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1、嵌入式操作系统多线程-实验报告 （11-多线程编程）程序实验二：11-多线程编程实验专业班级 实验日期 5.21 姓名 学号 实验一（p284：11-thread.c）1、软件功能描述创建3个线程，让3个线程重用同一个执行函数，每个线程都有5次循环，可以看成5个小任务，每次循环之间会有随即等待时间（1-10s）意义在于模拟每个任务到达的时间是随机的没有任何的特定规律。2、程序流程设计3部分程序代码注释(关键函数或代码)#include#include #include #define T_NUMBER 3#define P_NUMBER 5#define TIME 10.0void *thrd
2、_func(void *arg ) int thrd_num=(int)arg; int delay_time =0; int count =0; printf(Thread %d is staraingn,thrd_num); for(count=0;countP_NUMBER;count+) delay_time =(int)(rand()*TIME/(RAND_MAX)+1; sleep(delay_time); printf(tTH%d:job%d delay =%dn,thrd_num,count,delay_time); printf(%d finishedn,thrd_num);
3、 pthread_exit(NULL); int main() pthread_t threadT_NUMBER; int no=0,res; void * thrd_ret; srand(time(NULL); for(no=0;noT_NUMBER;no+) res=pthread_create(&threadno,NULL, thrd_func,(void*)no); if(res!=0) printf(Creay th %d faildn,no); exit(res); printf(successnwaitingn); for(no=0;noT_NUMBER;no+) res=pth
4、read_join(threadno,&thrd_ret); if(!res) printf(t %d joinedn,no); else printf(T %djoined faildn,no); return 0;4编译、运行方法及结果(抓屏)5结果分析由运行结果可以看出，创建线程、释放资源按照顺序，而每个线程的运行和结束是独立与并行的。实验二（p287: 11-thread_mutex.c）1、软件功能描述在试验1的基础上通过互斥锁，使原本独立，无序的多个线程能够按顺序进行2、程序流程设计3部分程序代码注释(关键函数或代码)#include#include#include#define
5、THREAD_NUMBER 3 /*线程数*/#define REPEAT_NUMBER 3 /*每个线程的小任务数*/#define DELAY_TIME_LEVELS 10.0 /*小任务间的最大时间间隔*/pthread_mutex_t mutex; void *thrd_func(void *arg) /线程函数例程 int thrd_num = (int)arg; int delay_time = 0, count = 0; int res; /互斥锁上锁 res = pthread_mutex_lock(&mutex); if(res) printf(Thread %d is st
6、artingn, thrd_num); pthread_exit(NULL); printf(Thread %d is startingn, thrd_num); for(count = 0; count REPEAT_NUMBER; count+) delay_time = (int)(rand() * DELAY_TIME_LEVELS/(RAND_MAX) + 1; sleep(delay_time); printf(tThread %d: job %d delay = %dn,thrd_num, count, delay_time); printf(Thread %d finished
7、n, thrd_num); pthread_exit(NULL); int main(void) pthread_t threadTHREAD_NUMBER; int no = 0, res; void * thrd_ret; srand(time(NULL); pthread_mutex_init(&mutex, NULL); for(no = 0; no THREAD_NUMBER; no+ ) res = pthread_create(&threadno, NULL, thrd_func, (void*)no); if(res != 0) printf(Create thread %d
8、failedn, no ); exit(res); printf(Create threads successn Waiting for threads to finish.n);/*这里的问题很奇怪，按照书上程序敲打，出现的线程首先是2而非0，没有按照书上所说：与创建顺序相同，但是在这里体现了互斥性，由于后面的释放资源程序从0开始，而一开始为线程2占用资源，所以无法释放资源，导致程序卡死，最后修改为先释放线程2的资源，之后则可以依次显示*/ for(no = 2; no THREAD_NUMBER; no-) res = pthread_join(threadno,&thrd_ret); i
9、f(!res) printf(Thread %d joinedn, no); else printf(Thread %d join failedn, no); pthread_mutex_unlock(&mutex); pthread_mutex_destroy(&mutex); return 0;4编译、运行方法及结果(抓屏)5结果分析实验结果体现了互斥性，3个线程有序运行。实验三（P291：11-thread_sem.c）1、软件功能描述该程序在实验1的基础上，用信号量同步机制实现3个线程的有序执行，利用pv操作来控制执行顺序，达到执行的顺序和创建的顺序刚好相反。2、程序流程设计3部分程序
10、代码注释(关键函数或代码)#include#include#include#include#define THREAD_NUMBER3#define REPEAT_NUMBER3#define DELAY_TIME_LEVELS10.0sem_t semTHREAD_NUMBER; void *thrd_func(void *arg)int thrd_num = (int)arg; int delay_time = 0; int count = 0; sem_wait(&semthrd_num); printf(Thread %d is startingn,thrd_num); for(cou
11、nt = 0; count REPEAT_NUMBER; count+)delay_time = (int)(rand() * DELAY_TIME_LEVELS/(RAND_MAX)+1; sleep(delay_time); printf(tThread %d: job %d delay = %dn,thrd_num, count, delay_time); printf(Thread %d finishedn, thrd_num); pthread_exit(NULL); int main(void)pthread_t threadTHREAD_NUMBER; int no = 0,res; void * thrd_ret; srand(time(NULL); for(no = 0; no THREAD_NUMBER; no
