Thread: Segmentation Fault :: Insertionsort Pointers

Im pulling my hair out ,, can someone give me feedback on what errors i am making ???

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
using namespace std;

void inssrt(void *akeys, int n, int size, int (*compare) (const void * , const void *))
{
    register int i,j;
    char *keys;
    char *tmp;

    keys= (char *) akeys;
    tmp = (char *) malloc(size*sizeof(char));
    
    for(j=1;j<n;j++) {
    memcpy(tmp,&keys[(j)*size],size);
    i = j - 1;
    while(i >= 0 && (compare(&keys[(i) * size],&keys[(i+1)* size]) < 0)) {
        memcpy(&keys[(i+1) * size], &keys[(i) * size],size);
        i = i - 1;
    }
    memcpy(&keys[(i + 1) * size],tmp,size);
    }
    free ((char *)tmp);
}