Re: Throwing exceptions in destructors


richard.furse@...
 

Thanks!

 

I’m probably misreading the code, but won’t the MamaQueue destructor throw if there are any open events? This seems like a potentially common situation if there’s a stack unwind happening because of an exception thrown in other parts of the application, which is also a situation where a crash is more or less guaranteed on the second throw?

 

Best wishes,

 

--Richard

 

 

From: Glenn McClements [mailto:gmcclements@...]
Sent: 14 November 2012 17:57
To: Furse, Richard (EQ/UK)
Cc: Openmama-dev@...
Subject: Re: [Openmama-dev] Throwing exceptions in destructors

 

Hi Richard,

Yes, this is the right place for those kind of questions. 

 

As a rule the mamaTry macro is called in the C++ wrapper before every call to the C layer, to translate the C return code to an exception on error conditions. However you are quite right in pointing out that this is dangerous practice in a destructor. 

 

In reality, in existing MAMA deployments this hasn't been an issue as the mama<object>_destroy() functions can not generally fail when called from the C++ wrapper. As more third party bridges are developed for OpenMAMA however this may become an issue. 

 

If you want to file a bug around this please do, at http://bugs.openmama.org 

 

Even better, if you wish to submit a patch for it then details for patch submission are below are at

 

Glenn 

 

From: <richard.furse@...>
Date: Tue, 13 Nov 2012 14:01:45 +0000
To: <Openmama-dev@...>
Subject: [Openmama-dev] Throwing exceptions in destructors

 

Hi there – I’m just taking a look through some of the OpenMAMA code and have a question. Is this the right place it?

 

The code I have (OpenMAMA 2.2.1.1) contains the following:

 

  MamaTransport::~MamaTransport (void)

    {

        if (mPimpl)

        {

        if ( mamaInternal_getCatchCallbackExceptions() && mPimpl->mCallback)

        {

          delete mPimpl->mCallback;

        }

            if (mPimpl->mDeleteCTransport)

            {

                mamaTry (mamaTransport_destroy (mTransport));

            }

            delete mPimpl;

            mPimpl = NULL;

        }

    }

 

Won’t this throw an exception and risk crashing if mamaTransport_destroy() fails? I can see similar code in other destructors, so I’m probably missing something.

 

Thanks,

 

--Richard

 

 

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