Autosar Guidelines C++14, example code compile list(161)Rule A18-5-5  Memory management functions

Guidelines for the use of the C++14 language in critical and
safety-related systems Sample code compile list(161)
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。


#A18-5-5.cpp
##算譜(source code)

```c++:A18-5-5.cpp
//Guidelines for the use of the C++14 language in critical and safety-related systems
const char* msg="Rule A18-5-5 (required, implementation, partially automated) Memory management functions shall ensure the following: (a) deterministic behavior resulting with the existence of worst-case execution time, (b) avoiding memory fragmentation, (c) avoid running out of memory, (d) avoiding mismatched allocations or deallocations, (e) no dependence on non-deterministic calls to kernel.(161)A18-5-3.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

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: A18-5-1.cpp 270728 2017-03-16 10:38:20Z piotr.tanski $

#define __GNU_SOURCE
#include <dlfcn.h>
#include <cstddef>

void* mallocBad(size_t size) // Non-compliant, malloc from libc does not
// guarantee deterministic execution time
{
  void* (*libc_malloc)(size_t) = dlsym(RTLD_NEXT, "malloc");
  return libc_malloc(size);
}

void freeBad(void* ptr) // Non-compliant, malloc from libc does not guarantee
// deterministic execution time
{
  void (*libc_free)(void*) = dlsym(RTLD_NEXT, "free");
  libc_free(ptr);
}

void* mallocGood(size_t size) // Compliant - custom malloc implementation that
// will guarantee deterministic execution time
{
// Custom implementation that provides deterministic worst-case execution
// time
}

void freeGood(void* ptr) // Compliant - custom malloc implementation that will
// guarantee deterministic execution time
{
// Custom implementation that provides deterministic worst-case execution
// time
}
/// @ 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.
}
```
##編纂・実行結果(compile and go)

```shell-session:cpa.sh
$ ../cpa.sh a18-5-5
$ clang++ a18-5-5.cpp -I./ -std=c++14 -Wall
a18-5-5.cpp:22:10: error: cannot initialize a variable of type 'void *(*)(size_t)' (aka 'void *(*)(unsigned long)') with an
      rvalue of type 'void *'
 void* (*libc_malloc)(size_t) = dlsym(RTLD_NEXT, "malloc");
         ^                      ~~~~~~~~~~~~~~~~~~~~~~~~~~
a18-5-5.cpp:29:9: error: cannot initialize a variable of type 'void (*)(void *)' with an rvalue of type 'void *'
 void (*libc_free)(void*) = dlsym(RTLD_NEXT, "free");
        ^                   ~~~~~~~~~~~~~~~~~~~~~~~~
2 errors generated.
$ clang++ a18-5-5.cpp  -I./ -std=c++17 -Wall
a18-5-5.cpp:22:10: error: cannot initialize a variable of type 'void *(*)(size_t)' (aka 'void *(*)(unsigned long)') with an
      rvalue of type 'void *'
 void* (*libc_malloc)(size_t) = dlsym(RTLD_NEXT, "malloc");
         ^                      ~~~~~~~~~~~~~~~~~~~~~~~~~~
a18-5-5.cpp:29:9: error: cannot initialize a variable of type 'void (*)(void *)' with an rvalue of type 'void *'
 void (*libc_free)(void*) = dlsym(RTLD_NEXT, "free");
        ^                   ~~~~~~~~~~~~~~~~~~~~~~~~
2 errors generated.
$ clang++ a18-5-5.cpp  -I./ -std=c++2a -Wall
a18-5-5.cpp:22:10: error: cannot initialize a variable of type 'void *(*)(size_t)' (aka 'void *(*)(unsigned long)') with an
      rvalue of type 'void *'
 void* (*libc_malloc)(size_t) = dlsym(RTLD_NEXT, "malloc");
         ^                      ~~~~~~~~~~~~~~~~~~~~~~~~~~
a18-5-5.cpp:29:9: error: cannot initialize a variable of type 'void (*)(void *)' with an rvalue of type 'void *'
 void (*libc_free)(void*) = dlsym(RTLD_NEXT, "free");
        ^                   ~~~~~~~~~~~~~~~~~~~~~~~~
2 errors generated.

$ g++-8 a18-5-5.cpp  -I./ -std=c++14  -Wall
a18-5-5.cpp: In function 'void* mallocBad(size_t)':
a18-5-5.cpp:22:38: error: invalid conversion from 'void*' to 'void* (*)(size_t)' {aka 'void* (*)(long unsigned int)'} [-fpermissive]
  void* (*libc_malloc)(size_t) = dlsym(RTLD_NEXT, "malloc");
                                 ~~~~~^~~~~~~~~~~~~~~~~~~~~
a18-5-5.cpp: In function 'void freeBad(void*)':
a18-5-5.cpp:29:34: error: invalid conversion from 'void*' to 'void (*)(void*)' [-fpermissive]
  void (*libc_free)(void*) = dlsym(RTLD_NEXT, "free");
                             ~~~~~^~~~~~~~~~~~~~~~~~~
a18-5-5.cpp: In function 'void* mallocGood(size_t)':
a18-5-5.cpp:38:2: warning: no return statement in function returning non-void [-Wreturn-type]
  }
  ^
$ g++-8 a18-5-5.cpp  -I./ -std=c++17  -Wall
a18-5-5.cpp: In function 'void* mallocBad(size_t)':
a18-5-5.cpp:22:38: error: invalid conversion from 'void*' to 'void* (*)(size_t)' {aka 'void* (*)(long unsigned int)'} [-fpermissive]
  void* (*libc_malloc)(size_t) = dlsym(RTLD_NEXT, "malloc");
                                 ~~~~~^~~~~~~~~~~~~~~~~~~~~
a18-5-5.cpp: In function 'void freeBad(void*)':
a18-5-5.cpp:29:34: error: invalid conversion from 'void*' to 'void (*)(void*)' [-fpermissive]
  void (*libc_free)(void*) = dlsym(RTLD_NEXT, "free");
                             ~~~~~^~~~~~~~~~~~~~~~~~~
a18-5-5.cpp: In function 'void* mallocGood(size_t)':
a18-5-5.cpp:38:2: warning: no return statement in function returning non-void [-Wreturn-type]
  }
  ^
$ g++-8 a18-5-5.cpp  -I./ -std=c++2a  -Wall
a18-5-5.cpp: In function 'void* mallocBad(size_t)':
a18-5-5.cpp:22:38: error: invalid conversion from 'void*' to 'void* (*)(size_t)' {aka 'void* (*)(long unsigned int)'} [-fpermissive]
  void* (*libc_malloc)(size_t) = dlsym(RTLD_NEXT, "malloc");
                                 ~~~~~^~~~~~~~~~~~~~~~~~~~~
a18-5-5.cpp: In function 'void freeBad(void*)':
a18-5-5.cpp:29:34: error: invalid conversion from 'void*' to 'void (*)(void*)' [-fpermissive]
  void (*libc_free)(void*) = dlsym(RTLD_NEXT, "free");
                             ~~~~~^~~~~~~~~~~~~~~~~~~
a18-5-5.cpp: In function 'void* mallocGood(size_t)':
a18-5-5.cpp:38:2: warning: no return statement in function returning non-void [-Wreturn-type]
  }
  ^

```

#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.ソースコードのIDが   A18-5-1.cppになっている。

###6.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