how --builtin--return--address() works??

[Andrew Haley]

RANJITH KUMAR KASUKURTHI wrote:

>               I know that __builtin_return_address() function returns the
> return address of the current function when zero is passed
> as an argument.
> 
> 1) In which header file  __builtin_return_address() function is defined?

None.  It's a compiler builtin.

> 2) Return address is stored on stack when a function is called. I think
> __builtin_return_address()
>   is reading that value on stack and returning. Am I right?

It depends on the target; some targets pass return address in a
register.

> If so
> 3) The location where that return address is stored on stack may vary 
> depending upon  number  of arguments  passed to the function, or number of
> local variables inside the function, or whether the function is returning
> a value or not........

Not usually, no.  On those machines that pass the return address on the stack,
that address is on the top.

> How __builtin_return_address() function knows where exactly the return
> address is stored on stack????

The compiler knows where everything is: the return address is nothing
special.

Andrew.