Date: Wed, 26 Apr 1995 13:15:29 -0400 (EDT)
From: Long Doan <ldoan1 AT osf1 DOT gmu DOT edu>
To: "B.S.Runnacles" <B DOT S DOT Runnacles AT soton DOT ac DOT uk>
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: Unable to free memory..

On Wed, 26 Apr 1995, B.S.Runnacles wrote

> LinkedList::~LinkedList(void)
> {
> listnode *Root,*Current; // a data structure with next pointer and data
> _go32_dpmi_meminfo info1,info2;
> for (Current = Root; Current != NULL; Current = Current->next) {
> 	_go32_dpmi_get_free_memory_information(&info1);
> 	delete Current;

*** After Current is 'deleted', you shoudn't use Current->Next!
*** I think that you're doing this backward.

> 	_go32_dpmi_get_free_memory_information(&info2);
> 	cout << info2.available_memory - info1.available_memory << endl;

*** Also, delete and free () will not affect the value that _go32.._ ()
*** returns. The memory block is still freed, however.
> 	}
> }
> 
> But the result says that there is no difference in the free memory before and 
> after the delete call.  Has anyone got any ideas as to why?  I may be doing
> something fundementally wrong here, any hints would be nice.  I think the
> memory isn't being freed because after a few hundred iterations the code
> falls over complaining of a full swap file.

  I think you're trying to use memory that was freed, and that prevent the
library routines to do their job correctly.

Hope that helps,
Long.

+--------------------------------------------------------+
| Long Doan                          ldoan1 AT osf1 DOT gmu DOT edu |
|                                          ld AT netrix DOT com |
+--------------------------------------------------------+