[Python-Dev] Using PEP384 Stable ABI for the lzma extension module

[Toshio Kuratomi]

On Wed, Oct 05, 2011 at 06:14:08PM +0200, Antoine Pitrou wrote:
> Le mercredi 05 octobre 2011 à 18:12 +0200, "Martin v. Löwis" a écrit :
> > >> Not sure what you are using it for. If you need to extend the buffer
> > >> in case it is too small, there is absolutely no way this could work
> > >> without copies in the general case because of how computers use
> > >> address space. Even _PyBytes_Resize will copy the data.
> > >
> > > That's not a given. Depending on the memory allocator, a copy can be
> > > avoided. That's why the "str += str" hack is much more efficient under
> > > Linux than Windows, AFAIK.
> > 
> > Even Linux will have to copy a block on realloc in certain cases, no?
> 
> Probably so. How often is totally unknown to me :)
> 
http://www.gnu.org/software/libc/manual/html_node/Changing-Block-Size.html

It depends on whether there's enough free memory after the buffer you
currently have allocated.  I suppose that this becomes a question of what
people consider "the general case" :-)

-Toshio
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