Using QIODevice to read a GPS filenode?

[hickscorp]

Hello people,

i am trying to achieve programmatically an async read on a IO node file which receives the outputs of a NMEA GPS.

i have tried to subclass QIODevice like this (For testing):

#include "QIOGpsReader.h"
#include <QIODevice>
 
QIOGpsReader::QIOGpsReader (QString node, QObject *parent) : QIODevice(parent) {
        qDebug("QIOGpsReader::ctor");
}
 
QIOGpsReader::~QIOGpsReader (void) {
        qDebug("QIOGpsReader::~ctor");
}
 
qint64 QIOGpsReader::readData (char *data, qint64 maxSize) {
        qDebug("QIOGpsReader::readData");
        strcpy(data, "1");
        return 1;
}
 
qint64 QIOGpsReader::writeData (const char *data, qint64 maxSize) {
        qDebug("QIOGpsReader::writeData");
        return 0;
}
 
qint64 QIOGpsReader::bytesAvailable (void) const {
        qDebug("QIOGpsReader::bytesAvailable");
        return 1;
}

#include "QIOGpsReader.h"
#include <QIODevice>

QIOGpsReader::QIOGpsReader (QString node, QObject *parent) : QIODevice(parent) {
        qDebug("QIOGpsReader::ctor");
}

QIOGpsReader::~QIOGpsReader (void) {
        qDebug("QIOGpsReader::~ctor");
}

qint64 QIOGpsReader::readData (char *data, qint64 maxSize) {
        qDebug("QIOGpsReader::readData");
        strcpy(data, "1");
        return 1;
}

qint64 QIOGpsReader::writeData (const char *data, qint64 maxSize) {
        qDebug("QIOGpsReader::writeData");
        return 0;
}

qint64 QIOGpsReader::bytesAvailable (void) const {
        qDebug("QIOGpsReader::bytesAvailable");
        return 1;
}

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Then in my main routine i instanciate a QIOGpsReader object and just connect the readyRead signal to a slot. Then i do a open(QIODevice::ReadOnly) "just to do it".

What i dont understand is, on what is based the "readReady" signal? When i look to my debug, i don't see any of my qDebug messages... What will make the QIODevice trigger a readyRead signal? i thought at a first that returning always 1 from readData and bytesAvailable would "tell" the QIODevice that it has to trigger, but it doesnt...

Basically, what is the method i have to reimplement which will tell the QIODevice object to signal a readReady event?

Thanks,
Pierre.

[EDIT:] i think it will not help but anyway here is my .h for my subclass:

#ifndef QIOGpsReader_h
#define QIOGpsReader_h
 
#include <QIODevice>
 
class QIOGpsReader      : public QIODevice {
 
Q_OBJECT
 
public:
                QIOGpsReader    (QString node, QObject *parent);
                ~QIOGpsReader   (void);
 
protected:
        qint64  readData        (char*, qint64);
        qint64  writeData       (const char *data, qint64 maxSize);
        qint64  bytesAvailable  (void)                                  const;
};
 
#endif

#ifndef QIOGpsReader_h
#define QIOGpsReader_h

#include <QIODevice>

class QIOGpsReader      : public QIODevice {

Q_OBJECT

public:
                QIOGpsReader    (QString node, QObject *parent);
                ~QIOGpsReader   (void);

protected:
        qint64  readData        (char*, qint64);
        qint64  writeData       (const char *data, qint64 maxSize);
        qint64  bytesAvailable  (void)                                  const;
};

#endif

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