有关pthread锁和条件同步-优快云博客

本文通过一个具体的C语言程序示例介绍了如何使用pthread库中的互斥锁和条件变量来实现多线程间的同步。两个线程分别递增全局变量并打印其值，通过互斥锁保护共享资源，条件变量用于线程间通信。

代码：

#include <stdio.h>
#include <stdlib.h>
#include <getopt.h> //getopt_long()头文件位置    
#include <string.h>
#include <unistd.h>
#include <syslog.h>
#include <pthread.h>

void *thread1_function(void *arg);
void *thread2_function(void *arg);
pthread_mutex_t mutex;
pthread_cond_t cond;
int g_value = 0;
int main(int argc, char *argv[])
{
    int rc1,rc2;
    char *str1="wenhaoll";
    char *str2="linglong";
    pthread_t thread1,thread2;

    pthread_mutex_init(&mutex,NULL);
    pthread_cond_init(&cond,NULL);
    if((rc1 = pthread_create(&thread1,NULL,thread1_function,str1)))
    {
        fprintf(stdout,"thread 1 create failed: %d\n",rc1);
    }

    if((rc2 = pthread_create(&thread2,NULL,thread2_function,str2)))
    {
        fprintf(stdout,"thread 2 create failed: %d\n",rc2);
    }

    pthread_join(thread1,NULL);
    pthread_join(thread2,NULL);
    return 0;
}

void *thread1_function(void *arg)
{
   pthread_cond_wait(&cond, &mutex);
   char i;
   for (i=0; i<9; i++)
   {
      pthread_mutex_lock(&mutex);
      g_value ++;
      pthread_cond_signal(&cond);
      pthread_mutex_unlock(&mutex);
      sleep(2);
   }
   return NULL;
}
void *thread2_function(void *arg)
{
   char i;
   for (i=0; i<9; i++)
   {
      pthread_mutex_lock(&mutex);
      pthread_cond_wait(&cond, &mutex);
      printf("g_value is: %d\n", g_value);
      pthread_mutex_unlock(&mutex);
   }
   return NULL;
}