qsort (quick sort) function

I want to use the built-in qsort function (stdlib.h) to sort a two dimensional array say arr[10][2];

could someone help me write the compare function if arr[m][] goes before arr[n][] if arr[m][0]<arr[n][0]

Two-dim arrays are tricky there...

Code:

---

// call qsort assuming arr[] is integer
qsort(&arr,10,sizeof(arr[0][0])*2, cmp)

int cmp(void *a, void *b){
        return ( (int*)a - (int*)b);
}

---

Expected something along those lines, but I was too tired to think properly about it.

But since he wants to compare the first element of the subarrays this
return ( (int*)a - (int*)b);
should be
return ( (*(int*)a) - (*(int*)b));