Can't link my library

Sareban

I made a library in qt creator as c++ dynamic library option. But now i can' compile the project im using it.

my .pro file is this;
QT += core gui multimedia

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = testlib2
TEMPLATE = app

DEFINES += QT_DEPRECATED_WARNINGS

#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0

CONFIG += c++11

SOURCES +=
main.cpp
mainwindow.cpp

HEADERS +=
mainwindow.h

FORMS +=
mainwindow.ui

Default rules for deployment.

qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

unix|win32: LIBS += -L$$PWD/../build-tonegenlib-Desktop_Qt_5_12_1_MinGW_64_bit-Debug/debug/ -ltonegenlib

INCLUDEPATH += $$PWD/../tonegenlib
DEPENDPATH += $$PWD/../tonegenlib

and the compile errror is this ;

debug/mainwindow.o: In function MainWindow::MainWindow(QWidget*)': C:\QT_workspace\build-testlib2-Desktop_Qt_5_12_1_MinGW_64_bit-Debug/../testlib2/mainwindow.cpp:6: undefined reference to __imp__ZN10TonegenlibC1Ev'
collect2.exe: error: ld returned 1 exit status
mingw32-make[1]: *** [Makefile.Debug:69: debug/testlib2.exe] Error 1
mingw32-make: *** [Makefile:38: debug] Error 2
mingw32-make[1]: Leaving directory 'C:/QT_workspace/build-testlib2-Desktop_Qt_5_12_1_MinGW_64_bit-Debug'
01:29:22: The process "C:\Qt\Qt5.12.1\Tools\mingw730_64\bin\mingw32-make.exe" exited with code 2.
Error while building/deploying project testlib2 (kit: Desktop Qt 5.12.1 MinGW 64-bit)
When executing step "Make"
01:29:22: Elapsed time: 00:01.

thank you so much for your help.

JonB

@Sareban
Where exactly is your tonelib file (full name & path) on the disk?
Do you build it yourself?
Are you sure it's MinGW and not, say, MSVC?
Are you sure it's 64-bit and not 32-bit?
Have you included the right header file for it, and are you calling a function in it which is correctly exported?

Sareban

@JonB
thanks for your reply. I supplied the full name and path to the .pro file with add library thing on qt. and i built it and qmake with the same kit and compiler i do with every other project. add library seeks for .a file and i provided it with that in the same folder of debug .dll .

Sareban

@JonB
#include <QMainWindow>
#include <tonegenlib.h>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

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

Tonegenlib tonegen;



void test();

private:
Ui::MainWindow *ui;
};

this is the header file of the project.

void MainWindow::test()
{
tonegen.m_freq = 240;
tonegen.playAudio();

}

and this is the .cpp where i call the function and change a variable.
without using the library there is no errors but when i define tonegen and then call the function gives error.

hskoglund

Hi, can you show the tonegenlib.h file?

Sareban

@hskoglund

#ifndef TONEGENLIB_H
#define TONEGENLIB_H

#include "tonegenlib_global.h"
#include <QBuffer>
#include <QByteArray>
#include <QMainWindow>
#include <QAudio>
#include <QtMultimedia/QAudioOutput>
#include <QScopedPointer>
#include <QFile>
#include <QObject>
#include <QFile>
#include <QDataStream>
#include <QIODevice>
#include <QtMultimedia/QAudioDeviceInfo>
#include <QtMultimedia/QAudioFormat>

class TONEGENLIBSHARED_EXPORT Tonegenlib : public QWidget
{
Q_OBJECT

public:
Tonegenlib();
void toneGenerate();
void playAudio();
void saveSound();
void readFile();
int SAMPLE_RATE = 44100;
int m_seconds=2;
int m_freq=50;
int m_ph;
int m_amp = 5;

private:

int len= m_seconds*SAMPLE_RATE;

QAudioFormat format;
QByteArray sinbuf;
QBuffer sininput;
QAudioOutput *audio;

private slots:
void handleStateChanged(QAudio::State newState);
void supplyData();
};

#endif // TONEGENLIB_H

this is my tonelib.h

hskoglund

Sorry, I was looking for where you #define TONEGENLIBSHARED_EXPORT, can you show the tonegenlib_global.h?

Sareban

@hskoglund

#ifndef TONEGENLIB_GLOBAL_H
#define TONEGENLIB_GLOBAL_H

#include <QtCore/qglobal.h>

#if defined(TONEGENLIB_LIBRARY)

define TONEGENLIBSHARED_EXPORT Q_DECL_EXPORT

#else

define TONEGENLIBSHARED_EXPORT Q_DECL_IMPORT

#endif

#endif // TONEGENLIB_GLOBAL_H

thanks for your help :)

hskoglund

Hmm, just a guess but it seems Tonegenlib's constructor isn't visible, can you show the code for Tonegenlib::Tonegenlib in your tonelib.cpp file?

Sareban

@hskoglund

oh ok. do i need a constructor and deconstructor in a shared library cpp file ? didnt know that. i just started the code with the first function needed.

void Tonegenlib::toneGenerate() i started like this.

is there anything i need to consider when writing the constructor of the cpp ?

or is it enough to start with tonegenlib::tonegenlib()

hskoglund

@Sareban You don't need a constructor because it's a shared library, but since you mention the constructor in tonelib.h:

...
public:
Tonegenlib();
...

either define an empty constructor in tonelib.cpp Tonegenlib::Tonegenlib() {} or remove the line from tonelib.h.

Sareban

@hskoglund
thank you so much :) first tried to define an empty constructor but it didnt work but then when i cleared the line from the .h it worked. thanks so much :))