Signal can't be emitted !

[Vladimir_]

Hello,

file1.h

class MyServer : public QTcpServer
{
    Q_OBJECT
 
.... // some code
 
signals:
    void _connection(int);
 
.... // rest of the code

class MyServer : public QTcpServer
{
    Q_OBJECT

.... // some code

signals:
    void _connection(int);

.... // rest of the code

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file1.cpp

void MyServer::incomingConnection(int handle)
{
    MyClient *client = new MyClient(this);
    client->setsocket(handle);
    emit _connection(handle); // i emit it here
}

void MyServer::incomingConnection(int handle)
{
    MyClient *client = new MyClient(this);
    client->setsocket(handle);
    emit _connection(handle); // i emit it here
}

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file2.h

#include "file1.h"
class Blabla: public QObject
{
    Q_OBJECT
 
... // code here
 
private:
    MyServer *server;
 
... // rest of code

#include "file1.h"
class Blabla: public QObject
{
    Q_OBJECT

... // code here

private:
    MyServer *server;

... // rest of code

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file2.cpp

server = new MyServer;
 
    connect(server,SIGNAL(_connection()), this, SLOT(connected())); // the slot is declared in the code

server = new MyServer;

    connect(server,SIGNAL(_connection()), this, SLOT(connected())); // the slot is declared in the code

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The issue:
----------
The signal is not emitted within the incoming connction.

The question:
-------------
Why ?


Thanks,
Vladimir.

[ChrisW67]

The code is never called. You are not running the code you think you are. You have not connected to the signal or object you think you have. There is no incoming connection, perhaps blocked by a firewall. Etc.

What have you done to debug this? Put a breakpoint in the routine? Single stepped?

[Vladimir_]

there's an incoming connection,

void MyServer::incomingConnection(int handle)
    {
    MyClient *client = new MyClient(this);
    client->setsocket(handle);
    QMessageBox::information(0, "connected", "new client"); // this runs, so the function worked.
    emit _connection(handle); // i emit it here
    }

void MyServer::incomingConnection(int handle)
    {
    MyClient *client = new MyClient(this);
    client->setsocket(handle);
    QMessageBox::information(0, "connected", "new client"); // this runs, so the function worked.
    emit _connection(handle); // i emit it here
    }

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the incomingConnection() is written in italic in the QtCreator. it's already coded.

here's a proof that the code worked:
000000000000000000000000000000000000000000000000000000000.png

but the signal is never emitted.

[wysota]

How do you know the signal is not emitted? Maybe a more appropriate topic to your problem would be "slot is not called" rather than "signal is not emitted"? Can you call connected() using e.g. invokeMethod()? Do the sender and receiver belong to the same thread?

[Vladimir_]

I used another signal, and the slot is called.

So i made sure that the slot has no issues .

[wysota]

Is the connection established properly? Does connect() return true? Do you get any messages, warnings on the console when your program is running?

[Vladimir_]

no messages or warnings at all !

the connection istablished well, and i even get the sent data via QByteArray and display it in QMessageBox.

only this can't be emitted !!

[wysota]

no messages or warnings at all !

I'm sure you are wrong about this. Maybe you are looking in the wrong place. We are talking about a runtime message to the console, not a warning during compilation.

the connection istablished well

Does connect() return true? I don't think so.

[Vladimir_]

connect() returns 0 , means "false" ....

What an I do now ?!

i posted all the codes I did, i need it working

The signal is not emitted because it does not exists.

see file1.h and file1.cpp .

what do you mean it does not exist ?

[Lesiok]

1. Is the class with method connected() derived from QObject ?
2. Is the method connected declared as slot ?

[anda_skoa]

file2.cpp

server = new MyServer;
 
    connect(server,SIGNAL(_connection()), this, SLOT(connected())); // the slot is declared in the code

server = new MyServer;

    connect(server,SIGNAL(_connection()), this, SLOT(connected())); // the slot is declared in the code

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The issue:
----------
The signal is not emitted within the incoming connction.

The signal is not emitted because it does not exists.

The application output would have told you that (Qt prints a warning) and the return value of the connect would have been "false".

Look at the content of the SIGNAL macro and the declaration of the signal and find the difference.

Cheers,
_


P.S.: unless you need SSL sockets, there is no need to derive from QTcpServer. I has a signal that is emitted for each incoming connection.