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I recently as the following question where I had issue with the object in the thread not getting deleted before the thread was killed:

Thread count increases a lot, even when deleting the threads

I decided to move the object to the main thread before deleting it like this: 

void WorkspaceBase::deleteFinishedUploader() {
    FileUploader *fileUploader = qobject_cast<FileUploader*>(sender());

    if(fileUploader != NULL) {
        fileUploader->moveToThread(this->thread());
        fileUploader->deleteLater();
    }
}

In windows I never got any warnings and it seem to work fine. Now in OSX I get the following warning eveytime this is done:

On Mac OS X, you might be loading two sets of Qt binaries into the same process. Check that all plugins are compiled against the right Qt binaries. Export DYLD_PRINT_LIBRARIES=1 and check that only one set of binaries are being loaded.
QObject::moveToThread: Current thread (0x102a07180) is not the object's thread (0x116428090).
Cannot move to target thread (0x102a07180)

I'm not too sure what the issue is but will try to describe my project as well as I can.

First I have a shared dylib that is used by my other dylib and app. The other dylib uses the Shared.dylib and contains all the functionallity when uplodaing stuff to the internet (QNetworkAccessManager etc). Then I have my app which includes this dylib, as well as the shared.dylib (which contains some helper methods and parsers). These libs, along with the date_time.dylib from boost and qjson.framework is added to the .app-package.

Everything builds and runs perfectly and it is ONLY when I'm trying to move the Uploader object to the main thread that this issue occur. The Uploader object is a part of the App executable and is not located in a .dylib (but it uses the libs to do the upload).

What might be the issue here? Not to sure if I had this issue before and I'm not too sure what I have done. If the info I've provided is not enough, I'm happy to add more. Just hard to know where to look when I don't know what the issue is.

Thanks!

EDIT:

These are the libs that I'm loading during runtime:

dyld: loaded: /Users/me/Documents/MyApp/MyApp.app/Contents/MacOS/./MyApp
dyld: loaded: /Users/me/Documents/MyApp/MyApp.app/Contents/MacOS/qjson.framework/Versions/0/qjson
dyld: loaded: /Users/me/Documents/MyApp/MyApp.app/Contents/MacOS/libboost_date_time.dylib
dyld: loaded: /Users/me/Documents/MyApp/MyApp.app/Contents/MacOS/libQt.Shared.1.dylib
dyld: loaded: /Users/me/Documents/MyApp/MyApp.app/Contents/MacOS/libQt.Framework.Network.1.dylib
dyld: loaded: /Users/me/QtSDK1.2.1/Desktop/Qt/4.8.1/gcc/lib/QtGui.framework/Versions/4/QtGui
dyld: loaded: /Users/me/QtSDK1.2.1/Desktop/Qt/4.8.1/gcc/lib/QtCore.framework/Versions/4/QtCore
dyld: loaded: /Users/me/QtSDK1.2.1/Desktop/Qt/4.8.1/gcc/lib/QtNetwork.framework/Versions/4/QtNetwork
dyld: loaded: /usr/lib/libstdc++.6.dylib
dyld: loaded: /usr/lib/libSystem.B.dylib
dyld: loaded: /usr/lib/libz.1.dylib
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/ApplicationServices
dyld: loaded: /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation
dyld: loaded: /System/Library/Frameworks/Security.framework/Versions/A/Security
dyld: loaded: /System/Library/Frameworks/CoreServices.framework/Versions/A/CoreServices
dyld: loaded: /usr/lib/system/libmathCommon.A.dylib
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/CoreGraphics
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ImageIO.framework/Versions/A/ImageIO
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreText.framework/Versions/A/CoreText
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ATS.framework/Versions/A/ATS
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ColorSync.framework/Versions/A/ColorSync
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/HIServices.framework/Versions/A/HIServices
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/LangAnalysis.framework/Versions/A/LangAnalysis
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/PrintCore.framework/Versions/A/PrintCore
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/QD.framework/Versions/A/QD
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/SpeechSynthesis.framework/Versions/A/SpeechSynthesis
dyld: loaded: /usr/lib/libbsm.0.dylib
dyld: loaded: /usr/lib/libicucore.A.dylib
dyld: loaded: /System/Library/Frameworks/IOKit.framework/Versions/A/IOKit
dyld: loaded: /usr/lib/system/libkxld.dylib
dyld: loaded: /usr/lib/libauto.dylib
dyld: loaded: /usr/lib/libobjc.A.dylib
dyld: loaded: /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/CarbonCore.framework/Versions/A/CarbonCore
dyld: loaded: /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/CFNetwork.framework/Versions/A/CFNetwork
dyld: loaded: /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/Metadata.framework/Versions/A/Metadata
dyld: loaded: /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/OSServices.framework/Versions/A/OSServices
dyld: loaded: /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/SearchKit.framework/Versions/A/SearchKit
dyld: loaded: /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/AE.framework/Versions/A/AE
dyld: loaded: /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/LaunchServices
dyld: loaded: /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/DictionaryServices.framework/Versions/A/DictionaryServices
dyld: loaded: /System/Library/Frameworks/DiskArbitration.framework/Versions/A/DiskArbitration
dyld: loaded: /System/Library/Frameworks/NetFS.framework/Versions/A/NetFS
dyld: loaded: /usr/lib/libsqlite3.dylib
dyld: loaded: /System/Library/Frameworks/SystemConfiguration.framework/Versions/A/SystemConfiguration
dyld: loaded: /usr/lib/libxslt.1.dylib
dyld: loaded: /usr/lib/libxml2.2.dylib
dyld: loaded: /System/Library/Frameworks/Accelerate.framework/Versions/A/Accelerate
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ImageIO.framework/Versions/A/Resources/libTIFF.dylib
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ImageIO.framework/Versions/A/Resources/libGIF.dylib
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ImageIO.framework/Versions/A/Resources/libPng.dylib
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ImageIO.framework/Versions/A/Resources/libRadiance.dylib
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ImageIO.framework/Versions/A/Resources/libJPEG.dylib
dyld: loaded: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vImage.framework/Versions/A/vImage
dyld: loaded: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/vecLib
dyld: loaded: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libvDSP.dylib
dyld: loaded: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libvMisc.dylib
dyld: loaded: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
dyld: loaded: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libLAPACK.dylib
dyld: loaded: /usr/lib/libcrypto.0.9.8.dylib
dyld: loaded: /System/Library/PrivateFrameworks/TrustEvaluationAgent.framework/Versions/A/TrustEvaluationAgent
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ATS.framework/Versions/A/Resources/libFontParser.dylib
dyld: loaded: /usr/lib/libcups.2.dylib
dyld: loaded: /System/Library/Frameworks/Foundation.framework/Versions/C/Foundation
dyld: loaded: /System/Library/Frameworks/Kerberos.framework/Versions/A/Kerberos
dyld: loaded: /usr/lib/libresolv.9.dylib
dyld: loaded: /Users/annatisch/QtSDK1.2.1/Desktop/Qt/4.8.1/gcc/lib/QtXml.framework/Versions/4/QtXml
dyld: loaded: /System/Library/Frameworks/Carbon.framework/Versions/A/Carbon
dyld: loaded: /System/Library/Frameworks/AppKit.framework/Versions/C/AppKit
dyld: loaded: /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/CommonPanels.framework/Versions/A/CommonPanels
dyld: loaded: /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/Help.framework/Versions/A/Help
dyld: loaded: /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/HIToolbox
dyld: loaded: /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/ImageCapture.framework/Versions/A/ImageCapture
dyld: loaded: /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/Ink.framework/Versions/A/Ink
dyld: loaded: /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/OpenScripting.framework/Versions/A/OpenScripting
dyld: loaded: /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/Print.framework/Versions/A/Print
dyld: loaded: /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/SecurityHI.framework/Versions/A/SecurityHI
dyld: loaded: /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/SpeechRecognition.framework/Versions/A/SpeechRecognition
dyld: loaded: /System/Library/PrivateFrameworks/CoreUI.framework/Versions/A/CoreUI
dyld: loaded: /System/Library/Frameworks/QuartzCore.framework/Versions/A/QuartzCore
dyld: loaded: /System/Library/PrivateFrameworks/DesktopServicesPriv.framework/Versions/A/DesktopServicesPriv
dyld: loaded: /System/Library/Frameworks/AudioToolbox.framework/Versions/A/AudioToolbox
dyld: loaded: /System/Library/PrivateFrameworks/FamilyControls.framework/Versions/A/FamilyControls
dyld: loaded: /System/Library/PrivateFrameworks/MultitouchSupport.framework/Versions/A/MultitouchSupport
dyld: loaded: /System/Library/Frameworks/CoreVideo.framework/Versions/A/CoreVideo
dyld: loaded: /System/Library/Frameworks/OpenGL.framework/Versions/A/OpenGL
dyld: loaded: /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGLImage.dylib
dyld: loaded: /System/Library/Frameworks/OpenCL.framework/Versions/A/OpenCL
dyld: loaded: /System/Library/Frameworks/IOSurface.framework/Versions/A/IOSurface
dyld: loaded: /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGLU.dylib
dyld: loaded: /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGL.dylib
dyld: loaded: /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGLProgrammability.dylib
dyld: loaded: /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libCoreVMClient.dylib
dyld: loaded: /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGFXShared.dylib
dyld: loaded: /System/Library/Frameworks/CoreAudio.framework/Versions/A/CoreAudio
dyld: loaded: /System/Library/Frameworks/AudioUnit.framework/Versions/A/AudioUnit
dyld: loaded: /System/Library/Frameworks/vecLib.framework/Versions/A/vecLib
dyld: loaded: /System/Library/Frameworks/SecurityFoundation.framework/Versions/A/SecurityFoundation
dyld: loaded: /System/Library/Frameworks/OpenDirectory.framework/Versions/A/OpenDirectory
dyld: loaded: /System/Library/PrivateFrameworks/CommerceKit.framework/Versions/A/Frameworks/CommerceCore.framework/Versions/A/CommerceCore
dyld: loaded: /System/Library/Frameworks/OpenDirectory.framework/Versions/A/Frameworks/CFOpenDirectory.framework/Versions/A/CFOpenDirectory
dyld: loaded: /System/Library/PrivateFrameworks/PasswordServer.framework/Versions/A/PasswordServer
dyld: loaded: /System/Library/Frameworks/DirectoryService.framework/Versions/A/DirectoryService
dyld: loaded: /usr/lib/libsasl2.2.dylib
dyld: loaded: /System/Library/Frameworks/CoreData.framework/Versions/A/CoreData
dyld: loaded: /usr/lib/liblangid.dylib
dyld: loaded: /usr/lib/libiconv.2.dylib
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/Resources/libCSync.A.dylib
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Frameworks/ColorSync.framework/Versions/A/Resources/ColorSyncDeprecated.dylib
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/Resources/libRIP.A.dylib
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ATS.framework/Versions/A/Resources/libFontRegistry.dylib
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/Resources/libCGXType.A.dylib
dyld: loaded: /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ATS.framework/Versions/A/Resources/libTrueTypeScaler.dylib
 QDir( 
dyld: loaded: /Users/me/QtSDK1.2.1/Desktop/Qt/4.8.1/gcc/plugins/bearer/libqcorewlanbearer.dylib
dyld: loaded: /System/Library/Frameworks/CoreWLAN.framework/Versions/A/CoreWLAN
dyld: loaded: /Users/me/QtSDK1.2.1/Desktop/Qt/4.8.1/gcc/plugins/bearer/libqgenericbearer.dylib
dyld: loaded: /usr/lib/libssl.0.9.8.dylib

I can't see any duplicates so it must have to do with the moving of the object. How would I be able to move the object to the main thread FROM the main thread. I've read somewhere that this is not possible for security reasons but I really need to move it so that it can be fully deleted (which means that it needs an event loop which is not its current QThread which will get killed)

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chikuba
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2 Answers2

6

From the documentation of QObject:

Warning: This function is not thread-safe; the current thread must be same as the current thread affinity

The owner must call moveToThread to relinquish ownership of the object, rather than another thread claiming ownership of the object. That is, you must call moveToThread from whichever thread owns the object (by default created the object). Also note that you cannot move objects that have parents.

David Rodríguez - dribeas
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  • i create the uploader and move it to the thread in the same class (main thread) as where im trying to move it back. the uploader doesnt have any parents but the uploader has objects in it that has the uploader as a parent. – chikuba May 23 '12 at 01:06
  • "in the same class" is not what you need to do. If threadA created the uploader, threadA is the only one that can move it somewhere else, @chikuba. – Mat May 23 '12 at 05:38
  • yes, the treadA is the one that is trying to move it back to itself so that the uploader can get deleted properly – chikuba May 23 '12 at 06:02
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    Mat wasn't clear. Only the thread that object is living in can move it to another thread. So if threadA moved object to threadB, then threadA CAN'T move it anymore. Only threadB can move it back to threadA – Kamil Klimek May 23 '12 at 08:36
0

You can also move it to your thread by doing it from the object's owner thread.

#include <thread>
#include <memory>
#include <condition_variable>
#include <QTimer>
#include <QThread>
#include <QApplication>


template <typename Func>
inline void runOnThread(QThread *qThread, Func &&func)
{
    QTimer *t = new QTimer();
    t->moveToThread(qThread);
    t->setSingleShot(true);
    QObject::connect(t, &QTimer::timeout, [=]()
    {
        func();
        t->deleteLater();
    });
    QMetaObject::invokeMethod(t, "start", Qt::QueuedConnection, Q_ARG(int, 0));
}



void moveToThread(QObject *ptr, QThread *targetThrd=QThread::currentThread())
{
    std::mutex mt;
    std::condition_variable_any cv;
    runOnThread(ptr->thread(),[&]
    {
        ptr->setParent(NULL);
        ptr->moveToThread(targetThrd);
        cv.notify_one();
    });
    cv.wait(mt);
}

You just need to call

moveToThread( fileUploader, this->thread());
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