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From: kehyoe@umn-cs.cs.umn.edu (Ong Keh Yoe)
Newsgroups: comp.lang.c,comp.windows.misc
Subject: Mysteries of Microsoft Windows and C
Keywords: Microsoft, C, Windows, MSC, Bugs
Message-ID: <7050@umn-cs.cs.umn.edu>
Date: 28 Aug 88 20:26:56 GMT
Organization: University of Minnesota, Computer Science
Lines: 67


Hello,

	I am currently debugging a package written for Microsoft Windows written
 in Microsoft C.  And I would like to know some information about applications
for Windows.  First, some information about the application that I am working
on.  The application calls a second application using a spawnlp.  The spawnlp
kills the parent using an option for spawnlp.  The first application provides
a graphical menu-driven environment.  The second application on termination
then spawnlps the first application.  Information to be shared are written
by each application to two designated files.  Each file created by one
of the two applications and destroyed by the second.  So fileA is create
by applicationOne but destroyed by applicationTwo.  And fileB created by
applicationTwo but destroyed by applicationOne.

	First, I would like to know if anyone has experienced that lack of memory 
has ever caused programs to terminate inexplicably.  It seems that the
memory can easily contain both applications.  If the spawnlp kills it's
parent, should the resources of the parent be automatically freed ?  And if
not, why not ?  Just what does a spawnlp that kills it's parent do and
are there dangerous side effects ?

	Second, the second application terminates properly and spawnlps the
first application, but the window manager behaves strangely at this
point (menus popup that are whited out, information displayed at the
border of the window is garbage, etc), has anyone experienced this
due to a lack of memory, errors in window management, interrupts,
etc.  Any information or experience on this is appreciated.  Or is 
the problem the application itself, e.g. writing in memory reserved
for the operating system ?  Sometimes, the second application terminates
properly and spawnlps the first application, but the system crashes
(you have to do switch off/ switch on to restart).  

	Third, is it possible to use Codeview to debug these applications
without significantly affecting the bugs produced (if these are produced
by lack of memory, then Codeview is bound to affect them, correct ?).
What are the net's experiences using Codeview to debug Window applications
written in Microsoft C ?

	Fourth, is the Microsoft window programming environment a stable
environment ?  Is it reliable ?  What are the best tools and methods
of tackling strange errors ?  E.g. 
		Using codeview, 
		Going into Window source (is this possible ?)
		Debugging at assembly level,
		Setting some obscure debug flags on ?
We seem to think we know where the error is, but the consequences of the
error (or errors) is so random, and the conditions that cause it so
random, we are not sure.  Any suggestions ?

	Lastly, we used a batch file to run the two applications.  First
it runs one.  When that terminates, it checks for the presence of
a file and runs the second and vice versa.  It stops when the
specified file is not created.  But, this also seems to bomb.  Yet,
when both applications are running independently, there is no
problem.  Any explanations ?

	I appreciate any response to the above queries.  My net address
presently is 'kehyoe@umn-cs.cs.umn.edu'.  Or post any of the
solutions to the net if you cannot contact me.  I wonder how many
of you netters I have bored to death already.  I hope this
topic interests enough people.  

								Thanks

									Keh Yoe
									(the happy hacker)