Two questions about inline functions in C++

Question

I have question when I compile an inline function in C++.

Can a recursive function work with inline. If yes then please describe how.

I am sure about loop

Answer 1

This particular function definitely can be inlined. That is because the compiler can figure out that this particular form of recursion (tail-recursion) can be trivially turned into a normal loop. And with a normal loop it has no problem inlining it at all.

Not only can the compiler inline it, it can even calculate the result for a compile-time constant without generating any code for the function.

With GCC 4.4

int fac = f(10); 

produced this instruction:

movl    $3628800, 4(%esp)

You can easily verify when checking assembly output, that the function is indeed inlined for input that is not known at compile-time.