Re: [boost] boost/checked_delete.hpp

8 Jun 2009


      Kizza George Mbidde:
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typedef char type_must_be_complete[ sizeof(T)? 1: -1 ];
   (void) sizeof(type_must_be_complete);
   delete x;
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* What's the result of applying sizeof to an incomplete type?
A compile-time error, unless the compiler chooses to return 0 as a 
nonstandard extension.
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* Why is sizeof called twice?
The second sizeof is a workaround for a Metrowerks CodeWarrior bug in which 
the first typeof is never instantiated unless used.
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* Why is the result of sizeof cast to void? What exactly does that line 
do?
Silences a compiler warning.
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* Is it an empty statement if the sizeof is legal?
Yes.
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* Why not apply x = 0; at the end?
It wouldn't do anything as x is passed by value.

--
Peter Dimov
http://www.pdplayer.com