Relocatable Object Module Format (OMF) Specification

Relocatable Object Module Format
88H COMENT—Comment Record
Description
The COMENT record contains a character string that may represent a plain text comment, a symbol meaningful to
a program accessing the object module, or even binary-encoded identification data. An object module can contain
any number of COMENT records.
History
Before the VENDEXT record was added for TIS, the COMENT record was the primary way of extending the OMF.
These extensions were added or changed for 32-bit linkers and continue to be supported in this standard. The
comment classes that have been added or changed are 9D, A0, A1, A2, A4, AA, B0, and B1.
Comment class A2 was added for Microsoft C version 5.0. Histories for comment classes A0, A3, A4, A6, A7, and
A8 are given later in this section.
68000 and big-endian comments were added for Microsoft C version 7.0.
Record Format
The comment records are actually a group of items, classified by comment class.
1 2 1 1 1
88 Record
Length
Comment
Type
Comment
Class
Commentary Byte String (optional)
Checksum
Comment Type
The Comment Type field is bit significant; its layout is
NP NL 0 0 0 0 0 0
where
NP
NL
(no purge bit) is set if the comment is to be preserved by utility programs that manipulate object
modules. This bit can protect an important comment, such as a copyright message, from deletion.
(no list bit) is set if the comment is not to be displayed by utility programs that list the contents of
object modules. This bit can hide a comment.
The remaining bits are unused and should be set to 0.
Comment Class and Commentary Byte String
The Comment Class field is an 8-bit numeric field that conveys information by its value (accompanied by a null
byte string) or indicates the information to be found in the accompanying byte string. The byte string's length is
determined from the record length, not by an initial count byte.
Tool Interface Standards (TIS) OMF Specification, Version 1.1 9