Article-I.D.: cvl.1122
Posted: Sat Jan 18 23:03:10 1986
Date-Received: Mon, 20-Jan-86 05:50:44 EST
Distribution: net
Organization: Computer Vision Lab, U. of Maryland, College Park
Lines: 17

*** REPLACE THIS LINE WITH YOUR MESSAGE ***

Anyone out there used the gemdos Pexec command?  It supposedly allows one
to call other programs from a main program.  I've tried everything I could
think of to get it to work, but I've had no luck.  It keeps returning error
code -39.  According to the gemdos manual, this indicates not enough memory.
But I know I've got enough memory, becase the main program is about ten
lines long and the sub-program is about five lines long and I have a one-
megabyte machine!  This is terribly frustrating!  If anyone can offer any
suggestions or perhaps a solution, I will greatly appreciate it.
-- 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Eli Liang  ---
        University of Maryland Computer Vision Lab, (301) 454-4526
        ARPA: eli@cvl, eli@lemuria, eli@asgard, eli@mit-mc, eli@mit-prep
        CSNET: eli@cvl  UUCP: {seismo,allegra,brl-bmd}!umcp-cs!cvl!eli

Article-I.D.: nlm-vax.1956
Posted: Tue Jan 21 09:41:58 1986
Date-Received: Fri, 24-Jan-86 08:34:12 EST
References: <1122@cvl.UUCP>
Reply-To: randy@nlm-vax.UUCP (Rand Huntzinger)
Distribution: net
Organization: NLM/LHNCBC, Bethesda, Md.
Lines: 28

In article <1122@cvl.UUCP> eli@cvl.UUCP (Eli Liang) writes:
[color=blue]> *** REPLACE THIS LINE WITH YOUR MESSAGE ***[/color]
[color=blue]> [/color]
[color=blue]> Anyone out there used the gemdos Pexec command?  It supposedly allows one[/color]
[color=blue]> to call other programs from a main program.  I've tried everything I could[/color]
[color=blue]> think of to get it to work, but I've had no luck.  It keeps returning error[/color]
[color=blue]> code -39.  According to the gemdos manual, this indicates not enough memory.[/color]
[color=blue]> But I know I've got enough memory, becase the main program is about ten[/color]
[color=blue]> lines long and the sub-program is about five lines long and I have a one-[/color]
[color=blue]> megabyte machine!  This is terribly frustrating!  If anyone can offer any[/color]
[color=blue]> suggestions or perhaps a solution, I will greatly appreciate it.[/color]
[color=blue]> -- [/color]
I usually reply to such things privately, but this frustrating problem comes
up with the developer's kit enough to warrant posting a reply.  For those
without the developer's kit, I beg your patience.

For some reason, the "gemstart.o" (or gems.o) module deallocates all but about
1K of user stack/heap space.  Thus, you can have a 1 meg machine with 3/4 meg
free, and still get the out of memory message.  I ran into the same problem
with Pexec() and had other problems as well, until I modified gemstart.s to
allocate more space.  Then the problems went away and I could get on with my
work.  I don't have the code at hand, so I can't give the exact fix.  But
somewhere there is a constant (400 or 500 hex) which gets added to the end of
the program area.  The stack is reset at this point and the rest of memory is
deallocated.  You get to use the space between the end of your code and the
stack pointer.  (400 or 500hex bytes)

					Randy Huntzinger