txid_snapshot_out(PG_FUNCTION_ARGS)
{
	TxidSnapshot *snap = (TxidSnapshot *) PG_GETARG_VARLENA_P(0);
	StringInfoData str;
	uint32		i;

	initStringInfo(&str);

	appendStringInfo(&str, TXID_FMT ":", snap->xmin);
	appendStringInfo(&str, TXID_FMT ":", snap->xmax);

	for (i = 0; i < snap->nxip; i++)
	{
		if (i > 0)
			appendStringInfoChar(&str, ',');
		appendStringInfo(&str, TXID_FMT, snap->xip[i]);
	}

	PG_RETURN_CSTRING(str.data);
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.