Steve McIntyre <[EMAIL PROTECTED]> wrote:
> >I would call this default behavior of GCC a bug.
> >
> >I'll try to verify this with the C99 standard, but in case GCC is able
> >to create working code at all (using __attribute__((packed))), it seems like
> >the default behavior does not make sense.
> >
> >Note that countless C-programs depend on sizeof(struct something) returning
> >useful values.
>
> In what way are these not useful values? They may not be what you
> expect, but It's a long-known feature of C that making assumptions
> about structure layout and alignment _will_ bite you.
Well, it returns size numbers of for unused space.
> The default behaviour here is (apparently) as specified by the
> designers of the hardware in this case. Alignment _really_ matters for
> performance on some architectures, and this is one of them.
The usual way to deal with this kind of alignement problems in C is to
add alignement _before_ the next var - not after the last var and counting the
numbers to inapropriate places.
> The quick-hack fix is to use the __attribute__((packed)) patch; the
> real fix is to stop depending on structure setup like this - use a
> byte array and work within that as appropriate.
Then must existing software would be void. Do you really intend this?
Jörg
--
EMail:[EMAIL PROTECTED] (home) Jörg Schilling D-13353 Berlin
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