c언어 소켓부분에서 궁금한점이 있습니다 제발 도와주십시오.ㅠㅠ

       if(read(sd,fileList, sizeof(fileList))==-1){
		error_handling("read()");
		break;
	}
	printf("-----------server_list----------------\n");
	printf("%s\n", fileList);
	printf("-----------client_list----------------\n");
	get_filelist_client();
   	printf("usage : menu, filename, (authority)\n");
	printf("menu : 1.download 2. upload 3.chmod 4.quit\n");
	gets(message);
	printf("%s\n", message);
        if(write(sd, message, sizeof(message))==-1){
		error_handling("write()");
		break;
	}

        get_filelist(filelist);
	if(write(clnt_sd, filelist, sizeof(filelist))==-1)
		{
			error_handling("send()");
		break;
		}
	if(read(clnt_sd, message, sizeof(message))==-1){
		error_handling("read()");
			break;
	}
	printf("message : %s\n", message);