How to compile a program to use electric fence library for debugging ?

$cat efence-p1.c
#include <stdio.h>
#include <stdlib.h>
int main()
{

char *ptr = (char *) malloc(1024);
ptr[0] = 0;

ptr[1024] = 0;
exit(0);
}
$gcc -g efence-p1.c -lefence
$./a.out

Electric Fence 2.2 Copyright (C) 1987-1999 Bruce Perens <bruce@perens.com>
Segmentation fault
$