#include <dispatch/dispatch.h>
#include <atomic>
#include <cstdio>
#include <memory>
std::atomic<long> destructor_counter(0);
struct MyStruct {
virtual ~MyStruct() {
usleep(10000);
std::atomic_fetch_add_explicit(&destructor_counter, 1, std::memory_order_relaxed);
}
};
int main(int argc, const char *argv[]) {
std::fprintf(stderr, "Hello world.\n");
dispatch_queue_t q = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_group_t g = dispatch_group_create();
for (int i = 0; i < 100; i++) {
std::shared_ptr<MyStruct> shared(new MyStruct());
dispatch_group_async(g, q, ^{
shared.get();
});
}
dispatch_group_wait(g, DISPATCH_TIME_FOREVER);
if (destructor_counter != 100) {
std::abort();
}
std::fprintf(stderr, "Done.\n");
}