Signals in the DLL giving unresolved external symbol error...

[TheCrowKaka]

Hello

I have made a library with this header file. This is library created to be used with C# and vb.net and follows the hierarchyax example.

#ifndef NEWCOSMIC17_H
#define NEWCOSMIC17_H

#include <QObject>

class NewCosmic17 : public QObject
{

    Q_OBJECT
    Q_CLASSINFO("ClassID","{4B2125A6-746A-4BDA-8F20-D2B97DE8839E}")
    Q_CLASSINFO("InterfaceID","{FC4F46E8-7875-4157-BFD7-2A448BD73E9B}")
    Q_CLASSINFO("EventsID","{41D6CF05-462F-4DCE-A328-8037659BCDC0}")

public:
    NewCosmic17(QObject *parent = nullptr);
    ~NewCosmic17();

//signals:
    /*
     * this signal is emitted when ever the state of machine changes or
     * a command to change the state of machine is called.
     *
     * */
    void MachineState(bool isConnected);
    /*
     * This signal is emitted whenever an error occurs.
     * */
    void ErrorEmitted(int ErrNum,QString ErrDescript);  //
    /*
     * This signal is emitted whenever the marking complete signal is recieved
     * from the marking machine.
     * */
    void MarkingComplete();

    /*
     * This signal is emitted whenever marking is stopped with a stop button.
     * */
    void MarkingStopped();

public slots:
    int ConnecttoMachine(QString ipaddress);
    void DisConnect();
    int StartMarking(bool issimulate);
    int AssignDesign(QString designnamewithpath);

private:
    void macstate(bool value);

    void StartBtnTriggered();

    void MarkComp();

    void EmStopisPressed();

    void DisconMachine();
};

#endif // NEWCOSMIC17_H

Now, if i remove the signals given here, the library compiles well.

However, with the signals, it gives errors...

Creating library release\newCosmic171.lib and object release\newCosmic171.exp
newcosmic17.obj : error LNK2019: unresolved external symbol "public: void __thiscall NewCosmic17::MachineState(bool)" (?MachineState@NewCosmic17@@QAEX_N@Z) referenced in function "private: void __thiscall NewCosmic17::macstate(bool)" (?macstate@NewCosmic17@@AAEX_N@Z)
newcosmic17.obj : error LNK2019: unresolved external symbol "public: void __thiscall NewCosmic17::ErrorEmitted(int,class QString)" (?ErrorEmitted@NewCosmic17@@QAEXHVQString@@@Z) referenced in function "public: int __thiscall NewCosmic17::AssignDesign(class QString)" (?AssignDesign@NewCosmic17@@QAEHVQString@@@Z)
newcosmic17.obj : error LNK2019: unresolved external symbol "public: void __thiscall NewCosmic17::MarkingComplete(void)" (?MarkingComplete@NewCosmic17@@QAEXXZ) referenced in function "private: void __thiscall NewCosmic17::MarkComp(void)" (?MarkComp@NewCosmic17@@AAEXXZ)
newcosmic17.obj : error LNK2019: unresolved external symbol "public: void __thiscall NewCosmic17::MarkingStopped(void)" (?MarkingStopped@NewCosmic17@@QAEXXZ) referenced in function "private: void __thiscall NewCosmic17::EmStopisPressed(void)" (?EmStopisPressed@NewCosmic17@@AAEXXZ)
release\newCosmic171.dll : fatal error LNK1120: 4 unresolved externals

Unable to find any clue as to what more is required to be done so that the signals work in the library.

[mrjj]

@TheCrowKaka
Hi
You must flag/place under it with
signals:
Else the compiler just see a function signature with no body defined and that's an undefined.

Also to emit signals, there must be an event loop running.
Its unclear how you handle that.

[TheCrowKaka]

Ha Ha

Thanks mrJJ for pointing out a very silly mistake that I was doing.

I just happened to comment out the signals: and forgot to uncomment that in the process of solving the other errors that i faced and solved step by step.

I just uncommented the signals and the library got compiled.

Thanks for poniting out my mistake.

[mrjj]

@TheCrowKaka
Super :)
Well that is why code review is super effective.
Its far easier to spot something in other code that one's own.