[linux-dvb] [PATCH] add DVB-S2 support to frontend.h

Johannes Stezenbach js at linuxtv.org
Thu Mar 2 13:43:11 CET 2006


On Thu, Mar 02, 2006, Andreas Oberritter wrote:
> On Thu, 2006-03-02 at 00:53 +0100, Johannes Stezenbach wrote:
> > The System V generic ABI http://www.caldera.com/developers/gabi/
> > says enums sizes are processor specific, the psABI for i386 and MIPS
> > say enums have the same size as int. For other platforms I don't know
> > but according to google ARM seems to have -fshort-enums as default.
> > Sigh...
> 
> I wonder why it is so important to know the size of an enum at all.
> Complete backwards compatibility is needed for desktop systems only,
> where users mix different precompiled software versions. There, on i386
> and probably others, we already have 32 bit enums. Maybe they are even
> larger on 64 bit systems. If the size of an enum changes on an embedded
> platform like ARM, because the kernel headers changed, then it is very
> likely that the userspace software will be recompiled, too.

Well, I got a bit distracted by this issue, I had to find out the
facts so I can sleep at night ;-)

But I agree with you, possibly breaking ARM binary compatibility
by introducing new enum values isn't something I am personally
worried about. PPC and MIPS have 32bit enums, and x86/46 and
the like too (int is 32 bits, long is 64 bits == sizeof(void *)).

Johannes



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