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From:	RayeR <glaux AT centrum DOT cz>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Upgrading from a bad C compiler
Date:	Thu, 26 Jul 2012 18:23:51 -0700 (PDT)
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> I'd assume alignment would increase the physical size.  I don't know if it
> increases sizeof()'s value though.  I would think not...  I would think that
> C should only return the total size for C elements and not padding or
> alignment.

No, sizeof() is called on a structure which is aligned by default it returns total size including padding bytes! Usually 8bit members are extended to 16bits to be placed on even address. If you need a srtucture that match exact size (e.g. reading some header from file to struct in memory) use __attribute__ ((packed)). Then sizeof will return number that is exact sum of all members size.

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