Is MODE_LOTSIZE in units of ???

 

Using MetaTrader, I get the following mini account information from my broker:

accountLeverage = AccountLeverage(); // value = 200

modeLotSize = MarketInfo("EURUSDm", MODE_LOTSIZE); // value = 10000

modeLotSize2 = MarketInfo("GBPJPYm", MODE_LOTSIZE); // value = 10000

modeLotStep = MarketInfo("EURUSDm", MODE_LOTSTEP); // value = .01

modeMinLot = MarketInfo("EURUSDm", MODE_MINLOT) ); // value = .01

In the data above, MODE_LOTSIZE specifies the size of 1.0 lot ( 1 contract ) in this mini account as 10,000 "units" of the base currency.

QUESTION: What is a unit? Why are EURUSD and GBPJPY both 10000 units?

 
Because the lot size is always in the base currency, e.g. EUR for EURUSD and GBP for GBPJPY. But if your account's currency is USD then the lot size in your account's currency will be different for both EURUSD and GBPJPY and will depend on the related exchange rates even though MODE_LOTSIZE is 10000.
Reason: