描述

Main items are used to either define or group certain types of data fields within a Report descriptor. There are two types of Main items: data and non-data. Datatype Main items are used to create a field within a report and include Input, Output, and Feature. Other items do not create fields and are subsequently referred to as non-data Main items.

主项用于在报告描述符中定义或分组特定类型的数据字段。主项有两种类型：数据型和非数据型。数据型主项用于在报告中创建一个字段，包括输入项、输出项和特征项。其他不创建字段的项，随后被称为非数据型主项。

格式

注释

• The default data value for all Main items is zero (0).

  所有主项的默认数据值均为零（0）。

• An Input item could have a data size of zero (0) bytes. In this case the value of each data bit for the item can be assumed to be zero. This is functionally identical to using a item tag that specifies a 4-byte data item followed by four zero bytes.

  输入项的数据长度可以为零（0）字节。在这种情况下，该项的每个数据位的值均可假定为零。这在功能上等同于使用一个指定了4字节数据项、后跟四个零字节的项标签。

笔记

• bit[3,2] = 00 - 主项(main item)