*About inline member function*

I was told that
(i) Every member function defined in the class body is an automatic inline function.
(ii) Every member function defined outside of the class body, but in the head file should be declared as inline.
(iii) Every member function defined outside of the class body, and in the cpp file should NOT be declared as inline.

Which is true?

For eg.:

Code:

---

//xxx.h
Class C1{
public:
C1(aa=1):a(aa){};
int foo1(){ return a;};
int foo2();
int foo3();
private:
int a;
};

inline C1::foo2(){
return 0;
}

//xxx.cpp
C1::foo3(){
return 0;
}

---

Is foo1 an inline function? Is it a must to declare foo2 as an inline function?
Can we declare foo3 as an inline function?

Create two source files (say f1.cpp and f2.cpp) which include xxx.h, and use your foo functions.

Then compile your f1.cpp f2.cpp and xxx.cpp files to see what sort of message(s) you may get by making various things either inline or not inline.

Thank you. But how can I tell if foo1 is inline or not?

Quote:

---

Originally Posted by Salem

Create two source files (say f1.cpp and f2.cpp) which include xxx.h, and use your foo functions.

Then compile your f1.cpp f2.cpp and xxx.cpp files to see what sort of message(s) you may get by making various things either inline or not inline.

---

The compiler can generally choose on its own whether a function is inline or not regardless of whether you mark it as inline.

However, by implementing foo1 inside the class definition you are asking the compiler to inline it, so the answer is that (1) is true, although I'm not sure how you would test that because I don't think you can un-inline something in the class definition.

As a rule of thumb, assume that your compiler will ignore your use of the 'inline' keyword or other equivalents completely. Assume that it will pay attention to its compiler-specific ways of saying "please compiler, pretty please inline this function for me," though.

saw this years ago... still think it's funny

Code:

---

int fibo(int n){

 if(n<=1) return 0;

 if(n==2) return 1;

 return fibo(n-1)+fibo(n-2);
}

inline int fibo(int n); // please inline it
__inline int fibo(int n); // pretty please it
__forceinline int fibo(int n); // no, seriously. INLINE IT!!
recursive_my_ass_just_inline_the_damn_thing int fibo(int n); // b@$tARD!!!!

---

:D

> Thank you. But how can I tell if foo1 is inline or not?
That wasn't your question, you asked what was necessary to make your program syntactically valid.

To which the answer is try and compile the code, and then make various 'foo' functions either inline or not inline.

What the compiler / linker finally decide to do about it is far too implementation specific.