--- Mike Nordell <[EMAIL PROTECTED]> wrote:
> Joaqu�n Cuenca Abela wrote:
>
> > #define DELETEP(ptr) \
> > do {} while(sizeof(*ptr) == 0); \
> > delete ptr; \
> > ptr = NULL;
> >
> > to prevent trying to delete a type not yet known
> to the compiler,
> > because the standard doesn't forces a compiler to
> issue a warning in
> > this case, and the result is undefined (the
> compiler can not known if
> > the type has a trivial destructor).
>
> ???
>
> How would the compiler allow deletion of an
> incomplete type that it
> therefore obviously has no accessible destructor
> for?
don't ask me...
> IMO a reasonable
> compiler should issue diagnostics, and AFAIK any
> compiler would have to
> abort translation.
would != should, unfortunately...
When you try with trivial examples with gcc, it aborts
translation, but I few months ago I was bitten by this
very same problem.
It was a class with a pimpl (using first
std::auto_ptr, and later boost::smart_ptr). My class
had a trivial destructor, so I (erronously) didn't
write it explicitely. I was missing that the compiler
was going to write a default **inline** destructor.
When I tried to use this class with std::auto_ptr, it
was working fine, but when I switched to
std::smart_ptr, the compiler it started to complain
about Impl not being a complete type.
First I though "of course it's not a complete type,
that's the whole point!!?". Seconds after I realized
my error, and I just though "oh my... I'm a moron"
I then read the whole checked_delete history. From
the boost webpage:
==============================================
Background
The C++ Standard specifies that delete on a pointer to
an incomplete types is undefined behavior if the type
has a non-trivial destructor in [expr.delete] 5.3.5
paragraph. No diagnostic is required. Some but not
all compilers issue warnings if the type is incomplete
at point of deletion.
===============================================
Cheers,
=====
Joaquin Cuenca Abela
[EMAIL PROTECTED]
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