Segment macros give access to the code and data segments that an application will use. These segments have the names, attributes, classes, and groups required by Windows:
| Macro name | Description |
| createSeg | Creates a new segment that has the specified name and segment attributes. |
| sBegin | Opens up a segment. This macro is similar to the SEGMENT assembler directive. |
| sEnd | Closes a segment. This macro is similar to the ENDS assembler directive. |
| assumes | Makes all references to data and code in the segName segment relative to the segment register given by segReg. This macro is similar to the ASSUME assembler directive. |
| dataOFFSET | Generates an offset relative to the start of the group to which the DATA segment belongs. This macro is similar to the OFFSET assembler operator but automatically provides the group name. |
| codeOFFSET | Generates an offset relative to the start of the group to which the CODE segment belongs. This macro is similar to the OFFSET assembler operator but automatically provides the group name. |
| segNameOFFSET | Generates an offset relative to the start of the group to which the user-defined segName segment belongs. This macro is similar to the OFFSET assembler operator, but automatically provides the group name. |
The Cmacros have two predefined segments, CODE and DATA, that any application can use without special definition.