[Solved] question about signals and slots

Aicou

hello
I started today a new Qt application and i wanted to use QFtp.
I'm stuck when I want to link QFtp signals to my own slots, sources compile but no signals are catch.
I read the signals and slots doc and use the ftp client example to start.

here is my code, i make it as simple as possible:

the my_ftp.h:
@
#include <QtNetwork/QFtp>
#include <QObject>
#include <iostream>

class my_ftp : public QObject
{
Q_OBJECT
public:

my_ftp() {}
~my_ftp() {}
void    run();

public slots:

void    cmd_end(int i, bool j);
void    cmd_start(int i);

public:

QFtp    *ff;

};
@

the main:

@

void my_ftp::cmd_end(int i, bool j)
{
std::cout << i << ": " << j << std::endl;

}

void my_ftp::cmd_start(int i)
{
std::cout << "start" << i << std::endl;
}

void my_ftp::run()
{
std::cout << "running" << std::endl;
this->ff = new QFtp(this);

this->connect(this->ff, SIGNAL(commandFinished(int,bool)), this, SLOT(cmd_end(int,bool)));
this->connect(this->ff, SIGNAL(commandStarted(int)), this, SLOT(cmd_start(int)));

}

int main()
{
my_ftp *f = new my_ftp();

f->run();
f->ff->connectToHost("***", 21);
while (true)
{

}

}
@

nothing never happened after the "running" i don't know why.

Franzk

You need to at least start an event loop (using Q(Core)Application) for this to work properly:
@
int main(int argc, char **argv)
{
QApplication app(argc, argv);
my_ftp *f = new my_ftp();

f->run();
f->ff->connectToHost("***", 21);
return app.exec&#40;&#41;;

}
@

Don't forget to connect a finished signal to the QApplication's quit slot.

stukdev

I don't know what you are doing but i think your application is blocking!

Maybe you can try add
@
while(true){QCoreApplication::instance()->processEvents(QEventLoop::ExcludeUserInputEvents);}
@

or use
@
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
my_ftp *f = new my_ftp();

f->run();
f->ff->connectToHost("***", 21);
return a.exec(&#41;;

}
@

This is idea i don't know if this can work correctly...

Aicou

this is working, thanks you ! I was thinking the QCoreApplication was only for graphical application ^^

i just add this to my main :

@
int main(int ac, char **av)
{
QCoreApplication my_app(ac, av);
my_ftp *f = new my_ftp();

f->run();
f->ff->connectToHost("***", 21);
my_app.exec(&#41;;

}
@

Franzk

QApplication is required for graphical applications. QCoreApplication for all Qt applications.

dangelog

[quote author="Franzk" date="1298572684"]QApplication is required for graphical applications. QCoreApplication for all Qt applications.[/quote]

This is just false. The point however is that QFtp is event (signal) driven, therefore it requires an event loop.

Franzk

Certainly. It's a decent guideline though.