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From: pipkins@qmsseq.imagen.com (Jeff Pipkins)
Newsgroups: comp.sys.ibm.pc
Subject: Re: HELP! Using DOS print
Message-ID: <51@qmsseq.imagen.com>
Date: 30 Nov 89 16:38:29 GMT
References: <6534@brspyr1.BRS.Com>
Reply-To: pipkins@qmsseq.UUCP (Jeff Pipkins)
Distribution: usa
Organization: QMS Inc., Mobile, Alabama
Lines: 44

In article <6534@brspyr1.BRS.Com> jillj@brspyr1.BRS.Com (Jill Jacomine) writes:
>I  am  trying to execute the DOS (version 3.1) print command from within
>an executable (compliled using MSC 5.1).  The command I am using is:
>
>	spawnvp(P_WAIT,"print.com",args);
>
>The  value  of  args  is  "print /D:prn filename".  Now, this works well
>enough to print the file out, the problem seems to be setting the device
>within the program eats up about 200k of memory, and never lets  it  go.
>(I  tried  setting the device before executing the program, and it seems
>to work fine, therefore I am relativly sure  the  problem  is  with  the
>/D:prn  option).  A chkdsk before running the program shows 655360 bytes
>total memory and 594256 bytes free, after execution it is  426720  bytes
>total memory and 356616 bytes free.

PRINT is a "TSR" program.  The first time you run it, it installs
itself into your precious memory.  If your program loads it, realize
that chances are very high that it will be loaded RIGHT AFTER your
program in memory.  After your program terminates, PRINT STAYS THERE --
and you have irrecoverable memory fragmentation.  DOS usually loads
new programs in the first hole that it will fit in, so a program
may use that hole, but if it tries to use the DOS SETBLOCK function
to increase its size, it will most likely fail.

This problem occurs any time a nonresident program loads a resident
program.  I have only thought of two possible work-arounds, and I
don't like either of them:

1) Reserve enough memory below your program so that you can load
the TSR there.

2) Modify DOSs memory control blocks to allocate just the right
size block high in memory; then use the overlay option of DOSs
EXEC function to load the program into that memory.

I would be very interested in hearing other possible solutions
from anyone else!

/*=======================================================================*\
   Jeff Pipkins: pipkins@imagen.com  My views are not necessarily shared
   by my employer or the IRS.  That explains a lot about my paycheck.

   "Why is it that unpitted dates have pits and pitted dates do not?"
\*=======================================================================*/