How is 'this' passed to member function calls?

["edA-qa mort-ora-y" <iend@spots.ab.ca>]

I have a situation where I want to directly call member functions, via 
a pointer to the member function and having an object pointer.  The 
only trouble is that I don't know the type of class, I only know the 
signature of the function.  That is, I'm sort of calling the function 
blind.

Obviously this is an optimization of the code, since it can be done 
another way, but it'd be a great optimization.  But I need to know 
whether there is a consistant manner in which the object ptr 'this' is 
passed on the stack.  In Win32 there is a common format due to 
COM, but does GCC have a common format on other operating 
systems?

--
edA-qa mort-ora-y
<mort-ora-y@disemia.com>