Error Undefined Reference To Vtable For Qt
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Qt Undefined Reference To Function
it only takes a minute: Sign up Undefined reference to vtable. Trying to compile a Qt project up vote 41 down vote favorite 4 I'm using Code::Blocks 8.02 and the mingw 5.1.6 compiler. I'm getting this error when I compile my Qt project: C:\Documents and Settings\The Fuzz\Desktop\GUI\App_interface.cpp|33|undefined reference to `vtable for AddressBook' File AddressBook.h: #ifndef ADDRESSBOOK_H #define ADDRESSBOOK_H #include undefined reference to signal qt
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Undefined Reference To Vtable For Class Qobject
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The Vtable Symbol May Be Undefined Because The Class Is Missing Its Key Function
us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just http://stackoverflow.com/questions/1552069/undefined-reference-to-vtable-trying-to-compile-a-qt-project like you, helping each other. Join them; it only takes a minute: Sign up Q_OBJECT throwing 'undefined reference to vtable' error [duplicate] up vote 40 down vote favorite 15 This question already has an answer here: Qt Linker Error: “undefined reference to vtable” 8 answers I'm using Qt Creator 2.0.1 with Qt 4.7.0 (32 bit) on http://stackoverflow.com/questions/4774291/q-object-throwing-undefined-reference-to-vtable-error Windows 7 Ultimate 32 bit. Consider the following code, which is a minimum to produce the error: class T : public QObject, public QGraphicsItem { Q_OBJECT public: T() {} QRectF boundingRect() const {return QRectF();} void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) {} }; int main() { T t; return 0; } The above code fragment causes the following linker errors: In function `T': undefined reference to `vtable for T' undefined reference to `vtable for T' In function `~T': undefined reference to `vtable for T' undefined reference to `vtable for T' If I comment out the line that contains Q_OBJECT, it compiles fine. I need signal and slots with QGraphicsItem so I need Q_OBJECT. What is wrong with the code? Thanks. c++ qt linker-error vtable share|improve this question asked Jan 23 '11 at 14:24 Donotalo 7,147145993 marked as duplicate by djf, Rubens, Phil Hannent, tjameson, John Doyle Jul 13 '13 at 19:03 This question has been asked before and already has an answer. If those ans
on April 24, 2009 by lizardo If you ever come across an error like this when compiling C++ code with Qt derived https://lizardo.wordpress.com/2009/04/24/undefined-reference-to-vtable-for-errors-in-qt-derived-classes/ class definitions:
g++ -Wl,--no-undefined -o test test.o -L/usr/lib -lQtGui http://www.qtcentre.org/threads/48602-undefined-reference-to-vtable-error -lQtCore -lpthread
test.o: In function `main':
test.cpp:(.text+0x2c): undefined reference to `vtable for MyClass'
collect2: ld returned 1 exit status
make: *** [test] Error 1
It is probably because either you defined a class in a .cpp file undefined reference or you forgot to add some header file to the HEADERS variable in the .pro file. This happens because moc (Qt's meta-object compiler) only runs on header files by default (and only on those listed in the HEADERS variable), therefore it did not generate the necessary MOC code for that class. The fix undefined reference to is to simply move the class definition to a header, and make sure it is added to the HEADERS variable in the qmake project file. Like this:Like Loading... Related About lizardo My hobby: figure out how systems are expected to work; induce them to work unexpectedly; and responsibly disclose. View all posts by lizardo → This entry was posted in Tricks and tagged qt. Bookmark the permalink. ← Setting up libc6 sources for analysis onDebian/Ubuntu Making icecream monitor (icemon) work onJaunty → 24 Responses to "undefined reference to `vtable for …' errors" in Qt derivedclasses Bruno Abinader says: April 24, 2009 at 11:44 … or you can add something like this (supposing that MyClass definition is under MyClass.cpp file): #include "MyClass.moc" At the end of MyClass.cpp file🙂 It is very useful when you need to define private classes (see http://techbase.kde.org/Policies/Library_Code_Policy#D-Pointers ) which doesn’t need to be visible from header files. Reply Arun says: February 7, 2010 at 1
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