Clarion DDE link to MT4

1

Has anyone a simple example of using dde? I do not need to do any sort of execution in excel or similar.
Just read some data from a server. The server in this case is an old program for trading forex (MT4). The exefile’s name is terminal.exe and I am just going to read some values from the program. I will use a timer to update the window/link.
I have source code in VB6/Delphi where this is easily implemented, but I would like to do it in Clarion.

VB code:

Qte:

Private Sub TimerCheckBrowsers_Timer()
    On Error GoTo err1
    TxtDDE(0).LinkTopic = "MT4|BID"
    TxtDDE(0).LinkItem = Combo1.Text
    TxtDDE(0).LinkMode = 1
    TxtDDE(0).LinkRequest
    
    TxtDDE(1).LinkTopic = "MT4|ASK"
    TxtDDE(1).LinkItem = Combo1.Text
    TxtDDE(1).LinkMode = 1
    TxtDDE(1).LinkRequest
    
    TxtDDE(2).LinkTopic = "MT4|HIGH"
    TxtDDE(2).LinkItem = Combo1.Text
    TxtDDE(2).LinkMode = 1
    TxtDDE(2).LinkRequest

    TxtDDE(3).LinkTopic = "MT4|LOW"
    TxtDDE(3).LinkItem = Combo1.Text
    TxtDDE(3).LinkMode = 1
    TxtDDE(3).LinkRequest

    TxtDDE(4).LinkTopic = "MT4|TIME"
    TxtDDE(4).LinkItem = Combo1.Text
    TxtDDE(4).LinkMode = 1
    TxtDDE(4).LinkRequest
   
   Exit Sub
err1:
    TxtDDE(0).Text = "N/A"
    TxtDDE(1).Text = "N/A"
    TxtDDE(2).Text = "N/A"
    TxtDDE(3).Text = "N/A"
    TxtDDE(4).Text = "N/A"
    

End Sub

Unqte

Suggestions?

I have tried the dde example that ships with Clarion, but has not been able to implement it myself in my own little application

2

In C1 -C6 the Clarion IDE could be driven by DDE so you could try to find source for a Batch compiler like Gordon Smith’s or SParker’s Go To Lunch.

I found this code to export a DCT

OpenTXD = CLIP(ShortPath()) & '\~' & Clock() & '.TXD'
Glo:FileSpec = OpenTXD
REMOVE(AsciiFile)
CWServer = DDECLIENT('ClarionWin')
IF NOT CWServer
   MESSAGE('Unable to make DDE Connection to CW.|You will have to start CW.|Be sure to exit the pick screen.', |
     'CW NOT RUNNING', ICON:Hand)
   DO ProcedureReturn
END
!DDEEXECUTE(Server,'[ExportDct(MyDCT.DCT,MyTXD.TXD,0)]')
SYSTEM{PROP:DDETimeOut}=6000 
DDEEXECUTE(CWServer,'[ExportDct(' & CLIP(SHORTPATH(ImportFile)) & ',' & CLIP(OpenTxd) & ',1)]')
IF ~ERRORCODE()
    DDEClose(CWServer)
    Exit
END
DDEClose(CWServer)
MESSAGE('An error occured trying to export a dictionary:'&|
     '||DCT: '&ImportFile&|
     '|TXD: '&OpenTxd&|
     '||Error: '&ERRORCODE()&' '&CLIP(ERROR()), |
     'DDE ERROR', ICON:Hand)
DO ProcedureReturn
EXIT
3

I still havent been able to make this to work in Clarion. It seems I am not able to find the correct server.
The exefil is ‘terminal.exe’, the description in the task manager is ‘MetaTrader’. I have tried to use ‘MT4’,'terminal. and ‘MetaTrader’. Nothing works.

In my 25 year old VB6 , it works without any problems. Strange.

4

Try DDEQuery(< server > , < topic> ) to get a list of servers and topics?

Maybe WinAPI has way to ask EXE for List of Server annd Topic Names.

WinOne WINDOW,AT(0,0,160,400)
      END
SomeServer   LONG
ServerString STRING(200)
  CODE
  OPEN(WinOne)
  LOOP
   ServerString = DDEQUERY()                     !Return all registered servers
   IF NOT INSTRING('SomeApp:MyTopic',ServerString,1,1)
    MESSAGE('Open SomeApp, Please')
   ELSE
    BREAK
   END
  END
  SomeServer = DDECLIENT('SomeApp','MyTopic')    !Open as client
  ACCEPT
  END
  DDECLOSE(SomeServer)
5

In past I used DDE for other things. DDE is long unsupported protocol and it was finally stopped working from some 3 years ago, at least in my experience. Clarion can not help here, it is windows thing.

6

Carl,
I tested your code, and I inserted a message showing ‘Serverstring’ into the loop to be kept advised about dde servers running…
I tested to open/close various programs like excel, word, access etc to see how the serverstring changed. The serverstring showed these correctly.

But when I tried to open/close ‘MT4’ there was now change in the serverstring. It only showed something called ‘progman’. The ‘MT4’ is set up to act as a ddeserver, and I can as said read it with vb6 using dde.
But Clarion does not pick it up. I know DDE is old fashioned and not used much any more, but MT4 is a very widely used Forex program and many times it is used together with Excel to obtain quotes using DDE into Excel.
But no luck with Clarion, so I guess this is as far as I can get with Clarion.

7

If Clarion DDE is not working then I would resort to calling the DDE functions in the WinAPI like a C++ programmer. I did a quick search and it seems well documented. Found DdeConnectList() appears to be like DDEQuery(). I would start by trying to get that to show MT4

HCONVLIST hconvList; // conversation list 
DWORD idInst;        // instance identifier 
HSZ hszSystem;       // System topic 
HCONV hconv = NULL;  // conversation handle 
CONVINFO ci;         // holds conversation data 
UINT cConv = 0;      // count of conv. handles 
HSZ *pHsz, *aHsz;    // point to string handles 
 
	// Connect to all servers that support the System topic. 
hconvList = DdeConnectList(idInst, NULL, hszSystem, NULL, NULL); 
 
	// Count the number of handles in the conversation list. 
while ((hconv = DdeQueryNextServer(hconvList, hconv)) != NULL) 
    cConv++; 
 
	// Allocate a buffer for the string handles. 
hconv = NULL; 
aHsz = (HSZ *) LocalAlloc(LMEM_FIXED, cConv * sizeof(HSZ)); 
 
	// Copy the string handles to the buffer. 
pHsz = aHsz; 
while ((hconv = DdeQueryNextServer(hconvList, hconv)) != NULL) 
{ 
    DdeQueryConvInfo(hconv, QID_SYNC, (PCONVINFO) &ci); 
    DdeKeepStringHandle(idInst, ci.hszSvcPartner); 
    *pHsz++ = ci.hszSvcPartner; 
} 
 
	// Use the handles; converse with the servers. 
 
	// Free the memory and terminate the conversations. 
LocalFree((HANDLE) aHsz); 
DdeDisconnectList(hconvList);