Re: PURESIZE increased (again)

[Ken Raeburn]

On Apr 27, 2006, at 18:12, Luc Teirlinck wrote:
> > From my previous message:
>
>    Of course, using different compilers or different C Libraries,
>    _including_ different version numbers for the same compiler or  
> library
>    will not have any effect on the .el file, but it can definitely  
> have
>    an effect on the .elc files
>
> On second thought, this seems less immediately obvious, from a purely
> "logical" point of view.  But apparently, from the empirical evidence,
> differences in compiler, library or OS do seem to matter much more
> compiled Lisp files.  Probably, the alignment issues are more complex
> for them.

From what I've seen of the Lisp structures and allocation code, I'd  
be very surprised if this were true.  You *may* get different  
compilers imposing different alignment/padding constraints for  
structures or unions, but such cases should be very rare and arguably  
reported as bugs (it'll lead to interoperability problems if they're  
used on the same system), and I doubt any of the types Emacs Lisp  
uses get any significant padding.  And I don't think there are many  
data types allocated in loading a .elc file that are not used when  
loading a .el file.

Ken