Abstract plugin inheritance error
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I'm trying to create a plugin system and I have an interface for the plugin and also an abstract plugin that others plugin will inherit however I'm getting a lot of errors:
Before the errors, here is how my structure looks like:
|-- myproject |-- myproject.pro |-- plugins | |-- plugins.pro | |-- pluginfoo | | |-- pluginfoo.cpp | | |-- pluginfoo.hpp | | |-- pluginfoo.json | | |-- pluginfoo.pro |-- myproject |-- myproject.pro |-- gui | |-- myprojectwindow.cpp | |-- myprojectwindow.hpp |-- src |-- main.cpp |-- plugininterface.hpp |-- abstractplugin.cpp |-- abstractplugin.hpp
TEMPLATE = subdirs SUBDIRS = myproject \ plugins
TEMPLATE = subdirs SUBDIRS = pluginfoo
pluginfoo.cpp
#include "pluginfoo.hpp"
pluginfoo.hpp
#ifndef PLUGINFOO_HPP #define PLUGINFOO_HPP #include "abstractplugin.hpp" class PluginFoo : public AbstractPlugin { Q_OBJECT Q_PLUGIN_METADATA(IID PluginInterface_iid FILE "pluginfoo.json") Q_INTERFACES(PluginInterface) }; #endif // PLUGINFOO_HPP
pluginfoo.json
{}
QT += core gui TARGET = pluginfoo TEMPLATE = lib CONFIG += plugin DESTDIR = ../../bin/plugins DEFINES += QT_DEPRECATED_WARNINGS INCLUDEPATH += ../../myproject/src SOURCES += pluginfoo.cpp HEADERS += pluginfoo.hpp DISTFILES += pluginfoo.json
QT += core gui widgets xml network TARGET = myproject TEMPLATE = app DESTDIR = ../bin DEFINES += QT_DEPRECATED_WARNINGS SOURCES += src/main.cpp \ gui/myprojectwindow.cpp src/abstractplugin.hpp HEADERS += gui/myprojectwindow.hpp \ src/plugininterface.hpp src/abstractplugin.hpp
myprojectwindow.cpp
#include "myprojectwindow.hpp" MyProjectWindow::MyProjectWindow(QWidget *parent) : QMainWindow(parent) { } MyProjectWindow::~MyProjectWindow() { }
myprojectwindow.hpp
#ifndef MYPROJECTWINDOW_HPP #define MYPROJECTWINDOW_HPP #include <QMainWindow> class MyProjectWindow : public QMainWindow { Q_OBJECT public: MyProjectWindow(QWidget *parent = 0); ~MyProjectWindow(); }; #endif // MYPROJECTWINDOW_HPP
main.cpp
#include "gui/myprojectwindow.hpp" #include <QApplication> int main(int argc, char *argv[]) { QApplication application(argc, argv); MyProjectWindow window; window.show(); return application.exec(); }
plugininterface.hpp
#ifndef PLUGININTERFACE_HPP #define PLUGININTERFACE_HPP class PluginInterface { public: virtual ~PluginInterface() {} }; #define PluginInterface_iid "PluginInterface/1.0" Q_DECLARE_INTERFACE(PluginInterface, PluginInterface_iid) #endif // PLUGININTERFACE_HPP
abstractplugin.cpp
#include "abstractplugin.hpp"
abstractplugin.hpp
#ifndef ABSTRACTPLUGIN_HPP #define ABSTRACTPLUGIN_HPP #include <QtPlugin> #include "plugininterface.hpp" class AbstractPlugin : public QObject, public virtual PluginInterface { Q_OBJECT Q_INTERFACES(PluginInterface) }; #endif // ABSTRACTPLUGIN_HPP
And I get this when compiling:
moc_pluginfoo.obj:-1: error: LNK2001: unresolved external symbol "public: static struct QMetaObject const AbstractPlugin::staticMetaObject" (?staticMetaObject@AbstractPlugin@@2UQMetaObject@@B)
moc_pluginfoo.obj:-1: error: LNK2001: unresolved external symbol "public: virtual struct QMetaObject const * __cdecl AbstractPlugin::metaObject(void)const " (?metaObject@AbstractPlugin@@UEBAPEBUQMetaObject@@XZ)
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "public: virtual void * __cdecl AbstractPlugin::qt_metacast(char const *)" (?qt_metacast@AbstractPlugin@@UEAAPEAXPEBD@Z) referenced in function "public: virtual void * __cdecl PluginFoo::qt_metacast(char const *)" (?qt_metacast@PluginFoo@@UEAAPEAXPEBD@Z)
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "public: virtual int __cdecl AbstractPlugin::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@AbstractPlugin@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z) referenced in function "public: virtual int __cdecl PluginFoo::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@PluginFoo@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z)
....\bin\plugins\pluginfoo.dll:-1: error: LNK1120: 4 unresolved externals
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I'm trying to create a plugin system and I have an interface for the plugin and also an abstract plugin that others plugin will inherit however I'm getting a lot of errors:
Before the errors, here is how my structure looks like:
|-- myproject |-- myproject.pro |-- plugins | |-- plugins.pro | |-- pluginfoo | | |-- pluginfoo.cpp | | |-- pluginfoo.hpp | | |-- pluginfoo.json | | |-- pluginfoo.pro |-- myproject |-- myproject.pro |-- gui | |-- myprojectwindow.cpp | |-- myprojectwindow.hpp |-- src |-- main.cpp |-- plugininterface.hpp |-- abstractplugin.cpp |-- abstractplugin.hpp
TEMPLATE = subdirs SUBDIRS = myproject \ plugins
TEMPLATE = subdirs SUBDIRS = pluginfoo
pluginfoo.cpp
#include "pluginfoo.hpp"
pluginfoo.hpp
#ifndef PLUGINFOO_HPP #define PLUGINFOO_HPP #include "abstractplugin.hpp" class PluginFoo : public AbstractPlugin { Q_OBJECT Q_PLUGIN_METADATA(IID PluginInterface_iid FILE "pluginfoo.json") Q_INTERFACES(PluginInterface) }; #endif // PLUGINFOO_HPP
pluginfoo.json
{}
QT += core gui TARGET = pluginfoo TEMPLATE = lib CONFIG += plugin DESTDIR = ../../bin/plugins DEFINES += QT_DEPRECATED_WARNINGS INCLUDEPATH += ../../myproject/src SOURCES += pluginfoo.cpp HEADERS += pluginfoo.hpp DISTFILES += pluginfoo.json
QT += core gui widgets xml network TARGET = myproject TEMPLATE = app DESTDIR = ../bin DEFINES += QT_DEPRECATED_WARNINGS SOURCES += src/main.cpp \ gui/myprojectwindow.cpp src/abstractplugin.hpp HEADERS += gui/myprojectwindow.hpp \ src/plugininterface.hpp src/abstractplugin.hpp
myprojectwindow.cpp
#include "myprojectwindow.hpp" MyProjectWindow::MyProjectWindow(QWidget *parent) : QMainWindow(parent) { } MyProjectWindow::~MyProjectWindow() { }
myprojectwindow.hpp
#ifndef MYPROJECTWINDOW_HPP #define MYPROJECTWINDOW_HPP #include <QMainWindow> class MyProjectWindow : public QMainWindow { Q_OBJECT public: MyProjectWindow(QWidget *parent = 0); ~MyProjectWindow(); }; #endif // MYPROJECTWINDOW_HPP
main.cpp
#include "gui/myprojectwindow.hpp" #include <QApplication> int main(int argc, char *argv[]) { QApplication application(argc, argv); MyProjectWindow window; window.show(); return application.exec(); }
plugininterface.hpp
#ifndef PLUGININTERFACE_HPP #define PLUGININTERFACE_HPP class PluginInterface { public: virtual ~PluginInterface() {} }; #define PluginInterface_iid "PluginInterface/1.0" Q_DECLARE_INTERFACE(PluginInterface, PluginInterface_iid) #endif // PLUGININTERFACE_HPP
abstractplugin.cpp
#include "abstractplugin.hpp"
abstractplugin.hpp
#ifndef ABSTRACTPLUGIN_HPP #define ABSTRACTPLUGIN_HPP #include <QtPlugin> #include "plugininterface.hpp" class AbstractPlugin : public QObject, public virtual PluginInterface { Q_OBJECT Q_INTERFACES(PluginInterface) }; #endif // ABSTRACTPLUGIN_HPP
And I get this when compiling:
moc_pluginfoo.obj:-1: error: LNK2001: unresolved external symbol "public: static struct QMetaObject const AbstractPlugin::staticMetaObject" (?staticMetaObject@AbstractPlugin@@2UQMetaObject@@B)
moc_pluginfoo.obj:-1: error: LNK2001: unresolved external symbol "public: virtual struct QMetaObject const * __cdecl AbstractPlugin::metaObject(void)const " (?metaObject@AbstractPlugin@@UEBAPEBUQMetaObject@@XZ)
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "public: virtual void * __cdecl AbstractPlugin::qt_metacast(char const *)" (?qt_metacast@AbstractPlugin@@UEAAPEAXPEBD@Z) referenced in function "public: virtual void * __cdecl PluginFoo::qt_metacast(char const *)" (?qt_metacast@PluginFoo@@UEAAPEAXPEBD@Z)
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "public: virtual int __cdecl AbstractPlugin::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@AbstractPlugin@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z) referenced in function "public: virtual int __cdecl PluginFoo::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@PluginFoo@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z)
....\bin\plugins\pluginfoo.dll:-1: error: LNK1120: 4 unresolved externals
You haven't exported any of your classes.
Also is the virtual inheritance really necessary? I shouldn't think so. -
You haven't exported any of your classes.
Also is the virtual inheritance really necessary? I shouldn't think so.@kshegunov It's not an export problem, I forgot to type the
src/plugininterface.hpp
in the pro file here on the example. I edited the question.
The virtual inheritance is to avoid the diamond problem. -
@kshegunov It's not an export problem, I forgot to type the
src/plugininterface.hpp
in the pro file here on the example. I edited the question.
The virtual inheritance is to avoid the diamond problem.@Defohin said in Abstract plugin inheritance error:
It's not an export problem
I would argue that it is. You're trying to use a class that's defined in the application project in the library. The
Q_OBJECT
macro generates members(!) that have to be accessible to the linker, and in your case they aren't. This is moot when dealing with interfaces, but it's significant when dealing with classes likeAbstractPlugin
.The virtual inheritance is to avoid the diamond problem.
If you have a diamond somewhere, then you've done something very, very, very wrong. I have had a need to deal with it only a couple of times in my 10 years of experience with C++. Virtual inheritance is evil, avoid it at (almost) any cost!
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@Defohin said in Abstract plugin inheritance error:
It's not an export problem
I would argue that it is. You're trying to use a class that's defined in the application project in the library. The
Q_OBJECT
macro generates members(!) that have to be accessible to the linker, and in your case they aren't. This is moot when dealing with interfaces, but it's significant when dealing with classes likeAbstractPlugin
.The virtual inheritance is to avoid the diamond problem.
If you have a diamond somewhere, then you've done something very, very, very wrong. I have had a need to deal with it only a couple of times in my 10 years of experience with C++. Virtual inheritance is evil, avoid it at (almost) any cost!
@kshegunov Thank you, for real, but what you think I should do? The entire code is here, but still I have no idea what is happening.
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@kshegunov Thank you, for real, but what you think I should do? The entire code is here, but still I have no idea what is happening.
Simply remove the
AbstractPlugin
class, it's not necessary anyway, it does nothing. Instead for each plugin derive fromQObject
and the interface as you've done. That should fix it for the most part. Namely:class PluginFoo : public QObject, public PluginInterface { Q_OBJECT Q_PLUGIN_METADATA(IID PluginInterface_iid FILE "pluginfoo.json") Q_INTERFACES(PluginInterface) };
Then (as you're working on windows) you'll probably get a linker error for the plugin class itself, exporting it from the dll should fix that as well.
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Simply remove the
AbstractPlugin
class, it's not necessary anyway, it does nothing. Instead for each plugin derive fromQObject
and the interface as you've done. That should fix it for the most part. Namely:class PluginFoo : public QObject, public PluginInterface { Q_OBJECT Q_PLUGIN_METADATA(IID PluginInterface_iid FILE "pluginfoo.json") Q_INTERFACES(PluginInterface) };
Then (as you're working on windows) you'll probably get a linker error for the plugin class itself, exporting it from the dll should fix that as well.
@kshegunov I will need the abstract class to add a few common methods. It's just an example code.
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@kshegunov I will need the abstract class to add a few common methods. It's just an example code.
@Defohin said in Abstract plugin inheritance error:
I will need the abstract class to add a few common methods. It's just an example code.
Then you must provide the linker with the appropriate binary. Meaning you must, in this case, move the abstract plugin class in a separate library to which your plugins will link (
look up the docs, there's examples how to make an ordinary dynamic librarylook here). In this library you need to export theAbstractPlugin
class (throughQ_DECL_EXPORT
andQ_DECL_IMPORT
again you can look how exactly in the docs). The interface can stay either in the application project or in the new library, that's up to you and is a matter of convenience. -
@kshegunov I tried to add this:
myprojectglobal.h
#ifndef MYPROJECTGLOBAL_HPP #define MYPROJECTGLOBAL_HPP #include <QtCore/qglobal.h> #if defined(MYPROJECT_LIBRARY) # define MYPROJECT_EXPORT Q_DECL_EXPORT #else # define MYPROJECT_EXPORT Q_DECL_IMPORT #endif #endif // MYPROJECTGLOBAL_HPP
DEFINES += MYPROJECT_LIBRARY
plugininterface.hpp
#ifndef PLUGININTERFACE_HPP #define PLUGININTERFACE_HPP #include "myprojectglobal.hpp" #include <QtPlugin> class MYPROJECT_EXPORT PluginInterface { public: virtual ~PluginInterface() {} }; #define PluginInterface_iid "PluginInterface/1.0" Q_DECLARE_INTERFACE(PluginInterface, PluginInterface_iid) #endif // PLUGININTERFACE_HPP
abstractplugin.hpp
#ifndef ABSTRACTPLUGIN_HPP #define ABSTRACTPLUGIN_HPP #include "plugininterface.hpp" class MYPROJECT_EXPORT AbstractPlugin : public QObject, public PluginInterface { Q_OBJECT Q_INTERFACES(PluginInterface) }; #endif // ABSTRACTPLUGIN_HPP
And now I'm getting these errors:
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual __cdecl PluginInterface::~PluginInterface(void)" (_imp??1PluginInterface@@UEAA@XZ) referenced in function "int
public: __cdecl PluginFoo::PluginFoo(void)'::
1'::dtor$0" (?dtor$0@?0???0PluginFoo@@QEAA@XZ@4HA)moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl PluginInterface::PluginInterface(void)" (_imp??0PluginInterface@@QEAA@XZ) referenced in function "public: __cdecl PluginFoo::PluginFoo(void)" (??0PluginFoo@@QEAA@XZ)
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual void * __cdecl AbstractPlugin::qt_metacast(char const *)" (_imp?qt_metacast@AbstractPlugin@@UEAAPEAXPEBD@Z) referenced in function "public: virtual void * __cdecl PluginFoo::qt_metacast(char const *)" (?qt_metacast@PluginFoo@@UEAAPEAXPEBD@Z)
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual int __cdecl AbstractPlugin::qt_metacall(enum QMetaObject::Call,int,void * *)" (_imp?qt_metacall@AbstractPlugin@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z) referenced in function "public: virtual int __cdecl PluginFoo::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@PluginFoo@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z)
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl AbstractPlugin::AbstractPlugin(void)" (_imp??0AbstractPlugin@@QEAA@XZ) referenced in function "public: __cdecl PluginFoo::PluginFoo(void)" (??0PluginFoo@@QEAA@XZ)
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual __cdecl AbstractPlugin::~AbstractPlugin(void)" (_imp??1AbstractPlugin@@UEAA@XZ) referenced in function "public: virtual __cdecl PluginFoo::~PluginFoo(void)" (??1PluginFoo@@UEAA@XZ)
moc_pluginfoo.obj:-1: error: LNK2001: unresolved external symbol "__declspec(dllimport) public: static struct QMetaObject const AbstractPlugin::staticMetaObject" (_imp?staticMetaObject@AbstractPlugin@@2UQMetaObject@@B)
....\bin\plugins\pluginfoo.dll:-1: error: LNK1120: 7 unresolved externals
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@kshegunov I tried to add this:
myprojectglobal.h
#ifndef MYPROJECTGLOBAL_HPP #define MYPROJECTGLOBAL_HPP #include <QtCore/qglobal.h> #if defined(MYPROJECT_LIBRARY) # define MYPROJECT_EXPORT Q_DECL_EXPORT #else # define MYPROJECT_EXPORT Q_DECL_IMPORT #endif #endif // MYPROJECTGLOBAL_HPP
DEFINES += MYPROJECT_LIBRARY
plugininterface.hpp
#ifndef PLUGININTERFACE_HPP #define PLUGININTERFACE_HPP #include "myprojectglobal.hpp" #include <QtPlugin> class MYPROJECT_EXPORT PluginInterface { public: virtual ~PluginInterface() {} }; #define PluginInterface_iid "PluginInterface/1.0" Q_DECLARE_INTERFACE(PluginInterface, PluginInterface_iid) #endif // PLUGININTERFACE_HPP
abstractplugin.hpp
#ifndef ABSTRACTPLUGIN_HPP #define ABSTRACTPLUGIN_HPP #include "plugininterface.hpp" class MYPROJECT_EXPORT AbstractPlugin : public QObject, public PluginInterface { Q_OBJECT Q_INTERFACES(PluginInterface) }; #endif // ABSTRACTPLUGIN_HPP
And now I'm getting these errors:
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual __cdecl PluginInterface::~PluginInterface(void)" (_imp??1PluginInterface@@UEAA@XZ) referenced in function "int
public: __cdecl PluginFoo::PluginFoo(void)'::
1'::dtor$0" (?dtor$0@?0???0PluginFoo@@QEAA@XZ@4HA)moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl PluginInterface::PluginInterface(void)" (_imp??0PluginInterface@@QEAA@XZ) referenced in function "public: __cdecl PluginFoo::PluginFoo(void)" (??0PluginFoo@@QEAA@XZ)
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual void * __cdecl AbstractPlugin::qt_metacast(char const *)" (_imp?qt_metacast@AbstractPlugin@@UEAAPEAXPEBD@Z) referenced in function "public: virtual void * __cdecl PluginFoo::qt_metacast(char const *)" (?qt_metacast@PluginFoo@@UEAAPEAXPEBD@Z)
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual int __cdecl AbstractPlugin::qt_metacall(enum QMetaObject::Call,int,void * *)" (_imp?qt_metacall@AbstractPlugin@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z) referenced in function "public: virtual int __cdecl PluginFoo::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@PluginFoo@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z)
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl AbstractPlugin::AbstractPlugin(void)" (_imp??0AbstractPlugin@@QEAA@XZ) referenced in function "public: __cdecl PluginFoo::PluginFoo(void)" (??0PluginFoo@@QEAA@XZ)
moc_pluginfoo.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual __cdecl AbstractPlugin::~AbstractPlugin(void)" (_imp??1AbstractPlugin@@UEAA@XZ) referenced in function "public: virtual __cdecl PluginFoo::~PluginFoo(void)" (??1PluginFoo@@UEAA@XZ)
moc_pluginfoo.obj:-1: error: LNK2001: unresolved external symbol "__declspec(dllimport) public: static struct QMetaObject const AbstractPlugin::staticMetaObject" (_imp?staticMetaObject@AbstractPlugin@@2UQMetaObject@@B)
....\bin\plugins\pluginfoo.dll:-1: error: LNK1120: 7 unresolved externals
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@Defohin Do you link your pluginfoo plugin against the lib containing AbstractPlugin and PluginInterface?
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Hi,
The usual setup when building a plugin based application is to have the plugin interfaces definitions and related code in a library that you will link to both the plugin and the application.
That's what is suggested here.
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Hi,
The usual setup when building a plugin based application is to have the plugin interfaces definitions and related code in a library that you will link to both the plugin and the application.
That's what is suggested here.
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Roughly :
pluginfoo.pro
QT += core gui TARGET = pluginfoo TEMPLATE = lib CONFIG += plugin DESTDIR = $$OUTPWD/bin/plugins LIBS += -L$$OUTPWD/lib -lmycoollib DEFINES += QT_DEPRECATED_WARNINGS INCLUDEPATH += ../mycoollib SOURCES += pluginfoo.cpp HEADERS += pluginfoo.hpp DISTFILES += pluginfoo.json
mycoollib.pro
QT += core gui TARGET = mycoollib TEMPLATE = lib DESTDIR = $$OUTPWD/lib INCLUDEPATH += . SOURCES += \ abstractplugin.cpp HEADERS += \ plugininterface.hpp abstractplugin.hpp
myproject.pro
QT += core gui widgets xml network TARGET = myproject TEMPLATE = app DESTDIR = $$OUTPWD/bin LIBS += -L$$OUTPWD/lib -lmycoollib INCLUDEPATH += ../mycoollib DEFINES += QT_DEPRECATED_WARNINGS SOURCES += src/main.cpp \ gui/myprojectwindow.cpp HEADERS += gui/myprojectwindow.hpp
Project structure
mycoolproject \ ---- mycoollib ---- pluginfoo ---- myproject
mycoolproject being a SUBDIR project building first mycoollib and then pluginfoo and myproject.
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Roughly :
pluginfoo.pro
QT += core gui TARGET = pluginfoo TEMPLATE = lib CONFIG += plugin DESTDIR = $$OUTPWD/bin/plugins LIBS += -L$$OUTPWD/lib -lmycoollib DEFINES += QT_DEPRECATED_WARNINGS INCLUDEPATH += ../mycoollib SOURCES += pluginfoo.cpp HEADERS += pluginfoo.hpp DISTFILES += pluginfoo.json
mycoollib.pro
QT += core gui TARGET = mycoollib TEMPLATE = lib DESTDIR = $$OUTPWD/lib INCLUDEPATH += . SOURCES += \ abstractplugin.cpp HEADERS += \ plugininterface.hpp abstractplugin.hpp
myproject.pro
QT += core gui widgets xml network TARGET = myproject TEMPLATE = app DESTDIR = $$OUTPWD/bin LIBS += -L$$OUTPWD/lib -lmycoollib INCLUDEPATH += ../mycoollib DEFINES += QT_DEPRECATED_WARNINGS SOURCES += src/main.cpp \ gui/myprojectwindow.cpp HEADERS += gui/myprojectwindow.hpp
Project structure
mycoolproject \ ---- mycoollib ---- pluginfoo ---- myproject
mycoolproject being a SUBDIR project building first mycoollib and then pluginfoo and myproject.
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You don't link the plugins. You link your plugins against that common library.
Yes, you have to use both
-l
and-L
.-L
just tells the linker where to look at. -
You don't link the plugins. You link your plugins against that common library.
Yes, you have to use both
-l
and-L
.-L
just tells the linker where to look at.@SGaist It works, but I have another question now.
I named the "commonlib" to "pluginmanager" this class will hold information about plugins, load, unload and so on using
QPluginLoader
, but... when I try to use it on the main application including the headerpluginmanager.hpp
it says that it cannot open the file, even if I have theINCLUDEPATH += ../pluginmanager
. On Qt Creator it does work, I'm able to ctrl+click, etc, but when I try to compile I get this error. -
@SGaist It works, but I have another question now.
I named the "commonlib" to "pluginmanager" this class will hold information about plugins, load, unload and so on using
QPluginLoader
, but... when I try to use it on the main application including the headerpluginmanager.hpp
it says that it cannot open the file, even if I have theINCLUDEPATH += ../pluginmanager
. On Qt Creator it does work, I'm able to ctrl+click, etc, but when I try to compile I get this error. -
@Defohin Did you run qmake again after changing the pro file? After qmake you should do a complete rebuild.
@jsulm It works, but now I'm getting unresolved external symbol on the main project when trying to use
PluginManager manager
on theMyProjectWindow
, and I haveLIBS += -L../libs -lpluginmanager
on the pro file.myprojectwindow.obj:-1: error: LNK2019: unresolved external symbol "public: __cdecl PluginManager::PluginManager(class QObject *)" (??0PluginManager@@QEAA@PEAVQObject@@@Z) referenced in function "public: __cdecl MyProjectWindow::MyProjectWindow(class QWidget *)" (??0MyProjectWindow@@QEAA@PEAVQWidget@@@Z)
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@jsulm It works, but now I'm getting unresolved external symbol on the main project when trying to use
PluginManager manager
on theMyProjectWindow
, and I haveLIBS += -L../libs -lpluginmanager
on the pro file.myprojectwindow.obj:-1: error: LNK2019: unresolved external symbol "public: __cdecl PluginManager::PluginManager(class QObject *)" (??0PluginManager@@QEAA@PEAVQObject@@@Z) referenced in function "public: __cdecl MyProjectWindow::MyProjectWindow(class QWidget *)" (??0MyProjectWindow@@QEAA@PEAVQWidget@@@Z)