add: fprintf(stderr, "pcnt: %llu - %llu = %llu\n", a->pcnt, b->pcnt answer->pcnt); fprintf(stderr, "bcnt: %llu - %llu = %llu\n", a->bcnt, b->bcnt answer->bcnt);
context: subtract_counters(STRUCT_COUNTERS *answer,		  const STRUCT_COUNTERS *a,		  const STRUCT_COUNTERS *b){	answer->pcnt = a->pcnt - b->pcnt;	answer->bcnt = a->bcnt - b->bcnt;}