Re: [boost] Warning from share_ptr

From: Peter Dimov (pdimov_at_[hidden])
Date: 2007-01-14 11:08:20

Paul A Bristow wrote:
> I am getting an annoying warning when building boost_math.dll AND
> generating Microsoft VS 8.0 'managed' code /clr:pure, even at warning
> level 1.
>
> (clr code is needed because we are building a Windows .net form in C#
> to demonstrate Math function and Statistics Distribution using John
> Maddock's Math Toolkit in C++.  Aside - with a lot of annoying
> wrapping, John has made this work).
>
> The message is:
>
> C4793 'vararg' : causes native code generation for function 'void
> boost::detail::sp_enable_shared_from_this(const
> boost::detail::shared_count &,...)'
>
> Adding this #pragma to the top of our boost_math.cpp file does NOT
> suppress it.
>
> #pragma warning(disable: 4793) // 'vararg' : causes native code
> generation for function 'void
> boost::detail::sp_enable_shared_from_this(const
> boost::detail::shared_count &,...)'
>
> Is this worrying?  Is there something wrong with the pushing and
> popping of warnings?

If you compile with /clr:pure, you presumably don't want native functions in 
your assembly, so the warning is legitimate (unless the optimizer is smart 
enough to see that the function is empty and not include it in the 
assembly).

Avoiding the ... isn't as trivial as it appears. You might want to try 
replacing

inline void sp_enable_shared_from_this( shared_count const & /*pn*/, ... )
{
}

with

struct sp_any_pointer
{
    template<class T> sp_any_pointer( T* ) {}
};

inline void sp_enable_shared_from_this( shared_count const & /*pn*/, 
sp_any_pointer, sp_any_pointer )
{
}

for the _MANAGED case and see if it helps.