检测成员变量的阴影 [英] Detecting shadowing of member variables

问题描述

我有一名成员的A类:

std::shared_ptr<class B> m_mySharedPtr;

我有一个初始化方法:

A::Init()
{
  std::shared_ptr<class B> m_mySharedPtr = m_factory->CreateMySharedPtr();
}

我花了一些时间才意识到，在执行初始化之后，shared_ptr为空.这是因为我重新定义了成员，将其视为本地成员，因此在A :: Init()范围之外时被释放.

It took me some time to realize that after my Init the shared_ptr is Empty. That is because I re-define the member, treated as a local and thus released when out of A::Init() scope.

我打算写:

A::Init()
{
  m_mySharedPtr = m_factory->CreateMySharedPtr();
}

为什么编译器不抱怨?至少是警告?类似于成员重新定义".

Why did the compiler not complain? At least a warning? Something like "member re-definition."

在特定情况下确实有效/有用吗?

Is it indeed valid/useful in a particular case?

也许我的警告级别太低.

Maybe my warning level is too low.

谢谢

Vincent

推荐答案

如果您使用的是GCC或Clang，请使用 -Wshadow 标志.您将获得如下编译器输出:

If you're using GCC or Clang, then use the -Wshadow flag. You get compiler output like this:

test.cc:5:7: warning: declaration shadows a field of 'A' [-Wshadow]
                std::shared_ptr<class B> m_mySharedPtr = m_factory->CreateMySharedPtr();
                                         ^
test.cc:2:15: note: previous declaration is here
        std::shared_ptr<class B> m_mySharedPtr;

• 参考资料: http://gcc.gnu.org/onlinedocs/gcc-4.8.2/gcc/Warning-Options.html#Warning-Options .

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