOSAR code without some code having /// comment in line.
//% $Id: A15-0-1.cpp 271752 2017-03-23 12:07:07Z piotr.tanski $
#include <fstream>
#include <stdexcept>
#include <string>
#include <vector>
std::uint8_t computeCrc(std::string& msg) {
cout << "computerCrc"<<msg <<endl;
return (uint8_t)true;
};/// @ {} for output
bool isMessageCrcCorrect1(std::string& message)
{
std::uint8_t computedCRC = computeCrc(message);
std::uint8_t receivedCRC = message.at(0);
if (computedCRC != receivedCRC)
{
throw std::logic_error(
"Computed CRC is invalid."); // Non-compliant - CheckMessageCRC()
// was able to perform
// its task, nothing exceptional about its invalid result
}
return true;
}
bool isMessageCrcCorrect2(std::string& message)
{
bool isCorrect = true;
std::uint8_t computedCRC = computeCrc(message);
std::uint8_t receivedCRC = message.at(0);
if (computedCRC != receivedCRC)
{
isCorrect =
false; // Compliant - if CRC is not correct, then return "false"
}
return isCorrect;
}
void sendData(std::string message)
{
if (message.empty())
{
throw std::logic_error("Preconditions are not met."); // Compliant -
// SendData() was
// not able to
// perform its
// task
}
bool sendTimeoutReached = false;
// Implementation
if (sendTimeoutReached)
{
throw std::runtime_error(
"Timeout on sending a message has been reached."); // Compliant -
// SendData()
// did not
// perform its
// task
}
}
std::int32_t findIndex(std::vector<std::int32_t>& v, std::int32_t x) noexcept
{
try
{
std::size_t size = v.size();
for (std::size_t i = 0U; i < size; ++i)
{
if (v.at(i) == x) // v.at() throws an std::out_of_range exception
{
throw i; // Non-compliant - nothing exceptional about finding a
// value in vector
}
}
}
catch (std::size_t
foundIdx) // Non-compliant - nothing exceptional about finding a
// value in vector
{
return foundIdx;
}
catch (std::out_of_range&
e) // Compliant - std::out_of_range error shall be handled
{
return -1;
}
return -1;
}
bool readFile(std::string& filename) noexcept
{
try
{
std::ifstream file(filename, std::ios_base::in);
if (!file.is_open())
{
throw std::runtime_error(
"File cannot be opened"); // Compliant - error on opening a
// file is an exceptional case
}
char c = file.get();
if (!file.good())
{
throw std::runtime_error(
"Cannot read from file"); // Compliant - error on reading from
// file is an exceptional case
}
cout <<"readFile:c="<<c<<endl;/// @ line for output
}
catch (std::exception& e)
{
return false;
}
return true;
}
void fn1(
std::uint32_t x) // Non-compliant - inefficient and less readable version
// than its obvious alternative, e.g. fn2()
// function
{
try
{
if (x < 10)
{
throw 10;
}
cout <<"x=" <<x<<" fn1:Action A"<<endl;/// @ line for output
// Action "A"
}
catch (std::int32_t y)
{
cout <<"y=" <<y<<" fn1:Action B"<<endl;/// @ line for output
// Action "B"
}
}
void fn2(
std::uint32_t x) // Compliant - the same functionality as fn1() function
{
if (x < 10)
{
// Action "B"
cout << "x<10:"<<x<<" fn2:Action B"<<endl;/// @ line for output
}
else
{
cout << "x>=10:"<<x<<" fn2:Action A"<<endl;/// @ line for output
// Action "A"
}
}
/// @ end AUTOSAR
int start() { /// @{} for start
uint32_t i=512;
fn1(i);
fn2(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 a15-0-1
$ clang++ a15-0-1.cpp -I./ -std=c++14 -Wall
x=512 fn1:Action A
x>=10:512 fn2:Action A
Rule A15-0-1 (required, implementation, non-automated)A function shall not exit with an exception if it is able to complete its task.(115)A15-0-1.cpp
$ clang++ a15-0-1.cpp -I./ -std=c++17 -Wall
x=512 fn1:Action A
x>=10:512 fn2:Action A
Rule A15-0-1 (required, implementation, non-automated)A function shall not exit with an exception if it is able to complete its task.(115)A15-0-1.cpp
$ clang++ a15-0-1.cpp -I./ -std=c++2a -Wall
x=512 fn1:Action A
x>=10:512 fn2:Action A
Rule A15-0-1 (required, implementation, non-automated)A function shall not exit with an exception if it is able to complete its task.(115)A15-0-1.cpp
$ g++-8 a15-0-1.cpp -I./ -std=c++14 -Wall
x=512 fn1:Action A
x>=10:512 fn2:Action A
Rule A15-0-1 (required, implementation, non-automated)A function shall not exit with an exception if it is able to complete its task.(115)A15-0-1.cpp
$ g++-8 a15-0-1.cpp -I./ -std=c++17 -Wall
x=512 fn1:Action A
x>=10:512 fn2:Action A
Rule A15-0-1 (required, implementation, non-automated)A function shall not exit with an exception if it is able to complete its task.(115)A15-0-1.cpp
$ g++-8 a15-0-1.cpp -I./ -std=c++2a -Wall
x=512 fn1:Action A
x>=10:512 fn2:Action A
Rule A15-0-1 (required, implementation, non-automated)A function shall not exit with an exception if it is able to complete its task.(115)A15-0-1.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. 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 20180612