Upside could be you come accross people who can contribute to your work. There are some veteran programmers here - to name but one: Edward - chances are he could give you a few tips on how not to flood the server.

Do you care to explain this:

<i>The potential downside, however, is large, for reasons people who have seen dealing desks being operated physically would know</i>

You mean you could get hosed by the broker if they knew your trading?

Either way, I'm interested in how dealing desks are being operated ... if you could share this information ... thanks.

You see? Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you.
Without looking at the ForexFactory link, here's a tip:
(it's on the page 4 in the <i>'Teach yourself MQL4 in 21 days'</i> ebook) always use NormalizeDouble.
Never worked with floating point numbers before?

My friend if you do some binary / floating point arithmetics by hand (on paper), you'd know it's possible that for example, OrderStopLoss returns 1.234500000000 while the result of <i>OrderOpenPrice() - StopLoss * Point</i> would be 1.234500000074857485 something. That's the way floating point numbers work. I wouldn't say it's a bug or a feature, anyway if you use Normalize, you can get what you want without the fuss. But I'm not the sharpest knife in the cupboard ... maybe Edward can give you a better explanation.

speki posted:
    My friend if you do some binary / floating point arithmetics by hand (on paper), you'd know it's possible that for example, OrderStopLoss returns 1.234500000000 while the result of <i>OrderOpenPrice() - StopLoss * Point</i> would be 1.234500000074857485 something. That's the way floating point numbers work. I wouldn't say it's a bug or a feature, anyway if you use Normalize, you can get what you want without the fuss.


I have to elaborate, immediately after my OrderSend, I successfully OrderModify by
OrderModify(OrderTicket(),OrderOpenPrice(),OrderOpenPrice()-StopLoss*Point,0,Red)

Notice no NormalizeDouble.

When I perform a check as in my previous post:
if(OrderStopLoss()!=(OrderOpenPrice()-StopLoss*Point))
OrderModify(OrderTicket(),OrderOpenPrice(),OrderOpenPrice()-StopLoss*Point,0,Red); //for buy orders
}

I get the OrderModify Error#1 that can only be resolved by writing this:
if(OrderStopLoss()!=(OrderOpenPrice()-StopLoss*Point))
OrderModify(OrderTicket(),OrderOpenPrice(),NormalizeDouble(OrderOpenPrice()-StopLoss*Point,Digits),0,Red); //for buy orders
}

Why would OrderStopLoss()!=OrderOpenPrice()-StopLoss*Point return true? It doesn't make any logical sense.

To be forced to use a NormalizeDouble is sloppy but I'm sure Metaquotes has their reason. Note that this issue was addressed by bugfixes in several MT4 releases but it clearly isn't not resolved completely. It should be better documented on their site.

And generally, rounding numbers before calculations are made gets ultimately the wrong answer, particularly with numerous calculations.

To summarise:

OrderStopLoss = A
OrderOpenPrice = B
StopLoss*Point=C

A=B-C

if(A is not equal to B-C) <b>make</b> A equal to B-C
test if A is now equal to B-C

OrderModify Error#1
OrderModify Error#1
OrderModify Error#1
OrderModify Error#1
...
..
.
*faint*

The point I would like to make is that OrderStopLoss() and OrderOpenPrice() are calculated differently by MT4. I do understand the computational limits of floating point numbers, but thank you for the links nonetheless, they are interesting and useful reads.

And you must understand it from my perspective when I first came across it, I didn't know it could be resolved by rounding. I thought it was an OrderModify problem and I scratched my head for a whole day reworking the OrderModify itself. I suspect comic relief from a coding angle is rather dry for most people so I'll leave it as that. Thanks for discussing though.