pthread 笔记

1.创建线程 

    res = pthread_create(&a_thread, NULL, thread_function1, NULL);
    if (res != 0)
    {
     perror("Thread creation failure");
    }

2.等待线程结束

pthread_join

3.线程退出时，语句：

    pthread_exit(NULL);
    return NULL;

4. 互斥锁  使用前必须初始化！！！

pthread_mutex_init(&mutex, NULL);
pthread_mutex_destroy(&mutex);

4.

#include <stdio.h>
#ifdef _WIN32
#include <windows.h>
#include <stdio.h>
#define sleep Sleep
#else
#include <unistd.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <semaphore.h>

sem_t bin_sem;
void *thread_function1(void *arg)
{
    printf("thread_function1--------------sem_wait
");
    sem_wait(&bin_sem);
    printf("sem_wait OK
");
    while (1)
    {
    }
    pthread_exit(NULL);
    return NULL;
}

void *thread_function2(void *arg)
{
    printf("thread_function2--------------sem_post
");
    sem_post(&bin_sem);
    printf("sem_post
");
    while (1)
    {
    }
    return NULL;
}



int main()
{
    int res;
    pthread_t a_thread;
    void *thread_result;

    res = sem_init(&bin_sem, 0, 0);
    if (res != 0)
    {
        perror("Semaphore initialization failed");
    }
     printf("sem_init
");
        res = pthread_create(&a_thread, NULL, thread_function1, NULL);
    if (res != 0)
    {
     perror("Thread creation failure");
    }
    printf("thread_function1
");
    sleep (5);
    printf("sleep
");
    res = pthread_create(&a_thread, NULL, thread_function2, NULL);
    if (res != 0)
    {
         perror("Thread creation failure");
    }
    while (1)
    {
    }
}

5 sem:

sem_post  每执行一次  则加1

sem_wait( &st )   等待直到st大于1 才向下执行，  每次执行st减去1；

6  条件锁

#include <pthread.h>
#include <stdio.h>
#ifdef _WIN32
#include <windows.h>
#define sleep(p) Sleep(p)
#else
#include <ustlib.h>
#define sleep(p) usleep((p)*1000)
#endif

pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; /*初始化互斥锁*/
pthread_cond_t cond = PTHREAD_COND_INITIALIZER;  //初始化条件变量 

void *thread1(void *);
void *thread2(void *);

int i = 1;
int main(void)
{
    pthread_t t_a;
    pthread_t t_b;
    pthread_create(&t_a, NULL, thread1, (void *)NULL);/*创建进程t_a*/
    pthread_create(&t_b, NULL, thread2, (void *)NULL); /*创建进程t_b*/
    pthread_join(t_b, NULL);/*等待进程t_b结束*/
    pthread_mutex_destroy(&mutex);
    pthread_cond_destroy(&cond);
    getchar();
    exit(0);
}

void *thread1(void *junk)
{
    for (i = 1; i <= 9; i++)
    {
        pthread_mutex_lock(&mutex);//
        if (i % 3 == 0)
            pthread_cond_signal(&cond);/*条件改变，发送信号，通知t_b进程*/
        else
            printf("thead1:%d
", i);
        pthread_mutex_unlock(&mutex);//*解锁互斥量*/
        printf("Up Unlock Mutex
");
        sleep(1);
    }
    return NULL;

}

void *thread2(void *junk)
{
    while (i<9)
    {
        pthread_mutex_lock(&mutex);

        if (i % 3 != 0)
            pthread_cond_wait(&cond, &mutex);/*等待*/
        printf("thread2:%d
", i);
        pthread_mutex_unlock(&mutex);
        printf("Down Ulock Mutex
");

        sleep(1);
    }
    return NULL;
}