So I'm trying to determine the range of the previous candle using priceHigh(1)-priceLow(1). I also figured I'd query the priceHigh(1) and priceLow(1) functions themselves. This is a sample of what I get for the AUD/USD pair on 5 min bars.

PreviousCandleRange 0
PreviousCandleHigh -1073741824
PreviousCandleLow 1073741824
PreviousCandleRange 0
PreviousCandleHigh -1073741824
PreviousCandleLow -2147483648
PreviousCandleRange 0

Now I'd expect a range of say 10 pips and priceHigh to be something like .7000 and priceLow to be something like .6990, not the massive numbers listed here.

Not enough information. Can you post your code?

printf("\nPreviousCandleHigh %1d", priceHigh(1));
printf("\nPreviousCandleLow %1d", priceLow(1));
printf("\nPreviousCandleRange %1d", (priceHigh(1)) - (priceLow(1)));

Dammit now I can see the problem. Use "f" not "d"