How can I move my normal c++ main() function code to qt main function?

[Ashish Tupate]

@aha_1980 I still didn't get the answer from this forum and the answer by the jsulm is not the expected answer for me. What I want is to write main() as it is like this

int main(int argc, char *argv[])
{
   QApplication a(argc, argv);
   MainWindow w;
   w.show();

   return a.exec();
}

and the code inside this

if (gpioInitialise() < 0) 
        return 1;
e_decoder dec(7, 8, callback);
sleep(50);
dec.re_cancel();
gpioTerminate();

and this code

void callback(int way)
{
   static int pos = 0;
   pos += way;
   std::cout << "pos=" << pos << std::endl;
}

I want to write somewhere in other file. Like I can create a new file (ex. test.cpp) and write it down there. So the code should work. Is it possible?I have tried to write the code.
encodercount.h

#ifndef ENCODERCOUNT_H
#define ENCODERCOUNT_H

namespace Encoder {
class EncoderCount;
}

class EncoderCount
{
public:
    explicit EncoderCount();
    ~EncoderCount();
    int pigpiotest();

private:
    static void callback(int way);
};

encodercount.cpp

#include <pigpio.h>
#include "rotary_encoder.hpp"
#include <iostream>
#include <stdio.h>
#include <unistd.h>

static int pos = 0;
void EncoderCount::callback(int way)
{
       pos += way;
       qDebug() << "pos=" << pos ;
}
 int EncoderCount::pigpiotest()
 {
     if (gpioInitialise() < 0) return 1;

     re_decoder dec(8, 11, callback);

     sleep(50);

     dec.re_cancel();

     gpioTerminate();

 }

Still no output.

[aha_1980]

@Ashish-Tupate said in How can I move my normal c++ main() function code to qt main function?:

So the code should work. Is it possible?

Yes, of course this is possible - it's a very common task for C++ programmers.

But did you actually try what I and @jsulm suggested you? I wrote "as a starting point". This should work with minimum change to your existing program.

If you want the code to reside in a separate file, you will have to refactor it. The sleep can not be used in Qt GUI programs! You can create the functions in a new file decoder.cpp:

void callback()
{
    //...
}

void initDecoder()
{
    if (gpioInitialise() < 0) 
        return 1;
     e_decoder dec(7, 8, callback);
}

void stopDecoder()
{
    dec.re_cancel();
    gpioTerminate();
}

and then call them, for example from main::

#include "decoder.h"

int main(int argc, char *argv[])
{
    initEncoder();

    QApplication a(argc, argv);
    Dialog w;
    w.show();

    int result = a.exec(); // exec() blocks until you close the app

    stopEncoder();

    return result;
}

But better try the examples we gave you yesterday first.

[jsulm]

@Ashish-Tupate said in How can I move my normal c++ main() function code to qt main function?:

Is it possible?

Sure it is, why not?

The code you put in test.cpp - is it called somewhere? I mean: do you use class EncoderCount somewhere? You're using a member function (method) as a callback - this will not work as you need a function.

[Ashish Tupate]

@jsulm test.cpp is encodercount.cpp and yes it is not working.

[jsulm]

@Ashish-Tupate What is not working? Can you please describe the problem clearly? Post the error message?

[Ashish Tupate]

@jsulm my main.cpp file look like this

#include "encodercount.h"

using namespace std;

int main(int argc, char *argv[])
{
    initEncoder();

    QApplication app(argc, argv);
    Dialog w;
    w.show();

    int result = a.exec(); // exec() blocks until you close the app
    stopEncoder();

    return app.exec();
}

and encodercount.h

#ifndef ENCODERCOUNT_H
#define ENCODERCOUNT_H

#include <rotary_encoder.hpp>


namespace Encoder {
class EncoderCount;
}

class EncoderCount
{
public:
    explicit EncoderCount();
    ~EncoderCount();

    void initDecoder();
    void stopDecoder();

};


#endif // ENCODERCOUNT_H

encodercount.cpp

void callback(int way)
{
    cout << " callback"<< endl;

    static int pos = 0;

       pos += way;
       qDebug() << "pos=" << pos ;
}

void initDecoder()
 {
     cout << "pigpio test"<< endl;

     if (gpioInitialise() < 0) return 1;

     re_decoder dec(8, 11, callback);

 }

 void stopDecoder()
 {
     dec.re_cancel();
     gpioTerminate();
 }

and I am getting error :
'initEncoder' was not declared in this scope
initEncoder();
^
'a' was not declared in this scope
int result = a.exec(); // exec() blocks until you close the app
^
'stopEncoder' was not declared in this scope
stopEncoder();
^

[jsulm]

@Ashish-Tupate Add initEncoder(); and stopEncoder(); to encodercount.h.

Change

int result = a.exec();

to

int result = app.exec();

[Ashish Tupate]

@jsulm I dont know why but this error again even if these functions are inside encodercount.h:

'initEncoder' was not declared in this scope
initEncoder();
^
'stopEncoder' was not declared in this scope
stopEncoder();
^

#ifndef ENCODERCOUNT_H
#define ENCODERCOUNT_H
#include <rotary_encoder.hpp>


namespace Encoder {
class EncoderCount;
}

class EncoderCount
{
public:
    explicit EncoderCount();
    ~EncoderCount();

    void initEncoder();
    void stopEncoder();

};


#endif // ENCODERCOUNT_H

[jsulm]

@Ashish-Tupate Please think about what you are doing: you put both functions inside EncoderCount class! And then you try to call them as if they would be simple functions.
You should learn C++.
It should be like this:

#ifndef ENCODERCOUNT_H
#define ENCODERCOUNT_H
#include <rotary_encoder.hpp>

void initEncoder();
void stopEncoder();

[Ashish Tupate]

@jsulm Yes you are right but you have to help me out.Again I got the error :
return-statement with a value, in function returning 'void' [-fpermissive]
if (gpioInitialise() < 0) return 1;
^

[jsulm]

@Ashish-Tupate "but you have to help me out" - no I don't have to.
You should really learn C++ and read the error messages carefully. What you are asking is completely unrelated to Qt.
Change

if (gpioInitialise() < 0) return 1;

to

if (gpioInitialise() < 0) return;

[Ashish Tupate]

@jsulm Thank you for your help.