Use DDE to retrieve values

[machok]

Hello to all.
I would like to communicate with an application using DDE. I tried with Excel by entering a formula "= app | topic_ Name" and it works very well.

I tried under Visual C + + express but I have not succeeded.

char * szApplication = "app";  
      char * szTopic = "TOPIC";  
      ATOM atomApplication = * szApplication == 0?  
		  NULL: GlobalAddAtom (szApplication);  
	  ATOM atomTopic = * szTopic == 0?  
		  NULL: GlobalAddAtom (szTopic);  

	  printf ( "Sending message ... \ n"); 
	  SendMessage (HWND_BROADCAST, 
		  WM_DDE_INITIATE, 
		  (WParam) NULL, 
		  MAKELONG (atomApplication, atomTopic)); 

	  printf ( "message sent \ n"); 

      if (atomApplication! = NULL)  
          GlobalDeleteAtom (atomApplication);  
      if (atomTopic! = NULL)  
          GlobalDeleteAtom (atomTopic); 


	  printf ( "Waiting for a message \ n"); 
	  MSG message; 
	  GetMessage (& message, 
		  NULL, 
		  0, 
		  0); 
          printf ( "Message received \ n");

Sending the message seems to be OK but I do not get any response.
If someone sees an error in my program or an example (simple) to use DDE in C it would be nice.

Thank you

[Mecurtis]

This is normal you do not loop until the message!
You call the getMessage but he spends it on something else!
If the DDE link in Excel takes a few ms and more you will receive nothing
So the basic solution is to make a timer, and looping over getMessage with a timeout value
Something more sophisticated would be a thread

Looking at the MSDN help on getMessage.

GetMessage Function


The getMessage function retrieves a message from the calling thread's message queue. The function dispatches incoming sent messages until a posted message is available for retrieval.

Unlike getMessage, the PeekMessage function does not wait for a message to be posted before returning.


An application typically uses the return value to determine whether to end the main message loop and exit the program.

[machok]

You call the getMessage but he spends it on something else!

Thank you for your answer but getMessage is blocking:

Unlike getMessage, the PeekMessage function does not wait for a message to be posted before returning.

In fact, I put a printf after getMessage and the program gets stuck on getMessage, therefore I do not get any message.

[Khushal]

Hi this prehistoric DDE is better to use COM, you can create a link OLE Automation / COM Excel to read / write to an Excel file
Otherwise I think it works better in the loop of messages from the application process messages DDE.

What type of project? win32 console UI?