How can I solve this?

[munna]

I think you should start looking at the examples and tutorials that are part of the Qt installation to know more about signal & slots and UI development using Qt. Qt Assistant has every thing that you need to get started.

[faldzip]

char DLLfunction()
{
    QLibrary myLib("dllprog");
    typedef char* (*MyPrototype)();
    MyPrototype myFunction =
    (MyPrototype) QLibrary::resolve("dllprog", "TestDll");
    char b = myFunction();
    return b;
}

char DLLfunction()
{
    QLibrary myLib("dllprog");
    typedef char* (*MyPrototype)();
    MyPrototype myFunction =
    (MyPrototype) QLibrary::resolve("dllprog", "TestDll");
    char b = myFunction();
    return b;
}

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there is something weird in your code as define MyPrototype as raturning char* and than you do:

char b = myFunction();

char b = myFunction();

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where you are assigning returned value to one char. Is it right?

[srohit24]

a mistake.

the line now is

typedef char (*MyPrototype)();

typedef char (*MyPrototype)();

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[srohit24]

I need a GUI application to display the contents of myFunction. I have a working console application.

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QLibrary>
#include <QLineEdit>
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent), ui(new Ui::MainWindowClass)
{
 
      ui->setupUi(this);
 
QLibrary myLib("dllprog");
typedef char* (*MyPrototype)();
MyPrototype myFunction = (MyPrototype) QLibrary::resolve("dllprog", "TestDll");
 
char* b = myFunction();
ui->lineEdit->setText(b);
 
}
 
MainWindow::~MainWindow()
{
    delete ui;
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QLibrary>
#include <QLineEdit>
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent), ui(new Ui::MainWindowClass)
{

      ui->setupUi(this);

QLibrary myLib("dllprog");
typedef char* (*MyPrototype)();
MyPrototype myFunction = (MyPrototype) QLibrary::resolve("dllprog", "TestDll");

char* b = myFunction();
ui->lineEdit->setText(b);

}

MainWindow::~MainWindow()
{
    delete ui;
}

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This is my code display the characters that myFunction returns in a linedit.

I have created a pushButton and a lineEdit in the .ui file.

I am getting this error.

:-1: error: collect2: ld returned 1 exit status

How can i solve this?

thanks for reading.