Programming to place Limit Order

[javadepro]

Hi,
I am using java as a programming language to be integrated with TWS API. I need a help for placing Limitorder through the program. I saw the method in ElientSockets.java

public synchronized void placeOrder( int id, Contract contract, Order order)

But am not able to use it. In the API documentation it says the following parameters
1. action
2. totalQuantity
3. m_orderType
4. m_lmtPrice
5. m_auxPrice

I understood the parameters from 1 to 4 but I am not able to get what's auxPrice.. I am in urgent need of this. Can anyone provide me suggestion or tips please?

Thanks in advance!!

cheers,