文件系统系统调用实例(2 / Copy loop * while(TRUe rd_count= read(in_fd, buffer, BUFSIZE); / read a block of data * if (rd_count <=O)break; /* if end of file or error, exit loop * wt_count= write(out_fd, buffer, rd_count); / write data * if (wt_count <=O)exit(4); /* wt_ count <=0 is an error / Close the files * close(in_fd) close(outfd) if (rd_count==O) / no error on last read * exit(O) Ise exit(5); / error on last read *文件系统系统调用实例(2)