Re: [Boost-Users] what's the purpose of the typedef in check_delete.hpp?

From: Beman Dawes (bdawes_at_[hidden])
Date: 2002-09-22 18:48:08

At 01:30 AM 9/22/2002, Darin Adler wrote:

 >The rules in the C++ standard are that if you delete using a pointer in
 >a context where the type of the object pointed to is not completely
 >defined, the object will be deleted, but the destructor will not be
 >called. Many people think that's a particularly bad rule, because the
 >code compiles and runs, but does the wrong thing.
 >
 >Since it contains a typedef that includes sizeof(T), this function will
 >fail to compile if the type T is not complete. This means that the
 >checked delete function template will only compile if the destructor
 >will be called. That way the compiler will detect a programming mistake
 >that would otherwise result in deleting the object without calling the
 >destructor. This is likely to save time that would otherwise be spent
 >debugging problems caused by destructors that are not called.

Darin,

Nice description of the problem, and the solution.

 >A lot of us are hoping that like a future version of the C++ standard
 >will make delete itself behave like this.

While I don't following the C++ committee's Evolution Working Group 
closely, I don't recall actually seeing a proposal the above. If not, maybe 
you should consider writing a paper.

Cheers,

--Beman