Re: [Boost-users] Boost.Function __stdcall, __fastcall, etc

Subject: Re: [Boost-users] Boost.Function __stdcall, __fastcall, etc
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2010-04-26 00:34:19

AMDG

Brian Rowlett wrote:
> I am writing a DLL that gets injected into another process, and 
> creates pointers to the target processes functions. The target process 
> uses all 3 calling conventions, __stdcall, __fastcall and __cdecl.
>  
> I have created a class whos constructor gets the address of the 
> function, and passes it to the base class boost::function:
>  
>
>     template <typename _Signature, enum LibraryId _LibraryId, int _Offset>
>     class FunctionPointer: protected OffsetPointer, public
>     boost::function<_Signature>
>     {
>     public:
>         FunctionPointer(void)
>         :
>     boost::function<_Signature>( OffsetPointer::_getOffset(_LibraryId,
>     _Offset )
>         { return; }
>     };
>
>  
> I instantiate this with:
>  
>
>     FunctionPointer<return_type__stdcall( argument_types ), LibraryId,
>     Offset> Function;
>
>     FunctionPointer<return_type __cdecl( argument_types ), LibraryId,
>     Offset> Function;
>
>  
> Whatever calling convention Visual Studio is setup to use (__cdecl by 
> default), works just fine. But trying to instantiate it with another 
> calling convention gives the following error:
>  
>
>     Error 1 error C2504: 'boost::function<Signature>' : base class
>     undefined
>
>  
> It seems weird that it would work for some calling conventions, and 
> not others..
>  
> Any ideas?

Don't try to specify a calling convention for Boost.Function.
return_type __cdecl(argument_types) works because it
is equivalent to return_type(argument_types) which is
what Boost.Function accepts.  A boost::function should
be able to store function pointers that use /any/ calling
convention.

In Christ,
Steven Watanabe