[fpc-devel] FPC micro controller

[Jonas Maebe]

On 30 Jul 2009, at 10:09, Michael Schnell wrote:

>> This is not usable for accessing particular bits of microcontroller
>> registers, because the internal format of a bitpacked record is
>> undefined and can change at any time for any reason.
>
> Is this likely to happen ?

That's irrelevant, unless you like writing programs of which it is  
documented that they may break with any new compiler release.

> AFAIK, in C the "struct ...:n" layout also is
> implementation depending and the memory layout in fact is not  
> identical
> between high-endian and low-endian processors.
>
> This _does_ offer problems when transferring such structures via  
> Network
> or files.

Even stronger: they are completely unsuited for that purpose. Just  
like Pascal set types, for that matter (for exactly the same reason).


Jonas