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Subject: Re: c programming q

Author: Dieter Buerssner

Date: 11:30:41 05/12/03

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The original question was:

"Is there any specific order in which the chars are aligned into the int, or is
it compiler-dependent?"

The discussion evolved around this question did at parts not touch the question
at all. From my reading it mainly touched another question: Is the order of
structure members defined?

The answer is: It is not only compiler dependent, it is even totally out of the
C-Standard. In Standard-C, one just cannot do union tricks, where one stores one
value in a union and convieniently gets out some other members. On many
implementations, one can reliably do it. But the code will not be portable. In
Standard C, unions are still useful, but not for such tricks.

And about padding bits, etc. In an array of unsigned chars (chars alone are not
enough), there will be no padding bits. I think, there is not much more
guarantee in Standard C.

Regards,
Dieter

PS. That I answered to your specific post is mor or less coincidence. It does
not imply, that you did not understand this well. Just my thought, after reading
the whole discussion.



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