Got it!
Thanks
On Tue, 23 Mar 1999, Richard Hartman wrote:
> Yes, it is all transparent to you -unless- you
> start trying to calculate offets from a void *,
> in which case you must be aware of the padding
> issues.
>
> (what to do with the void * param into the
> comparison function was what started this whole
> line of conversation off, if I recall correctly)
>
> If you cast it to a pointer to the proper struct,
> the compiler knows what it's dealing with (padding
> and all).
>
> If you use "sizeof(struct xxx)" as the size for
> MemMove() et al. then, again, the compiler knows
> what it's dealing with padding & all.
>
> But if you write the struct field-by-field into
> a data store, then try to read it as a whole into
> memory as a struct (or the other way 'round: write
> as a whole, attempt to read field-by-field), that's
> where the issue of padding might get to you.
>
> --
> -Richard M. Hartman
> [EMAIL PROTECTED]
>
> 186,000 mi./sec ... not just a good idea, it's the LAW!
>
>
> > -----Original Message-----
> > From: Michael S. Davis [mailto:[EMAIL PROTECTED]]
> >
> >
> > On Tue, 23 Mar 1999, Scott Johnson wrote:
> >
> > > "Michael S. Davis" wrote:
> > > > But my questions is, If I use DmWrite and MemMove, is
> > that padding
> > > > added automatically, with both of these functions.
> > >
> > > NO -- these functions just copy raw bytes around. The
> > parameters you
> > > pass specify exactly which bytes, with a 1-byte granularity.
> > >
> > > If you're familiar with the standard C library, DmWrite and
> > MemMove are
> > > both Palm equivalents to memmove.
> >
> > That's easy enough to understand. But what are the implications
> > to using these functions and saving and restoring structs that have
> > odd length strings (or even length with null term). Are my
> > doubles saved and restored properly.
> >
> > Some have said I must consider the even boundaries for doubles. Or,
> > it it that the compiler will compile the struct with or without
> > padding (depending on string length) and my DmWrites and MemMove
> > just move that data as is. Meaning: that this is all transparent
> > to me.
> >
>
>
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