标准文件操作

    FILE *fp;
    long file_size = 0;
    if (NULL == (fp = fopen(fname, "r")))
    {
       return -1;
    }
    fseek(fp, 0, SEEK_END);
    file_size = ftell(fp);
    fseek(fp, 0, SEEK_SET);
    fread(fc, 1, 1024, fp);  
    fwrite(&usvr_data, 1, sizeof(usvr_data), fp);
    fclose(fp);