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Subject: Re: [boost] boost/checked_delete.hpp
From: Peter Dimov (pdimov_at_[hidden])
Date: 2009-06-08 09:52:28

Kizza George Mbidde:
> typedef char type_must_be_complete[ sizeof(T)? 1: -1 ];
> (void) sizeof(type_must_be_complete);
> delete x;


> * 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.

> * 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.

> * Why is the result of sizeof cast to void? What exactly does that line
> do?

Silences a compiler warning.

> * Is it an empty statement if the sizeof is legal?


> * Why not apply x = 0; at the end?

It wouldn't do anything as x is passed by value.

Peter Dimov 

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