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putting pointers to objects in a set

General and Gameplay Programming Programming

Started by DevFred July 24, 2009 01:46 PM

21 comments, last by DevFred 14 years, 8 months ago

1,682

July 26, 2009 10:22 AM

Quote:Original post by SiCrane
A pointer converted to an integer of sufficient size (if any such exists on the implementation) and back to the same pointer type will have its original value

Which is all the OP needs; for that to work, distinct pointers must map to distinct integers, and integers have the necessary ordering properties for the set.

Oxyd

1,162

July 26, 2009 11:42 AM

I think the behaviour of the original snippet is defined. std::set uses std::less by default instead of op <. And std::less guarantees total ordering even for pointer types:

Quote:ISO/IEC 14882:2003 20.3.3.8
For templates greater, less, greater_equal, and less_equal, the specializations for any pointer type yield a total order, even if the built-in operators <, >, <=, >= do not.