Linux多线程的一个小例子

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>

#define MAX_COUNT 9
pthread_mutex_t mutex;	//互斥变量
pthread_cond_t cond;	//条件变量
int count = 0;

void AddCount_Odd_Func(void);
void AddCount_Even_Func(void);

int main()
{
	int ret;
	pthread_t odd_thread, even_thread;	//两个线程
	pthread_attr_t thread_attr;			//线程的属性结构

	count = 0;
	pthread_mutex_init(&mutex, NULL);	//互斥变量的初始化
	pthread_cond_init(&cond, NULL);		//条件变量的初始化
	ret = pthread_attr_init(&thread_attr);	//属性结构体初始化
	if (ret != 0)
	{
		perror("Attribute Creation Failed!");
		exit(EXIT_FAILURE);
	}

	pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);	//设置线程分离状态的函数，PTHREAD_CREATE_DETACHED(分离线程):不需要创建线程的线程等待
										//函数运行结束线程便终止，同时释放占用的系统资源
	ret = pthread_create(&odd_thread, &thread_attr, (void *)&AddCount_Odd_Func, NULL);
	if (ret != 0)
	{
		perror("Thread Creation Failed!");
		exit(EXIT_FAILURE);
	}
	ret = pthread_create(&even_thread, &thread_attr, (void *)&AddCount_Even_Func, NULL);
	if (ret != 0)
	{
		perror("Thread Creation Failed!");
		exit(EXIT_FAILURE);
	}

	while (count < MAX_COUNT);
	printf("Finished!\n");
	pthread_cond_destroy(&cond);		//销毁条件变量
	pthread_mutex_destroy(&mutex);
	return 0;
}

void AddCount_Odd_Func(void)
{
	pthread_mutex_lock(&mutex);
	while (count < MAX_COUNT)
	{
		if (count % 2 == 1)
		{
			count++;
			printf("AddCount_Odd_Func(): count = %d.\n", count);
			pthread_cond_signal(&cond);			//用来释放被阻塞在条件变量cond上的线程
		}
		else
			pthread_cond_wait(&cond, &mutex);	//使线程阻塞在条件变量cond上
	}
	pthread_mutex_unlock(&mutex);
}

void AddCount_Even_Func(void)
{
	pthread_mutex_lock(&mutex);
	while (count < MAX_COUNT)
	{
		if (count % 2 == 0)
		{
			count++;
			printf("AddCount_Even_Func(): count = %d.\n", count);
			pthread_cond_signal(&cond);
		}
		else
			pthread_cond_wait(&cond, &mutex);
	}
	pthread_mutex_unlock(&mutex);
}

gcc example.c -lpthread

运行结果如下：