[Help-smalltalk] Understanding the object layout.

[Mathieu Suen]

Hi All,

I am trying to understand how the object are layout in memory.
I found out some information in libgst/gst.h.

So if I understand correctly the main structures is 
object_s and oop_s.

object_s contain size and class pointer plus the object ivs.
oops_s contain flags for GC I guess plus the pointer to an object_s.

My first question is why 2 structure?

My second question is concerning the object_s struct why there will always be 
at least one data?
  OOP data[1];                  /* variable length, may not be objects, 
                                   but will always be at least this
                                   big.  */

In other word: what would contain data if the instance is from a class with no 
ivs?


Finally I am wondering why objSize has type OOP? Is it because it is a real 
pointer to a SmallInteger? 

I might not guessing right.
Thanks for your answer.


        Mth









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