<![CDATA[Error : can't run my program]]>Hello everyone, I'm new, and I'm trying to use qt for a Linux application.

I'm on Linux mint and the version of qt I'm using is 5.12.8.

I created an empty project to start with. My pro file contains the following configuration:

SOURCES += \
    main.cpp
QT += core
QT += widgets

and my main.cpp contains the following code:

#include <QApplicationStateChangeEvent>

int main(int argc, char *argv[]) {
   QApplication app(argc,argv);

    return app.exec();
}

The problem is that qt tells me on line 4:
variable has incomplete type Qapplication.

Can you help me solve this problem, thank you in advance.

]]>https://forum.qt.io/topic/117123/error-can-t-run-my-programRSS for NodeWed, 05 Aug 2026 05:13:24 GMTSat, 18 Jul 2020 04:15:30 GMT60<![CDATA[Reply to Error : can't run my program on Mon, 20 Jul 2020 08:18:00 GMT]]>@CyberSnake
You are claiming that if you copy & paste the following code:

#include <QApplication>

int main(int argc, char *argv[])
{
   QApplication app(argc,argv);

    return app.exec();
}

you will get one error message of

variable has incomplete type QApplication.

Is that right? If you copy & paste the above? With no other error about not being able to find the header file? Is this a compile-time error, or a message from Qt Creator when you just look at the code?

]]>https://forum.qt.io/post/607779https://forum.qt.io/post/607779Mon, 20 Jul 2020 08:18:00 GMT<![CDATA[Reply to Error : can't run my program on Sun, 19 Jul 2020 16:14:15 GMT]]>@CyberSnake Instead of looking for a needle in a haystack, are you able to build and run any Qt example?

]]>https://forum.qt.io/post/607679https://forum.qt.io/post/607679Sun, 19 Jul 2020 16:14:15 GMT<![CDATA[Reply to Error : can't run my program on Sat, 18 Jul 2020 22:36:27 GMT]]>@hskoglund Typing mistake... But even with QApplication I have the same mistake.

]]>https://forum.qt.io/post/607624https://forum.qt.io/post/607624Sat, 18 Jul 2020 22:36:27 GMT<![CDATA[Reply to Error : can't run my program on Sat, 18 Jul 2020 22:33:22 GMT]]>Hi, also please check, on line 4, that you have written
QApplication
and not
Qapplication

]]>https://forum.qt.io/post/607623https://forum.qt.io/post/607623Sat, 18 Jul 2020 22:33:22 GMT<![CDATA[Reply to Error : can't run my program on Sat, 18 Jul 2020 22:20:08 GMT]]>@SGaist said in Error : can't run my program:

Hi and welcome to devnet,

You are missing

#include <QApplication>

in your main.cpp file.

Hello again.

I had inclued <QApplication> but i have the same error :(

]]>https://forum.qt.io/post/607622https://forum.qt.io/post/607622Sat, 18 Jul 2020 22:20:08 GMT<![CDATA[Reply to Error : can't run my program on Sat, 18 Jul 2020 06:07:29 GMT]]>Hi and welcome to devnet,

You are missing

#include <QApplication>

in your main.cpp file.

]]>https://forum.qt.io/post/607529https://forum.qt.io/post/607529Sat, 18 Jul 2020 06:07:29 GMT