Re: socket communication: socket doesn't connect

Thanks! I just had to change the order of things:
Still first the C++ program brings up the Java program with ShellExecEx.
Then the C++ program constructs the Server.
Then the Java program constructs the Client and send some items.
Then the C++ program accepts and tries to receive the items.

Now the Server constructs and accepts.

However I just accomplished this in the debugger, because I was able to stop
the C++ program before it accepts and cause the Java program to first
construct the Client and send the items, which in my case has to happen when
the Java program gets closed.

I only have two communications between my C++ program and my Java program.
To make this clear, let me explain again what my C++ and Java programs do.
My Java program draw curves and my C++ program makes it a plugin to Photoshop
bringing up its own window. The first communication I need is to bring the
image and the workpath from Photoshop into my Java program. And the second
communication I need is to bring the curves of my Java program back to
Photoshop.

So my final question here is, how can I program my C++ so that after
constsructing the Server it waits until the Java Client is created and some
Java communication has been sent before it tries to accept? Does
WSAEventSelect help with that? But how is this done?

Thanks for your patience with me!


"Dave Lowther" wrote:

so why did it not connect?

Your server has to be running for client to be able to connect, but if your
server stops running on error 10035 from accept, then it won't be running
when you try to connect from your client.

"Ananya" <Ananya@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:BB5AE518-4724-4E8E-822D-BD8B9E060A75@xxxxxxxxxxxxxxxx
Well, I did call the constructor of the Client in Java:

public Client(int p, InetAddress address, int rev) throws IOException,
IllegalArgumentException
{
port = p;

try
{
sock = new Socket(address, port);
input = new BufferedInputStream(sock.getInputStream(), BUFFSIZE);
output = new BufferedOutputStream(sock.getOutputStream(), BUFFSIZE);
}
catch (IOException e)
{
}
catch (IllegalArgumentException ie)
{
}

buff = new byte[BUFFSIZE];
data = new byte[BUFFSIZE];

output.write(rev);
output.flush();
}

so why did it not connect?


"Dave Lowther" wrote:

10035 = A non-blocking socket operation could not be completed
immediately.

So it's not really an error.

If you want accept() to block until a client connects, then don't put the
socket in non blocking mode.

If you want to poll accept(), then 10035 is to be expected if no client
has
connected since last time you called accept().

HTH

Dave.

"Ananya" <Ananya@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:978D94FD-0194-474E-B00C-A85452EF0AE2@xxxxxxxxxxxxxxxx
Thanks for your response!

Ok, now in my connectServer method I am no more calling the connect
method,
but I am calling the accept method from WinSock2.h. Well, the accept
method
also returns -1.

Before calling the accept method, WSAGetLastError() returns 0, and
afterwards it returns 10035.

Please help!

"Michael K. O'Neill" wrote:

"Ananya" <Ananya@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:6E597362-E344-4299-84DE-91835941DC4A@xxxxxxxxxxxxxxxx
I originally published my question with the title above in the
Visual Tools & Languages > C/C++ & Visual C++ > vc.language forum at


http://msdn.microsoft.com/newsgroups/default.aspx?&guid=&sloc=en-us&dg=microsoft.public.vc.language&p=1&tid=e730aa77-f91f-41f4-9c1f-12a17efbcc97

and I was told that it really belongs here. So here it is again:

I am trying to establish socket communication between my C++ and
Java
program.

I bring up the Java program from the C++ program with ShellExecEx.

Then I start in the Java program with:
int port = 3000;
int rev = 1;
InetAddress address = InetAddress.getLocalHost();
Client client = new Client(port, address, rev);
int[] ints = new int[1];
ints[0] = 1;
client.send_ints(ints, 1);
client.closesocket();
using my Java Client class.

Then I continue in my C++ program with:
int port = 3000;
Server* server = new Server(port);
server->connectServer();
using my C++ Server class.

It looks like the server gets constructed properly and the
connectServer
method calls the connect method from WinSock.h, which I have
included
(and
its library WSock32.Lib is at Additional Dependences in the Input of
the
Linker).

Why does this connect method from WinSock.h return - 1?

< snip >

To determine why connect() is failing, call WSAGetLastError() and tell
us
its value. It might be something like WSAENOTSOCK or
WSAENOTINITIALISED

You explanation reverses the "typical" roles of client and server. In
a
typical scenario, it's the client that calls connect() to connect to
the
server, whereas in your example, it's the server that's calling
connect()
to
connect to the client. Was that intentional? Frankly, since your C++
Server class is apparently calling bind() and listen(), the Java
client
should be the one calling Connect(), and your C++ server should be
accepting
these connections by calling accept().

Mike









.

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