if(a == NULL) return 1; if(b == NULL) return -1;
gint sort_cons_strength(gconstpointer a, gconstpointer b){	const rsc_constraint_t *rsc_constraint1 = (const rsc_constraint_t*)a;	const rsc_constraint_t *rsc_constraint2 = (const rsc_constraint_t*)b;  	if(rsc_constraint1->strength > rsc_constraint2->strength)		return 1;	if(rsc_constraint1->strength < rsc_constraint2->strength)		return -1;	return 0;}