c++ 缺少 vtable 错误

Question

我收到一个非常奇怪的错误，与给定类构造函数和析构函数缺少 vtable 有关。请帮我解决这个问题。

架构 i386 的 undefined symbol :

  "vtable for A", referenced from:
      A::A() in A.o
      A::~MissionController() in A.o
  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

代码片段；

.h 文件:

class A: public B

  public:
     A();
    ~A();

};

.cpp 文件..

 A::A()   
{


}

A::~A()
{


}

Answer 1

找到了，试了下样例，这里有一个例子。

class Shape{

public:
virtual int areas();
virtual void display();

virtual ~Shape(){};
};

编译器提示

Undefined symbols for architecture x86_64:
"typeinfo for Shape", referenced from:
  typeinfo for trian in main_file.o
 "vtable for Shape", referenced from:
  Shape::Shape() in main_file.o
  NOTE: a missing vtable usually means the first non-inline virtual member      function has no definition.
   ld: symbol(s) not found for architecture x86_64
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  make: *** [cpp_tries] Error 1enter code here

修改为空或虚函数旁边{}内的任何内联内容

class Shape{

public:
    virtual int areas(){};
    virtual void display(){};

    virtual ~Shape(){};
};

基本上，它没有找到非内联虚函数的函数定义。