[Python-Dev] Malloc interface (was: [Patches] Re: Garbage collection patches for Python (fwd)

[Fredrik Lundh]

Vladimir Marangozov wrote:
> The goal is to remove Python's dependency on the standard POSIX =
interface
> (malloc/realloc/free) so that we can cleanly and easily plug in the =
future
> a "proprietary" mem manager, other than the one in the C library.

(hmm.  I've been forced to use interfaces like this a lot, but
never ever stumbled upon a situation where we couldn't just
tweak malloc/free to mean what we wanted, either by relinking
or via the preprocessor.  I'm sceptical, in other words...)

> For this purpose, the Python core should be patched and "cleaned" to =
use
> one or more of the following APIs:
>=20
> 1) PyMem_MALLOC        2) PyMem_NEW  =20
>    PyMem_REALLOC  =3D=3D>     PyMem_RESIZE
>    PyMem_FREE             PyMem_DEL
>                           PyMem_XDEL

is XDEL simply a "if (p) free(p)" variant?

if so, don't forget that ANSI C requires that free() does the right
thing if handled a NULL pointer.  since Python 1.6 will be ANSI C,
it's probably better to force users of broken platforms to work
around bugs in PyMem_FREE, rather than expose two different
alternatives.  I'm pretty sure there are standard macros for auto-
conf that tests for this.

in other words,=20

> > ! if (md->off_num)    free(md->off_num);=20
> > ! if (md->offset_top) free(md->offset_top);=20
> > ! if (md->r1)         free(md->r1);=20
> > ! if (md->r2)         free(md->r2);=20
> > ! if (md->eptr)       free((char *)md->eptr);=20
> > ! if (md->ecode)      free((char *)md->ecode);

would become:

> > ! PyMem_FREE(md->off_num);=20
> > ! PyMem_FREE(md->offset_top);=20
> > ! PyMem_FREE(md->r1);=20
> > ! PyMem_FREE(md->r2);=20
> > ! PyMem_FREE(md->eptr);=20
> > ! PyMem_FREE(md->ecode);

</F>