void g()
{
time_point t0 = Clock::now();
m.lock_shared();
time_point t1 = Clock::now();
m.unlock_shared();
ns d = t1 - t0;
assert(d < Tolerance); // within tolerance
}
void f()
{
time_point t0 = Clock::now();
assert(!m.try_lock_shared());
assert(!m.try_lock_shared());
assert(!m.try_lock_shared());
while(!m.try_lock_shared())
;
time_point t1 = Clock::now();
m.unlock_shared();
ns d = t1 - t0 - ms(250);
assert(d < ms(200)); // within 200ms
}
/**
* lookup method: just traverse the list in order, and see if we find the
* val
*/
bool lookup(int val)
{
mtx.lock_shared();
Node* curr = sentinel->next;
while (curr != NULL) {
if (curr->val >= val)
break;
curr = curr->next;
}
bool tmp = ((curr != NULL) && (curr->val == val));
mtx.unlock_shared();
return tmp;
}
int main()
{
m.lock();
std::vector<std::thread> v;
for (int i = 0; i < 5; ++i)
v.push_back(std::thread(f));
std::this_thread::sleep_for(WaitTime);
m.unlock();
for (auto& t : v)
t.join();
m.lock_shared();
for (auto& t : v)
t = std::thread(g);
std::thread q(f);
std::this_thread::sleep_for(WaitTime);
m.unlock_shared();
for (auto& t : v)
t.join();
q.join();
}