Important Notice
The pages on this site contain documentation for very old MS-DOS software,
purely for historical purposes.
If you're looking for up-to-date documentation, particularly for programming,
you should not rely on the information found here, as it will be woefully
out of date.
Overlay Syntax
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─────Overlay Syntax─────────────────────────────────────────────────────────
Specify overlays by enclosing object (and possibly library)
filenames in parentheses in the <objfiles> field. Each group of
object files bracketed by parentheses represents one overlay.
Overlays cannot be nested.
The remaining files (those not in parentheses), and any drawn
from the run-time libraries, constitute the resident (or root)
part of your program. The entry point to the program (such as
main() in C, or PROGRAM in FORTRAN) must be in the root.
For example, the following list of files contains three overlays:
a + (b+c) + (d+e) + f + (g)
In this example, the groups (b+c), (d+e), and (g) are overlays.
The remaining files a and f and any modules from libraries in the
<libraries> field remain memory-resident throughout the execution
of the program.
A library listed in the <objfiles> field can be put in an overlay.
See: ◄Entering Library Files as Object Files►
It is important to remember that whichever object file first
defines a segment gets all contributions to that segment. In the
example above, if D.OBJ and F.OBJ both define the same segment,
the contribution from F.OBJ to that segment goes into the (d+e)
overlay rather than into the root.
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