Use Dos startsession when Dosexecpgm doesn't work.
  heh heh.
  Start session allows you to run programs of a different type
(windows/dos/os2/pm...) than the one that is running. 
  The book says execpgm won't run another program that isn't of the same
type. This is because it shares the same window when running a program this
way. The child process is more related (it inhereits file handles and such
that startsession does not)
  I have however gotten a windowed os/2 text program to dosexecpgm a
fullscreen program, though they say it won't. But I'm sure it won't run a
PM program from a text or windowed text program. That is when you use dos
start session.
  One of the biggest annoying things about startsession is that you can't
wait for it to end, I.E., can't run synchronously.
  Well, you can, you have to make a queue, and right after you do the Dos
startsession, wait on the queue (the termination queue) and then effectivly
you've got DosStartAndWaitSession.

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