stack overflow in a simple float array initialization

Question

I am trying to get code that was working on Linux to also work on my Windows 7.

When I retried the same code, it crashed with stack overflow. I then removed everything I could to find out the line which is causing it to crash, and it left me with this:

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

#include <cuda_runtime.h>

/* 256k == 2^18 */
#define ARRAY_SIZE 262144
#define ARRAY_SIZE_IN_BYTES (sizeof(float) * (ARRAY_SIZE))


int main(void)
{

    float a[ARRAY_SIZE] = { };

    float result = 0;

    printf("sum was: %f (should be around 1 300 000 with even random distribution)\n", result);

    return 0;
}

If I change ARRAY_SIZE to 256, the code runs fine. However with the current value, the float a[ARRAY_SIZE] line crashes runtime with stack overflow. It doesn't matter if I use float a[ARRAY_SIZE]; or float a[ARRAY_SIZE] = { }; , they both crash the same way.

Any ideas what could be wrong?

Using Visual Studio 2010 for compiling.

---

Ok, the stack sizes seem to be explained here , saying 1M is the default on Windows.

Apparently it can be increased in VS 2010 by going Properties -> Linker -> System -> Stack Reserve Size and giving it some more. I tested and the code works by pumping up the stack to 8M.

In the long run I should probably go the malloc way.

Answer 1

Your array is too large to fit into the stack, try using the heap:

float *a;
a = malloc(sizeof(float) * ARRAY_SIZE);

Segmentation fault when allocating large arrays on the stack

Answer 2

Well, let me guess. I've heard default stack size on Windows is 1 MB. Your ARRAY_SIZE_IN_BYTES is exactly 1 MB btw (assuming float is 4 bytes). So probably that's the reason

See this link: C/C++ maximum stack size of program