为什么std :: string没有虚拟析构函数？ [英] Why doesn’t std::string have a virtual destructor?

问题描述

当我在一个涉及以给定语言定义句子的项目上工作时，我惊讶地发现 std :: string 析构函数不是虚拟的。这使得很难专门化这个类（我不得不创建一个包装）。为什么标准委员会决定让这个类不是虚拟的？

When I was working on a project that involved defining sentences in a given language, I was surprised to discover that std::string destructor was not virtual. This made it a lot more difficult to specialize this class (I had to create a wrapper). Why did the standard committee decide to have this class not virtual?

在/usr/lib64/gcc/x86_64-pc-linux-gnu/4.5.3/include/ g ++ - v4 / bits / basic_string.h，我们有：

in /usr/lib64/gcc/x86_64-pc-linux-gnu/4.5.3/include/g++-v4/bits/basic_string.h, we have:

template<typename _CharT, typename _Traits, typename _Alloc>
class basic_string
{
   ...

  /**
   *  @brief  Destroy the string instance.
   */
  ~basic_string()
  { _M_rep()->_M_dispose(this->get_allocator()); }

推荐答案

我认为设计器暗示类不应该是子类。

It is by design. I think the designer is hinting that the class should not be sub-classed.

还要看这个：为什么不应该从c ++ std string类派生？

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