Q:

How can I prove that fread calls ReadFile and fopen calls CreateFile

I know it sounds a little stupid but is there a way to prove that on Windows:

fopen function calls winapi function CreateFile (or CreateFileEx)
fread function calls winapi function ReadFile (or ReadFileEx)

If there is a more general way to determine how some C library functions call the winapi functions, I'm also happy with that as an answer.
We're having a debate and I'm interested in some proof. I'm mainly interested in Visual C.

A:

Visual C comes with the source code for the C runtime library.  Would that settle things?

