Auto_ptr to external C struct

Question

I would like to create an Auto_Ptr to a legacy C struct; I only have header files and static libraries so I cannot modify the source code. I wondered wouldn't the auto_ptr automatically try to call the Destructor ~foo() if I call p.release() or p.reset()? This destructor does not exist for the C struct. My current solution is to write a C++ wrapper class that presents a destructor interface (internally it uses the library-specific C methods to release memory and destroy other resources). Is there a nicer way to do it; or has this problem already been solved by Boost etc.?

Remember that in C++ the only difference between `struct` and `class` is that `members are by default `public` in a `struct` but `private` in a `class`. This means that you can have member functions in a `struct` like in a `class`, including constructors/destructors. And that the C++ compiler will add default constructors/destructors if you don't have any. — Some programmer dude, Jul 27 '12 at 09:53
I was aware of that-- in my case C++ cannot possibly do the correct thing in the auto-generated destructor. I could edit the header-file and add functions but this wouldn't be a clean solution since for each new revision of the system header I would have to do that modification again. Does using a C++ wrapper sound like a good solution though? — Matthias Hueser, Jul 27 '12 at 10:45

yuri kilochek · Answer 1 · 2012-07-27T10:05:17.053

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There still exists an implicit destructor when compiled with c++, so its fine. If the struct is allocated with new, that is.

edited Jul 27 '12 at 10:05

answered Jul 27 '12 at 09:52

yuri kilochek

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Also note, that auto_ptr is depricated, consider using unique_ptr instead. – yuri kilochek Jul 27 '12 at 09:55
How can you give `auto_ptr` a custom deleter?? – Kerrek SB Jul 27 '12 at 10:02
@Kerrek SB my bad, you can not. As you can see it is too infexible and has thus been depricated. Edited answer accoringly. – yuri kilochek Jul 27 '12 at 10:05
I cannot use C++11 due to portability reasons; the library needs to be compiled with GCC 4.3.2 – Matthias Hueser Jul 27 '12 at 10:46
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@MatthiasHueser there is boost::unique_ptr that works in c++03 – yuri kilochek Jul 27 '12 at 11:09

Auto_ptr to external C struct

1 Answers1