C++ Qt: undefined reference to `_imp___ZN12QApplicationC1ERiPPci'

Question

I am trying to remind myself some C++, and also learn about Qt.

I am working on Windows. I have installed Qt (5.1.0), MinGW (g++ 4.6.2), Gnu Make (3.81).

I am trying to compile a simple Qt app. The most basic case is this:

#include <QtWidgets>
#include <QtGui>

int main (int argc, char* argv[]) {               
    QApplication app(argc, argv);                  
    QTextStream cout(stdout);                               
    return EXIT_SUCCESS;
}

The project file is:

TEMPLATE = app
TARGET = example1
INCLUDEPATH += .

# Input
SOURCES += fac1.cpp
QT += gui widgets core

When I run

qmake

it generates the Makefile.

But then with make I get this:

C:\src\early-examples\example1>make
make -f Makefile.Release
make[1]: Entering directory `C:/src/early-examples/example1'
g++ -Wl,-s -Wl,-subsystem,console -mthreads -o release\example1.exe release/fac1.o  -LC:\Qt\Qt5.1.0\\5.1.0\msvc2012_64\lib -lQt5Widgets -lQt5Gui -lQt5Core -llibEGL -llibGLESv2 -lgdi32 -luser32
release/fac1.o:fac1.cpp:(.text.startup+0x2e): undefined reference to `_imp___ZN12QApplicationC1ERiPPci'
release/fac1.o:fac1.cpp:(.text.startup+0x37): undefined reference to `_imp___ZN12QApplicationD1Ev'
collect2: ld returned 1 exit status
make[1]: *** [release\example1.exe] Error 1
make[1]: Leaving directory `C:/src/early-examples/example1'
make: *** [release] Error 2

Can you tell me what is wrong?

It looks like you are mixing compilers here. Why are you using visual studio libraries with gcc? — drescherjm, Aug 15 '13 at 19:51
I am trying to use g++, but there might me some settings/env variables that I am not aware of. How can you tell? — ynka, Aug 15 '13 at 19:53
You have "-LC:\Qt\Qt5.1.0\\5.1.0\msvc2012_64\lib" in the output you posted. — drescherjm, Aug 15 '13 at 19:54
1. Please consider turning your comment into an answer, I would like to accept it. — ynka, Aug 15 '13 at 20:41
Thanks. I assume you got by the problem on the deleted comment. — drescherjm, Aug 15 '13 at 21:04
And the other deleted comment - yes :) lol. I am tired. Thanks. — ynka, Aug 15 '13 at 21:06

score 11 · Accepted Answer · answered Aug 15 '13 at 21:01

11

The problem here is you appear to be using Visual Studio 2012 libraries for your mingw builds. You need to link to the mingw compiled Qt instead.

answered Aug 15 '13 at 21:01

drescherjm

10,365
5
44
64

Yes. I downloaded (from http://qt-project.org/downloads) Qt 5.1.0 for Windows 64-bit (VS 2012, 525 MB) instead of Qt 5.1.0 for Windows 32-bit (MinGW 4.8, OpenGL, 666 MB). Works fine now! – ynka Aug 15 '13 at 21:04
1

This is the reason why there are so many Qt binary releases on the downloads. Even mixing different visual studio versions can give you problems. – drescherjm Aug 15 '13 at 21:06

score 0 · Answer 2 · answered Nov 08 '13 at 04:24

0

Add "greaterThan(QT_MAJOR_VERSION, 4): QT += widgets" into your .pro file

answered Nov 08 '13 at 04:24

bevin

11

C++ Qt: undefined reference to `_imp___ZN12QApplicationC1ERiPPci'

2 Answers2

Linked