纯指定器对函数定义 [英] pure-specifier on function-definition

问题描述

在GCC上编译时，我得到错误：函数定义上的纯说明符，但是当我使用VS2005编译相同的代码时不会。

While compiling on GCC I get the error: pure-specifier on function-definition, but not when I compile the same code using VS2005.

class Dummy {   
  //error: pure-specifier on function-definition, VS2005 compiles 
  virtual void Process() = 0 {};
};

但是当这个纯虚函数的定义不是内联时，它工作：

But when the definition of this pure virtual function is not inline, it works:

class Dummy
{
  virtual void Process() = 0;
};
void Dummy::Process()
{} //compiles on both GCC and VS2005

$ b b

错误是什么意思？为什么我不能内联？是否合法逃避编译问题，如第二个代码示例所示？

What does the error means? Why cannot I do it inline? Is it legal to evade the compile issue as shown in the second code sample?

推荐答案

纯虚函数必须声明如下：

Ok, I've just learned something. A pure virtual function must be declared as follows:

class Abstract 
{
public:
   virtual void pure_virtual() = 0;
};

它可以有一个主体，但在声明时包含它是非法的。这意味着要有一个body，纯虚函数必须在类外定义。请注意，即使它有一个主体，该函数仍然必须被从 Abstract 派生的任何具体类覆盖。他们只是有一个选项，如果他们需要显式调用 Abstract :: pure_virtual（）。

It may have a body, although it is illegal to include it at the point of declaration. This means that to have a body the pure virtual function must be defined outside the class. Note that even if it has a body, the function must still be overridden by any concrete classes derived from Abstract. They would just have an option to call Abstract::pure_virtual() explicitly if they need to.

是此处。

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