[MacPerl] Memory fragmentation when using CommConnect calls...

["Robert A. Decker" <comrade@umich.edu>]

Matthias or Alex Metcalf,

  I have a Perl script with one of the functions doing a do...until
call that has two commConnect calls inside it (these are going to
Serial Tool 1.0.2 while using System 7.5.5). This seems to eat up
memory pretty quick. Here is the function:
******************************************************************
############
#       ReceiveData accepts the data from the Tool. It stops when the Tool
sends the DONESENDING
# command. Also wrote it so that the script closes the connection to
the tool when the Tool
# hasn't sent anything for 30 seconds (which probably means the Newton
hasn't sent anything
# to the tool for 30 seconds).
############
sub ReceiveData {
        my $data;
        my $alldata;
        my $startTime =3D time();
        my $currentTime =3D $startTime;
        my $differenceTime;
        print "Attempting to receive the data...\n";
        do { 
                $currentTime =3D time();
                &CommConnect'Idle();
                $data =3D &CommConnect'Receive();
                if ($data) { print $data, "\n"; }       # Here for debugging. May have to
remove if output is too messy.
                if ($data) { $startTime =3D $currentTime; } # restart the counter.
                if (!$data) { 
                        $differenceTime =3D $currentTime - $startTime;
                        if ($differenceTime > 15) {
                                print "No data has been sent for $differenceTime seconds. Closing
the connection. \n";
                                &CloseToolConnection;
                                print "alldata is: \n", $alldata, "\n";
                                print "Aborting the script. The Newton never sent the DONESENDING
command!";
                                exit 0;
                        }
                }       
                $alldata .=3D $data if $data;   
        }
        until ($alldata =3D~ /DONESENDING/);
        print "\n...Finished sending.\n\n";
        print "alldata is: \n", $alldata, "\n\n\n";
        ModifyData($alldata);
} # sub ReceiveData
***********************************************************************=


  When I run ZoneRanger and the sript at the same time I can watch the
Free Memory dissapear, but even more interestingly, I can watch the
number of MacPerl handles increasing _very_ quickly.

  When I use ZoneRanger to look at MacPerl's blocks I have a pattern th=
at repeats over and over, which probably means it's the result of the
loop. Here is a sample of the pattern:
Address     Type           Size  Attr Resource    ID  Name
-----------------------------------------------------------------------=
--------0x0156AB80  Handle            0  ...  
0x0156ABA0  Free             20  ...  
0x0156ABC0  Handle            0  ...  
0x0156ABE0  Free             20  ...  
0x0156AC00  Handle            0  ...  
0x0156AC20  Free             20  ...  


  From this, it looks like a NewHandle is called (or NewPtr?) to make
a large handle. That handle is then resized to 20. Next, a NewHandle
is called, but then this handle is resized to 0 (and not disposed),
then the first handle is freed, leaving a 20 byte free block and a 0
byte handle.



 Here's another interesting point. This is what one of the free blocks
look like:
    Offset   Hex Contents                              ASCII Contents 

-----------------------------------------------------------------------=

0x00000000 | 7265 6365 6976 6500 000E 8020 0156 AC50 | receive...=C4
.V=A8P
0x00000010 | 0156 AC90 AB00 0014 0000 0020 001C 01F8 |
.V=A8=EA=B4...... ....
 All the free blocks look like this. 'receive' is one of the calls I
make in commConnect.


  So, where's the problem at? In the Serial Tool? In the MacPerl XFCN
adapter? Is there any hope of having this fixed?

  I'll mail the entire script to anyone that's interested.

thanks,


rob
--
<mailto: "Robert A. Decker" comrade@umich.edu>
Programmer Analyst - Health Media Research Lab
University of Michigan Comprehensive Cancer Center 

"Get A Life" quote #8: "Wow. A doctor. Maybe you can help me with
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