Function ExecEvalFuncExprStrictFusage

src/backend/executor/execExprInterp.c:2450–2479

* Evaluate EEOP_FUNCEXPR_STRICT_FUSAGE */

 * Evaluate EEOP_FUNCEXPR_STRICT_FUSAGE
 */
void
ExecEvalFuncExprStrictFusage(ExprState *state, ExprEvalStep *op,
							 ExprContext *econtext)
{

	FunctionCallInfo fcinfo = op->d.func.fcinfo_data;
	PgStat_FunctionCallUsage fcusage;
	NullableDatum *args = fcinfo->args;
	int			nargs = op->d.func.nargs;
	Datum		d;

	/* strict function, so check for NULL args */
	for (int argno = 0; argno < nargs; argno++)
	{
		if (args[argno].isnull)
		{
			*op->resnull = true;
			return;
		}
	}

	pgstat_init_function_usage(fcinfo, &fcusage);

	fcinfo->isnull = false;
	d = op->d.func.fn_addr(fcinfo);
	*op->resvalue = d;
	*op->resnull = fcinfo->isnull;

	pgstat_end_function_usage(&fcusage, true);
}

/*
 * Evaluate a PARAM_EXEC parameter.