说明:对多线程与相互排斥锁不熟悉的请參考其他
#include <pthread.h> #include <stdio.h> #include <stdlib.h> pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;/*初始化相互排斥锁*/ 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_a, NULL);/*等待进程t_a结束 和windows的waitForSingleObject 相似*/ pthread_join(t_b, NULL);/*等待进程t_b结束 和windows的waitForSingleObject 相似*/ /* 释放资源*/ pthread_mutex_destroy(&mutex); pthread_cond_destroy(&cond); exit(0); } void *thread1(void *junk) { for(i=1;i<=6;i++) { printf("now i = %d ", i); pthread_mutex_lock(&mutex);/*锁住相互排斥量*/ printf("thread1: lock %d ", __LINE__); if(i%3==0){ printf("thread1:signal 1 %d ", __LINE__); pthread_cond_signal(&cond);/*条件改变,发送信号,通知t_b进程*/ printf("thread1:signal 2 %d ", __LINE__); sleep(1); } pthread_mutex_unlock(&mutex);/*解锁相互排斥量*/ printf("thread1: unlock %d ", __LINE__); sleep(1); } } void *thread2(void *junk) { while(i<6) { pthread_mutex_lock(&mutex); printf("thread2: lock %d ", __LINE__); if(i%3!=0){ printf("thread2: wait 1 %d ", __LINE__); /*pthread_cond_wait 函数将解锁mutex。并使当前线程堵塞在cond指向的条件变量上*/ pthread_cond_wait(&cond,&mutex);/*解锁mutex,并等待cond改变*/ printf("thread2: wait 2 %d ", __LINE__);; } pthread_mutex_unlock(&mutex); printf("thread2: unlock %d ", __LINE__); sleep(1); } }
root@ubuntu:/usr/syw/linux/Thread# gcc -g threadDemo3_arg.c -o thread3 -lpthread
root@ubuntu:/usr/syw/linux/Thread# ./thread3
now i = 1
thread2: lock 44
thread2: wait 1 46
thread1: lock 27
thread1: unlock 35
now i = 2
thread1: lock 27
thread1: unlock 35
now i = 3
thread1: lock 27
thread1:signal 1 29
thread1:signal 2 31
thread1: unlock 35
thread2: wait 2 49
thread2: unlock 52
now i = 4
thread2: lock 44
thread2: wait 1 46
thread1: lock 27
thread1: unlock 35
now i = 5
thread1: lock 27
thread1: unlock 35
now i = 6
thread1: lock 27
thread1:signal 1 29
thread1:signal 2 31
thread1: unlock 35
thread2: wait 2 49
thread2: unlock 52