AVR-Chat

On Mon, Apr 25, 2005 at 07:16:15PM -0000, arhodes19044 wrote:
> 
> Yes, I can see that the structure will provide a convenient 
> technique to read & write the entire block.
> 
> It has been a long time since I worked with structures.  Is there a 
> way to get the offset of the element within the structure?  
> Something like "&structure.element".  This way, I can start with the 
> location of the structure in SRAM or in EEPROM and then access the 
> individual element by base + offset.  Will sizeof() work with 
> structure elements?

Yes, and yes.

But remember if one tries (&structure.element - &structure) pointer
arithmetic may come into play. Make casts to (size_t) before doing the
math. Thats the point of the offsetof() macro mentioned.

#define offsetof(type, field) ((size_t)(&((type *)0)->field))

For the above to work your structure has to be in a typedef.

-- 
David Kelly N4HHE, dkelly@HiWAAY.net
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Whom computers would destroy, they must first drive mad.