Re: [PHP-DEV] PHP3 and 64-bit land From: sas <email protected>
Date: 02/27/99

On Sat, Feb 27, 1999 at 06:50:13PM +0200, Zeev Suraski wrote:
>
>
> On Sat, 27 Feb 1999 sas <email protected> wrote:
>
> > Well, I don't intend to change that specific part. It appears to me that
> > index_ptr is just recycled.
>
> As a general approach, PHP usually uses void pointers to store any
> enumerated type (long, pointer, int, etc). There's one exception I can
> think of, which is the hash, that uses unsigned integers to store the
> numeric offsets.
> Resources use hash tables to store themselves, and they usually use the
> numeric indices. I think it's extremely safe to use 32-bit integers as
> unique identifiers for 64-bit pointers, by simply casting them. You'd
> have to be extremely unlucky to bump into a problem because of this data
> loss. Your chances of winning the lottery are much much bigger.

I disagree here. The chance of having the same ptr in 32 bit is about 1 in
2^32 = 4,294,967,296. If you come to Germany, your chance to win the lottery
("6 aus 49") is about 1 to 49!/43! = 10,068,347,520.

It's extremly safe, but you risk random, non repeatable crashes produced by
playing that way. 

-- 

          Regards,

                            Sascha Schumann | 
                                 Consultant | finger sas <email protected>
                                            | for PGP public key

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