Stefan van der Walt wrote in a message to All:

 SvdW>    1) How to do time slicing in Pascal for OS/2 running in a
 SvdW> DOS Session?
 SvdW>    2) How do I detect if OS/2 is running so that I can enable 
 SvdW> time slicing?

While you may receive varying answers, my opinion is that the best policy
is to check for DPMI and use the DPMI release timeslice call if DPMI is
present.  Since OS/2 provides DPMI services, this works well.

1. Make sure that Int 2Fh is safe to use.

   Call Int 21h, AX=352Fh.  Check that ES:BX is not 0000:0000h.

2. Verify that DPMI is available.

   Call Int 2Fh, AX=1687h.  Check that AX is 0000h.

3. Release timeslice.

   Call Int 2Fh, AX=1680h.  Check that AL is 00h.

The first two steps are only required at program startup.  Once you know
that DPMI services are available, you can release the timeslice whenever
you want.
 
-- Mike


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