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POHow to free an object which is in a record?
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  1. POHow to free an object which is in a record?
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    copied!<p>Here I have a tricky situation, I guess. I need to be able to free an object which is a field of a record. I would normally write the cleanup code in the destructor, if it was a class. But since record types can't introduce a "destructor", how would it be possible to call <strong>TObject(Field).Free;</strong> ?</p> <p>There'll be two types of usage I predict:</p> <ol> <li><p>Replacing the record with a new one.</p> <p>I think this usage would be easy to implement. Since records are value types and so they are copied on assignment, I can overload the assigning operator and free the objects owned by old record.</p> <p>( <strong>Edit:</strong> Assignment overloading wasn't able. That's a new info to me.. )</p></li> <li><p>Exiting the scope where record variable defined.</p> <p>I can think of a private method that frees the objects and this method could be called on scope excitation manually. BUT, here is the same question: How to make it more <strong>recordly</strong>? This behaviour kind of feels like a class...</p></li> </ol> <p>Here is a sample (and obviously <strong>not the intended usage</strong>):</p> <pre><code>TProperties = record ... some other spesific typed fields: Integers, pointers etc.. FBaseData: Pointer; FAdditionalData: TList&lt;Pointer&gt;; //FAdditionalData: array of Pointer; this was the first intended definition end; </code></pre> <p>Assume,</p> <pre><code>FAdditionalData:=TList&lt;Pointer&gt;.Crete; </code></pre> <p>called in record constructor or manually in record variable scope by accessing the field publicly like</p> <pre><code>procedure TFormX.ButtonXClick(Sender: TObject); var rec: TProperties; begin //rec:=TProperties.Create(with some parameters); rec.FAdditionalData:=TList&lt;Pointer&gt;.Create; //do some work with rec end; </code></pre> <p>After exiting the ButtonClick scope the <strong>rec</strong> is no more but a <strong>TList</strong> still keeps its existance which causes to memory leaks...</p>
 

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