Thanks Peter. This clears things up for me. However, concerning the last point x is passed by reference (pointer), as in inline void checked_delete(T * x) Thank you once again. ______________________________________________________________________ Kizza George Mbidde Interconnect Billing Systems Analyst IT cell: +256 77 221 2982 email: mbiddeg@mtn.co.ug -----Original Message----- From: boost-bounces@lists.boost.org [mailto:boost-bounces@lists.boost.org] On Behalf Of Peter Dimov Sent: Monday, June 08, 2009 16:52 To: boost@lists.boost.org Subject: Re: [boost] boost/checked_delete.hpp 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?
Yes.
* 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 _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost