#469 winpthreads cleanup handlers not called after pthread_exit()

[Keri Harris]

I've noticed some unexpected behaviour with winpthreads which I believe is a bug. Thread-cancellation cleanup handlers are not called when a thread terminates due to a call to pthread_exit(). This is unexpected; the pthread_cleanup_push(), pthread_cleanup_pop() specification [1] mentions:

The cancellation cleanup handler shall be popped from the cancellation cleanup stack
and invoked with the argument arg when:

The thread exits (that is, calls pthread_exit()).

[1] http://pubs.opengroup.org/onlinepubs/000095399/functions/pthread_cleanup_pop.html

An example program illustrating winpthreads failing to invoke cleanup handlers follows:

include <pthread.h>

include <stdio.h>

void cleanup_func(void arg)
{
printf("cleanup_func()\n");
}

void func(void arg)
{
printf("func()\n");
pthread_cleanup_push(cleanup_func, 0);
pthread_exit(NULL);
pthread_cleanup_pop(1);
}

int main()
{
pthread_t t;
void *ret;

pthread_create(&t, NULL, func, (void*)NULL);
pthread_join(t, &ret);

return 0;

}