In which case, realloc returns NULL???
 

hi pals,

My win32 console application has allocated memory of 350MB in Memory usage
column and 400MB in Virtual memory column. While reallocating a global
variable , getting NULL if the size is too high (say 200MB). What is the
maximum memory size that an application can use? What are the scenario, that
realloc returns NULL.


@ Shahul.

Re: In which case, realloc returns NULL???
 

"shahul" <shahul@chellasoft.com> wrote in message
news:efYasx$UGHA.4608@tk2msftngp13.phx.gbl...
> hi pals,
>
> My win32 console application has allocated memory of 350MB in Memory
> usage
> column and 400MB in Virtual memory column. While reallocating a global
> variable , getting NULL if the size is too high (say 200MB). What is the
> maximum memory size that an application can use? What are the scenario,
> that
> realloc returns NULL.

*alloc uses heap memory. What you would need is VirtualAlloc then. But
still, a win32 app, cannot address more memory than 4GB (even if you have
installed more hardware RAM). However, in practise, this memory never will
go beyond 2GB unless you use specific hardware & software extensions
(windows (win32) enterprise edition can address 64 GYG)

Still, if you allocate that much virtual memory, your swap disk, really gets
stressed. I would redesign your solution. If you are talking about a
database table, or something like that that uses that much memory, use a
cursor mechanism.

Re: In which case, realloc returns NULL???
 

Hi shahul!

> My win32 console application has allocated memory of 350MB in Memory usage
> column and 400MB in Virtual memory column. While reallocating a global
> variable , getting NULL if the size is too high (say 200MB). What is the
> maximum memory size that an application can use? What are the scenario, that
> realloc returns NULL.

If there is no continues chunck of memory in the requested size. See:

How to get the largest available continues memory block
http://blog.kalmbachnet.de/?postid=9


--
Greetings
Jochen

My blog about Win32 and .NET
http://blog.kalmbachnet.de/

Re: In which case, realloc returns NULL???
 

On Thu, 30 Mar 2006 18:48:27 +0530, shahul wrote:

> hi pals,..

You're NOT making any "pals" by crossposting to groups that have nothing to
do with your post. See the link below for information on how to use
newsgroups properly.

Shame on the MVPs who crossposted their responses and set no follow up. Of
course, if you're using a sad newsreader like OE or Thunderbird...

Follow up set to:

microsoft.public.win32.programmer.directx.sdk


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