计算机操作系统-进程间互斥与同步

1、进程间互斥与同步实验内容：编写算法，实现进程间对临界资源的互斥访问以及进程间的同步关系。实验要求：1、要求进程互斥使用文本文件；2、假定文本文件txtl最大可写入30个字符；3、写满后复制进程将文本文件的内容复制到另一个文 本文件txt2中(无长度限制)。4、复制进程复制完毕写入进程可再重新写入，重复执行3, 4,直到给由停止命令。5、实现进程间的同步和互斥。代码：#include#include/stdio.h#include/函数库#include/linux/unix 的系统调用#include/信号量#includeusing namespace std ;typedef union

2、_semnuint val;structsemid_ds *buf;ushort * array ;semun;/v操作void v( int &sem_id)structsembuf sem_b;sem_b.sem_num= 0;sem_b.sem_op= 1;sem_b.sem_flg=SEM_UNDO;if (semop(sem_id,&sem_b, 1 )=- 1) cout error endl;exit (0);/p操作void p( int &sem_id)struct sembuf sem_b;sem_b.sem_num=0;sem_b.sem_op=-1;sem_b.sem_

3、flg=SEM_UNDO;if (semop(sem_id,&sem_b, 1 )=- 1) cout error endl;exit (0);/设置信号量初值void set ( int sem_id, int val= 1)semun sem_un;sem_un.val=val;if (semctl(sem_id, 0,SETVAL,sem_un)=- 1) if (errno=EEXIST)cout exist endl;cout set val error endl;exit ( 0 );void del( int sem_id)semun sem_un;if (semctl(sem_

4、id, 0,IPC_RMID,sem_un)=- 1) cout error endl;int main()/互斥量int sem_mutex=semget(key_t) set (sem_mutexk, 1);8888 , 1 ,IPC_CREAT);int sem_full=semget(key_t)1234 , 1,IPC_CREAT);cout sem_fullendl;/set semaphore fullset (sem_full, 0);int sem_empty=semget(key_t)1235 , 1 ,IPC_CREAT);cout sem_empty 0) /paren

5、t/produce/p(empty)/v(full)for ( int i= 0;i 5;i+)p(sem_empty);p(sem_mutex);/锁定临界区cout writing.iendl;fseek(fp1,0,SEEK_SET);,fp1);fputs ( QWERTYUIOPASDFGHJKLZXCVBNM1234” fflush(fp1);sleep(1 );cout write done endl;v(sem_mutex);v(sem_full);fclose(fp1);cout txt2: endl;system( cat txt2 n); else if (id= 0)/

6、consume/p(full)/v(empty)char buf 32 ;buf 31 = 0;fill(buf,buf+20, 0);for ( int i= 0;i 5;i+) ( p(sem_full);p(sem_mutex);/锁定临界区cout reading. iendl;fseek(fp2,0,SEEK_SET);fgets(buf,30 ,fp2);fputs (buf,fp3);fflush(fp3);/由于缓冲方式的影响，30个字符不会立刻读取到buf中，需要fflush cout bufendl; cout read done endl; cout endl;sleep

7、(1);v(sem_mutex);v(sem_empty);fclose(fp2);fclose(fp3); exit (0); else /error (cout 创建子进程失败！ endl; exit (0);/ del(sem_full);/ del(sem_empty);return 0;输生结果：/注意要以root用户运行程序196608229377writing.0write donereading.0QWERTYUIOPASDFGHJKLZXCVBNM123read done TOC o 1-5 h z writing.1write done reading.1QWERTYUIOPASDFGHJKLZXCVBNM123 read donewriting.2write donereading.2QWERTYUIOPASDFGHJKLZXCVBNM123 read donewriting.3write donerea