What is good programming style for writing C-language functions and function calls to functions which return pointers?

For example, if I have a function `my_function` which return two integers through pointer arguments. How should I call this function, such that it is easy for a person who is not familiar with my code, to see that it returns two values?

And how should I write the function definition? 

For example, I could always put the return values last in the parameter list, and
when I call the function, I could add some extra space to separate input arguments from return values.

Also, for the function definition, I could add an empty line with a comment between the input parameters and the return values. For example:

```c
void my_function(
   int a,
   int b,
/* return values */
   int *c,
   int *d)
{
   /* do something */
}

int main()
{
   int a = 1;
   int b = 2;
   int c;
   int d;

   my_function(a,b,   &c, &d);
}

```