Re: Re: Re: Re: Re: Re: boost.function with CW 8.2 on W2k

From: Bertolt Mildner (Bertolt.Mildner_at_[hidden])
Date: 2002-09-10 12:03:29

> shared_ptr reuses shared_ptr::get as the nonnull value, without a dummy
> nested class:
> 
>     // implicit conversion to "bool"
> 
>     typedef T * (this_type::*unspecified_bool_type)() const;
> 
>     operator unspecified_bool_type() const // never throws
>     {
>         return px == 0? 0: &this_type::get;
>     }
> 
> Perhaps something along these lines will work for boost::function.

Ok, here is my next try:

diff -r1.33 function_base.hpp
271c271
<     function_base() : manager(0), functor(static_cast<void*>(0)) {}
---
>     inline function_base() : manager(0), functor(static_cast<void*>(0)) {}
274c274
<     bool empty() const { return !manager; }
---
>     inline bool empty() const { return !manager; }
284c284
<     operator bool () const { return !this->empty(); }
---
>     inline operator bool () const { return !this->empty(); }
287,291c287
<     struct dummy {
<       void nonnull() {};
<     };
< 
<     typedef void (dummy::*safe_bool)();
---
>     typedef bool (function_base::*safe_bool)() const;
294,295c290,294
<     operator safe_bool () const 
<       { return (this->empty())? 0 : &dummy::nonnull; }
---
>     inline operator safe_bool () const 
>       { return (this->empty())? 0 : &function_base::empty; }
> 
>     inline bool operator!() const
>       { return !this->empty(); }
297,298d295
<     safe_bool operator!() const
<       { return (this->empty())? &dummy::nonnull : 0; }
which again results in this error:
Error   : illegal use of precompiled header
(included from:
 function.hpp:22
 KeyStorage.h:12
 HostMemoryKeyStorage.h:9
 DesKey.h:10
 MWPrefixWin32.pch++:15)
function_base.hpp line 274       inline bool empty() const { return !manager; }
Bertolt
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