STRUCT -statement

-<struct-statement> -struct-statement ::= -STRUCT <struct-name> [ BYTE | WORD ] { <struct-member-list> } -

A STRUCT statement defines the format of a struct; all -resources are defined in terms of structs. The struct has a name designated -by struct-name, and some items designated by struct-member-list.

Struct names

The following rules must -be observed for struct-names:

they must be given in -upper case
they must begin with -an alphabetic character, although subsequent characters may be numeric
they may not begin with -any of the 12 struct type-names (see STRUCT -members), or the keywords: GLOBAL, STRUCT, LEN or RESOURCE. -This restriction applies only to the struct-name, not the member-name of -any individual struct members.

So the following struct definition will -generate an error
STRUCT BUFTHING - { - BUF buffer; - }
whereas this struct definition will compile correctly
STRUCT ABUFTHING - { - BUF buffer; - }

Struct member list

The struct-member-list is -a sequence of struct-member s where each member is terminated -by a semi-colon. The complete list is enclosed within a pair of braces.

See STRUCT members for -more details.

BYTE/WORD keywords

STRUCT definitions -allow resource instances to be of variable length, as the struct can allow -default variables for its members. A resource’s entire length can be deduced -from the position of the next resource; this information is available in a -resource file’s index. If the resource is used as a member within an instance -of another resource, however, its length must be identified another -way.

Use BYTE to -prefix the struct with a single byte indicating its length (zero to 255 characters).
Use WORD to -prefix the struct with a word indicating its length (zero to 65,535 characters).

The following are valid STRUCT statements:

STRUCT STRING - { - LTEXT str; - }

This defines a struct called STRING which -contains a single LTEXT item.

STRUCT TEST BYTE - { - WORD status; - STRUCT text; - }

This defines a struct called TEST which -contains a WORD and an embedded struct. The total length -of TEST is unknown, but should not exceed 255 characters: -the BYTE directive in the definition indicates that, when -this struct is embedded within another, it should be preceded with a byte -indicating its length (zero to 255 characters).