Re: a reminder about 64-bit machines

["Gareth Pearce" <tilps hotmail com>]

> "Gareth Pearce" <tilps hotmail com> writes:
> > >
> > >I don't see why ... usually, these warnigns just indicate
> > >that an standard cast from void * to int needs to be switched
> > >to use the G[U]INT_TO_POINTER() / GPOINTER_TO_[U]INT macros.
> > >
> > >It's very seldom that when you are storing an integer in a pointer
> > >you actually want to store a 64-bit quanity.
> >
> > umm, the problems which occur are when your doing pointer arithmatic
> > and storing differences between pointers in integer temp variables
> > (instead of ptr_diff_t).  Or storing pointers in integers.  Maybe all
> > the cases in the code are just ints being stored in pointers, but I
> > thought I had seen some that were not.
>
> I don't think that will give you that particular warning
> (The result of pointer arithmetic is an integral
> type, not a pointer, so it's not a cast from a pointer to
> an integer of a different size.) As far as I know, there
> is no way to get GCC to warn about casts from size_t to
> int when int is smaller ... and that's probably good
> since there would be lots of false positives.

hmm okay - you are indeed correct - however the possibility of pointers 
being stored into ints remains.

Interesting that gcc will complain about long* being cast to int* - even 
without the allignment issue but wont complain about long to int.
(wonder if I can hack it so it does - just for debugging purposes)
> For 2.0, I actually went through and tried to make GLib work
> with 64-bit quantities
>
>  - Use size_t/ssize_t for string sizes / byte counts
>  - Use long for counts of non-byte objects.
>
> But in almost all places, 32 bits is perfectly fine.
indeed glib looks quite good and it doesnt have any of the warnings of the 
type I mention in the first place anyway.  And indeed its not frequent by 
any measure that 64bits is needed.

Regards,
Gareth


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