I use ubuntu 20.04 and QtCreator 4.11.0. My Qt application builds ok, but Qt creator can not recognized it own libraries like QObjec, QCoreApplication, QQmlApplicationEngine, etc. Warnings are: /home/evgeny/QtProjects/Server/main.cpp:7: error: use of undeclared identifier 'QCoreApplication' etc
main.cpp
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include <QObject>
int main(int argc, char *argv[])
{
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
const QUrl url(QStringLiteral("qrc:/main.qml"));
QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
&app, [url](QObject *obj, const QUrl &objUrl) {
if (!obj && url == objUrl)
QCoreApplication::exit(-1);
}, Qt::QueuedConnection);
engine.load(url);
return app.exec();
}
Server.pro
QT += quick core network
CONFIG += c++11
# The following define makes your compiler emit warnings if you use
# any Qt feature that has been marked deprecated (the exact warnings
# depend on your compiler). Refer to the documentation for the
# deprecated API to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += \
main.cpp
RESOURCES += qml.qrc
# Additional import path used to resolve QML modules in Qt Creator's code model
QML_IMPORT_PATH =
# Additional import path used to resolve QML modules just for Qt Quick Designer
QML_DESIGNER_IMPORT_PATH =
# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target
That must I do in this situation?
Related
I'm trying to use opencv in a QT project for a raspberry pi 4. I'm on a Linux machine
Here is my .pro file and errors I get. And my mainwindow.cpp
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
CONFIG += c++17
# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += \
main.cpp \
mainwindow.cpp
HEADERS += \
mainwindow.h
FORMS += \
mainwindow.ui
TRANSLATIONS += \
SCWWS_fr_FR.ts
CONFIG += lrelease
CONFIG += embed_translations
# Default rules for deployment.
qnx: target.pHere is my mainwindow.cppath = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target
RESOURCES += \
resources.qrc
unix:!macx: LIBS += -L$$PWD/../../Documents/Qt-CrossCompile-RaspberryPi/raspberrypi4/sysroot/usr/lib/arm-linux-gnueabihf -lopencv_core -lopencv_highgui -lopencv_imgproc -lopencv_imgcodecs -lopencv_shape -lopencv_videoio
INCLUDEPATH += $$PWD/../../Documents/Qt-CrossCompile-RaspberryPi/raspberrypi4/sysroot/usr/include
DEPENDPATH += $$PWD/../../Documents/Qt-CrossCompile-RaspberryPi/raspberrypi4/sysroot/usr/include
Here is my mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtCore>
#include <QFontDatabase>
#include <QDebug>
#include <QImage>
//#include "opencv2/core.hpp"
//#include "opencv2/highgui.hpp"
//using namespace cv;
mainwindow::mainwindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::mainwindow)
{
QFontDatabase::addApplicationFont(":/fonts/roboto-light.ttf");
ui->setupUi(this);
qDebug() << "Hello World !";
//cv::VideoCapture camera = VideoCapture(0);
//
//Mat frame;
//camera >> frame;
//QImage img(frame.data, frame.cols, frame.rows, frame.step, QImage::Format_RGB888);
//ui->label->setPixmap(QPixmap::fromImage(img));
}
mainwindow::~mainwindow()
{
delete ui;
}
And here are errors I get
libXinerama.so.1, needed by /home/lolix/Documents/Qt-CrossCompile-RaspberryPi/raspberrypi4/sysroot/usr/lib/arm-linux-gnueabihf/libgdk-3.so.0, not found (try using -rpath or -rpath-link)
libmmal_core.so, needed by /home/lolix/Documents/Qt-CrossCompile-RaspberryPi/raspberrypi4/sysroot/usr/lib/arm-linux-gnueabihf/libavcodec.so.58, not found (try using -rpath or -rpath-link)
libmmal_vc_client.so, needed by /home/lolix/Documents/Qt-CrossCompile-RaspberryPi/raspberrypi4/sysroot/usr/lib/arm-linux-gnueabihf/libavcodec.so.58, not found (try using -rpath or -rpath-link)
.
.
.
liblapack.so.3, needed by /home/lolix/Documents/Qt-CrossCompile-RaspberryPi/raspberrypi4/sysroot/lib/libarmadillo.so.9, not found (try using -rpath or -rpath-link)
/home/lolix/Documents/Qt-CrossCompile-RaspberryPi/raspberrypi4/sysroot/usr/lib/arm-linux-gnueabihf/libopenmpt.so.0:-1: error: undefined reference to `std::random_device::_M_getentropy() const#GLIBCXX_3.4.25'
Errors arrives has soon has I uncomment my code. The version of open cv on the RP4 is 3.2 and when I install it on my machine it's 4.5. Event if I use the same command sudo apt-get install libopencv-dev
Thanks for your help
**EDIT**
I was able to get rid of these errors with this response. But a new one appeared
undefined reference to std::random_device::_M_getentropy() const#GLIBCXX_3.4.25
Regarding OpenCV I suggest to build it from source, for the RPi I always cross-compile using docker, as described here (just remove the references to openvino).
At this point you also need to cross-compile Qt for the RPi, but I guess you already did it.
I want to use an SDK I got for using a scanner. I'm using Qt 5.3 with MingW32 (on Windows 7).
The very first test I wanted to build should just print the SDK version.
Here is my project file
QT += core
QT -= gui
TARGET = Kojak1
CONFIG += console
CONFIG -= app_bundle
KOJAKDIR = "C:/Program Files/Integrated Biometrics/IBScanUltimateSDK_x64"
TEMPLATE = app
INCLUDEPATH += $$KOJAKDIR/Include
SOURCES += main.cpp
LIBS +=-L$$KOJAKDIR/lib/ -lIBScanUltimate
and here is the source code
#include <QCoreApplication>
#include "stdio.h"
#include <windows.h>
#include "IBScanUltimateApi.h"
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
IBSU_SdkVersion sdk_version;
IBSU_GetSDKVersion(&sdk_version);
printf("%s %s",sdk_version.File,sdk_version.Product);
return a.exec();
}
Unforturnately I get the message
D:\devt\QTProjects\Kojak1\main.cpp:10: error: undefined reference to `IBSU_GetSDKVersion#4'
when trying to compile the program.
My lib directory does contain IBScanUltimate.lib and IBScanUltimate.dll.
I am relatively new to Qt and was going through many tutorials. Everything was fine. All scripts compiled and ran.
Then, at some point, I am getting the error for even a new Qt widget application created with Qt Creator 4.3.1:
C:\ \Documents\111\main.cpp:-1: In function 'int qMain(int, char**)':
C:\ \Documents\111\main.cpp:6: error: variable 'QApplication a' has initializer but incomplete type
QApplication a(argc, argv);
^
C:\ \Documents\111\main.cpp:11: warning: control reaches end of non-void function [-Wreturn-type]
}
^
I am not sure what happened, yet seems like some setups were messed up.
QApplication is included, and not missing in the script.
111.pro
# Project created by QtCreator 2018-02-23T01:36:28
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = 111
TEMPLATE = app
DEFINES += QT_DEPRECATED_WARNINGS
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += \
main.cpp \
mainwindow.cpp
HEADERS += \
mainwindow.h
FORMS += \
mainwindow.ui
main.cpp
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
mainview.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;
}
It seems to me that this issue appeared after trying to run qt5.6_src.zip examples from https://en.ids-imaging.com/open-source.html.
Without completed code, I guess you need to add #include <QApplication> to main.cpp
The error message told you what is missing.
According to Qt's docs, the constructor's signature is QApplication(int &argc, char **argv).
Therefore, if you inherit from QApplication then the subclass's constructor must pass argc by reference. From your description, it appears that the constructor of your subclass is actually passing argc by value (i.e., int qMain(int, char**) ). That will cause some problems.
The issue is fixed by deleting the Qt folder and QtCreator folder in the <drive>:\Users\<username>\AppData\Roaming\QtProject and <drive>:\Users\<username>\AppData\Roaming\Qt. It stored incorrect settings, which I somehow setup by running open source scripts. For more information visit Where does QtCreator save its settings?.
I am back to Qt and C++ programming after a year break. I am trying to install boost library into Qt on Mac (10.9.4) and I am completely confused. This is what I did:
I installed boost using homebrew.
I see that hpp files are installed here:
/usr/local/Cellar/boost/1.55.0_2/include/boost
and libraries here:
/usr/local/Cellar/boost/1.55.0_2/lib
Now I start a new Qt console project.
the project file:
QT += core
QT -= gui
TARGET = testQt
CONFIG += console
CONFIG -= app_bundle
TEMPLATE = app
SOURCES += main.cpp
INCLUDEPATH += /usr/local/Cellar/boost/1.55.0_2
And the main file:
#include <QCoreApplication>
#include <QtCore>
#include <iostream>
#include <QDebug>
#include <boost/regex.hpp>
using namespace std;
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
std::string line;
boost::regex pat( "^Subject: (Re: |Aw: )*(.*)" );
while (std::cin)
{
std::getline(std::cin, line);
boost::smatch matches;
if (boost::regex_match(line, matches, pat))
std::cout << matches[2] << std::endl;
}
return a.exec();
}
Not compiling. Issues:
Symbol(s) not found for architectures x86_64
linker command failed with exist code 1
Since I am absolutely noob with boost, did I do it right? If yes, why is it not compiling?
Thanks a lot!
You need to link with boost too!
LIBS += -L/usr/local/Cellar/boost/1.55.0_2/lib -lboost
Working with Qt 5 and QtQuick 2.0
.pro
# Add more folders to ship with the application, here
folder_01.source = qml/untitled
folder_01.target = qml
DEPLOYMENTFOLDERS = folder_01
# Additional import path used to resolve QML modules in Creator's code model
QML_IMPORT_PATH =
# If your application uses the Qt Mobility libraries, uncomment the following
# lines and add the respective components to the MOBILITY variable.
# CONFIG += mobility
# MOBILITY +=
#CONFIG += qt plugin
#QT += qml quick
# The .cpp file which was generated for your project. Feel free to hack it.
SOURCES += main.cpp \
../DummyClass.cpp \
../aa.cpp
# Installation path
# target.path =
# Please do not modify the following two lines. Required for deployment.
include(qtquick2applicationviewer/qtquick2applicationviewer.pri)
qtcAddDeployment()
HEADERS += \
../DummyClass.h \
../aa.h
main.cpp
#include <QtGui/QGuiApplication>
#include "qtquick2applicationviewer.h"
#include "/home/***/qmllistproperties/DummyClass.h"
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
const char* ocuui = "OCUUI"; // #uri OCUUI
qmlRegisterType <DummyClass> (ocuui, 1, 0, "DummyClass");
QtQuick2ApplicationViewer viewer;
viewer.setMainQmlFile(QStringLiteral("qml/untitled/main.qml"));
viewer.showExpanded();
return app.exec();
}
qmlRegisterType is in QtQml. You have to include QtQml:
#include <QtQml>