Re: question about Qnil representation

[Eli Zaretskii]

> Date: Wed, 26 Oct 2022 09:40:30 -0600
> From: Troy Hinckley <troyhinckley@gmail.com>
> 
> I have been reading through the C source to try and learn it and understand 
> it better. I saw in Changeling.13 an
> entry From Paul Eggert on 2015-01-05 with “Use 0 for Qnil” As a fix for 
> Bug#15880. How does this work in
> practice? It looks like symbols are just pointers, but 0 would not be a valid 
> pointer. I don’t see any special code
> for handling the null case. 

Symbols are not pointers, they have the same C type as any other
Lisp_Object.  If Lisp_Object is represented by an integer number, then
zero is a valid integer number as well.