QtPlugin and undefined symbol

[Mikoskay]

FilePluginInterface.h

#ifndef FILEPLUGININTERFACE_H
#define FILEPLUGININTERFACE_H
 
#include "Geocache.h"
 
#include <QtPlugin>
#include <QIODevice>
#include <QString>
#include <QList>
 
class FilePluginInterface {
public:
    virtual ~FilePluginInterface() {}
 
    virtual const char *getName() const throw() = 0;
    virtual const char *getVersion() const throw() = 0;
    virtual const char *getAuthor() const throw() = 0;
    virtual const char *getAuthorEmail() const throw() = 0;
    virtual bool isValid(QIODevice *source) = 0;
 
    virtual QList<Geocache*> getAll(QIODevice *source) = 0;
};
 
Q_DECLARE_INTERFACE(FilePluginInterface, "com.Something.Plugins.FilePlugin/1")
 
#endif // FILEPLUGININTERFACE_H

#ifndef FILEPLUGININTERFACE_H
#define FILEPLUGININTERFACE_H

#include "Geocache.h"

#include <QtPlugin>
#include <QIODevice>
#include <QString>
#include <QList>

class FilePluginInterface {
public:
    virtual ~FilePluginInterface() {}

    virtual const char *getName() const throw() = 0;
    virtual const char *getVersion() const throw() = 0;
    virtual const char *getAuthor() const throw() = 0;
    virtual const char *getAuthorEmail() const throw() = 0;
    virtual bool isValid(QIODevice *source) = 0;

    virtual QList<Geocache*> getAll(QIODevice *source) = 0;
};

Q_DECLARE_INTERFACE(FilePluginInterface, "com.Something.Plugins.FilePlugin/1")

#endif // FILEPLUGININTERFACE_H

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GeocachingComGpx.cpp

#include "../../../src/FilePluginInterface.h"
 
class GeocachingComGpx : public QObject, public FilePluginInterface {
    Q_OBJECT
    Q_INTERFACES(FilePluginInterface)
 
public:
    const char *getName() const throw();
    const char *getVersion() const throw();
    const char *getAuthor() const throw();
    const char *getAuthorEmail() const throw();
 
    bool isValid(QIODevice *source);
 
    QList<Geocache*> getAll(QIODevice *source);
};
 
const char *GeocachingComGpx::getName() const throw()
{
    return "Geocaching.com GPX Files";
}
 
const char *GeocachingComGpx::getVersion() const throw()
{
    return "0.1.0";
}
 
const char *GeocachingComGpx::getAuthor() const throw()
{
    return "James Marshall Hendrix";
}
 
const char *GeocachingComGpx::getAuthorEmail() const throw()
{
    return "jimi@hendrix.com";
}
 
bool GeocachingComGpx::isValid(QIODevice *source)
{
    Q_UNUSED(source);
    return true;
}
 
QList<Geocache*> GeocachingComGpx::getAll(QIODevice *source)
{
    Q_UNUSED(source);
    return QList<Geocache*>();
}
 
Q_EXPORT_PLUGIN2(GeocachingComGpx, GeocachingComGpx);

#include "../../../src/FilePluginInterface.h"

class GeocachingComGpx : public QObject, public FilePluginInterface {
    Q_OBJECT
    Q_INTERFACES(FilePluginInterface)

public:
    const char *getName() const throw();
    const char *getVersion() const throw();
    const char *getAuthor() const throw();
    const char *getAuthorEmail() const throw();

    bool isValid(QIODevice *source);

    QList<Geocache*> getAll(QIODevice *source);
};

const char *GeocachingComGpx::getName() const throw()
{
    return "Geocaching.com GPX Files";
}

const char *GeocachingComGpx::getVersion() const throw()
{
    return "0.1.0";
}

const char *GeocachingComGpx::getAuthor() const throw()
{
    return "James Marshall Hendrix";
}

const char *GeocachingComGpx::getAuthorEmail() const throw()
{
    return "jimi@hendrix.com";
}

bool GeocachingComGpx::isValid(QIODevice *source)
{
    Q_UNUSED(source);
    return true;
}

QList<Geocache*> GeocachingComGpx::getAll(QIODevice *source)
{
    Q_UNUSED(source);
    return QList<Geocache*>();
}

Q_EXPORT_PLUGIN2(GeocachingComGpx, GeocachingComGpx);

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GeocachingComGpx.pro

NAME = GeocachingComGpx
VERSION = 0.1.0
HEADERS += ../../../src/FilePluginInterface.h
SOURCES += GeocachingComGpx.cpp
 
TEMPLATE = lib
TARGET = $${NAME}
DESTDIR = ../../../bin/plugins/file/
DEPENDPATH += $$PWD
INCLUDEPATH += $$PWD
CONFIG += plugin
 
target.path = /usr/share/something/plugins/file/
 
INSTALLS += target

NAME = GeocachingComGpx
VERSION = 0.1.0
HEADERS += ../../../src/FilePluginInterface.h
SOURCES += GeocachingComGpx.cpp

TEMPLATE = lib
TARGET = $${NAME}
DESTDIR = ../../../bin/plugins/file/
DEPENDPATH += $$PWD
INCLUDEPATH += $$PWD
CONFIG += plugin

target.path = /usr/share/something/plugins/file/

INSTALLS += target

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And when I'm trying to load a plugin:

QStringList files = path.entryList(QDir::Files);
 
        for (QStringList::iterator it2 = files.begin(); it2 != files.end(); it2++) {
            QPluginLoader pluginLoader(path.absoluteFilePath(*it2));
            QObject *plugin = pluginLoader.instance();
 
            if (plugin) {
                filePlugins.append(qobject_cast<FilePluginInterface*>(plugin));
                qDebug() << "Loaded plugin" << filePlugins.last()->getName()
                         << filePlugins.last()->getVersion();
            } else {
                qDebug() << pluginLoader.errorString();
            }
        }

QStringList files = path.entryList(QDir::Files);

        for (QStringList::iterator it2 = files.begin(); it2 != files.end(); it2++) {
            QPluginLoader pluginLoader(path.absoluteFilePath(*it2));
            QObject *plugin = pluginLoader.instance();

            if (plugin) {
                filePlugins.append(qobject_cast<FilePluginInterface*>(plugin));
                qDebug() << "Loaded plugin" << filePlugins.last()->getName()
                         << filePlugins.last()->getVersion();
            } else {
                qDebug() << pluginLoader.errorString();
            }
        }

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pluginLoader.errorString() gives me

/some/nice/path/bin/plugins/file/libGeocachingComGpx.so: undefined symbol: _ZTV16GeocachingComGpx

/some/nice/path/bin/plugins/file/libGeocachingComGpx.so: undefined symbol: _ZTV16GeocachingComGpx

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_ZTV16GeocachingComGpx seems to be the symbol of my plugin's class (I looked into binary, methods symbols are prepended by it). Why it's missing from the binary? And if it's not, what's going on then?

Thanks for your time

[Mikoskay]

Ok, that was lame. I've just moved class declaration to a header file, and added it to HEADERS in .pro. Now everything works. Q_OBJECT macro just doesn't like source files.