C ++如何防止我的团队开发人员使用abs的整数版本错误？ [英] C++ How can I prevent my team developers from using integer version of abs by mistake?

问题描述

我的团队正在编写代码来为两个Windows（使用 VS2015 ）和Android（使用 GCC 4.9 调用 QtCreator ）。

我们发现Android二进制文件有 abs 函数。

  double a = 1.0; 
 double b = 0.5; 
 std :: cout<< abs（a-b）< std :: endl; 
 std :: cout<< std :: abs（a-b）<< std :: endl; 
  

显示：

 code> 1 
 0.5 
  

这是一个已知问题，其他）：
使用abs时的奇怪错误（）我最近遇到了

有很多地方我们使用 abs 将它们全部替换为 std :: abs 。精细。 但是，如何防止 abs 以后再次使用？

找到本主题：避免使用abs（）的编译器问题，但它没有帮助。 / p>

我无法启用将所有警告视为错误（-Werror -Wall），因为g ++比MSVC容许的多。即使我们努力在MSVC上编写0警告，我们仍然得到吨的g ++（其中可能有一个关于abs使用不当），我们历史上忽略它们。修复它们将花费我们太多的精力。

解决方案

你有一个头文件基本上包括在内吗？某种持有人的基本面？如果是，你可以把它放在这里：

  extern void NeverDefined（）; 
 
 inline int abs（int a）{
 NeverDefined（）; 
 return a; 
} // abs（int）
  

c $ c> NeverDefined ，你会知道有问题！

通常我不会定义有问题的函数，

编辑

事实上：不要打扰与头文件（标准定义就足够了）。用上面的代码（无 inline ）编写自己的 abs.cc ，它将取代库定义。 p>

当然，如果原始文件标记函数 inline ，这将无法工作 - 在这种情况下，原定义...

My team is writting code to be compiled for both Windows (using VS2015) and Android (using GCC 4.9 invoked by QtCreator).

We figured out that Android binaries had a problem with abs function.

double a = 1.0;
double b = 0.5;
std::cout << abs( a - b ) << std::endl;
std::cout << std::abs( a - b ) << std::endl;

Displays:

1
0.5

This is a known issue, found this topic (among others): Strange bug in usage of abs() I encountered recently

There are lots of places where we use abs, I'll replace them all by std::abs. Fine. But how can I prevent abs to be used again in the future?

Found this topic: Avoiding compiler issues with abs(), but it did not help.

I can't enable treating all warnings as errors (-Werror -Wall) because g++ is much less permissive than MSVC. Even if we make the effort to compile with 0 warning on MSVC, we still get tons of them with g++ (among them there could be one about abs being used badly) and we historically ignore them. Fixing them all would take us too much effort.

解决方案

Do you have a header file that is basically included by everything? Some kind of holder-of-all-fundamentals? If so, you can put this in there:

extern void NeverDefined();

inline int abs(int a) {
    NeverDefined();
    return a;
} // abs(int)

If you then get a linker error on NeverDefined, you'll know there's a problem!

Normally I simply wouldn't define the function in question, but since it's a library function I had to have this second level.

Edit

In fact: don't bother with a header file (the standard definition will suffice). Write your own abs.cc with the above code (no inline) and it will supersede the library definition.

Of course, this won't work if the original file marks the function inline - in which case you could always edit the original definition...

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