As dynamic libraries to use class variables?

[Mikee]

I can call the void StrategyCod() .
I did:
strategycod.h:

#ifndef STRATEGYCOD_H
#define STRATEGYCOD_H

#include "strategycod_global.h"


extern "C" {STRATEGYCODSHARED_EXPORT void StrategyCod(MainWinow * main);}

class STRATEGYCODSHARED_EXPORT StrategyCod
{

//public:
   // StrategyCod1();
};

#endif // STRATEGYCOD_H

strategycod.cpp:

#include "strategycod.h"
#include <QDebug>
//#include "C:\\Qt\project\\MyCandleSrick\\mainwindow.h"
//#include <mainwindow>
//StrategyCod::StrategyCod1(){qDebug()<<"Library work1";}



void StrategyCod(MainWinow * main)
{
    //MainWindow w;
    qDebug()<<"Library work2";//<<w.NBar;
}

6 errors:
C:\Qt\project\StrategyCod\strategycod.h:7: error: variable or field 'StrategyCod' declared void
extern "C" {STRATEGYCODSHARED_EXPORT void StrategyCod(MainWinow * main);}
^
C:\Qt\project\StrategyCod\strategycod.h:7: error: 'MainWinow' was not declared in this scope
C:\Qt\project\StrategyCod\strategycod.h:7: error: 'main' was not declared in this scope
extern "C" {STRATEGYCODSHARED_EXPORT void StrategyCod(MainWinow * main);}
^
C:\Qt\project\StrategyCod\strategycod.cpp:9: оerror: variable or field 'StrategyCod' declared void
void StrategyCod(MainWinow * main)
^
C:\Qt\project\StrategyCod\strategycod.cpp:9: error: 'MainWinow' was not declared in this scope
C:\Qt\project\StrategyCod\strategycod.cpp:9: error: 'main' was not declared in this scope
void StrategyCod(MainWinow * main)
^

[mrjj]

Hi
You must include mainwindw.h so it knows type

trategycod.cpp:
#include "mainwindow.h" // should know where to find it due to the INCLUDEPATH in .pro file

[Mikee]

When i do this same error appers:
C:\Qt\project\MyCandleSrick\mainwindow.h:4: error: QMainWindow: No such file or directory

In the file C:/Qt/project/MyCandleSrick/mainwindow.h:
4:#include <QMainWindow>

[mrjj]

@Mikee
Well you library is with

QT -= gui

so it dont know QMainwindow type ( or any Qt widget type)

[Mikee]

I fixed strategycod.pro:

QT       += core gui

TARGET = StrategyCod
TEMPLATE = lib

DEFINES += STRATEGYCOD_LIBRARY
DEFINES += QT_DEPRECATED_WARNINGS
SOURCES += \
        strategycod.cpp

HEADERS += \
        strategycod.h \
        strategycod_global.h 

unix {
    target.path = /usr/lib
    INSTALLS += target
}
INCLUDEPATH = "C:/Qt/project/MyCandleSrick"

But the error is the same.

[Mikee]

I done this in strategycod.pro

INCLUDEPATH = "C:/Qt/project/MyCandleSrick"  "C:/Qt/Qt5.9.2/5.9.2/Src/qtbase/include/QtWidgets"

Now it included <QMainWindow>. But it isnt working now

extern "C" {STRATEGYCODSHARED_EXPORT void StrategyCod(MainWinow * main);}

and

void StrategyCod(MainWinow * main)

errors:
C:\Qt\project\StrategyCod\strategycod.h:7: error: variable or field 'StrategyCod' declared void
extern "C" {STRATEGYCODSHARED_EXPORT void StrategyCod(MainWinow * main);}
^
C:\Qt\project\StrategyCod\strategycod.h:7: error: 'MainWinow' was not declared in this scope
C:\Qt\project\StrategyCod\strategycod.h:7: error: 'main' was not declared in this scope
extern "C" {STRATEGYCODSHARED_EXPORT void StrategyCod(MainWinow * main);}
^
C:\Qt\project\StrategyCod\strategycod.cpp:9: оerror: variable or field 'StrategyCod' declared void
void StrategyCod(MainWinow * main)
^
C:\Qt\project\StrategyCod\strategycod.cpp:9: error: 'MainWinow' was not declared in this scope
C:\Qt\project\StrategyCod\strategycod.cpp:9: error: 'main' was not declared in this scope
void StrategyCod(MainWinow * main)

[SGaist]

Because when you do INCLUDEPATH = you replace the content of that variable with what follows. Use INCLUDEPATH += to append your folders to it.

[Mikee]

Now all includes are working.
When I use function

void StrategyCod(MainWindow * main)
{
    //MainWindow w;
    main->NBar;
    qDebug()<<"Library work2"<<main->NBar;//<<w.NBar;
}

qDebug message is not a valid value NBar

[Mikee]

I think that need to do reference class variable. But this code isn't working

void StrategyCod(/*MainWindow * main*/)
{
    long long &NBar1 =MainWindow.NBar;
    qDebug()<<"Library work2";//<<w.NBar;
}

How can i do reference?

[mrjj]

@Mikee

via the parameter ( main or what u called it)

void StrategyCod(MainWindow * main) {
    qDebug()<<"Library work2"<<main->NBar;
}

if NBAr is wrong, then something else is wrong. not the function
it might be you call StrategyCod BEFORE setting it in mainwindow or
something like that.

[Mikee]

I checked:
library:
void StrategyCod(double Parametr)

{
    MainWindow *w;
    qDebug()<<"Library work2"<<Parametr<<w->NBar;
}

main.cpp:

QLibrary MyLib("C:\\Qt\\project\\build-StrategyCod-Desktop_Qt_5_9_2_MinGW_32bit-Debug\\debug\\StrategyCod");  
    MyLib.load();
    typedef void (*MyPrototype)();
    MyPrototype StrategyCod = (MyPrototype) MyLib.resolve("StrategyCod");
    qDebug()<<w.NBar;  //NBar=0 is hear 
    StrategyCod();  //NBar=5943858560 is hear 
    MyLib.unload();

Maybe here typedef void (*MyPrototype)(); need append void (*MyPrototype)(class); ?

[mrjj]

@Mikee
Yes it must all match.

typedef void (*MyPrototype)();

means pointer to function takes no parameters
which is untrue.

[Mikee]

But what to do with NBar?

void StrategyCod()
{
    MainWindow *w;
    qDebug()<<"Library work2"<<w->NBar;
  
}

[jsulm]

@Mikee

typedef void (*MyPrototype)(MainWindow *w);

[Mikee]

I have done this and it's working

 QLibrary MyLib("C:\\Qt\\project\\build-StrategyCod-Desktop_Qt_5_9_2_MinGW_32bit-Debug\\debug\\StrategyCod");  
    MyLib.load();
    typedef void (*MyPrototype)(MainWindow *);
    MyPrototype StrategyCod = (MyPrototype) MyLib.resolve("StrategyCod");
    StrategyCod(&w);  
    qDebug()<<"q1"<< q1;
    MyLib.unload();

Thank you

[mrjj]

Congrats :)

[Mikee]

I have are new problem.

qDebug()<<NBar;

return NBar=1064,

qDebug()<<"Library work2"<< Parametr<<w->NBar;

return NBar=0
In class MainWindow:

void MainWindow::on_ButtonRuneOne_clicked()//запуск стратегии на одном ядре
{
    bool ok;
    double d = QInputDialog::getDouble(this, tr("ParametrForStrategy"),
                                           tr("double:"), 37.56, -100000, 100000, 6, &ok);
    if (ok) {ParametrForStrategyCod=d; }

    QLibrary MyLib("C:\\Qt\\project\\build-StrategyCod-Desktop_Qt_5_9_2_MinGW_32bit-Debug\\debug\\StrategyCod");  
    MyLib.load();
    typedef void (*MyPrototype)(double,MainWindow *);
    MyPrototype StrategyCod = (MyPrototype) MyLib.resolve("StrategyCod");
    MainWindow w;
    qDebug()<<NBar;
    StrategyCod(ParametrForStrategyCod,&w);  /
    MyLib.unload();
}

In library:

void StrategyCod(double Parametr, MainWindow *w)
{
    qDebug()<<"Library work2"<< Parametr<<w->NBar;
}

But in main.cpp it works good. How can I fix problem with link of object class?

[SGaist]

You're passing w to your method which is not the current MainWindow object you are calling StrategyCod from.

Pass this to the method.

On a side note, you are doing some pretty convoluted stuff here for what seems to be a pretty simple task. I'd encourage you to re-think a bit the design of your application.

[Mikee]

Thank you. I wrote it like this

StrategyCod(ParametrForStrategyCod,this); 

and it works

[Mikee]

How can I create lamda function in the slot of the class?

       QVector <double> Perebor1;
       for (double i=d1;i<=d2;i=i+d3) 
       {
           Perebor1.append(i);
       }
       QLibrary MyLib("C:\\Qt\\project\\build-StrategyCod-Desktop_Qt_5_9_2_MinGW_32bit-Debug\\debug\\StrategyCod");  
       MyLib.load();
       typedef void (*MyPrototype)(double,MainWindow *);
       MyPrototype StrategyCod = (MyPrototype) MyLib.resolve("StrategyCod");
       //StrategyCod(ParametrForStrategyCod,this);  
       QFuture<void> Perebor2 = QtConcurrent::map(Perebor1,[&](const double& d){ StrategyCod(d,this);}); 
       MyLib.unload();