Re: C11 threads ABI - mtx_t and cnd_t types

[Torvald Riegel <triegel@redhat.com>]

On Mon, 2014-10-06 at 15:52 +0000, Joseph S. Myers wrote:
> On Mon, 6 Oct 2014, Torvald Riegel wrote:
> 
> > On Sat, 2014-08-30 at 22:52 -0400, Rich Felker wrote:
> > > Another issue I have on the ABI for C11 threads pertains to the types
> > > for mtx_t and cnd_t. My understanding, and I agree with this, is that
> > > it was already decided to use the same underlying sizes/alignment, and
> > > for now representations, as the corresponding POSIX types.
> > 
> > I don't remember a decision being made rather than just people
> > expressing their opinion at that time, but maybe I'm wrong.
> > 
> > Anyway, for mtx_t I'm starting to wonder whether a fresh start would
> > indeed be better, with some additional room for expanding the lock
> > representation to state elsewhere.  (That is, mtx_t would at least be
> > pointer-sized.)
> 
> If mtx_t isn't a thin wrapper round pthread_mutex_t, then doesn't that 
> mean cnd_wait and cnd_timedwait can no longer be thin wrappers around the 
> corresponding pthread functions?

Right.  But I suspect we should still be able to reuse most of the
source.