NTDirect.dll Orders() function

[Jaba1n]

Hello

I'm trying to build a simple test app in VB6 using NTDirect.dll, and I'm having trouble with the Orders, and OrderStatus functions. The other functions work ok.

Here are the snippets:

Private Declare Function Orders Lib "NTDirect.dll" (ByVal acct As String) As String

then I run the following from button_click()

Text1.Text = Orders("sim101")

The text1.text becomes empty. The app is connected, and, I can read the MarketPosition, MarketData just fine. I suspect it's something about the differences in how VB and C treat strings. Can anyone help please? Thanks in advance.
J

[NinjaTrader_Bertrand]

Hi Jaba1n, we could unfortunately not really support coding at that level, but from a quick glance - can you please try with Text1.Text = Orders("Sim101")

[Jaba1n]

Hi Bertrand

Thank you for your reply. Yes, I tried Sim101, no luck. It simply doesn't return anything. The open orders are in the account, I made some transactions previously too. Thanks again.

J

[NinjaTrader_Bertrand]

From where did you submit the orders to the Sim101 account? From your external application or within NT only?

[Jaba1n]

I tried both.

Are you saying that Orders() will return only the orders sumbitted by the external app? If so, how do I get all open orders, including those submitted by NT, or the broker app?

Thanks
J

[NinjaTrader_Bertrand]

Conceptually it should be working bidirectional - having tried as well passing in an empty account, so it would use the default ATI account set under Tools > Options > ATI?

[Jaba1n]

I tested the empty string, as you suggested, Orders(""). unfortunately I got the same results. Sim101 is set as the default account.

Maybe I should pass a pointer to a string buffer to the Orders() call if the NtDirect.DLL was written in C? http://support.microsoft.com/kb/187912

Thanks
J

[NinjaTrader_Bertrand]

Jaba1n, certainly worth a try from the doc you linked us to. Would you mind contacting me directly at support at ninjatrader dot com with the project you have thus far so I could give a run here?

Thanks,

[Jaba1n]

Email with attachment sent. Thanks a lot.

J

[N4Apound]

Hello,
Bertrand, can you or Jaba1n share the resolution of this issue?

What are the specifications for the string parameters that the NTdirect.dll functions are expecting:
1) Address of Null-terminated ASCII string (as per C)?
2) Address of handle of dynamic string?
3) Unicode variation of either of the above?
4) other?

For me, the Connect function works fine (toggles correctly with AT enable), but I cannot get the other functions to work and I think it's the strings.

Thanks,
N4

[NinjaTrader_Brett]

Hello,

I will ask Bertrand to see if he can recall the resolution. He will get into the office tomorrow morning.

As far as an outright answer we are not c or C++ programmers and work primary in c#. Therefor you may be on to something here, unfortunately I would just need to try a few configurations until I got it working. We use the c# string class for all of our strings in NinjaScript.

-Brett

[N4Apound]

Hi Brett,
Thanks for your fast reply.

It seems to work for me now when I pass the strings (dynamic ASCII) as BYVAL.
As I understand it this makes a copy of the string, and passes the new string handle to the DLL.

However, for those DLL functions that return as a string, they appear to pass back a pointer to a null-terminated ascii string.

After decoding this, all seems to work well now and I REALLY like the clean and simple DLL interface.

Best regards,
N4

[Jaba1n]

N4Apound, could you post the code that worked for you, please? I kind of gave up on VB for this reason, and started coding in C#. Your code would be beneficial for the NT community, I believe. Thanks in advance.

J

[N4Apound]

Hi Jaba1n,
I am using PowerBasic not VB. There should be VB equivalents to the following PB implementation but I haven't tried that.

For the NtDirect.dll function declarations, I did the following:
1) All string parameters passed in the DLL functions must have "BYVAL" added in the declares.
2) All DLL functions returned as strings should be changed to DWORDs, for pointers to null-terminated (fixed length) ascii strings.

Examples of DLL function declares:

DECLARE FUNCTION NTNewOrderId IMPORT "NtDirect.DLL" ALIAS "NewOrderId" () AS DWORD '(was STRING)
 
DECLARE FUNCTION NTOrders IMPORT "NtDirect.DLL" ALIAS "Orders" (BYVAL account AS STRING) AS DWORD '(was STRING)
 
DECLARE FUNCTION NTRealizedPnL IMPORT "NtDirect.DLL" ALIAS "RealizedPnL" (BYVAL account AS STRING) AS DOUBLE

Example of usage:

    LOCAL sNTorderId AS STRINGZ * 256
    LOCAL ptrNTorderId AS STRINGZ POINTER
    ptrNTorderId = NTNewOrderId()
    sNTorderId = @ptrNTorderId
    IF sNTorderId = "" THEN sErrText = FUNCNAME$ & " Error: NTNewOrderId() failed." : AbortFlag = %TRUE : GOTO ErrorTrap
 
    LOCAL sNTaccountName AS STRING
    sNTaccountName = "Sim101"
    LOCAL dblNTPnL AS DOUBLE
    dblNTPnL = NTRealizedPnL(sNTaccountName)
    MSGBOX "NT PnL =" & STR$(dblNTPnL)