C++, Seg Faults, and Memory Management

Question

I'm moving from Java to C++ and have really enjoyed it. One thing I don't enjoy is not understanding memory at all because Java used to do that for me.

I've purchased a book : Memory as a Programming Concept in C and C++ - Frantisek Franek

Are there some good sites for me to go and learn interactively about C/C++ and memory use (tutorials, forums, user groups)?

This thread has a lot of useful info: http://stackoverflow.com/questions/395123/raii-and-smart-pointers-in-c — Manuel, Feb 09 '10 at 19:52
Well, you're putting emphasis on the right thing, since understanding resource management is (IMHO) absolutely critical to being a competent C++ developer. — Scott Smith, Feb 09 '10 at 20:06
@JesperE Indeed, I was amazed myself. I should probably mention that I'm doing this for educational reasons and not for work. I think if my boss wanted me to suddenly write an app in C++ it would be much more frustrating than fun. — Stephano, Feb 09 '10 at 20:42
I think "fascinated" is the term you're looking for, not "enjoying". ;-) — JesperE, Feb 10 '10 at 07:03

score 5 · Answer 1 · edited May 23 '17 at 12:01

5

Memory management is nearly automatic in C++ (with a few caveats).

Most of the time don't dynamically allocate memory.
Use local variables (and normal member variables) and they will construct and destruct automatically.

When you do need pointers use a smart pointer.
Start with using boost::shared_pointer<T> instead of pointers.
This will get you on the correct path and stop accidently deleting memory at the wrong time and 90% of your code will release correctly (unfortunately cycles will cause a problem (in terms of leaks only) and you will need to design accordingly (but we have other smart pointers to deal with cycles weak_ptr))

My fundamental rule is that a class never contain a RAW pointer. Always use some form of standard container or a smart pointer. Using these; destructor calls become automatic.

Once you have the feeling start reading about the other smart pointers and when to use them:

Smart Pointers: Or who owns you baby?

edited May 23 '17 at 12:01

Community

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answered Feb 09 '10 at 19:52

Martin York

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+1, especially for "Most of the time don't dynamically allocate memory." – Fred Larson Feb 09 '10 at 19:58
@Martin - out of genuine interest: isn't using `shared_ptr` everywhere a bit slow? Would you recommend it, say, for a simulation or a videogame? – Manuel Feb 09 '10 at 20:07
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What makes you think it is slow? But no I am not recomending it for everywhere. I am recomending it as a starting point for learning about smart pointers. Use the correct smart pointer to solve the problem at hand (but you have to start somwhere and smart pointers is a rather large topic to jump in). PS. I have no problems with smart pointers in simulators (correctness is king, optimize after you show it is bottleneck). – Martin York Feb 09 '10 at 20:12