program out of control

[Bob Calbridge]

Perhaps someone can give me a suggestion on this.  I'm writting a fairly
large program under Turbo C.  So far, with the debugging information in 
the program, the executable is about 70K.  Without the debugging info its
closer to 50K.  The program allocates some of the heap, potentially up to
100K but for the testing phase it uses about half that.  Each of the allocated
areas is in the 10K and under range.  All of this information is by way of
information just in case it has any bearing on the situation.  This is the
first time I've attempted to use malloc() so it might have some effect on
the program.

Here is the problem.  The program takes information from one file and uses 
the allocated space to build information which is eventually output to 
another file.  During this process there are several errors that can be
generated.  If no error is generated the program prints a message to that
effect and waits for the user to press any key to return to the menu.  If
an error occurs the program prints an error message and prints the line where
the error was detected.  The user is prompted to press any key to return to
the menu.  This is where the problem comes in.

In the case of an error, when the user presses a key the program appropriately
returns to the menu and prints it.  However, the system usually locks up at
this point.  Last night when I made some changes to the program that were not
related to correcting the problem (I decided to get the rest of the program
working before tackling this problem) the symptoms changed.  Instead of
locking up, the system started to beep and display the menu continuously.  The
beep is appropriate if there is an invalid input to getch() which is used to get
the option for the menu.

All functions pass a status back to the calling routine to indicate a success
or failure status so I don't suspect any stack problems.  Can anyone suggest
what might be causing this to happen.  I can't understand why it would happen
only with errors.  I'm just about ready to experiment with another unfamiliar
routine, longjmp(), if I can't get rid of this problem.

I should mention that I attempt to free all allocated space before returning
to the menu.  I don't think that it is being done completely since coreleft()
keeps reporting increasingly smaller amounts of memory left.

Many thanks,
Bob
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