static Member Function

// Test.h

class Test
{
private:
  Test() ;
  ~Test() ;
public:
  static Test &instance() ;     // Maybe a singleton pattern
} ;

// Test.cpp

Test &Test::instance()         // Don't respecify the static keyword!
{
  static Test g_t ;
  return g_t ;
}

   

   当在类外定义一个静态成员是, 我们不能重复指定 static 关键字. 这个关键字只能出现在类中的声明中.

In C++ Primer:

   When we define a static member outside the class, we do not respecify the static keyword. The keyword appears only with the declaration inside the class body.(p.469)