Re: [PATCH V2] sparse: Allow override of sizeof(bool) warning

From: James Hogan
Date: Thu Feb 27 2014 - 12:23:23 EST


On 27/02/14 16:52, H. Peter Anvin wrote:
> On 02/27/2014 08:10 AM, Dan Carpenter wrote:
>>
>> That last assumption has to change for the Meta architecture.
>>
>> https://lwn.net/Articles/522188/
>>
>> On meta, the structs and unions are padded to 4 bytes unless they are
>> explicitly marked as __packed.
>>
>
> One have to wonder how likely they are to have that not continually break...

Well it's only when it deals with stored/portable data formats that it's
an issue, and in those cases some amount of care over packing has
usually already been taken. It most often causes problems when one small
struct/union containing only chars or shorts is nested inside another
struct which is marked as packed (on the unfortunately mistaken
assumption that the inner struct cannot have padding at the end so
doesn't need packing itself).

But yeh, it is a PITA.

Cheers
James
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