Function fetch_cursor_param_value

src/backend/executor/execCurrent.c:532–569

* fetch_cursor_param_value * * Fetch the string value of a param, verifying it is of type REFCURSOR. */

 * Fetch the string value of a param, verifying it is of type REFCURSOR.
 */
static char *
fetch_cursor_param_value(ExprContext *econtext, int paramId)
{
	ParamListInfo paramInfo = econtext->ecxt_param_list_info;

	if (paramInfo &&
		paramId > 0 && paramId <= paramInfo->numParams)
	{
		ParamExternData *prm;
		ParamExternData prmdata;

		/* give hook a chance in case parameter is dynamic */
		if (paramInfo->paramFetch != NULL)
			prm = paramInfo->paramFetch(paramInfo, paramId, false, &prmdata);
		else
			prm = &paramInfo->params[paramId - 1];

		if (OidIsValid(prm->ptype) && !prm->isnull)
		{
			/* safety check in case hook did something unexpected */
			if (prm->ptype != REFCURSOROID)
				ereport(ERROR,
						(errcode(ERRCODE_DATATYPE_MISMATCH),
						 errmsg("type of parameter %d (%s) does not match that when preparing the plan (%s)",
								paramId,
								format_type_be(prm->ptype),
								format_type_be(REFCURSOROID))));

			/* We know that refcursor uses text's I/O routines */
			return TextDatumGetCString(prm->value);
		}
	}

	ereport(ERROR,
			(errcode(ERRCODE_UNDEFINED_OBJECT),
			 errmsg("no value found for parameter %d", paramId)));
	return NULL;
}

/*
 * search_plan_tree