Re: [Boost-users] Trouble with asio using lib pion and boost.function

Subject: Re: [Boost-users] Trouble with asio using lib pion and boost.function
From: Stephan Menzel (stephan.menzel_at_[hidden])
Date: 2008-11-27 03:51:00

Hi Steven

> >>>     return static_cast<vtable_type*>(vtable)->invoker
> >>>              (this->functor BOOST_FUNCTION_COMMA BOOST_FUNCTION_ARGS);
> >>>   }

> >> a) Is the error on the static_cast or on reading the function pointer?

> You could look at the disassembly...

Good call!

Neat feature, this Visual stuff has got here. I see lots of things along those lines. I try to boil it down to a more interesting part:

#if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)
  template<typename R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_PARMS>
  typename BOOST_FUNCTION_FUNCTION<
      R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_ARGS>::result_type
   BOOST_FUNCTION_FUNCTION<R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_ARGS>
  ::operator()(BOOST_FUNCTION_PARMS) const
  {
1004E4B0  push        ebp  
1004E4B1  mov         ebp,esp 
1004E4B3  push        0FFFFFFFFh 
1004E4B5  push        offset __ehhandler$??R?$function1_at_XV?$shared_ptr_at_VTCPConnection@net_at_pion@@@boost@@@boost@@QBEXV?$shared_ptr_at_VTCPConnection@net_at_pion@@@1@@Z (1005A600h) 
1004E4BA  mov         eax,dword ptr fs:[00000000h] 
1004E4C0  push        eax  
1004E4C1  sub         esp,40h 
1004E4C4  push        edi  
1004E4C5  push        ecx  
1004E4C6  lea         edi,[ebp-4Ch] 
1004E4C9  mov         ecx,10h 
1004E4CE  mov         eax,0CCCCCCCCh 
1004E4D3  rep stos    dword ptr es:[edi] 
1004E4D5  pop         ecx  
1004E4D6  mov         eax,dword ptr [___security_cookie (1007C920h)] 
1004E4DB  xor         eax,ebp 
1004E4DD  push        eax  
1004E4DE  lea         eax,[ebp-0Ch] 
1004E4E1  mov         dword ptr fs:[00000000h],eax 
1004E4E7  mov         dword ptr [ebp-10h],ecx 
1004E4EA  mov         dword ptr [ebp-4],0 
    if (this->empty())
1004E4F1  mov         ecx,dword ptr [ebp-10h] 
1004E4F4  call        boost::function_base::empty (100033B4h) 
1004E4F9  movzx       eax,al 
1004E4FC  test        eax,eax 
1004E4FE  je          boost::function1<void,boost::shared_ptr<pion::net::TCPConnection> >::operator()+7Dh (1004E52Dh) 
      boost::throw_exception(bad_function_call());
1004E500  lea         ecx,[ebp-3Ch] 
1004E503  call        boost::bad_function_call::bad_function_call (100015B9h) 
1004E508  mov         dword ptr [ebp-44h],eax 
1004E50B  mov         ecx,dword ptr [ebp-44h] 
1004E50E  mov         dword ptr [ebp-48h],ecx 
1004E511  mov         byte ptr [ebp-4],1 
1004E515  mov         edx,dword ptr [ebp-48h] 
1004E518  push        edx  
1004E519  call        boost::throw_exception<boost::bad_function_call> (100024FAh) 
1004E51E  add         esp,4 
1004E521  mov         byte ptr [ebp-4],0 
1004E525  lea         ecx,[ebp-3Ch] 
1004E528  call        boost::bad_function_call::~bad_function_call (10002199h) 

    return static_cast<vtable_type*>(vtable)->invoker
             (this->functor BOOST_FUNCTION_COMMA BOOST_FUNCTION_ARGS);
1004E52D  sub         esp,8 
1004E530  mov         ecx,esp 
1004E532  mov         dword ptr [ebp-40h],esp 
1004E535  lea         eax,[ebp+8] 
1004E538  push        eax  
1004E539  call        boost::shared_ptr<pion::net::TCPConnection>::shared_ptr<pion::net::TCPConnection> (10003003h) 
1004E53E  mov         dword ptr [ebp-4Ch],eax 
1004E541  mov         ecx,dword ptr [ebp-10h] 
1004E544  add         ecx,8 
1004E547  push        ecx  
1004E548  mov         edx,dword ptr [ebp-10h] 
1004E54B  mov         eax,dword ptr [edx] 
1004E54D  mov         ecx,dword ptr [eax+4] 
1004E550  call        ecx  

and so on and so forth and suchlike.

> However, in the light of the following, it seem more likely that
> the "this" pointer is invalid.

Indeed. There's even a 

    if (this->empty())
      boost::throw_exception(bad_function_call());

to be seen.
What I see is either this exception or it is a crash trying to access this. In any case, it's platform specific. 

But I still don't know how to proceed. Wouldn't here be a bug report in order?

Cazart,
Stephan