hstore_skeys(PG_FUNCTION_ARGS)
{
	FuncCallContext *funcctx;
	HStore	   *hs;
	int			i;

	if (SRF_IS_FIRSTCALL())
	{
		hs = PG_GETARG_HS(0);
		funcctx = SRF_FIRSTCALL_INIT();
		setup_firstcall(funcctx, hs, NULL);
	}

	funcctx = SRF_PERCALL_SETUP();
	hs = (HStore *) funcctx->user_fctx;
	i = funcctx->call_cntr;

	if (i < HS_COUNT(hs))
	{
		HEntry	   *entries = ARRPTR(hs);
		text	   *item;

		item = cstring_to_text_with_len(HS_KEY(entries, STRPTR(hs), i),
										HS_KEYLEN(entries, i));

		SRF_RETURN_NEXT(funcctx, PointerGetDatum(item));
	}

	SRF_RETURN_DONE(funcctx);
}

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