Is there another way to tell the compiler to make a member function inline?, C++ FAQ

C++ FAQ / Section 9 / FAQ 9.8

Section 9:

9.1	What's the deal with `inline` functions?
9.2	What's a simple example of procedural integration?
9.3	Do `inline` functions improve performance?
9.4	How can `inline` functions help with the tradeoff of safety vs. speed?
9.5	Why should I use `inline` functions instead of plain old `#define` macros?
9.6	How do you tell the compiler to make a non-member function `inline`?
9.7	How do you tell the compiler to make a member function `inline`?
9.8	Is there another way to tell the compiler to make a member function `inline`?
9.9	What's a good way to define inline member functions outside the class body?

[9.8] Is there another way to tell the compiler to make a member function inline?

Yep: define the member function in the class body itself:

class Fred {
public:
  void f(int i, char c)
    {
      ...
    }
};

Although this is easier on the person who writes the class, it's harder on all the readers since it mixes "what" a class does with "how" it does them. Because of this mixture, we normally prefer to define member functions outside the class body with the inline keyword. The insight that makes sense of this: in a reuse-oriented world, there will usually be many people who use your class, but there is only one person who builds it (yourself); therefore you should do things that favor the many rather than the few. This approach is further exploited in the next FAQ.