signal-wait-adptive-mutex.c

signal-wait-adptive-mutex.c

#include <pthread.h>
#include <semaphore.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>

pthread_mutex_t mutex;
sem_t semaphore1, semaphore2;
pthread_mutexattr_t attr;
pthread_t id1, id2;
int gotoSleep = 0;

void p(void *para)
{
    for (int i = 0; i < 100; i++)
    {
        pthread_mutex_lock(&mutex);
        sem_post(&semaphore1);

        if (gotoSleep)
            usleep(1);

        pthread_mutex_unlock(&mutex);
        sem_wait(&semaphore2);
    }
}

void q(void *para)
{
    for (int i = 0; i < 100; i++)
    {
        sem_wait(&semaphore1);

        pthread_mutex_lock(&mutex);
        pthread_mutex_unlock(&mutex);

        sem_post(&semaphore2);
    }
}

int main(int argc, char **argv)
{
    for (int i = 0; i < argc; i++)
    {
        if (strcmp(argv[i], "-s") == 0)
        {
            gotoSleep = 1;
        }
    }

    sem_init(&semaphore1, 0, 0);
    sem_init(&semaphore2, 0, 0);

    pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ADAPTIVE_NP);
    pthread_mutex_init(&mutex, &attr);

    pthread_create(&id1, NULL, (void *)p, NULL);
    pthread_create(&id2, NULL, (void *)q, NULL);

    pthread_join(id1, NULL);
    pthread_join(id2, NULL);

    pthread_mutex_destroy(&mutex);
    pthread_mutexattr_destroy(&attr);

    sem_destroy(&semaphore1);
    sem_destroy(&semaphore2);

    return 0;
}