Re: Possiblly bug of cygwin1.dll

[Takashi Yano <takashi.yano@nifty.ne.jp>]

On Sat, 20 Jan 2024 10:13:22 +0100
ASSI wrote:
> Takashi Yano via Cygwin writes:
> > I might find the culprit in gcc's libstdc++ code such as:
> > libstdc++-v3/include/ext/concurrentce.h:
> >   class __mutex
> >   {
> >   private:
> > #if __GTHREADS && defined __GTHREAD_MUTEX_INIT
> >     __gthread_mutex_t _M_mutex = __GTHREAD_MUTEX_INIT;
> > #else
> >     __gthread_mutex_t _M_mutex;
> > #endif
> >
> > __GTHREAD_MUTEX_INIT here is PTHREAD_MUTEX_INITIALIZER and
> > __gthread_mutex_t is pthread_mutex_t.
> >
> > I think this code vaiolates the POSIX statement.
> 
> So what happens if you undefine __GTHREAD_MUTEX_INIT?

I have tried. The test case:
#include <mutex>
int main()
{
  for (;;) {
    std::mutex *m = new std::mutex;
    m->lock();
    m->unlock();
    delete m;
  }
  return 0;
}
gets working fine. However, this test case:
#include <future>
int func() { return 0; }
int main()
{
  for (;;) {
    std::future<int> f = std::async(std::launch::async, func);
    f.get();
  }
  return 0;
}
still has the problem.

pthread_mutex_t might be initialized also at another place...


-- 
Takashi Yano <takashi.yano@nifty.ne.jp>