id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
4073	<boost/function/function_template.hpp> compile errors with Visual Studio 2010 - mem_fn ADL issue	cpboost@…	Daniel James	"'''Problem:'''
Using boost::function in Microsoft Visual Studio 2010 can cause an argument-dependent name lookup problem when given arguments that include std:: components. I ''believe'' this will happen with any compiler that has mem_fn in the std:: namespace, but have only verified it on VS 2010.

'''Solution:'''
Change two instances of mem_fn in function_template.hpp (lines 539 and 552 of the current Subversion checkout) to prefix them with the boost:: namespace qualifier. It appears that this is already done at the other two mem_fn calls at lines 207 & 225.

'''How to Reproduce'''
Build the following code with Visual Studio 2010:

{{{
#include <boost/function.hpp>
#include <string>

class PrimitiveBuilder
{
public:
  bool someFunction( std::string& token );
  void registerSomeFunction() {
    mPrimitiveFunctor = &PrimitiveBuilder::someFunction; // ambiguity error is here
}
private:
  typedef boost::function<bool (PrimitiveBuilder*, std::string& token)> PrimitiveFunctor;
  PrimitiveFunctor mPrimitiveFunctor;
};
}}}


It will produce the following error message:

{{{
1>e:\stellar\controlled\trunk\3rdparty\boost\boost\function\function_template.hpp(539):
 error C2668: 'boost::mem_fn' : ambiguous call to overloaded function
1>         e:\stellar\controlled\trunk\3rdparty\boost\boost\bind\mem_fn_cc.hpp(25):
 could be 'boost::_mfi::mf1<R,T,A1> boost::mem_fn<bool,PrimitiveBuilder,std::string&>
 (R (__thiscall PrimitiveBuilder::* )(A1))'
1>         with
1>         [
1>             R=bool,
1>             T=PrimitiveBuilder,
1>             A1=std::string &
1>         ]
1>         c:\program files (x86)\microsoft visual studio 10.0\vc\include\xxmem_fn(32):
 or     'std::tr1::_Mem_fn2<_Rx,_Pmf,_Arg0,_Arg1> std::tr1::mem_fn<bool,PrimitiveBuilder,std::string&>
 (_Rx (__thiscall PrimitiveBuilder::* )(_Arg1))' [found using argument-dependent lookup]
1>         with
1>         [
1>             _Rx=bool,
1>             _Pmf=bool (__thiscall PrimitiveBuilder::* )(std::string &),
1>             _Arg0=PrimitiveBuilder,
1>             _Arg1=std::string &
1>         ]
1>         while trying to match the argument list '(bool (__thiscall PrimitiveBuilder::* )(std::string &))'

}}}

'''More problem explanation'''
Deep inside of boost there's a call to ""this->assign_to_a(mem_fn(f), functor, a);"". mem_fn used to be unambiguous, but now because one of our function's arguments is an std::string, the new std::mem_fn is introduced as a candidate. I verified that if I change std::string to int in the above example, the code compiles fine. I've also verified that the solution - adding ""boost::"" in front of the two unqualified mem_fn calls - resolved the problem.
"	Bugs	closed	Boost 1.47.0	function	Boost 1.46.0	Problem	fixed	argument dependent lookup, function, visual studio 2010. mem_fn