How many GB can malloc allocate for your program

I used the following code to find it out but I always get 1 as the answer. is there something wron开发者_StackOverflow社区g. Thanks

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

int main(){
    int mult = 0;
    int chk =8;
    do{
        mult+=1;
        int *p = (int*)malloc(1024*1024*1024*mult);
        if(p==0){
            chk =0;

        }else{
            free(p);
        }
    }while(chk !=0);
    mult = mult -1;
    printf("The number of gigs allocated is : %d\n",mult);
    return 0;
}

Just to help, I have a 64 bit system with both windows and linux installed. Thus, is the above logic correct even though I am getting just 1 gb as the answer on a 64 bit system?

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If it is a 32-bit OS, then it is not surprising that the largest contiguous block would be 1GB (or somewhere between that and 2GB). On a 64-bit OS, larger blocks would be possible.

If you change your code to allocate smaller individual pieces, you will likely be able to allocate more than 1GB total.

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These questions might help you a bit: How much memory was actually allocated from heap for an object? and How do I find out how much free memory is left in GNU C++ on Linux

---

int main(void){
    int MB = 0;
    while(malloc(1<<30)){
        ++MB;
    }
    printf("The number of gigs allocated is : %d\n",MB);
    return EXIT_SUCCESS;
}