Socket recvied and signal and slot

m_pahlevanzadeh

Dear all,

I wrote the following signal that it can specify socket has data or not:
@bool NetworkSocket::isDataReady()
{

/// Got here because iSelectReturn > 0 thus data available on at least one descriptor
// Is our socket in the return list of readable sockets
bool             res;
fd_set          sready;
struct timeval  nowait;

FD_ZERO(&sready);
FD_SET((unsigned int)this->socketFD,&sready);
//bzero((char *)&nowait,sizeof(nowait));
memset((char *)&nowait,0,sizeof(nowait));

res = select(this->socketFD+1,&sready,NULL,NULL,&nowait);
if( FD_ISSET(this->socketFD,&sready) )
    res = true;
else
    res = false;

if (res)
    emit createThread( );
return res;

}@

Then i wrote a slot that it work standalone and create thread:
@bool NetworkSocket::createThread()
{

bool returnValue = true ;
void * args = NULL;
pthread_t tempID;
if (!firstTime)
{   /*(void*(*)(void*))*/

/* if (pthread_create(&tempID, NULL,(void * ()(void )) &threadProcedure , (void )this) != 0)
{
//error
}
this->threadCounter++;
this->threadVector.push_back(tempID);
this->firstTime = false;/
}
else
{
/(void()(void))/
if (pthread_create(&tempID, NULL, (void()(void)) &NetworkSocket::threadProcedure , reinterpret_cast<void *>(this)) != 0)
{
//error
}

    this->threadVector.push_back(tempID);
    ++this->threadCounter;

}

    returnValue = false;
return returnValue;

}@
I put in theradProcudre a cout, and the following line in contructor:
@QObject::connect(this,SIGNAL(isDataReady()),this,SLOT(createThread( )));@
But my slot doesn't run.. what's happen?

Neutron Stein

Did you subclass QObject?
And you should call the method isDataReady().

m_pahlevanzadeh

my class definition:
@class NetworkSocket : public QObject{
Q_OBject
signals:
inline bool isDataReady();
public slots:
bool createThread();

};
@

guziemic

Hi,

You should use Q_OBJECT not Q_OBject (but this error for sure is catched at compilation time).
Next, I do not see in the code where you call

@
emit isDataReady();
@

Maybe this is a problem?

Mario84

...and Signals shouldn't have an implementation or return value!
As the name says: its just a signal, that somebody else can react to...

Neutron Stein

in your code you are emiting createThread( ) signal using @emit createThread( );@
This doesn't call the method createThread( ) but tries to emit a signal named createThread( ) which you don't have. That is why it not working.I thin you should have this
@
class NetworkSocket : public QObject{
Q_OBject
public:
bool isDataReady();
signals:
void dataReady();
public slots:
bool createThread();

};

@

@
bool NetworkSocket::isDataReady()
{

    /// Got here because iSelectReturn > 0 thus data available on at least one descriptor
    // Is our socket in the return list of readable sockets
    bool             res;
    fd_set          sready;
    struct timeval  nowait;
 
    FD_ZERO(&sready);
    FD_SET((unsigned int)this->socketFD,&sready);
    //bzero((char *)&nowait,sizeof(nowait));
    memset((char *)&nowait,0,sizeof(nowait));
 
    res = select(this->socketFD+1,&sready,NULL,NULL,&nowait);
    if( FD_ISSET(this->socketFD,&sready) )
        res = true;
    else
        res = false;
 
    if (res)
        emit dataReady( );
    return res;
 
}

@

@
QObject::connect(this,SIGNAL(dataReady()),this,SLOT(createThread( )));
@

franku

What about using QTcpSocket, QTcpServer or similar?

Neutron Stein

what do you mean ?
In QTcpSocket there is a signal readyRead() emited every time that data is written in the socket. Are talking about that?

franku

Well, there's very much functionality already built in Qt, like waiting on a socket to connect or data to be ready on a peer. In the code above I saw Qt signals and slot mechanism being wrapped around native posix socket code. This is probalbly not that much portabel in comparison to using the Qt-built-in socket functionality, however, coding yourself again may lead to bugs.