ep_narg
if (plan->type==N_EXEC && plan->ep_narg)
plan->ep_bxp[plan->ep_narg++] = plan->ep_p;
if (plan->ep_narg == plan->ep_maxargs)
plan->ep_bxp[plan->ep_narg++] = plan->ep_p;
plan->ep_bxp[plan->ep_narg] = NULL;
plan->ep_narg = 0;
plan->ep_bxp[plan->ep_narg] = NULL;
new->ep_narg = 0;