c++sizeof

c++ sizeof() of a class with functions

I have a C++ question. I wrote the following class:

class c
{
    int f(int x, int y){ return x; }
};

the sizeof() of class c returns "1". I I really don't understand why it returns 1.

Trying to understand better what is going on, I added another function:

class c
{
     int f(int x, int y){ return x; }
     int g(int x, int y){ return x; }
};

Now the following really got me confused! sizeof(c) is still 1 (!?!?!?!). So I guess that functions doesn't change the size of the class, but why? and why does the size is 1? And is it compiler specific?

Solution

  • The class contains no data members, so it's empty. The standard demands that every class have at least size 1, so that's what you get. (Member functions aren't physically "inside" a class, they're really just free functions with a hidden argument and a namespace and access control.)