Re: [PATCH] c++/58796 Make nullptr match exception handlers of pointer type

[Jakub Jelinek]

On Fri, Jul 15, 2016 at 10:07:03PM +0100, Jonathan Wakely wrote:
> >+      if (typeid (*this) == typeid(__pointer_type_info))
> >+        {
> >+          *thr_obj = nullptr;
> >+          return true;

But you have the above store too.
Can't you rethrow_exception in certain threads trying to catch it as pointer
to data member and in other threads as a pointer?

#include <exception>
#include <thread>
#include <cassert>

std::exception_ptr p;

struct A { };

void t()
{
 try {
   std::rethrow_exception(p);
 } catch (int A::* const& e) {
   assert( e == nullptr );
 }
}

void h()
{
 try {
   std::rethrow_exception(p);
 } catch (int *& e) {
   assert( e == nullptr );
 }
}

int main()
{
 try {
   throw nullptr;
 } catch (...) {
   p = std::current_exception();
 }
 std::thread t1(t);
 std::thread t2(h);
 std::thread t3(t);
 std::thread t4(h);
 t1.join();
 t2.join();
 t3.join();
 t4.join();
}

        Jakub