Subject: Re: ancillary data alignment and binary backward compatibility
To: Chris G. Demetriou <>
From: Jun-ichiro itojun Hagino <>
List: tech-net
Date: 03/08/2000 18:33:16
>I read that bit.  That's not a justification.
>For binaries of MACHINE_ARCH sparc (i.e. sparc32 binaries), ALIGNBYTES
>(and friends) have a particular definition.
>Emulation of the binaries for that different MACHINE_ARCH (and yes, it
>is emulation, just as linux emulation on x86 is emulation; it's a
>different ABI) must respect that definition, to be correct.
>The compiler, for instance, isn't gonna start using a larger structure
>alignment for random structures compiled for sparc32 when run on
>sparc64 -- it doesn't, can't, and shouldn't know about what the kernel
>thinks the alignment "should be."

	are you suggesting to have different CMSG_ALIGN (= have different
	ALIGNBYTES) for use in the kernel, based on binary emulation modes?
	I'm not sure if this is possible for the kernel side to dance like