problem with QString and QsharedData

hi folkz im trying for a new project for first time Qt 4.7 (was used to 3.x) and i thought in using smart pointers but whatever i try i get this

#0 0x00007ffff66c865d in QString::operator=(QString const&) () from /usr/lib/libQtCore.so.4
#1 0x00007ffff7bd9631 in RDCI::RDebug::append (this=0x7fffffffe000, value=..., varname=..., linenumber=@0x7fffffffe060, filename=...,
sourcelocation=...) at rdcitypes.cpp:28
#2 0x0000000000401324 in main (argc=1, argv=0x7fffffffe178) at ../rdcitest/main.cpp:11


here is my source code as an attachmentAttachment 6638

in the main.cpp i tried several form from normal pointers to smart pointers and qstring break always there, probably is something stupid but i just don't see it

my os info
kubuntu natty 11.04
kde 4.6.4
qt 4.7.2 latest update
kernel 3.0.0 rc-6 preemp and no preemt just in case ;)

thx in advance for any help

Your RDebug constructors never allocate an RDebugData object for your private data. As soon as you access the uninitialised d pointer... BOOM. Take a closer look at the Employee constructors in the example from the QSharedDataPointer docs.

BTW: gzipping an already gzipped tar file makes your archive tricky to extract.

Quote:

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Originally Posted by ChrisW67

Your RDebug constructors never allocate an RDebugData object for your private data. As soon as you access the uninitialised d pointer... BOOM. Take a closer look at the Employee constructors in the example from the QSharedDataPointer docs.

BTW: gzipping an already gzipped tar file makes your archive tricky to extract.

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it make sense now, i feel stupid lol. ill try later

thx for your answer

weird it should be a .tar.gz i don't know why it gzipped the file twice, maybe a bug in dolphin ark plugin. ill check that later.

chris all is working as it should now, you were right but i found some weird behavior.

everytime i pass float types or double or long double, etc qvariant class emit a crash, i tried with almost any other type including QT ones and it work perfectly it just crash with floating point values

here is the back trace

#0 0x00007ffff6787383 in QVariant::~QVariant() () from /usr/lib/libQtCore.so.4
#1 0x00007ffff7bd9935 in RDCI::RDebugData::~RDebugData (this=0x60a940, __in_chrg=<value optimized out>) at rdcitypes_p.hpp:9
#2 0x00007ffff7bd9a07 in QSharedDataPointer<RDCI::RDebugData>::~QSharedData Pointer (this=0x7fffffffe008,
__in_chrg=<value optimized out>) at /usr/include/qt4/QtCore/qshareddata.h:90
#3 0x00007ffff7bd938e in RDCI::RDebug::~RDebug (this=0x7fffffffe000, __in_chrg=<value optimized out>) at rdcitypes.cpp:5
#4 0x000000000040189e in main (argc=1, argv=0x7fffffffe178) at ../rdcitest/main.cpp:10

my code

main.cpp

Code:

---

#include <QtCore/QCoreApplication>
#include "rdcitypes.hpp"
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    using namespace std;
    using namespace RDCI;
    QString var = "hola";
    float var2 = 500;
    RDebug  prueba;
    cout << prueba.saveValues(var2) << endl;
    cout << prueba.getSourceLocation().toStdString() << endl;
    cout << prueba.getSize() << endl;
    return 0;
}

---

rdcitypes_p.hpp

Code:

---

#ifndef RDCITYPES_P_H
#define RDCITYPES_P_H
 
#include "definitions.hpp"
 
namespace RDCI
{
	class SO_LOCAL RDebugData : public QSharedData
	{
	public:
		RDebugData()
		{}
		RDebugData(const RDebugData &other)
				: QSharedData(other), fileName(other.fileName), sourceLocation(other.sourceLocation), varName(other.varName), lineNumber(other.lineNumber), Value(other.Value), size(other.size)
		{ }
		~RDebugData()
		{}
		QString fileName, sourceLocation, varName;
		quint64 lineNumber, size;
		QVariant Value;
	};
}
#endif

---

rdcitypes.hpp

Code:

---

#ifndef RDCITYPES_H
#define RDCITYPES_H
 
#include "rdcitypes_p.hpp"
 
namespace RDCI
{
    class RDebugData;
    class SO_PUBLIC RDebug
    {
    public:
        RDebug()
        {
            d = new RDebugData;
        }
        RDebug(const RDebug &other): d (other.d)
        {}
        virtual ~RDebug();
        bool isEmpty();
        QVariant getValue() const
        {
            return d->Value;
        }
        QString getFileName() const
        {
            return d->fileName;
        }
        QString getSourceLocation() const
        {
            return d->sourceLocation;
        }
        QString getVarName() const
        {
            return d->varName;
        }
        quint64 getLineNumber() const
        {
            return d->lineNumber;
        }
        quint64 getSize() const
        {
            return d->size;
        }
        template <typename U>
        U saveValues_p(U const &value, const QString &varname, quint64 linenumber, const QString &filename, const QString &sourcelocation, const quint64 size)
        {
            d->varName = varname;
            d->lineNumber = linenumber;
            d->fileName = filename;
            d->sourceLocation = sourcelocation;
            d->Value = value;
            d->size = size;
            return value;
        }
    private:
        QSharedDataPointer<RDebugData> d;
    };
 
}
#endif // RDCITYPES_H

---

definition.hpp

Code:

---

ifndef DEFINITIONS_H
#define	DEFINITIONS_H
 
#include <QtPlugin>
#include <QObject>
#include <QMetaType>
#include <QSharedData>
#include <QSharedDataPointer>
#include <QtCore/QVariant>
#include <QtDBus/QDBusConnection>
#include <QtDBus/QDBusMessage>
#include <QtDBus/QtDBus>
#include <QtCore/QList>
 
#include <sys/types.h>
#include <iostream>
#include <algorithm>
 
namespace RDCI
{
 
#if __GNUC__ >= 4
#define SO_PUBLIC __attribute__ ((visibility("default")))
#define SO_LOCAL  __attribute__ ((visibility("hidden")))
#define saveValues(value) \
				saveValues_p( value, #value, __LINE__, __FILE__, __PRETTY_FUNCTION__, sizeof(value))
#endif
}
#endif	/* DEFINITIONS_H */

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it seems i forgot to clean my build, so at the end it only crash with float not with double, checking the source code it seems qvariant don't support float variables