Message-Id:	<199902172204.RAA21716@delorie.com>
From:	"Stefan Viljoen" <rylan AT intekom DOT com>
To:	<djgpp AT delorie DOT com>
Subject:	Memory leaks, and allegro
Date:	Wed, 17 Feb 1999 23:56:51 -0800
X-MSMail-Priority:	Normal
X-Priority:	3
X-Mailer:	Microsoft Internet Mail 4.70.1155
Reply-To:	djgpp AT delorie DOT com

Hi!

I have encountered something strange while working with Allegro 3.1 - the
function

_go32_dpmi_remaining_physical_memory

always reports 4k (4096 bytes) less memory as "remaining" if you call it
before and after any Allegro GUI dialog procedure that handles a DIALOG
object. I. e. the code looks something like this:

phys_before = (unsigned int)_go32_dpmi_remaining_physical_memory();

do_dialog(test_dialog,-1);

phys_after = (unsigned int)_go32_dpmi_remaining_physical_memory();

Subtracting phys_after from phys_before consistently reports 4096 bytes
discrepancy - why? Is this 'cause the do_dialog() code uses static
variables somewhere? Does this apparent memory leak increase if you call
the function again?

I ask this cause I encountered an extremely severe memory leak in a
function that makes quite extensive use of the Allegro dialog procedures.
After 2 or 3 entries into the function that calls the Allegro dialog stuff,
my system starts slowing down with lots of disk access that keeps on
getting more severe - I also build up a linked list in one of these
functions that is deallocted again on exit (I think!). 

My question is, where is the most likely cause of the memory leak? In the
code that deallocates the list (it is all I can think off) or because of
this apparent 4k leak in do_dialog? Or is it a feature of do_dialog? ;)

How can I test for memory leaks in DJGPP programs? Will remaining_physical
and remaining_virtual work for this? Or must I go "back to the drawing
board" on any linked list code that might be in the gui functions called by
the dialog function? 'cause I tested the linked list code outside of being
used in a do_dialog procedure and it worked just fine (no apparent leaks)?

Fanx!

Please reply by mail if at all possible.
-- 
Spawned By Rylan
Rylan AT intekom DOT co DOT za
http://home.intekom.com/rylan/

Power Overwhelming

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