linux互斥锁的应用

//使用互斥锁同步线程
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>

pthread_mutex_t mutex;
static int tickets = 100;

void *thrd_func1(void *arg);
void *thrd_func2(void *arg);

int main()
{
    pthread_t thr_id1;
    pthread_t thr_id2;
    void *ret1;
    void *ret2;
    pthread_mutex_init(&mutex, NULL);
    if(pthread_create(&thr_id1, NULL, thrd_func1, NULL) != 0)
    {
        printf("Create thread1 error\n");
        exit(1);
    }
    if(pthread_create(&thr_id2, NULL, thrd_func2, NULL) != 0)
    {
        printf("Create thread2 error\n");
        exit(1);
    }
    if(pthread_join(thr_id1, &ret1) != 0)
    {
        printf("Join thr1 error!\n");
        exit(1);
    }


    if(pthread_join(thr_id2, &ret2) != 0)
    {
        printf("Join thr2 error!\n");
        exit(1);
    }

    pthread_mutex_destroy(&mutex);
    return 0;
}

void *thrd_func1(void *arg)
{
    while(tickets > 0)
    {
        pthread_mutex_lock(&mutex);
        if(tickets <= 0)
             break;
        printf("thr1 tickets = %d\n", tickets--);
        pthread_mutex_unlock(&mutex);
        usleep(100000);
    }
    pthread_exit(NULL);
}

void *thrd_func2(void *arg)
{
    while(tickets > 0)
    {
        pthread_mutex_lock(&mutex);
        if(tickets <= 0)
             break;
        printf("thr2 tickets = %d\n", tickets--);
        pthread_mutex_unlock(&mutex);
        usleep(100000);
    }
    pthread_exit(NULL);
}

//多个信息号量控制多个线程
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <semaphore.h>
#include <unistd.h>

#define THREAD_NUM 3
#define REPEAT_TIMES 5
#define DELAY 4

sem_t  sem[THREAD_NUM];

void *thrd_func(void *arg);

int main(void)
{
    pthread_t thread[THREAD_NUM];
    int no;
    void *tret;

    for(no = 0; no < THREAD_NUM - 1; no++)
    {
        sem_init(&sem[no], 0, 0);
    }
    sem_init(&sem[2], 0, 1);

    for(no = 0; no < THREAD_NUM; no++)
    {
        if(pthread_create(&thread[no], NULL, thrd_func, (void *)no) != 0)
        {
            printf("Create thread %d fail\n", no);
            exit(1);

        }
        else
        {
            printf("Create thread %d success\n", no);
        }
    }

    for(no = 0; no < THREAD_NUM; no++)
    {
        if(pthread_join(thread[no], &tret) != 0)
        {

            printf("join thread %d error\n", no);
            exit(1);
        }
        else
        {
            printf("Join thread %d success\n", no);

        }
    }

    for(no = 0; no < THREAD_NUM; no++)
    {
        sem_destroy(&sem[no]);
    }
    return 0;
}

void *thrd_func(void *arg)
{
    int thrd_num = (int )arg;
    sem_wait(&sem[thrd_num]);
    printf("Thread %d is starting.\n",thrd_num);
    sleep(1);
    sem_post(&sem[(thrd_num+THREAD_NUM-1)%THREAD_NUM]);
    return (void *)arg;
}