Re: Re: NPTL for hppa-linux is not backwards compatible with Linuxthreads.

On 2/23/07, Roland McGrath <[email protected]> wrote:
> > Unfortunatly, due to alignment the NPTL pthread_cond_t grows larger
> > than the Linuxthreads version when I add the padding. This is the only
> > structure the grows larger in size than before. Is there any way I can
> > avoid adding the padding?
>
> It looks to me like you have one word to spare.  That's all you really
> need.  That word will only ever be 1 from old PTHREAD_COND_INITIALIZER.
> Checking all three padding words is really just paranoia trying to
> distinguish clobbered structs from old initialized data.

I did a couple of tests and I verified that I have no words to spare.
Adding an extra "int __pad" forces the structure to grow by 8 bytes
due to the "long long" alignment requirements.

Would I be allowed to allocated a temporary pthread_cond_t in the
wrapper, store the address in one of the 3 unused lock words, and have
all the wrapper functions use that after allocation?

Cheers,
Carlos.