how can i know that my LAN is working or not

jsulm

@victor-wang Even better is http://doc.qt.io/qt-5/qiodevice.html#errorString

victor wang

@jsulm
You mean change like this?
If not where i should add this on?

I had tried it. and will show the error
"QAbstractSocket::SocketTimeoutError"

And if i use

qDebug <<socket->errorString();

It will show this error "Socket operation timed out"

jsulm

@victor-wang Yes, like this. Even better is http://doc.qt.io/qt-5/qiodevice.html#errorString

victor wang

@jsulm
I'm using port 8888.

I had tried it. and will show the error
"QAbstractSocket::SocketTimeoutError"

And i if i use

qDebug<<socket->errorString();

It will show this error "Socket operation timed out"

So is that mean i had set the time too long?

victor wang

@the_
My code is too long.
I'm using qtcreator via Xming.
So i can't copy my code, i just can type it.
And because of there are too many codes i have no time to type it.
That's why i using as picture.

jsulm

@victor-wang said in how can i know that my LAN is working or not:

So is that mean i had set the time too long?

No, it means that it was not possible to connect in that time.
You're doing it wrong. Please read documentation (http://doc.qt.io/qt-5/qabstractsocket.html#connectToHost): hostName is a URL not IP.
If you want to use IP then use http://doc.qt.io/qt-5/qabstractsocket.html#connectToHost-1

victor wang

@jsulm
Ok, i see.
Now i tried to connect to the IP 192.168.120.115 like here

And i print the error out shows "Connection refused"
Is that because this IP address need the password to enter it?

If it is, what should i do to solve this problem?

jsulm

@victor-wang You're still doing it wrong. Please read documentation - I posted the links.
If you want to use IP address you need to pass http://doc.qt.io/qt-5/qhostaddress.html as parameter not a string.

victor wang

@jsulm
Is that mean i have to set address first like this?

hostaddress->setAddress(192.168.120.115);

Then connect it like this?

socket->connectToHost(hostaddress,PT_lanHostPort);

Is that right?

jsulm

@victor-wang Yes

socket->connectToHost(QHostAddress("192.168.120.115"), PT_lanHostPort);

Why do you allocate everything on the heap with new? hostaddress can be just a local variable:

QHostAddress hostaddress("192.168.120.115");
socket.connectToHost(hostaddress, PT_lanHostPort); // No need to allocate socket on the heap with new as well!

victor wang

@jsulm
Sorry, i'm new in Qt.Please be patient to me :)
This is my code here

It still print "connection refused".

Why will it refused to connect?

"192.168.120.115" this is an IP which is a server and i need password and user to login.
Is this a factor that cause the error?

jsulm

@victor-wang It is not a Qt thing, it is C++.
It should actually work even if authentication is required. Is port number correct? Can you ping this IP?

victor wang

@jsulm
I'm sure that i can ping this IP address!
But i don't know how to check the port number.

jsulm

@victor-wang Well, you should know on which port your server is listening.

the_

@victor-wang

A socket connection to the server is always possible, even if you need a username and a password to authenticate for using its service.
In case you do not provide any login data or incorrect login data the server is still responding to your request.

What kind of service is running on this host?
How do you usually connect to this host?

victor wang

@jsulm

Is there any way that i can know the port it is listening?

@the_
It is linux on it.
i will connect it through PUTTY.

jsulm

@victor-wang Check your server configuration. How, depends on what server it is (Apache, NGNX,...). Or ask the people who manage the server.

victor wang

@jsulm
I've change the port and it success!
Thank you so much !
I think i need to practice more.

jsulm

@victor-wang Good!
And don't forget to read documentation :-)

Julian Guarin

@jsulm You are a patience ninja and a Gentleman. Great to see still people like you in these forums!!!