hi i'm just trying to compile an easy project in qt
#include <QApplication>
#include <QPushButton>
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QPushButton bouton("Salut les Zéros, la forme ?");
bouton.show();
return app.exec();
}
but i have this error : /home/eid/test/easyprojet/main.cpp:1: error: QApplication: No such file or directory
can anyone help me ?
sorry for my english
In Qt5, it resides in , while in Qt4 it was .
In Qt5 you need to add QT += widgets to your .pro file.
It may be also because the project is not in the workspace of QT creator.
It happened with me before.
so,try to put the project in the workspace .
Related
I am searching "QCleanlooksStyle" belongs to which "QT +=". please help, ive centos 6.4 and Qt 5.3.
#include <QApplication>
#include <QCleanlooksStyle>
#include <QtWidgets>
#include "buttonbox.h"
int main( int argc, char **argv )
{
QApplication app( argc, argv );
app.setStyle( new QCleanlooksStyle );
ButtonBoxDialog dlg;
dlg.show();
return app.exec();
}
According to the docs:
QMotifStyle, QPlastiqueStyle, QCleanlooksStyle, and QCDEStyle are
replaced with a new fusion style. If your application depends on any
of these removed styles, you can either use the qtstyleplugins project
to get these styles or update your application to use the new fusion
style. For more details about this change, see
https://blog.qt.io/blog/2012/10/30/cleaning-up-styles-in-qt5-and-adding-fusion/.
So you must clone the project, compile it and install it:
git clone git://code.qt.io/qt/qtstyleplugins.git
cd qtstyleplugins/
qmake
make
sudo make install
Then you must set the style using the following (you should not modify the .pro):
app.setStyle("cleanlooks");
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
I've tried to compile the following code using Qt(4.6.3) + MinGW:
#include <QtCore/QCoreApplication>
#include <exception>
int main(int argc, char *argv[])
{
throw std::runtime_error("");
QCoreApplication a(argc, argv);
return a.exec();
}
... and got this error:
..\untitled11\main.cpp:6: error: 'runtime_error' is not a member of 'std'
Project created from scratch(console application), the pro file:
QT += core
QT -= gui
TARGET = untitled11
CONFIG += console
CONFIG -= app_bundle
TEMPLATE = app
SOURCES += main.cpp
Tried to compile this using Qt+MSVC2008 compiler - works fine.
This is a standard exception, have no idea why is missing.
<exception> defines only the base std::exceptionclass; if you want child classes like std::runtime_error, you must include the <stdexcept> header.