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I have been attempting to write my own weak/strong pointer's but I am not clearly understanding the relationship. Everything I seem to come across does not make it and clear and quite often one doc will contridict what another doc says. Could anyone please explain the weak/strong pointer relationship in detail, with maybe an image or code sample also?

(Please do not just tell me to "use boost" or "use tr1", etc. This is not homework, I want to learn).

Kate Gregory
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chadb
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  • You might be interested in watching [this video](http://channel9.msdn.com/Shows/Going+Deep/C9-Lectures-Stephan-T-Lavavej-Advanced-STL-1-of-n). – fredoverflow Mar 20 '11 at 19:39
  • It's OK to want to learn. But one should be able to understand how a car engine works before on start trying to work on the engine of a harrier. Th basic principles may be the same but there is host of specialized knowledge. If you want to see how the professional version works break open boost and try and understand their implementation first. – Martin York Mar 20 '11 at 21:35

1 Answers1

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A strong pointer owns the underlying raw pointer. Its existence can keep the raw pointer alive, and as a result it can't point to something that's been cleaned up. Its destruction can cause a delete on the raw pointer. A weak pointer only knows the raw pointer, and whether or not it's still valid. It doesn't keep the raw pointer alive by existing and it can't make the raw pointer go away by being cleaned up.

To get a more detailed answer you would need to show the contradictions you've found or the question that you have about a specific part of the definition.

Kate Gregory
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    IMHO it would be good to add here difference between weak_ptr and raw pointer - weak_ptr knows whether the object has been deleted or not, and an attempt to access the deleted object through weak_ptr will produce _defined_ behaviour - exception – maxim1000 Mar 20 '11 at 20:21