I am a bit confused about the volume param in the PositionOpen function https://www.mql5.com/en/docs/standardlibrary/tradeclasses/ctrade/ctradepositionopen
The function definition does not give you any info on it, so I do not know what the volume is based on but I am guessing that it means how many lots, so 1 is one lot. And if that is the case, is there a way of finding out the lot size programmatically? Also, is it possible to open positions with a fraction of a lot like 0.7 ?
Ideally what I am really looking for is a way to open positions based on how much money I want to invest and with how much margin in the simplest way possible.
Thanks in advance for the help.