[Qt-interest] LNK2001 after extracting an Interface

[Thomas Ehrnhoefer]

Thanks Jesus

That worked like a charm, plugin compiling again.
I would have wished it's some QT related thing I could have maybe not known,
but this one I should have. Thanks for pointing it out

Thomas

On Sat, Jul 16, 2011 at 3:53 AM, Jesus Fernandez <jsfdez at gmail.com> wrote:

> Hi.
>
> In the ClassA definition you need to tell the compiler that methodA is a
> pure virtual method:
>   *virtual void methodA() = 0;*
> If not you need to provide an implementation to this method or the linker
> will try to find the implementation.
>
> On Fri, Jul 15, 2011 at 20:41, Thomas Ehrnhoefer <
> thomas.ehrnhoefer at tasktop.com> wrote:
>
>> Hi
>>
>> I got some code working, with ClassA being being a normal class extending
>> QObject.
>> Now a new requirement came up, and I need ClassA to be turned into an
>> interface, and ClassAImpl to implement it.
>>
>> I moved all private methods and fields to ClassAImpl, made the public
>> declarations virtual in ClassA and added them along with the implementation
>> in ClassAImpl.
>>
>> When I am compiling, I get problems related to the meta object compiler:
>> classa.obj : error LNK2001: unresolved external symbol "public: virtual
>> void __thiscall ClassA::methodA(void)" (?methodA at ClassA@@UAEXXZ)
>>
>> I searched for a bit and all I found was people not having the Q_OBJECT
>> macro, which I do. I am admitting that I am still a bit fuzzy about the meta
>> object model.
>>
>> Would be great if anybody has some hints on what I have obviously or maybe
>> done wrong here. I will add some code samples at the bottom
>>
>> Thanks
>> Thomas
>>
>> *So basically ClassA looks like this:*
>> *classa.h*
>> #ifndef CLASSA_H
>> #define CLASSA_H
>> #include <QObject>
>>
>> class ClassA : public QObject
>> {
>>     Q_OBJECT
>> public:
>>    ClassA(QObject *parent = 0);
>> public slots:
>>     virtual void methodA();
>>
>> };
>>
>> #endif // CLASSA_H
>>
>> *classa.cpp*
>> #include "classa.h"
>>
>> ClassA::ClassA(QObject *parent) :
>>     QObject(parent)
>> {
>> }
>>
>> *And ClassAImpl like this:*
>>
>> *classaimpl.h*
>> #ifndef CLASSAIMPL_H
>> #define CLASSAIMPL_H
>> #include "classa.h"
>>
>> class ClassAImpl : public ClassA
>> {
>>     Q_OBJECT
>> public:
>>     ClassAImpl(QObject *parent = 0);
>>     ~ClassAImpl();
>> public slots:
>>     void methodA();
>> private slots:
>>     void privateMethodB(QString str);
>> private:
>>     QString *memberC;
>> };
>> #endif // CLASSAIMPL_H
>>
>> *classaimpl.cpp*
>> #include "classaimpl.h"
>>
>> ClassAImpl::ClassAImpl(QObject *parent) :
>>     ClassA(parent),
>>     memberC("test")
>> {
>> }
>>
>> ClassAImpl::~ClassAImpl()
>> {
>> }
>>
>> void ClassAImpl::methodA()
>> {
>>     memberC.append(" called");
>> }
>>
>> void ClassAImpl::privateMethodB(QString str)
>> {
>>     memberC.append(str);
>> }
>>
>>
>> --
>> Thomas Ehrnhoefer
>> Software Developer, http://tasktop.com
>>
>> _______________________________________________
>> Qt-interest mailing list
>> Qt-interest at qt.nokia.com
>> http://lists.qt.nokia.com/mailman/listinfo/qt-interest
>>
>>
>


-- 
Thomas Ehrnhoefer
Software Developer, http://tasktop.com
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