[Bug libstdc++/40296] [C++0x] std::exception_ptr comparisons

[tfautre at pandora dot be]

------- Comment #10 from tfautre at pandora dot be  2010-06-02 16:54 -------
(In reply to comment #5)
> (In reply to comment #1)
> > I'm under the impression we should simply not provide operator __safe_bool()
> 
> Agreed, there is no requirement for conversion to bool, explicit or implicit. 
> Even if it can be done unambiguously, adding that non-standard conversion would
> encourage non-portable code.  I think operator! should be removed for the same
> reason.

I disagree with that statement (the draft may have changed since your comment
was made).

In the latest C++0x draft,

Section 18.8.5: "exception_ptr shall satisfy the requirements of
NullablePointer (20.2.3)."

Section 20.2.3 (NullablePointer Requirements): "An object p of type P can be
contextually converted to bool (Clause 4). The effect shall be as if p !=
nullptr had been evaluated in place of p."

AFAIK, the following code should work but does not anymore cause of this bug
fix:

std::exception_ptr e;

if (e)
{
    /* ... */
}


-- 

tfautre at pandora dot be changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tfautre at pandora dot be


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40296