ConnectEx fails

Richard Andrew x64

The documentation says that when you call ConnectEx, the socket must be already bound. The connect function binds the socket for you. That must be why connect succeeds when ConnectEx fails.

followait

tried, still not work

int main()
{
WSADATA wsa;
int res = WSAStartup(MAKEWORD(2,2), &wsa);
assert(res==0);

SOCKADDR\_IN addr\_in;
addr\_in.sin\_family = AF\_INET;
addr\_in.sin\_addr.s\_addr = inet\_addr("127.0.0.1");
addr\_in.sin\_port = htons(5150);
ZeroMemory(&addr\_in.sin\_zero, sizeof(addr\_in.sin\_zero));

SOCKET s = WSASocket(AF\_INET, SOCK\_STREAM, IPPROTO\_TCP, NULL, 0, 0);
assert(s!=INVALID\_SOCKET);
SOCKADDR\_IN addr\_in\_local;
addr\_in\_local.sin\_family = AF\_INET;
addr\_in\_local.sin\_addr.s\_addr = INADDR\_ANY;
addr\_in\_local.sin\_port = 0;
ZeroMemory(&addr\_in\_local.sin\_zero, sizeof(addr\_in\_local.sin\_zero));
res = bind(s, (sockaddr\*)&addr\_in\_local, sizeof(addr\_in\_local));
assert(res==0);

//prepare function
{
	DWORD dwBytes;
	int res = WSAIoctl(s,
		SIO\_GET\_EXTENSION\_FUNCTION\_POINTER,
		&GuidConnectEx,
		sizeof(GuidConnectEx),
		&g\_lpfnConnectEx,
		sizeof(g\_lpfnConnectEx),
		&dwBytes,
		NULL,
		NULL);

	int err = WSAGetLastError();

	assert(res==0);
}	

DWORD bytes\_sent;
BOOL ok = (\*g\_lpfnConnectEx)(s, (sockaddr\*)&addr\_in, sizeof(addr\_in), NULL, 0, &bytes\_sent, NULL);
int err = WSAGetLastError();
assert(ok);
//int ok = connect(s, (sockaddr\*)&addr\_in, sizeof(addr\_in));
//assert(ok==0);

for (int i=0; i<10; ++i)
{
	char buf\[256\];
	sprintf\_s(buf, sizeof(buf), "message %d", i);
	WSABUF wsa\_buf;
	wsa\_buf.buf = buf;
	wsa\_buf.len = strlen(buf);
	DWORD bytes\_sent;
	int res = WSASend(s, &wsa\_buf, 1, &bytes\_sent, 0, NULL, NULL);
	assert(res==0 && bytes\_sent==wsa\_buf.len);
	printf\_s("sent: %s\\n", buf);
	Sleep(1000);
}

WSACleanup();

return 0;

}

Lost User

followait wrote:

tried, still not work

What does this mean? Please explain which part of the program does not work, what results you receive, what messages you see, what error codes are returned. We cannot guess what happens by looking at your source code.

It's time for a new signature.

followait

As he suggests, bind the socket used by ConnectEx, but still can't connect successfully.

Lost User

followait wrote:

but still can't connect successfully.

Did you actually read my previous post? What is the error code returned when your connect call fails?

It's time for a new signature.

followait

sure, the error code of ConnectEx is 87, it means "The parameter is incorrect.".

Lost User

followait wrote:

the error code of ConnectEx is 87, it means "The parameter is incorrect.".

OK, so check all your parameters and make sure that they contain values appropriate to the call.

It's time for a new signature.

Lost User

I just took a copy of your code and ran it on my Windows 7 system and it runs fine; must be something local to you. [edit]Actually no it didn't, I had to change a couple of things and misread a fail status. I will test some more tomorrow in the absence of a solution.[/edit]

It's time for a new signature.

modified on Saturday, August 7, 2010 1:05 PM

Luc Pattyn

followait wrote:

BOOL ok = (*g_lpfnConnectEx)(s, (sockaddr*)&addr_in, sizeof(addr_in), NULL, 0, &bytes_sent, NULL);

Now what would be the most fishy aspect of that statement? You should realize that for every cast the programmer takes the responsibility away from the compiler; you are simply passing a SOCKADDR_IN thingy and casting it to something else (a sockaddr) in order to make the compiler happy. However if they aren't compatible, that will not work out at run-time. So back to the documentation and the drawing board. :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum

Please use <PRE> tags for code snippets, they preserve indentation, and improve readability.

Lost User

Well, I went and did what I should have done in the first place and looked here[^] at the MSDN documentation. Take a look at the final parameter lpOverlapped which must not be NULL, and compare with your code.

It's time for a new signature.

followait

Fine, it is the reason why it doesn't work. So ConnectEx works only in asynchronous mode, doesn't it? Thanks a lot.