I am building a macOS project where I m creating a thread using pthread in cpp. I am setting the QOS class using the pthread_attr_set_qos_class_np and later checking the value of the QOS class using the pthread_attr_get_qos_class_np. These calls are successful but the QOS class is not being set. Below is the cpp function that I m invoking from my swift code.
bool CppThread::CreateThread ()
{
pthread_t threadId;
pthread_attr_t attr;
qos_class_t qos_class;
int relative_priority;
int rc = pthread_attr_init(&attr);
if (rc) {
printf ("pthread_attr_init failed");
}
if (pthread_attr_set_qos_class_np (&attr, QOS_CLASS_BACKGROUND, 5)) {
printf ("pthread_attr_set_qos_class_np failed\n");
}
int retval = pthread_create(&threadId, &attr, threadFunction, NULL);
if (retval) {
std::cerr << "Error creating thread" << std::endl;
return false;
}
if (pthread_attr_get_qos_class_np (&attr, &qos_class, &relative_priority)) {
printf ("pthread_attr_get_qos_class_np failed\n");
}
printf ("QoS class: %d, Relative priority: %d\n", qos_class, relative_priority);
pthread_join(threadId, NULL); // Wait for thread to finish
std::cout << "Thread finished" << std::endl;
return true;
}
OUTPUT:
QoS class: 0, Relative priority: 0
Thread finished
I have tried setting multiple QOS values but the output always shows the QOS class value as 0. Why is it not getting set?
