Poco::SystemException in ofxOscParameterSync() destructor

[pierrep]

On destructing ofxOscParameterSync(), I'm getting the following error:

terminate called after throwing an instance of 'Poco::SystemException'
  what():  System exception

The offending line appears to be this on line 17 of ofxOscParameterSync:

ofRemoveListener(syncGroup->parameterChangedE,this,&ofxOscParameterSync::parameterChanged);

Removing this line avoids the exception.
I'm not sure why this is happening...the ofRemoveListener call seems legit.

[bilderbuchi]

pinging @arturoc

[admsyn]

I can't reproduce this, at least not with a minimal setup. There's been a fair amount happening w/r/t event listening lately so it's possible this got silently fixed in the process? Here's my minimal repro attempt nonetheless:

#include "ofMain.h"
#include "ofxOscParameterSync.h"

struct ofApp : public ofBaseApp {

    void setup() {
        params.setName("Params");
        resetSync();
    }

    void resetSync() {
        sync = shared_ptr<ofxOscParameterSync>(new ofxOscParameterSync);
        sync->setup(params, 8080, "localhost", 8081);
    }

    void keyPressed(int key) {
        resetSync();
    }

    ofParameterGroup params;
    shared_ptr<ofxOscParameterSync> sync;
};

int main( ){
    ofSetupOpenGL(320,240,OF_WINDOW);
    ofRunApp(new ofApp());
}

[bilderbuchi]

@pierrep can you still reproduce this on latest master?

[ofTheo]

I get this issue with current master.

console message is:

libc++abi.dylib: terminating with uncaught exception of type std::__1::system_error: mutex lock failed: Invalid argument

[bilderbuchi]

pinging @arturoc

[ofTheo]

yeah I see this with Xcode 6.01 and 6.1 - really not sure what is causing it.
Maybe the order of destruction?

[ofTheo]

changing

        ofxOscParameterSync sync;

        ofParameter<float> size;
        ofParameter<int> number;
        ofParameter<bool> check;
        ofParameterGroup parameters;
        ofParameter<ofColor> color;
        ofxPanel gui;

to

        ofParameter<float> size;
        ofParameter<int> number;
        ofParameter<bool> check;
        ofParameterGroup parameters;
        ofParameter<ofColor> color;
        ofxPanel gui;

        ofxOscParameterSync sync;

in ofApp.h stops the crash -

[ofTheo]

Hmm I bet the issue is simply that syncGroup which is ofParameterGroup parameters; has been deleted as things higher up are deleted first. So syncGroup in ofxOscParameterSync is a pointer to a deleted object - hence the crash

ofxOscParameterSync::~ofxOscParameterSync(){
    if(syncGroup)
        ofRemoveListener(syncGroup->parameterChangedE,this,&ofxOscParameterSync::parameterChanged);
}

[tgfrerer]

That would make sense - the order in which members are declared in cpp determines the order in which they will be deleted. Could it make sense to use weak_ptr instead of shared_ptr there, to not propagate ownership?

[ofTheo]

Thats partially the problem. Its a regular pointer

    ofParameterGroup * syncGroup;

So there isn't a way to do weak_ptr without making the user use shared_ptr in ofApp