[SOLVED]QVariant passed in SIGNAL LNK 2019 Unresolved External Symbol
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Still really new to QT development
Not entirely sure why I am seeing the linker error:
debug\myproject.exe : fatal error LNK1120: 1 unresolved externals
jom: C:\Qt\build-myproject-Desktop_Qt_5_2_1_MSVC2012_OpenGL_64bit-Debug\Makefile.Debug [debug\myproject.exe] Error 1120
jom: C:\Qt\build-myproject-Desktop_Qt_5_2_1_MSVC2012_OpenGL_64bit-Debug\Makefile [debug] Error 2
10:55:42: The process "C:\Qt\Qt5.2.1\Tools\QtCreator\bin\jom.exe" exited with code 2.
Error while building/deploying project myproject(kit: Desktop Qt 5.2.1 MSVC2012 OpenGL 64bit)
When executing step 'Make'
10:55:42: Elapsed time: 00:04.Here's what I did...
Here's some code:
@MyConsumerClass:signals:
void configValueChanged(QVariant val);MyProducerClass:
public slots:
void configValueChangeHandler(QVariant val);@I added @#include <QVariant>@ to both classes and tried to build. That's when I saw the error. Using QT Creator 5.2.1 on Windows 7.
I also noticed that if I move the method from the public slots: to be just a public regular method, I can compile just fine. But I am hoping to be able to use SIGNALS to pass data around so I can avoid coupling.
Can QVariant not be used as a signal argument??
Thank you for any guidance.
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Hi,
Sure they can, did you implement configValueChangeHandler ?
If so, you would need to post what exact symbols are missing
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I did:
@void configValueChangedHandler(QVariant val){
...
}
@How do I see what exact symbols are missing. Those two messages are all Im getting in the compile and issues windows:
moc_myclass.obj:-1: error: LNK2019: unresolved external symbol "public: void __cdecl MyClass::configValueChangedHandler(class QVariant)" (?configValueChangedHandler@MyClass@@QEAAXVQVariant@@@Z) referenced in function "private: static void __cdecl MyClass::qt_static_metacall(class QObject *,enum QMetaObject::Call,int,void * *)" (?qt_static_metacall@MyClass@@CAXPEAVQObject@@W4Call@QMetaObject@@HPEAPEAX@Z)
When I try to make the implementation public (like the slot accessor), I get a different error... so this :
@public void configValueChangedHandler(QVariant val){
...
}
@
doesnt work.Ive been away from c++ for about a decade (please forgive my ignorance).
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Are you missing the Q_OBJECT macro in your class ? Does it properly inherit from QObject ?
If the macro is missing, don't forget to re-run qmake before compiling
