[SOLVED] How to use connect in a shared library?

[Mohammadsm]

Hi
I've written an application, now I copied the functions in a shared library to make a dll.
Now I can see a weird error:

 #include "library1.h"

Library1::Library1()
{
}

void Library1::Inint_Lib()
{
    if(Scan_Port())
    {
        Serial=new QSerialPort;
QObject::connect(Serial,SIGNAL(readyRead()),this,SLOT(Capture_Received_Data()));
    }
}

It's working in the application with GUI, but this error occurs in the shared library project:

Library1\library1.cpp:16: error: no matching function for call to 'QObject::connect(QSerialPort*&, const char*, Library1* const, const char*)'
Library1\library1.cpp:16: candidates are:
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\qiodevice.h:47: In file included from D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore/qiodevice.h:47:0,
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\QIODevice:1: from D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore/QIODevice:1,
Library1\library1.h:7: from ..\Library1\library1.h:7,
Library1\library1.cpp:1: from ..\Library1\library1.cpp:1:
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\qobject.h:198: static QMetaObject::Connection QObject::connect(const QObject*, const char*, const QObject*, const char*, Qt::ConnectionType)
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\qobject.h:201: static QMetaObject::Connection QObject::connect(const QObject*, const QMetaMethod&, const QObject*, const QMetaMethod&, Qt::ConnectionType)
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\qobject.h:201: note:   no known conversion for argument 2 from 'const char*' to 'const QMetaMethod&'
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\qobject.h:440: QMetaObject::Connection QObject::connect(const QObject*, const char*, const char*, Qt::ConnectionType) const
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\qobject.h:440: note:   no known conversion for argument 3 from 'Library1* const' to 'const char*'
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\qobject.h:214: template<class Func1, class Func2> static QMetaObject::Connection QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, const typename QtPrivate::FunctionPointer<Func2>::Object*, Func2, Qt::ConnectionType)
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\qobject.h:214: note:   template argument deduction/substitution failed:
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\qobject.h:-1: In substitution of 'template<class Func1, class Func2> static QMetaObject::Connection QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, const typename QtPrivate::FunctionPointer<Func2>::Object*, Func2, Qt::ConnectionType) [with Func1 = const char*; Func2 = const char*]':
\Library1\library1.cpp:16: required from here
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\qobject.h:214: error: no type named 'Object' in 'struct QtPrivate::FunctionPointer<const char*>'
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\qobject.h:244: template<class Func1, class Func2> static typename QtPrivate::QEnableIf<((int)(QtPrivate::FunctionPointer<Func2>::ArgumentCount) >= 0), QMetaObject::Connection>::Type QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, Func2)
.
.
.
D:\Qt-5.1.0\5.1.0\mingw48_32\include\QtCore\qobject.h:267: template<class Func1, class Func2> static typename QtPrivate::QEnableIf<(QtPrivate::FunctionPointer<Func2>::ArgumentCount == (-1)), QMetaObject::Connection>::Type QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, Func2)
Library1\library1.cpp:16: note:   candidate expects 3 arguments, 4 provided

How can I connect a signal to the library slot?
Thank you all

[sierdzio]

Is the slot declared as a slot? Does live in a class that inherits from QObject, and is there Q_OBJECT macro there in the header?

[koahnig]

@Mohammadsm
I have added markdown tags for code sections of post.
Please checkout the "markdown tags" at the end of thread.

[Mohammadsm]

@sierdzio
Yes :

class LIBRARY1SHARED_EXPORT Library1
{
    Q_OBJECT
public:
    Library1();
    void Inint_Lib();
private slots:
    void Capture_Received_Data();

[edit: koahnig, code markers]

[Mohammadsm]

@koahnig
I used code format but seems not working!

[koahnig]

@Mohammadsm
You need to use three of ` at start and end of your code block.Check the end of the whole thread here. There is a short explanation.
Some keyboards do not support ` as a key. In this case you can go to the end of the thread and copy the three characters required and paste them where needed.

[sierdzio]

@koahnig said:

You need to use three of ` at start and end of your code block

No need for that. You can just make a code block by having a separate paragraph that has a four-space intendation

[sierdzio]

@Mohammadsm

Your class does not inherit from QObject. Try this:

class LIBRARY1SHARED_EXPORT Library1 : public QObject

Then remeber to rebuild and relink the library, and your project that uses it.

[SGaist]

@sierdzio Indeed the back ticks are not mandatory, however it gives the forum engine a good hint of what is following

[Mohammadsm]

@sierdzio
It worked by adding ": public QObject"
Thank you, very much

[koahnig]

@SGaist said:

@sierdzio Indeed the back ticks are not mandatory, however it gives the forum engine a good hint of what is following

in the cheat sheet you can actually find:
Blocks of code are either fenced by lines with three back-ticks ```, or are indented with four spaces. I recommend only using the fenced code blocks -- they're easier and only they support syntax highlighting.

The question is what is the syntax highlighting now?