[Scorpiion]

Hi, I tried to do a simple program that would allocate all or a lot of memory on my computer so that I could see it with "free -m" from the command line (Linux program to see how much memory is free). But I don't really see any difference when I'm running my test program, I guess I have done something wrong here? Any clues?

#include <stdio.h>
#include <stdlib.h>

int main()
{
        void *memory;
        int mem_to_allocate;

        while( 1 ) {
                printf("Memory to allocate ");
                scanf("%d", &mem_to_allocate);

                if( (memory = malloc(mem_to_allocate)) == NULL) {
                        printf("Out of memory\n");
                }
                else {
                        printf("Memory allocated! \n");
                }
        }


        return 0;
}

[Aphex19]

I'm pretty sure that malloc() simply reserves the memory space, basically marking it as reserved memory. If you wish for the memory to be used, then you will need to actually fill it with date.

Just use a simple fixed loop that initializes all the memory to some arbitrary value, and you should see the memory being used.

This post has been edited by Aphex19: 08 April 2010 - 07:06 AM

[Scorpiion]

Might be true... I'll try that..

[Martyn.Rae]

You will have to remember that if you allocate a large amount of memory, it will probably end up as virtual memory on disc. Both Linux and Microsoft Windows are extremely good at implementing this mechanism. The result is that you may not see an awful lot of difference in the memory usage.

[Scorpiion]

Okey, that might explain some parts.. Good to know!