AU vs. VST and juce


I have some plugins (midi only no audio), they are pure JUCE and are using VST wrapper. I wanted to build the same plugins
but with AU wrapper, i got the build to work, but. I get assertions from JUCE all around the place, first from Timer and second
anywhere i try to create any UI components, i get assertions from line 2017 in juce_Component.cpp. The same code works perfectly
with VST but AU causes those assertions.

I create my UI class in the filter code, and it stays there so i don’t have to re-create the editor each time it’s closed/opened, i just add
it to a wrapper editor that get’s recreated. Theese assertions happen when the plugins are scanned, and later when i try to open the UI
in the host. Is there something that might be causing this ? Are there any special considerations when using AU. I used the JuceDemoPlugin
project and just added my sources, so the build parameters are the same, i just added the ObjC prefix stuff as a global define for the project
and the JucePlugin_Build_AU.

I tried removing the UI creation from the filter code, and made it run only when the editor is requested, but i still get the assertions when
opening the plugin editor.


Looks like a dangling pointer - what’s the call stack?

#0	0x929a2402 in __pthread_kill
#1	0x929a224f in pthread_kill
#2	0x9368f190 in Debugger
#3	0x0018c387 in juce::Component::removeComponentListener at juce_Component.cpp:2017
#4	0x00237857 in juce::Component::SafePointer<juce::Component>::detach at juce_Component.h:1948
#5	0x0023795f in juce::Component::SafePointer<juce::Component>::~SafePointer at juce_Component.h:1915
#6	0x00237edb in juce::Component::BailOutChecker::~BailOutChecker at juce_Component.h:1960
#7	0x00191a45 in juce::Component::sendVisibilityChangeMessage at juce_Component.cpp:199
#8	0x001d20cc in juce::Component::setVisible at juce_Component.cpp:172
#9	0x152f5b20 in juce::Component::addAndMakeVisible at juce_Component.cpp:1146
#10	0x1532938c in juce::Slider::lookAndFeelChanged at juce_Slider.cpp:342
#11	0x15329c01 in juce::Slider::Slider at juce_Slider.cpp:138
#12	0x150ead03 in MBase01Editor::MBase01Editor at MBase01Editor.cpp:53
#13	0x150e7965 in MBase01Controller::getEditor at MBase01Controller.cpp:40
#14	0x150eeb7b in EdoController::createEditor at EdoController.cpp:115
#15	0x152119c1 in juce::AudioProcessor::createEditorIfNeeded at juce_AudioProcessor.cpp:232
#16	0x150e16ca in -[JuceDemoAU_V1 uiViewForAudioUnit:withSize:] at
#17	0x000fd1a3 in juce::AudioUnitPluginWindowCocoa::createView at
#18	0x00107b7a in juce::AudioUnitPluginWindowCocoa::AudioUnitPluginWindowCocoa at
#19	0x000ef540 in juce::AudioUnitPluginInstance::createEditor at
#20	0x000be595 in juce::AudioProcessor::createEditorIfNeeded at juce_AudioProcessor.cpp:232
#21	0x00008e76 in PluginWindow::getWindowFor at GraphEditorPanel.cpp:80
#22	0x0000cccf in FilterComponent::mouseUp at GraphEditorPanel.cpp:305
#23	0x001a695c in juce::Component::internalMouseUp at juce_Component.cpp:2457
#24	0x0023c2cd in juce::MouseInputSourceInternal::sendMouseUp at juce_MouseInputSource.cpp:134
#25	0x002485b2 in juce::MouseInputSourceInternal::setButtons at juce_MouseInputSource.cpp:160
#26	0x00248e9b in juce::MouseInputSourceInternal::handleEvent at juce_MouseInputSource.cpp:271
#27	0x001cf1d3 in juce::MouseInputSource::handleEvent at juce_MouseInputSource.cpp:508
#28	0x001cf2b8 in juce::ComponentPeer::handleMouseEvent at juce_ComponentPeer.cpp:108
#29	0x002c2458 in juce::NSViewComponentPeer::sendMouseEvent at
#30	0x002c70b9 in juce::NSViewComponentPeer::redirectMouseUp at
#31	0x002be683 in -[JuceNSView_1_51_12_3 asyncMouseUp:] at
#32	0x002be646 in -[JuceNSView_1_51_12_3 mouseUp:] at
#33	0x9152c1d1 in -[NSWindow sendEvent:]
#34	0x914f8cd9 in -[NSApplication sendEvent:]
#35	0x9145662f in -[NSApplication run]
#36	0x002c7dcf in juce::MessageManager::runDispatchLoop at
#37	0x000ec1f4 in juce::JUCEApplication::main at juce_Application.cpp:171
#38	0x000ec3c7 in juce::JUCEApplication::main at juce_Application.cpp:301
#39	0x0000d1ad in main at HostStartup.cpp:111


info: A Demo Plugin demonstrating Juce
JUCE v1.51.12
EdoPresetManager::ctor presetDir exists
EdoPresetManager::ctor default bank loaded
Initialising AU: Juce Demo Plugin
JUCE Assertion failure in /Users/atom/devel/juce/extras/audio plugin host/Builds/MacOSX/../../JuceLibraryCode/../../../amalgamation/../src/gui/components/juce_Component.cpp, line 2017
Debugger() was called!

the call that causes this is in the ctor of Slider, lookAndFeelChanged()


Very peculiar. If you add another assertion:

void Component::addComponentListener (ComponentListener* const newListener) { jassert (isValidComponent()); componentListeners.add (newListener); }

…does that get triggered?


no it does not, the method get’s called but no assertion.


Weird. Does this make a difference?

[code]void Component::setVisible (bool shouldBeVisible)
if (flags.visibleFlag != shouldBeVisible)
// if component methods are being called from threads other than the message
// thread, you’ll need to use a MessageManagerLock object to make sure it’s thread-safe.

    SafePointer<Component> safePointer (this);

    flags.visibleFlag = shouldBeVisible;

    internalRepaint (0, 0, getWidth(), getHeight());


    if (! shouldBeVisible)
        if (currentlyFocusedComponent == this
            || isParentOf (currentlyFocusedComponent))
            if (parentComponent_ != 0)

    if (safePointer != 0)

        if (safePointer != 0 && flags.hasHeavyweightPeerFlag)
            ComponentPeer* const peer = getPeer();

            jassert (peer != 0);
            if (peer != 0)
                peer->setVisible (shouldBeVisible);



no change i’m afraid


Ah, I bet I know what this is.

If you create a component, then shutdown and re-start juce, that component won’t work any more, because it was registered with a messagemanager object that no longer exists. Not keeping any components as statics, are you?


static as in static variables no, almost all UI components are created with Jucer, i have non jucer components in my UI wrapper class theese are two LookAndFeel classes one File class and a TooltipWindow. The rest are normaln components. If you wish to see this the code is public and in svn


Ok, suggestion #2: It could be a symbol linkage clash between your plugin and the host - looks like the plugin is getting the wrong instance of Messagemanager, and using the host’s copy instead of its own. I’ve seen this kind of thing happen when c++ symbols are exported rather than being hidden or stripped - try a release build of the host (make sure it’s stripped) and I bet it’ll work fine.

Like obj-c, you can get cross-linkage problems in c++ too, but fortunately you can fix it by making the symbols private.


BTW as far as I know AU doesn’t support MIDI out plugins


it’s not a problem, i use MIDI hardware directly and via the process() method, it’s a lot if you can use the MIDI hardware, you get some control over
your hardware, it’s better then no control at all.


Well allright the Release build of the Host helped. The window shows up i can edit my controls, but i can’t resize the window, something that was possible in VST, here when i try to resize the window the component get’s redrawn in some weird way and the window size does not change, i need to close/re-open my plugin to get the new size.