General Overlay Support

The support for overlays in Turbo Pascal requires the program to 
open the overlay support file as a file and set up an overlay 
buffer. This can cause problems if overlaid units need to execute 
initialization code before the main program can call the overlay 
setup routines. The solution to this problem is generally to include 
a special unit which initializes the overlay file.

The general overlay support unit (GENOVR.PAS) is designed to open an 
overlay file in the same directory as the program being executed. It 
will open the overlay, then attempt to load it into EMS memory. If 
there is no EMS memory available, the program will then attempt to 
expand the overlay buffer to allow as much of the program as 
possible into memory, leaving 64 kilobytes of memory free for the 
heap.

Restrictions: this unit uses the command parameter routines to 
obtain the name of the overlay file, so they will not work under any 
version of DOS earlier than 3.0 without being modified.

Disclaimer: this unit is provided as is, without warranty of any 
kind. Use it at your own risk.