mctx->max_bkref_len = 0;
mctx->max_mb_elem_len = 0;
match_ctx_init (mctx, eflags, input, n)    re_match_context_t *mctx;    int eflags, n;    re_string_t *input;{  mctx->eflags = eflags;  mctx->input = input;  mctx->match_last = -1;  if (n > 0)    {      mctx->bkref_ents = re_malloc (struct re_backref_cache_entry, n);      if (BE (mctx->bkref_ents == NULL, 0))        return REG_ESPACE;    }  else    mctx->bkref_ents = NULL;  mctx->nbkref_ents = 0;  mctx->abkref_ents = n;  mctx->max_bkref_len = 0;  return REG_NOERROR;}