线程1——互斥锁
头文件：
#include <pthread.h>
创建新线程函数：
int pthread_create(pthread_t *thread, const pthread_attr_t *attr,void *(*start_routine) (void *), void *arg);
结束线程函数：
void pthread_exit(void *retval);
等待线程结束：
int pthread_join(pthread_t thread, void **retval);
创建互斥锁
pthread_mutex_t *mutex
pthread_mutex_init(互斥锁指针,NULL)
//线程互斥锁加锁
int pthread_mutex_lock(pthread_mutex_t *mutex)
//线程互斥锁解锁
int pthread_mutex_unlock(pthread_mutex_t *mutex)
//线程互斥锁销毁
int pthread_mutex_distory(pthread_mutex_t *mutex)
案例：分别用三个线程打出1-30报数
1 #include <pthread.h> 2 #include <stdio.h> 3 #include <unistd.h> 4 #include <stdlib.h> 5 //声明三个新进程 6 void* task1(void *arg); 7 void* task2(void *arg); 8 void* task3(void *arg); 9 pthread_mutex_t lock; //互斥锁指针 10 static int buf[30]={1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30}; 11 12 13 14 int main(void) 15 { 16 int ret; 17 18 //创建初始化互斥锁 19 pthread_mutex_init(&lock,NULL); 20 21 //声明三个指针，指向线程的id 22 pthread_t tid1,tid2,tid3; 23 //创建三个新线程，用刚才的指针， 24 pthread_create(&tid1,NULL,task1,(void*)5); 25 pthread_create(&tid2,NULL,task2,(void*)6); 26 pthread_create(&tid3,NULL,task3,(void*)7); 27 28 printf("Main thread\r\n"); 29 //等待线程结束运行 30 pthread_join(tid1,(void **)&ret); 31 pthread_join(tid2,(void **)&ret); 32 pthread_join(tid3,(void **)&ret); 33 34 sleep(1); 35 printf("New thread1 id:%ld\r\n",tid1); 36 printf("New thread2 id:%ld\r\n",tid2); 37 printf("New thread3 id:%ld\r\n",tid3); 38 39 //销毁互斥锁 40 pthread_mutex_destroy(&lock); 41 42 } 43 44 int i = 0; 45 46 void* task1(void *arg) 47 { 48 while(i<30){ 49 50 //上锁 51 pthread_mutex_lock(&lock); 52 printf("task1:%d\r\n",buf[i]); 53 i += 1; 54 //解锁 55 pthread_mutex_unlock(&lock); 56 usleep(1); 57 } 58 pthread_exit(NULL); 59 } 60 61 62 void* task2(void *arg) 63 { 64 65 while(i<30) 66 { 67 68 //上锁 69 pthread_mutex_lock(&lock); 70 printf("task2:%d\r\n",buf[i]); 71 i += 1; 72 //解锁 73 pthread_mutex_unlock(&lock); 74 usleep(1); 75 } 76 pthread_exit(NULL); 77 } 78 79 void* task3(void *arg) 80 { 81 82 while(i<30) 83 { 84 85 //上锁 86 pthread_mutex_lock(&lock); 87 printf("task3:%d\r\n",buf[i]); 88 i += 1; 89 //解锁 90 pthread_mutex_unlock(&lock); 91 usleep(1); 92 } 93 pthread_exit(NULL); 94 }
上锁和解锁，要放在使用公共资源的前后，比如例中的 i 前后。
