Error LNK2019 at compile a program whit Serial Port class

Alan_641

Hi! I im trying to compile a program whit serial port comunication but it show me the Error LNK2019 file not found:main.obj

this is the main.cpp code:

#include "mainwindow.h"
#include <QApplication>

#include <QTextStream>
#include <QCoreApplication>
#include <QFile>
#include <QtCore>
#include <QStringList>
#include <QIODevice>
#include <iostream>
#include <QtSerialPort/QSerialPort>
#include <QDebug>
#include <Windows.h>
#include <QElapsedTimer>

QT_USE_NAMESPACE
QSerialPort serial;

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

    QApplication a(argc, argv);

    QByteArray output;
    serial.setPortName ("COM3");
    serial.open (QIODevice::ReadOnly);
    serial.setBaudRate (QSerialPort::Baud9600);
    serial.setDataBits (QSerialPort::Data8);
    serial.setParity(QSerialPort::NoParity);
    serial.setStopBits (QSerialPort::OneStop);
    serial.setFlowControl (QSerialPort::NoFlowControl);

    while (!serial.isOpen()) serial.open(QIODevice::ReadOnly);
    while (true) {
        output = "a";
        serial.write(output);
        serial.flush();
        timer.start();
        serial.waitForBytesWritten(100);
    }


    MainWindow w;
    w.show();

    return a.exec();
}
//your code here

this is the mainwindow.cpp:

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

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

void MainWindow::on_mano_abierto_clicked()
{

}
//your code here

this is the mainwindow.h:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

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

private slots:
    void on_mano_abierto_clicked();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

//your code here

and this is the .pro file:


QT       += core gui
QT += serialport

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = brazo_gui
TEMPLATE = app


SOURCES += main.cpp\
        mainwindow.cpp

HEADERS  += mainwindow.h

FORMS    += mainwindow.ui
//your code here

and this is the error :

main.obj:-1: error: LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl QSerialPort::QSerialPort(class QObject *)" (_imp??0QSerialPort@@QEAA@PEAVQObject@@@Z) referenced in function "void __cdecl `dynamic initializer for 'serial''(void)" (??__Eserial@@YAXXZ)

appear one of this for every line that include a funcion of the Serial Port class
when i delete it the program compile without errors
even if i only add the line QSerialPort serial; it not compile

please, someone could help me and tell me what is the error and how compile it correctly?

jsulm

Does your Qt installation contain Qt5SerialPort.dll?
Is it a debug or release build?
Another possible problem: you're declaring serial outside of main, so it is initialized before main is executed. You should move it to main (after QApplication a(argc, argv), same for timer).
One note: you should include it like this (no need for QtSerialPort):

#include <QSerialPort>

Alan_641

@jsulm
It's a debug project and yes, the installation contains the Qt5SerialPort.dll. I've already put the QSerialPort serial; code line inside the main after the QApplication a(argc, argv); line but when i compile it the same problem continues.

SGaist

Hi,

Why are you creating a static QSerialPort object ?

jsulm

For debug build you need Qt5SerialPortd.dll. Do you have it?