SOLVED - Qt slot problem - don't forget the Q_OBJECT macro!!!!!!

philmacu

Hi,
I am currently writing a small project, in it I have an object (mainWindow.cpp) that has several slots that are triggered by time events. They all work fine. In my main class I have a member (serialPort.cpp) which is a class that controls a serial port, I am trying to set up a signal/slot that does a one shot. This will be used so that I can timeout if I don;t get any serial back.

So a function in mainWindow.cpp ceates an instance of a serialPort.cpp at some time mainWindow.cpp starts the process to send serial data, I would like a one shot to 'go-off' at some time in the future if I don't have a response. When I try the following code I get a warning in my output dialog that the slot can't be found.

in the header of serialPort.cpp
private:

   QTimer *ATresponseTimer;

private slots:

void ATcommandResponseTimeout(void);

In the constructor of serialPort.cpp

ATresponseTimer = new QTimer;

connect ( ATresponseTimer, SIGNAL ( timeout() ), this, SLOT ( ATcommandResponseTimeout () ) );

ATresponseTimer->setSingleShot(true);

ATresponseTimer->stop();

also is serialPort.cpp
void serialPort::ATcommandResponseTimeout(void)
{
// we sent an AT command but never got a response in time,
qDebug() << "Modem response timed out";
}

The error I get is
Object::connect: No such slot QMainWindow::ATcommandResponseTimeout():serialPort in serialPort.cpp:10

I am sure I am forgetting to do something simple, any pointers ;-) would be great

Phil

Rondog

I would check the name of the slot (it is likely a typo in the name 'ATcommandResponseTimeout').

You could do it another way possibly.

You could use a timer (maybe one of your existing ones) to check if any data was received between events. All you need to do is set a variable every time you receive data and clear it on the timer event. If your variable is not set between events nothing was received. It might be simpler to implement.

philmacu

Thanks Rondog, I went for a walk and a cup of coffee, when I got back I suddenly realised that I forgot to place Q_OBJECT in serialPort.h

It re-emphasises the idea of taking a break when the wheels start falling off!