invalid use of non-static member function

[aqdam]

Hi all,
i build a qt-app to run my program(capture program to take picture using v4l2 and entire code is in c) and show the captured photo using qt-widgets,so in qt-app i used qprocess to run my program, i finished it.
now i want to write qt-app which will take pic using my c code which is in c without using qprocess, so i thought of creating my entire program's shared library and use its functions(written in c) to take picture and show.
from the following steps i added my program as shared library...
http://doc.qt.io/qtcreator/creator-project-qmake-libraries.html

#-------------------------------------------------

Project created by QtCreator 2017-11-08T12:09:02

#-------------------------------------------------

//qt-app.pro

 QT       += core gui multimedia multimediawidgets

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = qt_app
TEMPLATE = app
SOURCES += \
        main.cpp \
        mainwindow.cpp

HEADERS += \
        mainwindow.h#INCLUDEPATH += /u/cam_prog1/Include


FORMS += \
        mainwindow.ui

unix:!macx: LIBS += -L$$PWD/../../u/cam_prog1/Library/ -lcam1

INCLUDEPATH += $$PWD/../../u/cam_prog1/Include
DEPENDPATH += $$PWD/../../u/cam_prog1/Include

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QDebug>
#include <QProcess>
#include <QCameraViewfinder>
#include <QMessageBox>

QString file_name,img_path="/u/images/",X,Y,s,br,ct,st,sh,rotate,effects,fr;
int brig,cont,sat,sharp,frames;

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    s = "/u/cam_prog1/Output/cam_main.out";
    qDebug() << s;

}

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


void MainWindow::on_pushButton_5_clicked()
{
    QStringList args;
    QProcess *process = new QProcess(this);
    camera->stop();
    file_name = ui->lineEdit_6->text();

    if((frames = ui->spinBox->value()) == 0)
        frames = 10;
    if((brig = ui->spinBox_2->value()) == 0)
        brig = 100;
    if((cont = ui->spinBox_3->value()) == 0)
        cont = 100;
    if((sat = ui->spinBox_4->value()) == 0)
        sat = 100;
    if((sharp = ui->spinBox_5->value()) == 0)
        sharp = 100;
    if(ui->radioButton->isChecked())
        rotate = 90;
    if(((X = ui->lineEdit_4->text()) == '\0') || (  (Y = ui->lineEdit_5->text()) == '\0'))
    {
        X = "640";   Y = "480";
    }

    br = QString::number(brig);
    ct = QString::number(cont);
    st = QString::number(sat);
    sh = QString::number(sharp);
    rotate = ui->comboBox->currentText();
    effects = ui->comboBox_2->currentText();
    fr = QString::number(frames);
    file_name = img_path + file_name;
    args << X << Y << fr << file_name << "B" << br << "C" << ct << "S" << st << "R" << rotate << "N" << sh << "V" << "E" << effects;
    process->start( s, args);
    QPixmap b(file_name);
    ui->label_6->setPixmap(b.scaled(ui->label_6->width(),ui->label_6->height()));
}

void MainWindow::on_pushButton_6_clicked()
{
        this->close();
}

void MainWindow::on_pushButton_4_clicked()
{
    void * ptr;
    file_name = ui->lineEdit_6->text();
    file_name = img_path + file_name;
    convert_jpeg(file_name,ptr,x,y,x,y);
    QPixmap b(file_name);
    ui->label_6->setPixmap(b.scaled(ui->label_6->width(),ui->label_6->height()));
}


void MainWindow::on_pushButton_clicked()
{
    if (QCameraInfo::availableCameras().count() > 0)
            {
                QList<QCameraInfo> cameras = QCameraInfo::availableCameras();
                foreach (const QCameraInfo &cameraInfo, cameras) {
                    if (cameraInfo == QCameraInfo::defaultCamera())
                       camera= new QCamera(cameraInfo);
                    }
            }
            else
            {
                QMessageBox::warning(this, tr("Error"), tr("No Camera is available."));
               // QMetaObject::invokeMethod(this, "close", Qt::QueuedConnection);
            }
            camera->setViewfinder(ui->viewfinder);
            ui->stackedWidget->setCurrentIndex(0);
            camera->start();
}

here i want to use my library funtion as
convert_jpeg(file_name,ptr,x,y,x,y);

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QCamera>
#include <QCameraImageCapture>
#include <QCameraInfo>

extern "C"{
#include "/u/cam_prog1/Include/cam_main.h"
}
namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private slots:

    void on_pushButton_6_clicked();

    void on_pushButton_5_clicked();

    void on_pushButton_4_clicked();

    void on_pushButton_clicked();

private:
    Ui::MainWindow *ui;
    QCamera * camera;
};

#endif // MAINWINDOW_H

now when i run this above program i'm getting the following error...

/root/qt_app_1_0/mainwindow.cpp:80: error: invalid use of non-static member function
     convert_jpeg(file_name,ptr,x,y,x,y);
                                       ^

quick respose would be appreciated
thanks

[aha_1980]

Hi @aqdam,

You didn't provide the most important thing: the function definition of convert_jpeg. I guess it's a function within a class?

quick respose would be appreciated

This is a user to user forum. People helping in their spare time and for free. Be nice to them ;)

[aqdam]

@aha_1980
thanks for your reply,
the function convert_jpeg() is there in the my library(whose path i gave).
i think the problem is that library which gave is dynamic.
i dont know to how to proceed further?

[SGaist]

Hi,

It has nothing to do with the type of library you are using.

You didn't answer @aha_1980's question: is convert_jpeg part of a class or maybe a namespace ?

The error states that you are trying to use it like a free function and it's not the case of convert_jpeg.