Hallo Welt mit QT4

[Alex44]

Hallo

ich wollt mich mal näher mit QT4 beschäftigen, aber schon das "Hallo Welt" macht mir Schwierigkeiten.

Ich habe ein Tutorium gefunden und möchte es nun gerne abarbeiten.

Ich arbeite mit Geany unter Suse.

Hier der Code:

#include <QtCore/QTextStream>

int main(int argc, char** argv)
{
	QTextStream out(stdout);
	out << "Hallo Welt\n";
	return 0;
}

und hier die Fehlermeldung, die ich nicht nachvollziehen kann:

g++ -Wall -o "main" "main.cpp"
/tmp/cciF8mjs.o: In function main': main.cpp:(.text+0x37): undefined reference toQTextStream::QTextStream(_IO_FILE*, QFlagsQIODevice::OpenModeFlag)'
main.cpp:(.text+0x4b): undefined reference to QTextStream::operator<<(char const*)' main.cpp:(.text+0x5c): undefined reference toQTextStream::~QTextStream()'
main.cpp:(.text+0x74): undefined reference to `QTextStream::~QTextStream()'
collect2: ld returned 1 exit status
Kompilierung fehlgeschlagen.

Was möchte mir mein Kompilator damit sagen???

Gruß und Dank
Alex

[padreigh]

Normalerweise gehört dazu auch ein .pro file ... und qmake ... und so ... ich vermute mal aufgrund des collect2: ld returned 1 exit status das du die richtige Lib nicht eingebunden hast ...

[Alex44]

Hm - gibt es unterschiedliche libs mit gleichen Namen??? ich habe nur die eine auf meinem Rechner.

In der QTextStream steht nur ein include von qtextstream.h.
Und die sieht inhaltlich so aus....

/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef QTEXTSTREAM_H
#define QTEXTSTREAM_H

#include <QtCore/qiodevice.h>
#include <QtCore/qstring.h>
#include <QtCore/qchar.h>
#include <QtCore/qlocale.h>
#include <QtCore/qscopedpointer.h>

#ifndef QT_NO_TEXTCODEC
#  ifdef QT3_SUPPORT
#    include <QtCore/qtextcodec.h>
#  endif
#endif

#include <stdio.h>

#ifdef Status
#error qtextstream.h must be included before any header file that defines Status
#endif

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

QT_MODULE(Core)

class QTextCodec;
class QTextDecoder;

class QTextStreamPrivate;
class Q_CORE_EXPORT QTextStream                                // text stream class
{
    Q_DECLARE_PRIVATE(QTextStream)

public:
    enum RealNumberNotation {
        SmartNotation,
        FixedNotation,
        ScientificNotation
    };
    enum FieldAlignment {
        AlignLeft,
        AlignRight,
        AlignCenter,
        AlignAccountingStyle
    };
    enum Status {
        Ok,
        ReadPastEnd,
        ReadCorruptData
    };
    enum NumberFlag {
        ShowBase = 0x1,
        ForcePoint = 0x2,
        ForceSign = 0x4,
        UppercaseBase = 0x8,
        UppercaseDigits = 0x10
    };
    Q_DECLARE_FLAGS(NumberFlags, NumberFlag)

    QTextStream();
    explicit QTextStream(QIODevice *device);
    explicit QTextStream(FILE *fileHandle, QIODevice::OpenMode openMode = QIODevice::ReadWrite);
    explicit QTextStream(QString *string, QIODevice::OpenMode openMode = QIODevice::ReadWrite);
    explicit QTextStream(QByteArray *array, QIODevice::OpenMode openMode = QIODevice::ReadWrite);
    explicit QTextStream(const QByteArray &array, QIODevice::OpenMode openMode = QIODevice::ReadOnly);
    virtual ~QTextStream();

#ifndef QT_NO_TEXTCODEC
    void setCodec(QTextCodec *codec);
    void setCodec(const char *codecName);
    QTextCodec *codec() const;
    void setAutoDetectUnicode(bool enabled);
    bool autoDetectUnicode() const;
    void setGenerateByteOrderMark(bool generate);
    bool generateByteOrderMark() const;
#endif

    void setLocale(const QLocale &locale);
    QLocale locale() const;

    void setDevice(QIODevice *device);
    QIODevice *device() const;

    void setString(QString *string, QIODevice::OpenMode openMode = QIODevice::ReadWrite);
    QString *string() const;

    Status status() const;
    void setStatus(Status status);
    void resetStatus();

    bool atEnd() const;
    void reset();
    void flush();
    bool seek(qint64 pos);
    qint64 pos() const;

    void skipWhiteSpace();

    QString readLine(qint64 maxlen = 0);
    QString readAll();
    QString read(qint64 maxlen);

    void setFieldAlignment(FieldAlignment alignment);
    FieldAlignment fieldAlignment() const;

    void setPadChar(QChar ch);
    QChar padChar() const;

    void setFieldWidth(int width);
    int fieldWidth() const;

    void setNumberFlags(NumberFlags flags);
    NumberFlags numberFlags() const;

    void setIntegerBase(int base);
    int integerBase() const;

    void setRealNumberNotation(RealNumberNotation notation);
    RealNumberNotation realNumberNotation() const;

    void setRealNumberPrecision(int precision);
    int realNumberPrecision() const;

    QTextStream &operator>>(QChar &ch);
    QTextStream &operator>>(char &ch);
    QTextStream &operator>>(signed short &i);
    QTextStream &operator>>(unsigned short &i);
    QTextStream &operator>>(signed int &i);
    QTextStream &operator>>(unsigned int &i);
    QTextStream &operator>>(signed long &i);
    QTextStream &operator>>(unsigned long &i);
    QTextStream &operator>>(qlonglong &i);
    QTextStream &operator>>(qulonglong &i);
    QTextStream &operator>>(float &f);
    QTextStream &operator>>(double &f);
    QTextStream &operator>>(QString &s);
    QTextStream &operator>>(QByteArray &array);
    QTextStream &operator>>(char *c);

    QTextStream &operator<<(QBool b);
    QTextStream &operator<<(QChar ch);
    QTextStream &operator<<(char ch);
    QTextStream &operator<<(signed short i);
    QTextStream &operator<<(unsigned short i);
    QTextStream &operator<<(signed int i);
    QTextStream &operator<<(unsigned int i);
    QTextStream &operator<<(signed long i);
    QTextStream &operator<<(unsigned long i);
    QTextStream &operator<<(qlonglong i);
    QTextStream &operator<<(qulonglong i);
    QTextStream &operator<<(float f);
    QTextStream &operator<<(double f);
    QTextStream &operator<<(const QString &s);
    QTextStream &operator<<(const QByteArray &array);
    QTextStream &operator<<(const char *c);
    QTextStream &operator<<(const void *ptr);

#ifdef QT3_SUPPORT
    // not marked as QT3_SUPPORT to avoid double compiler warnings, as
    // they are used in the QT3_SUPPORT functions below.
    inline QT3_SUPPORT int flags() const { return flagsInternal(); }
    inline QT3_SUPPORT int flags(int f) { return flagsInternal(f); }

    inline QT3_SUPPORT int setf(int bits)
    { int old = flagsInternal(); flagsInternal(flagsInternal() | bits); return old; }
    inline QT3_SUPPORT int setf(int bits, int mask)
    { int old = flagsInternal(); flagsInternal(flagsInternal() | (bits & mask)); return old; }
    inline QT3_SUPPORT int unsetf(int bits)
    { int old = flagsInternal(); flagsInternal(flagsInternal() & ~bits); return old; }

    inline QT3_SUPPORT int width(int w)
    { int old = fieldWidth(); setFieldWidth(w); return old; }
    inline QT3_SUPPORT int fill(int f)
    { QChar ch = padChar(); setPadChar(QChar(f)); return ch.unicode(); }
    inline QT3_SUPPORT int precision(int p)
    { int old = realNumberPrecision(); setRealNumberPrecision(p); return old; }

    enum {
        skipws       = 0x0001,                        // skip whitespace on input
        left         = 0x0002,                        // left-adjust output
        right        = 0x0004,                        // right-adjust output
        internal     = 0x0008,                        // pad after sign
        bin          = 0x0010,                        // binary format integer
        oct          = 0x0020,                        // octal format integer
        dec          = 0x0040,                        // decimal format integer
        hex          = 0x0080,                        // hex format integer
        showbase     = 0x0100,                        // show base indicator
        showpoint    = 0x0200,                        // force decimal point (float)
        uppercase    = 0x0400,                        // upper-case hex output
        showpos      = 0x0800,                        // add '+' to positive integers
        scientific   = 0x1000,                        // scientific float output
        fixed        = 0x2000                         // fixed float output
    };
    enum {
        basefield = bin | oct | dec | hex,
        adjustfield = left | right | internal,
        floatfield = scientific | fixed
    };

#ifndef QT_NO_TEXTCODEC
    enum Encoding { Locale, Latin1, Unicode, UnicodeNetworkOrder,
                    UnicodeReverse, RawUnicode, UnicodeUTF8 };
    QT3_SUPPORT void setEncoding(Encoding encoding);
#endif
    inline QT3_SUPPORT QString read() { return readAll(); }
    inline QT3_SUPPORT void unsetDevice() { setDevice(0); }
#endif

private:
#ifdef QT3_SUPPORT
    int flagsInternal() const;
    int flagsInternal(int flags);
#endif

    Q_DISABLE_COPY(QTextStream)

    QScopedPointer<QTextStreamPrivate> d_ptr;
};

Q_DECLARE_OPERATORS_FOR_FLAGS(QTextStream::NumberFlags)

/*****************************************************************************
  QTextStream manipulators
 *****************************************************************************/

typedef QTextStream & (*QTextStreamFunction)(QTextStream &);// manipulator function
typedef void (QTextStream::*QTSMFI)(int); // manipulator w/int argument
typedef void (QTextStream::*QTSMFC)(QChar); // manipulator w/QChar argument

class Q_CORE_EXPORT QTextStreamManipulator
{
public:
    QTextStreamManipulator(QTSMFI m, int a) { mf = m; mc = 0; arg = a; }
    QTextStreamManipulator(QTSMFC m, QChar c) { mf = 0; mc = m; ch = c; arg = -1; }
    void exec(QTextStream &s) { if (mf) { (s.*mf)(arg); } else { (s.*mc)(ch); } }

private:
    QTSMFI mf;                                        // QTextStream member function
    QTSMFC mc;                                        // QTextStream member function
    int arg;                                          // member function argument
    QChar ch;
};

inline QTextStream &operator>>(QTextStream &s, QTextStreamFunction f)
{ return (*f)(s); }

inline QTextStream &operator<<(QTextStream &s, QTextStreamFunction f)
{ return (*f)(s); }

inline QTextStream &operator<<(QTextStream &s, QTextStreamManipulator m)
{ m.exec(s); return s; }

Q_CORE_EXPORT QTextStream &bin(QTextStream &s);
Q_CORE_EXPORT QTextStream &oct(QTextStream &s);
Q_CORE_EXPORT QTextStream &dec(QTextStream &s);
Q_CORE_EXPORT QTextStream &hex(QTextStream &s);

Q_CORE_EXPORT QTextStream &showbase(QTextStream &s);
Q_CORE_EXPORT QTextStream &forcesign(QTextStream &s);
Q_CORE_EXPORT QTextStream &forcepoint(QTextStream &s);
Q_CORE_EXPORT QTextStream &noshowbase(QTextStream &s);
Q_CORE_EXPORT QTextStream &noforcesign(QTextStream &s);
Q_CORE_EXPORT QTextStream &noforcepoint(QTextStream &s);

Q_CORE_EXPORT QTextStream &uppercasebase(QTextStream &s);
Q_CORE_EXPORT QTextStream &uppercasedigits(QTextStream &s);
Q_CORE_EXPORT QTextStream &lowercasebase(QTextStream &s);
Q_CORE_EXPORT QTextStream &lowercasedigits(QTextStream &s);

Q_CORE_EXPORT QTextStream &fixed(QTextStream &s);
Q_CORE_EXPORT QTextStream &scientific(QTextStream &s);

Q_CORE_EXPORT QTextStream &left(QTextStream &s);
Q_CORE_EXPORT QTextStream &right(QTextStream &s);
Q_CORE_EXPORT QTextStream &center(QTextStream &s);

Q_CORE_EXPORT QTextStream &endl(QTextStream &s);
Q_CORE_EXPORT QTextStream &flush(QTextStream &s);
Q_CORE_EXPORT QTextStream &reset(QTextStream &s);

Q_CORE_EXPORT QTextStream &bom(QTextStream &s);

Q_CORE_EXPORT QTextStream &ws(QTextStream &s);

inline QTextStreamManipulator qSetFieldWidth(int width)
{
    QTSMFI func = &QTextStream::setFieldWidth;
    return QTextStreamManipulator(func,width);
}

inline QTextStreamManipulator qSetPadChar(QChar ch)
{
    QTSMFC func = &QTextStream::setPadChar;
    return QTextStreamManipulator(func, ch);
}

inline QTextStreamManipulator qSetRealNumberPrecision(int precision)
{
    QTSMFI func = &QTextStream::setRealNumberPrecision;
    return QTextStreamManipulator(func, precision);
}

#ifdef QT3_SUPPORT
typedef QTextStream QTS;

class Q_CORE_EXPORT QTextIStream : public QTextStream
{
public:
    inline explicit QTextIStream(const QString *s) : QTextStream(const_cast<QString *>(s), QIODevice::ReadOnly) {}
    inline explicit QTextIStream(QByteArray *a) : QTextStream(a, QIODevice::ReadOnly) {}
    inline QTextIStream(FILE *f) : QTextStream(f, QIODevice::ReadOnly) {}

private:
    Q_DISABLE_COPY(QTextIStream)
};

class Q_CORE_EXPORT QTextOStream : public QTextStream
{
public:
    inline explicit QTextOStream(QString *s) : QTextStream(s, QIODevice::WriteOnly) {}
    inline explicit QTextOStream(QByteArray *a) : QTextStream(a, QIODevice::WriteOnly) {}
    inline QTextOStream(FILE *f) : QTextStream(f, QIODevice::WriteOnly) {}

private:
    Q_DISABLE_COPY(QTextOStream)
};
#endif

QT_END_NAMESPACE

QT_END_HEADER

#endif // QTEXTSTREAM_H

Und was genau meinst Du mit der .pro Datei??? Wozu ist die da?

[padreigh]

du brauchst hier nicht wirklich header files zu posten ... du scheinst mit Qt noch nicht viel gemacht zu haben, daher würde ich dir QtCreator ans Herz legen (als IDE).

libQt3Support.prl              libQtCLucene.so        libQtDBus.so.4                    libQtDesigner.so.4.6    libQtHelp.so.4.6.2        libQtOpenGL.prl       libQtScriptTools.so        libQtSvg.so.4       libQtWebKit.so             libQtXml.so.4
libQt3Support.so               libQtCLucene.so.4      libQtDBus.so.4.6                  libQtDesigner.so.4.6.2  libQtMultimedia.prl       libQtOpenGL.so        libQtScriptTools.so.4      libQtSvg.so.4.6     libQtWebKit.so.4           libQtXml.so.4.6
libQt3Support.so.4             libQtCLucene.so.4.6    libQtDBus.so.4.6.2                libQtGui.prl            libQtMultimedia.so        libQtOpenGL.so.4      libQtScriptTools.so.4.6    libQtSvg.so.4.6.2   libQtWebKit.so.4.6         libQtXml.so.4.6.2
libQt3Support.so.4.6           libQtCLucene.so.4.6.2  libQtDesignerComponents.prl       libQtGui.so             libQtMultimedia.so.4      libQtOpenGL.so.4.6    libQtScriptTools.so.4.6.2  libQtTest.prl       libQtWebKit.so.4.6.2
libQt3Support.so.4.6.2         libQtCore.prl          libQtDesignerComponents.so        libQtGui.so.4           libQtMultimedia.so.4.6    libQtOpenGL.so.4.6.2  libQtSql.prl               libQtTest.so        libQtXmlPatterns.prl
libQtAssistantClient.prl       libQtCore.so           libQtDesignerComponents.so.4      libQtGui.so.4.6         libQtMultimedia.so.4.6.2  libQtScript.prl       libQtSql.so                libQtTest.so.4      libQtXmlPatterns.so
libQtAssistantClient.so        libQtCore.so.4         libQtDesignerComponents.so.4.6    libQtGui.so.4.6.2       libQtNetwork.prl          libQtScript.so        libQtSql.so.4              libQtTest.so.4.6    libQtXmlPatterns.so.4
libQtAssistantClient.so.4      libQtCore.so.4.6       libQtDesignerComponents.so.4.6.2  libQtHelp.prl           libQtNetwork.so           libQtScript.so.4      libQtSql.so.4.6            libQtTest.so.4.6.2  libQtXmlPatterns.so.4.6
libQtAssistantClient.so.4.6    libQtCore.so.4.6.2     libQtDesigner.prl                 libQtHelp.so            libQtNetwork.so.4         libQtScript.so.4.6    libQtSql.so.4.6.2          libQtUiTools.a      libQtXmlPatterns.so.4.6.2
libQtAssistantClient.so.4.6.2  libQtDBus.prl          libQtDesigner.so                  libQtHelp.so.4          libQtNetwork.so.4.6       libQtScript.so.4.6.2  libQtSvg.prl               libQtUiTools.prl    libQtXml.prl
libQtCLucene.prl               libQtDBus.so           libQtDesigner.so.4                libQtHelp.so.4.6        libQtNetwork.so.4.6.2     libQtScriptTools.prl  libQtSvg.so                libQtWebKit.prl     libQtXml.so

das ist mal so das was bei mir mit libQt anfängt ... deutlich mehr als eine - du musst für QTextStream gegen libQtCore linken ... denke ich.

[Alex44]

Habe das mal durchgescheckt. Habe all die Dateien ebenso installiert, aber trotzdem der Fehler.

Muss ich was beim Kompilieren beachten?

[l'abra d'or]

Alex44 schrieb:

Muss ich was beim Kompilieren beachten?

Doku lesen, qmake verwenden. Oder einen anderen "Qt-kompatiblen" Makefile-Generator wie cmake. Jedenfalls für den Anfang.

[Alex44]

ich habs

dank Eurer Hinweise:

Das muss in der Reihenfolge in der Konsole ausgeführt werden (natürlich im Ordner, wo auch die Programmdatei drin ist) und das Resultat ist eine ausführbare Datei mit dem Name des Ordners

> qmake -project
> qmake
> make

Danke an alle