函数定义上的纯说明符 [英] pure-specifier on function-definition

问题描述

在 GCC 上编译时，我收到 error: pure-specifier on function-definition，但在我使用 VS2005 编译相同的代码时却没有.

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，它是有效的:

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

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

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

好的，我刚刚学到了一些东西.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;
};

它可能有一个主体，尽管在声明点包含它是非法的.这意味着要拥有主体，必须在类之外定义纯虚函数.请注意，即使它有一个主体，该函数仍然必须被任何从 Abstract 派生的具体类覆盖.如果需要，他们可以选择显式调用 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.

详情在这里.

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