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C++ copy operator of TPsVar (and derived classes)
August 24, 2016
12:26, EEST
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Fransua33
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October 27, 2014
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Hi,

Just a doubt with the C++ copy operator. Is it correct to use it?

For example if I want to create the same object in a different piece of memory like this:

TPsBool tag = new TPsBool(NULL);
tag->OnChange = onChangeRoutine;
TPsBool tag2 = new TPsBool(NULL);
*tag2 = *tag;

And this piece of code results in 2 TPsBool objects with differents pointers and the same properties, methods and events. Is that right?

Best regards!!!

August 24, 2016
13:57, EEST
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Jouni Aro
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Must admit that I haven’t used C++ enough to say for sure, but I don’t think this works as expected.

The Delphi classes have the Assign() method, instead, which you can use to make a deep copy of the objects – also in C++.

August 25, 2016
17:19, EEST
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Fransua33
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So the correct code must be:

TPsBool tag = new TPsBool(NULL);
tag->OnChange = onChangeRoutine;
TPsBool tag2 = new TPsBool(NULL);
tag2->Assign(tag);

Does Assign copies also the events configured in the source?

August 26, 2016
10:03, EEST
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Jouni Aro
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No, it only copies the “Variable Properties”. This is the full implementation:

procedure TPsVar.Assign(Source: TPersistent);
begin
if Source is TPsVar then
CopyProps([vpValue..vpOther2], TPsVar(Source))
else
inherited Assign(Source);
end;
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