[PATCH] pthread_once hangs when init routine throws an exception [BZ #18435]

[Rich Felker]

On Wed, Jun 03, 2015 at 01:03:47PM +0200, Torvald Riegel wrote:
> On Mon, 2015-06-01 at 12:41 -0600, Martin Sebor wrote:
> > Beyond call_once, C++ 11 encourages implementations to
> > provide a member function called native_handle() that
> > returns a reference to the underlying native object.
> > libstdc++ mutex (and other classes) expose this member
> > function to provide interoperability with pthreads. As
> > a result, reimplementing libstdc++ independently of libc
> > is impossible without losing such interoperability and
> > without breaking compatibility with existing code.
> 
> Note that the interoperability is also a dependency.  I think it's
> actually better for libstdc++ to not make an ABI guarantee that
> native_handle() returns a pointer to a PThreads entity;  this way, we do
> have the freedom to improve libstdc++ independently of glibc and more
> importantly of POSIX.
> I don't know for sure whether Jonathan has applied the change already,
> but IIRC, we agreed that native_handle() should return void*.

I'm strongly in favor of having the underlying implementations be
opaque and not guaranteeing pthread.

Rich