《Effective C++》 Item 30

Bear in mind that inline is a request to compilers, not a command. The request can be given implicitly or explicitly. The implicit way is to define a function inside a class definition:

 

class Person {

public:

  ...

  int age() const { return theAge; } // an implicit inline request: age is


  ... // defined in a class definition




private:

  int theAge;

};


friend functions can also be defined inside classes. When they are, they're also implicitly declared inline.

both inline functions and templates are typically defined in header files，Inlining in most C++ programs is a compile-time activity

If an exception is thrown during construction of an object, any parts of the object that have already been fully constructed are automatically destroyed.