Help with QtGStreamer undefined reference to QGST::init

JackCWallace

I am having some trouble with implementing QtGStreamer with QT. I have downloaded the source code for QtGStreamer and put it in "C:/qt-gstreamer-1.2.0" I am trying to run one of the examples that was provided, the player example.

Here is my code:

player.pro

TEMPLATE = app
TARGET = player

CONFIG += silent

CONFIG += pkgconfig

contains(QT_VERSION, ^4\\..*) {
    PKGCONFIG += QtGStreamer-1.0 QtGStreamerUi-1.0 QtGlib-2.0 QtGStreamerUtils-1.0
    QT += widgets
}
contains(QT_VERSION, ^5\\..*) {
    PKGCONFIG += Qt5GStreamer-1.0 Qt5GStreamerUi-1.0 Qt5Glib-2.0 Qt5GStreamerUtils-1.0 Qt5GStreamerQuick-1.0
    QT += widgets \
        enginio
}

QMAKE_CXXFLAGS += -std=c++0x

DEFINES += QT_NO_KEYWORDS

HEADERS += mediaapp.h player.h
SOURCES += main.cpp mediaapp.cpp player.cpp

INCLUDEPATH += C:\qt-gstreamer-1.2.0\src \
    C:\boost_1_58_0

main.cpp

#include "mediaapp.h"
#include <QApplication>
#include <QGst/Init>


int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QGst::init(&argc, &argv);



    MediaApp media;
    media.show();

    if (argc == 2) {
        media.openFile(argv[1]);
    }

    return app.exec();
}

There are other cpp files in the example, but they are all giving the same type of error. When I try to build the project, I get the error "undefined reference to 'QGst::init'" I cannot figure out what I am doing wrong. I think there needs to be something changed in the .pro file, but I couldn't find anything telling me what to do to fix it. I am on Windows, using with mingw compiler.

SGaist

Hi and welcome to devnet,

Might be a silly question but: do you have pkg-config running on Windows ?

JackCWallace

Yes, I do have it running, however now I am getting an error "QtCore/QtGlobal: No such file or directory, so I added the include path, "C:\Qt\Qt5.4.1\5.4\mingw491_32\include" but i am still getting the same error.

SGaist

Then there's something wrong with either your project or your setup. You shouldn't need to add anything to find Qt's headers

JackCWallace

Do you have any ideas that could help?

SGaist

Recheck your pro file: do you have any line line QT = or INCLUDEPATH = ? Note the missing +

JackCWallace

No, this is my code:

# This is a qmake project file, provided as an example on how to use qmake with QtGStreamer.

TEMPLATE = app
TARGET = player

# produce nice compilation output
CONFIG += silent

# Tell qmake to use pkg-config to find QtGStreamer.
CONFIG += pkgconfig

# Now tell qmake to link to QtGStreamer and also use its include path and Cflags.
contains(QT_VERSION, ^4\\..*) {
    PKGCONFIG += QtGStreamer-1.0 QtGStreamerUi-1.0
}
contains(QT_VERSION, ^5\\..*) {
    PKGCONFIG += Qt5GStreamer-1.0 Qt5GStreamerUi-1.0
}

QT += core quick widgets
CONFIG += qt console bootstrap

# Recommended if you are using g++ 4.5 or later. Must be removed for other compilers.
#QMAKE_CXXFLAGS += -std=c++0x

# Recommended, to avoid possible issues with the "emit" keyword
# You can otherwise also define QT_NO_EMIT, but notice that this is not a documented Qt macro.
DEFINES += QT_NO_KEYWORDS

# Input
HEADERS += mediaapp.h player.h
SOURCES += main.cpp mediaapp.cpp player.cpp

INCLUDEPATH += C:\qt-gstreamer-1.2.0\src

Line 3 and 4 (TEMPLATE and TARGET) made no difference when I added a '+' before the '='

SGaist

TEMPLATE and TARGET should be used with = . They contain only one value.

Do you still have that error if you don't use pkgconfig ?

JackCWallace

@SGaist Yes, If I take out the line for PKGCONFIG, I still get the same error

SGaist

Then create a default widget project and see if you can built it

JackCWallace

@SGaist Hi, I built an blank widget project, and I build one of the examples from Qt, and it worked fine

SGaist

Then keep that one and introduce one by one the elements of your other project until it either fails to build or build successfully

JackCWallace

For every element in the pro file, it does not fail if I put '#include <QGst/Init>' then I get the error 'QtCore/QtGlobal: No such file or directory' Then if I comment it back out, and run qmake, then build, I get no error. If I comment it out I get the error 'cannot find boost/config.hpp' until I run qmake again.

I added 'C:\boost_1_58_0' to the include path, commented out '#include <QGst/Init>' ran qmake, and uncommented it, and it built with no error. Then I ran qmake again, and it game me the 'QtCore/QtGlobal' error again

SGaist

Ok… Then the silly question: do you have a QtGlobal file ? If so where is it ?

JackCWallace

Yes, I have 5 copies, they are in
"C:\Qt\Qt5.4.1\5.4\android_armv5\include\QtCore\QtGlobal"
"C:\Qt\Qt5.4.1\5.4\android_armv7\include\QtCore\QtGlobal"
"C:\Qt\Qt5.4.1\5.4\android_x86\include\QtCore\QtGlobal"
"C:\Qt\Qt5.4.1\5.4\mingw491_32\include\QtCore\QtGlobal"
"C:\Qt\Qt5.4.1\5.4\Src\qtbase\include\QtCore\QtGlobal"

Should I have a different one somewhere else? I am building with Mingw

SGaist

Did you modify your kits ?

JackCWallace

No, I even just got done uninstalling and reinstalling Qt 5.4.1 and QtCreator 3.3.2 and I just got the same QtCore error

JackCWallace

I then added the pkgconfig and config then instead of '#include <QGst/Init>' I did '#include <QGst/init.h>' and I got back to the error of undefined reference to 'QGst::init

SGaist

Check the output of pkg-config for QtGStreamer, compare it to the build output of your application. Check the -I lines to see if something is currently modifying them in the wrong way