Datasocket connection check

Question

Hello,
I have created a simple application that reads datasockets from datasocket server using Measurement Studio for C++. Here is the piece of my code:
code DSRead::Connect(char* url)
m_DataSocket.InstallEventHandler(*this, &DSRead:ataUpdatedEventHandler);
m_DataSocket.InstallEventHandler (*this, &DSRead:tatusUpdatedEventHandler);
CNiString targetURL = url; 
m_DataSocket.Connect(targetURL, CNiDataSocket::ReadAutoUpdate);
MSG msg; 
do
while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
TranslateMessage(&msg);
DispatchMessage(&msg);
connectionStatus = m_DataSocket.Status;
while ((connectionStatus != CNiDataSocket::ConnectionError)
&& (connectionStatus != CNiDataSocket::Unconnected));
if (connectionStatus == CNiDataSocket::ConnectionError)
return CONNECTIONERROR;
return OK;
In DataUpdatedEventHandler function I process received data.
The do-while construction is used because the CNiDataSocket Connect function requires that application processes Windows messages while the DataSocket is connecting (as is explained in this post).
This works fine while connection to the datasocket server is alive. However, when connection is lost, nothing is changed. I mean,  m_DataSocket.IsConnected() is still true and connectionStatus is still CNiDataSocket::ConnectionActive. Moreover, if connection to DataSocket server reappears, the data is still not retrieved. 
The question is: How can loss of connection be detected in this case?
I have a feeling, that some windows functions should be used, but I failed to find answer in internet.

Answer 1

Hi Josh,
Thank you for the reply. These two links, as far as I understand, are about Windows socket connection issue rather than DataSocket connection issue. Of course, one solution to this problem is to periodically send winsocket echo requests to DS server, but I believe it is not the optimal one.
Probably I have explained the problem ambiguously.
I will try to explain again, taking as an example "Simple DataSocket" project from "Visual C++ Examples" of Measurement Studio. In this example there are 3 actors: Writer, DS Server and Reader. I have a virtual machine which is connected to host in "host only" mode and has ip address 192.168.7.29. The only thing I change in the code of "Simple DataSocket" example is url: I change "dstp://localhost/wave" to "dstp://192.168.7.29?/wave" for both Reader and Writer.
Then I launch Reader and Writer in 2 scenarios:
1) I launch Writer, DS Server and Reader on virtual machine. Reader and Writer operate successfully: Writer writes data to DS server, Reader reads data. Both statuses are "Active:Connected".
Then I disable network adapter of virtual machine. As is expected, we have an error both for Writer and Reader:
2) I launch Writer and DS Server on virtual machine, and I launch Reader on the host. Reader and Writer also operate successfully: statuses are "Active:Connected". But if I disable network adapter of virtual machine, then the situation is different from first scenario:
I.e., Writer detects network disconnection, while Reader is still "Active:Connected", while really it isn't. As I have already written, m_DataSocket.IsConnected() property is also true.
The similar problem arises even if there is no virtual machine: when Writer and DS Server are on host A and Reader is in host B and if I unplug network cable for host A. Then again Reader cannot detect connection fail.
Basically the question is: how automatically it is possible to detect fail of connection in such situations?
I will explain why I ask this question. I have a simulation program that generates data and publishs it to DS Server (both are located on virtual machine). I also have Reader application located on host. I simulate network fail by disabling network adapter for virtual machine. I want Reader to automatically detect network fail and generate an error. As I have explained above, currently Reader does not detect it.