On Thu, 30 May 2024 20:50:12 +0900
Takashi Yano <takashi.y...@nifty.ne.jp> wrote:
> On Thu, 30 May 2024 12:14:10 +0200
> Bruno Haible wrote:
> > Takashi Yano wrote in cygwin-patches:
> > > int
> > > pthread::once (pthread_once_t *once_control, void (*init_routine) (void))
> > > {
> > > - // already done ?
> > > - if (once_control->state)
> > > + /* Sign bit of once_control->state is used as done flag */
> > > + if (once_control->state & INT_MIN)
> > > return 0;
> > >
> > > + /* The type of &once_control->state is int *, which is compatible with
> > > + LONG * (the type of the first argument of InterlockedIncrement()).
> > > */
> > > + InterlockedIncrement (&once_control->state);
> > > pthread_mutex_lock (&once_control->mutex);
> > > - /* Here we must set a cancellation handler to unlock the mutex if
> > > needed */
> > > - /* but a cancellation handler is not the right thing. We need this in
> > > the thread
> > > - *cleanup routine. Assumption: a thread can only be in one
> > > pthread_once routine
> > > - *at a time. Stote a mutex_t *in the pthread_structure. if that's non
> > > null unlock
> > > - *on pthread_exit ();
> > > - */
> >
> > Sorry, in a unified diff form this is unreadable. One needs to look at the
> > entire function. A context diff would have been better. So:
> >
> > int
> > pthread::once (pthread_once_t *once_control, void (*init_routine) (void))
> > {
> > /* Sign bit of once_control->state is used as done flag */
> > if (once_control->state & INT_MIN)
> > return 0;
> >
> > /* The type of &once_control->state is int *, which is compatible with
> > LONG * (the type of the first argument of InterlockedIncrement()). */
> > InterlockedIncrement (&once_control->state);
> > pthread_mutex_lock (&once_control->mutex);
> > if (!(once_control->state & INT_MIN))
> > {
> > init_routine ();
> > once_control->state |= INT_MIN;
> > }
> > pthread_mutex_unlock (&once_control->mutex);
> > if (InterlockedDecrement (&once_control->state) == INT_MIN)
> > pthread_mutex_destroy (&once_control->mutex);
> > return 0;
> > }
With v3 patch:
int
pthread::once (pthread_once_t *once_control, void (*init_routine) (void))
{
/* Sign bit of once_control->state is used as done flag */
if (once_control->state & INT_MIN)
return 0;
/* The type of &once_control->state is int *, which is compatible with
LONG * (the type of the first argument of InterlockedIncrement()). */
InterlockedIncrement (&once_control->state);
pthread_mutex_lock (&once_control->mutex);
if (!(once_control->state & INT_MIN))
{
init_routine ();
InterlockedOr (&once_control->state, INT_MIN);
}
pthread_mutex_unlock (&once_control->mutex);
if (InterlockedDecrement (&once_control->state) == INT_MIN)
pthread_mutex_destroy (&once_control->mutex);
return 0;
}
--
Takashi Yano <takashi.y...@nifty.ne.jp>
