万网云服务器怎么上传网站,自己做的网站怎么赚钱,什么网站可以买世界杯,wordpress 登陆信息实现多线程拷贝命令,如#xff1a;./multithread_copy srcfile destfile N(拷贝线程个数)难点#xff1a;内存映射mmap。给每一个线程合理的分配任务。多线程的实现。具体的实现代码如下#xff1a;/********************************************************************…实现多线程拷贝命令,如./multithread_copy srcfile destfile N(拷贝线程个数)难点内存映射mmap。给每一个线程合理的分配任务。多线程的实现。具体的实现代码如下/************************************************************************* File Name: multithread_copy.c Author: lucifer Mail: lucifer163.com Created Time: 2014年11月14日 星期五 17时43分36秒************************************************************************/#include #include #include #include #include #include #include #include #include #define N 5int nthread 0;struct allocate_task{char *start;char *end;int size;int num;};void sys_err(const char *str){perror(str);exit(-1);}void *thread_copy(void *arg){int i;struct allocate_task *s (struct allocate_task *)arg;for(i 0;i nthread;i){memcpy(s[i].end,s[i].start,s[i].size);}}int main(int argc, char *argv[]){int fdsrc, fddest, i, err, total_size,task_size;struct stat sbuf;char *psrc,*pdest;if(argc 3){fprintf(stdout,%s srcname destname\n,argv[0]);exit(-1);}if(argc 3)nthread N;elsenthread atoi(argv[3]);if(stat(argv[1],sbuf) 0)sys_err(stat);total_size sbuf.st_size;fddest open(argv[2],O_CREAT |O_RDWR | O_TRUNC,0664);if(fddest 0)sys_err(open);if(lseek(fddest,total_size - 1,SEEK_SET) 0)sys_err(lseek);write(fddest,\0,1);fdsrc open(argv[1],O_RDONLY);if(fdsrc 0)sys_err(open);psrc mmap(NULL,total_size,PROT_READ,MAP_PRIVATE,fdsrc,0);if(psrc MAP_FAILED)sys_err(mmap);pdest mmap(NULL,total_size,PROT_WRITE,MAP_SHARED,fddest,0);if(pdest MAP_FAILED)sys_err(mmap);close(fdsrc);close(fddest);struct allocate_task *work malloc(nthread * sizeof(struct allocate_task));task_size total_size / nthread;for(i 0;i nthread - 1;i){work[i].start psrc i * task_size;work[i].end pdest i * task_size;work[i].size task_size;}work[i].start psrc i * task_size;work[i].end pdest i * task_size;work[i].size total_size - task_size * (nthread - 1);work[i].num i;pthread_t tid[nthread];for(i 0;i nthread;i){err pthread_create(tid[i],NULL,thread_copy,(void *)work);if(err ! 0){printf(%s\n,strerror(err));break;}}for(i 0;i nthread; i){pthread_join(tid[i],NULL);}free(work);return 0;}
