undefined reference to qt_static _plugin
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Hi,
I am trying to load a static plugin in Qt for which I have tried the below code. My project name is "static_plugin_qmake".
I am creating a static plugin called "plugin_qmake" and trying to load it through a application "launcher"static_plugin_qmake.pro
TEMPLATE = subdirs SUBDIRS = plugin_qmake \ launcher launcher.pro TEMPLATE = app QT += widgets HEADERS = interface.h SOURCES += main.cpp LIBS += "/home/uidm9805/Qt Projects/static_plugin_qmake/build/plugin_qmake/libplugin_qmake.a"interface.h
#ifndef INTERFACE_H #define INTERFACE_H #include <QtPlugin> class Interface { public: virtual ~Interface() {} virtual void setValue(int value) = 0; virtual int getValue() = 0; }; #define Interface_iid "interface_identifier_id" Q_DECLARE_INTERFACE(Interface, Interface_iid) #endif // INTERFACE_Hmain.cpp
#include <QApplication> #include <QtPlugin> #include <QDebug> Q_IMPORT_PLUGIN(plugin_qmake) int main(int argc, char *argv[]) { QApplication app(argc, argv); qDebug() << "Hello World"; return app.exec(); }plugin_qmake.pro
TEMPLATE = lib CONFIG += plugin static QT += widgets INCLUDEPATH += ../.. HEADERS = pluginqmake.h SOURCES = pluginqmake.cpp TARGET = $$qtLibraryTarget(plugin_qmake)pluginqmake.h
#ifndef PLUGINQMAKE_H #define PLUGINQMAKE_H #include <QObject> #include <QtPlugin> #include "../launcher/interface.h" class PluginQmake : public QObject, public Interface { Q_OBJECT Q_PLUGIN_METADATA(IID Interface_iid) Q_INTERFACES(Interface) public: void setValue(int value); int getValue(); private: int mValue; }; #endif // PLUGINQMAKE_Hpluginqmake.cpp
#include "pluginqmake.h" void PluginQmake::setValue(int value) { mValue = value; } int PluginQmake::getValue() { return mValue; }But when I build this project, I get following errors:
/home/uidm9805/Qt Projects/static_plugin_qmake/launcher/main.cpp:6: error: undefined reference to 'qt_static_plugin_plugin_qmake()' collect2: error: ld returned 1 exit statusI don't understand why I am getting this error? I need help to make it work.....
@NIXIN I think you forgot "QTPLUGIN += " in your pro file as described here: http://doc.qt.io/qt-5/plugins-howto.html#static-plugins
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@NIXIN I think you forgot "QTPLUGIN += " in your pro file as described here: http://doc.qt.io/qt-5/plugins-howto.html#static-plugins
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Lifetime Qt Championwrote on 3 Jan 2019, 12:02 last edited by jsulm 1 Mar 2019, 12:03
@NIXIN Sorry, my post was wrong.
"Link your application with your plugin library using LIBS in the .pro file." - so, using LIBS is correct. But you're using it wrongly, it should be:LIBS += -L"/home/uidm9805/Qt Projects/static_plugin_qmake/build/plugin_qmake" -lplugin_qmakeBetter to use relative paths, see http://doc.qt.io/qt-5/qtwidgets-tools-plugandpaint-app-example.html
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@NIXIN Sorry, my post was wrong.
"Link your application with your plugin library using LIBS in the .pro file." - so, using LIBS is correct. But you're using it wrongly, it should be:LIBS += -L"/home/uidm9805/Qt Projects/static_plugin_qmake/build/plugin_qmake" -lplugin_qmakeBetter to use relative paths, see http://doc.qt.io/qt-5/qtwidgets-tools-plugandpaint-app-example.html
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@jsulm I tried using LIBS += the way you suggested, however still it is not working...
getting same errors again@NIXIN Can you show your LIBS line from your pro file?
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wrote on 3 Jan 2019, 12:16 last edited by
TEMPLATE = app QT += widgets HEADERS = interface.h SOURCES += main.cpp #LIBS += "/home/uidm9805/Qt Projects/static_plugin_qmake/build/plugin_qmake/libplugin_qmake.a" LIBS += -L"/home/uidm9805/Qt Projects/static_plugin_qmake/build/plugin_qmake" -lplugin_qmake -
TEMPLATE = app QT += widgets HEADERS = interface.h SOURCES += main.cpp #LIBS += "/home/uidm9805/Qt Projects/static_plugin_qmake/build/plugin_qmake/libplugin_qmake.a" LIBS += -L"/home/uidm9805/Qt Projects/static_plugin_qmake/build/plugin_qmake" -lplugin_qmake@NIXIN You should check the linker call as you have a space in your path which can cause issues (you should avoid spaces in paths).
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@NIXIN You should check the linker call as you have a space in your path which can cause issues (you should avoid spaces in paths).
wrote on 3 Jan 2019, 12:21 last edited by@jsulm I tried same thing with this example http://doc.qt.io/qt-5/qtwidgets-tools-plugandpaint-app-example.html and its working fine there
LIBS += "/home/uidm9805/Qt Projects/plugandpaint/build/plugandpaint/plugins/libpnp_basictools.a"don't know why this project is behaving in odd manner
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@jsulm I tried same thing with this example http://doc.qt.io/qt-5/qtwidgets-tools-plugandpaint-app-example.html and its working fine there
LIBS += "/home/uidm9805/Qt Projects/plugandpaint/build/plugandpaint/plugins/libpnp_basictools.a"don't know why this project is behaving in odd manner
@NIXIN Is your plug-in really located here: /home/uidm9805/Qt Projects/static_plugin_qmake/build/plugin_qmake? And was it build with exact same compiler and Qt version?
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@NIXIN Is your plug-in really located here: /home/uidm9805/Qt Projects/static_plugin_qmake/build/plugin_qmake? And was it build with exact same compiler and Qt version?
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wrote on 4 Jan 2019, 09:52 last edited by
can anybody help me with this issue??
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wrote on 4 Jan 2019, 10:50 last edited by
After lot of hit and trial, I got the mistake I was doing
Q_IMPORT_PLUGIN(plugin_qmake)this line should have the class name of plugin
Q_IMPORT_PLUGIN(PluginQmake)now it works fine....
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wrote on 4 Jan 2019, 15:09 last edited by
If it's solved, Please set it to "Solved" from unsolved.
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