I would recommend to break down this question to two questions:
1) "I wanted to know how it works for frameworks written in C, example - IOSurface, IOMobileFramebuffer etc."
I had exactly the same question: Getting signatures of private API methods for iOS
The answer is
a) Try to google C method to see whether somebody else has disassembled it and found method signature.
b) If nobody did this before, you can be the first who will do it
2) "how do I make out what functions inside the frameworks are being called by the app ?"
There are two types of references to functions in frameworks/libraries:
- Compile time references
You use some disassembler, it will list all compile time references to frameworks/dylibs.
- Runtime references
These are references when somebody does dlopen
, dlsym
or NSBundle
to use some functions.
You will have to disassemble and look/grep through disassembled code to find where they are used. There will be strings with the names of methods which are used.