how to add new class ?

Lost User

I am seriously trying to learn more about C++_. I did add a new class to the constructor, just following an examples , and I do not understand why I am getting this error. My own add is duplicate of existing , working class, and I do no see why it does no like the pointer.

     m\_serial(new QSerialPort(this),
       // sequence 1\` st add HERE
        m\_TAB\_Ext(new A\_BT\_TAB\_DIALOG\_EXT)

/mnt/A_BT_DEC10/A_APR13_APR15/A_APR9_MAR7_MAR19_CLEAN/A_BT_LIBRARY/terminal_Bluetooth/mainwindow_Bluetooth_copy.cpp:3088: error: called object type 'A_BT_TAB_DIALOG_EXT *' is not a function or function pointer
mainwindow_Bluetooth_copy.cpp:3088:22: error: called object type 'A_BT_TAB_DIALOG_EXT *' is not a function or function pointer
m_TAB_Ext(new A_BT_TAB_DIALOG_EXT())
~~~~~~~~~^

here is my class declaration

namespace Ui {
class A_BT_TAB_DIALOG_EXT;
// add forward declarations ??
class QMdiArea;
}

class A_BT_TAB_DIALOG_EXT : public QWidget
{
Q_OBJECT

public:
explicit A_BT_TAB_DIALOG_EXT(QWidget *parent = nullptr);
~A_BT_TAB_DIALOG_EXT();

private:
Ui::A_BT_TAB_DIALOG_EXT *ui;

// 3 define / declare members / parameters

QLabel \*m\_status = nullptr;
QMdiArea \*m\_mdiarea = nullptr;
QSerialPort \*m\_serial = nullptr;

};

Mircea Neacsu

There is a slight discrepancy in your code. You wrote:

m_serial(new QSerialPort(this),
// sequence 1` st add HERE
m_TAB_Ext(new A_BT_TAB_DIALOG_EXT)

Meanwhile the compiler error message is:

m_TAB_Ext(new A_BT_TAB_DIALOG_EXT())

(note the extra pair of parenthesis). The code you posted is potentially correct, assuming m_TAB_Ext is declared as:

A_BT_TAB_DIALOG_EXT *m_TAB_Ext;

However the compiler error message seems to indicate that you have those extra parenthesis and, in this case, the compiler interprets it as a function call.

Mircea

Lost User

Good catch, but even after removing the () I get same error.

  //! \[1\]
        //! add rfcomm ??
        m\_serial(new QSerialPort(this),
       // sequence 1\` st add HERE
        m\_TAB\_Ext(new A\_BT\_TAB\_DIALOG\_EXT)

Mircea Neacsu

I think you are missing the declaration for m_tab_ext. Your class should look like:

class A_BT_TAB_DIALOG_EXT : public QWidget
{
Q_OBJECT

public:
explicit A_BT_TAB_DIALOG_EXT(QWidget *parent = nullptr);
~A_BT_TAB_DIALOG_EXT();

private:
Ui::A_BT_TAB_DIALOG_EXT *ui;

// 3 define / declare members / parameters

QLabel \*m\_status = nullptr;
QMdiArea \*m\_mdiarea = nullptr;
QSerialPort \*m\_serial = nullptr;

A\_BT\_TAB\_DIALOG\_EXT \*m\_TAB\_Ext;
//...blah, blah, more stuff here

}

Mircea

Mircea Neacsu

Not sure I understand what you try to do. Maybe the code samle is a bit too short. Where is the `m_TAB_ext` initialization line? I don;t see a declaration for `m_TAB_ext`.

Mircea

CPallini

Quote:

m_serial(new QSerialPort(this), // sequence 1` st add HERE m_TAB_Ext(new A_BT_TAB_DIALOG_EXT)

Which of the overloaded constructors of the QSerialPort class are you trying to call? Could you please show full details of m_TAB_Ext variable?

"In testa che avete, Signor di Ceprano?" -- Rigoletto

Lost User

What is the definition of m_TAB_Ext? It looks like it, or m_serial, is looking for a function reference/pointer, but you are passing it a pointer to a A_BT_TAB_DIALOG_EXT object.

BernardIE5317

May I please inquire what is a Q_OBJECT .

Lost User

Here are all parameters definitions (?) PS There are no other errors / issues . So what is

QSerialPort *m_serial = nullptr;

contributing to the issue / error and why is it part of the discussion? ( just asking )

private:
// sequence 4th*
public:
A_BT_TAB_DIALOG_EXT *m_TAB_Ext = nullptr;

private:

    void showStatusMessage(const QString &message);
    Ui::MainWindow\_Bluetooth \*m\_ui = nullptr;
    // add MDIarea ??
    QMdiArea  \*m\_mdiarea = nullptr;

    QLabel \*m\_status = nullptr;
    Console \*m\_console = nullptr;
    SettingsDialog \*m\_settings = nullptr;
    QSerialPort \*m\_serial = nullptr;


    // STEP 2 define class ??
    // spelling error  !!!
    SettingsDialog\_RFcomm \*m\_settings\_RFcomm = nullptr;

Lost User

SOLVED THANKS, you have a very nice , positive , constructive way to lead to solution.

BernardIE5317

I inquire re/ Q_OBJECT because I do not understand why the compiler does not report an error re/ its usage in the code as written as I assume it is either the name of a type perhaps a class type or an identifier of an object of some type. In either case it would of course be a syntax error exempli gratia as per below:

class cfoo
{
int // syntax error
public:
void foo();
}

Likewise it is a syntax error to write the identifier of an object without a type specifier exempli gratia as per below:

class cfoo
{
xyz // syntax error
public:
void foo();
}

Perhaps Q_OBJECT is a macro hiding these details. In conclusion I do not see the answer to my inquiry.

Lost User

Sorry , I got sidetracked fixing the issue. I have been told , not just advised, NOT to post Qt questions. Since I am not welcomed to do so I , on my own, do not want to discuss Qt here. I think that is fair. Cheers