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    <p>Hopefully I'm understanding this correctly.</p> <p>It seems to me that the problem is trying to copy those vtrTextTrack structs improperly. This:</p> <pre><code>//texttrack = track; </code></pre> <p>just copies the pointer. If the owner of the struct (probably the caller of the callback function) destroys/deletes the vtrTextTrack, then you're holding on to an invalid pointer.</p> <p>This one:</p> <pre><code>memcpy(texttrack,track,sizeof(*track)); </code></pre> <p>will copy all the members of the vtrTextTrack, but will not copy what's being pointed to by it's member pointers (e.g. <code>texttrack-&gt;best</code>). Again, if the owner destroys/deletes the track, then you're holding on to invalid pointers.</p> <p>And since</p> <pre><code>//texttrack = new vtrTextTrack (*track); </code></pre> <p>didn't work, I'm guessing that vtrTextTrack doesn't provide a copy constructor.</p> <p>As for a workaround, first check if your third party library provides a function to copy these structs. If that's not the case (could this be by design?), then you may have to implement one yourself. This might be hard because there might be all kinds of internals that you don't know about. If you don't need the whole vtrTextTrack, I'd say define another struct and store only the information you need. Something along the lines of</p> <pre><code>SomeType* bestCopier(SomeType* src) { SomeType* temp; /* copy over struct */ return temp; } Foo* fooCopier(Foo* src) { /*...*/ } struct myTextTrack { public: myTextTrack(vtrTextTrack* src) { //copy over stuff m_best = bestCopier(src-&gt;best); m_foo = fooCopier(src-&gt;foo); } private: /* the members you care about*/ SomeType* m_best; Foo * m_foo; } </code></pre>
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    1. POAccessing variable outside scope of a callback c++
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    1. POAccessing variable outside scope of a callback c++
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    1. COThank you for your answer. Let me play with your idea and report back.
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    2. COAs I play with this two question come up. 1) best in the APIs vtrTextTrack is a pointer. Does that mean that SomeType in your above example should be SomeType * best? Does that change anything in your example? 2) SomeType is actually another struct (in C not C++). Does that mean I have to create my own copy constructor for that struct that is declared in your above example? SomeType has pointers as well.
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    3. COYou're right, my code wasn't quite right. I made some changes, and it's just one way you could approach it. Since these are all C structs and there is no copy constructor, you may just have to write a copy function for each part. It won't be fun, that's for sure. Do you need to keep the actual vtrTextTrack struct, or just certain info inside it? Because the latter would be easier. Also, it might be worth it to take a step back and think whether there's another way of accomplishing the same thing that fits better with the model of the 3rd party library.
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