Mail Archives: djgpp/1997/04/12/10:07:19
Anthony Appleyard writes:
> "Oleg Yu. Polyanski" <luke AT eed DOT miee DOT ru> wrote:-
> > Well, I see no reasons to use packed structures *at all*. This way is
> > unportable between different platforms and often even between different
> > compilers on the same platform. ... `-fpack-struct' ...
>
> (1) When calling an interrupt, I often need to declare a packed struct which
> matches the layout of the data needed or provided by the interrupt.
oh.... when I wrote my previous letter (about packed
structures) I forgot all about other cases, when portability isn't
primary task or when programmer should use DOS internal structures etc
Yesterday I wrote such programm (to recover data from my DOS partition with
destroyed root directory) and I've used -fpack-struct :-) So please
excuse me for too harsh answer....
> (2) If I am declaring `struct(long i; char c;} X[0x4000];', having 5 rather
> than 8 bytes in each array element can save a lot of space.
You'll have big performance penalties applying `packed'
attribute to this structure.
--
Sincerely yours, necrofriend.
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