Process memory in task manager shows less than i am allocating

Asked Apr 05 '15 at 15:41

Active Apr 05 '15 at 16:04

Viewed 106 times

I have written a small program just to check if my program can acquire entire RAM of my PC. i am trying to allocate 4 GB. When i check with task manager it shows around 2 GB. i believe OS has some kind of memory management mechanism. If someone can provide me what is really happening it will be helpful for me. [i am not taking care of memory leak as this is a test code]

int main()
{

    char* p;

    p = (char*)malloc((1024 * 1024 * 1024));
    p = (char*)malloc((1024 * 1024 * 1024));
    p = (char*)malloc((1024 * 1024 * 1024));
    p = (char*)malloc((1024 * 1024 * 1024));

    while (1){}

    return 0;
}

Thanks in Advance,

Sagar

edited Apr 05 '15 at 16:04

LogicStuff

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asked Apr 05 '15 at 15:41

Sagar

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1

It's a pretty deep and philosophical question what it means to "allocate memory". Have a thought. What should it mean? What could it mean? How would an OS deal with requests to allocate memory? – Kerrek SB Apr 05 '15 at 15:44
2

Is it a 32- or 64-bit application? Have you checked the result (value of `p`) after each allocation? – Mats Petersson Apr 05 '15 at 15:53
If you are using Windows 32, Windows allows only 2GB for user programs. – Valentin H Apr 05 '15 at 15:53
Thanks, It is 32 bit. I will try with 64bit – Sagar Apr 05 '15 at 16:04
Even then you won't be able to "acquire entire RAM of my PC". – Weather Vane Apr 05 '15 at 16:11
possible duplicate of [maximum memory which malloc can allocate](http://stackoverflow.com/questions/2798330/maximum-memory-which-malloc-can-allocate) – timday Apr 05 '15 at 17:10

Process memory in task manager shows less than i am allocating

0 Answers0