Hi all,
I'm having a problem using Boost.Bind on the above platform.
The simple test file I'm using looks like this:
=== snip ===
#include <iostream>
#include <algorithm>
#include <map>
#include
struct Argument
{
int value_;
};
struct Operator
{
Operator &compute(Argument const &arg)
{
std::cout << arg.value_ << std::endl;
return *this;
}
// Warning is gone if I declare the above function as:
//Operator const &compute(Argument const &arg) const {...}
};
int main()
{
typedef std::map OperatorMap;
OperatorMap ops;
ops.insert(std::make_pair(0, Operator()));
Argument arg0 = { 1 };
std::for_each(
ops.begin(), ops.end(),
boost::bind(&Operator::compute,
boost::bind(&OperatorMap::value_type::second, _1),
boost::cref(arg0)));
}
=== snip ===
The idea is that I want to put a parameter through a collection of
Operators objects stored in an std::map. However, I always get the
following warning from the compiler:
=== snip ===
test.cpp
..\..\..\boost-1.x\include\boost-1_33_1\boost\bind.hpp(276) : warning
C4239: nonstandard extension used : 'argument' : conversion from
'boost::_bi::result_traits::type' to 'Operator &'
with
[
R=Operator,
F=boost::_mfi::dm>
]
A reference that is not to 'const' cannot be bound to a non-lvalue
..\..\..\boost-1.x\include\boost-1_33_1\boost\bind\bind_template.hpp(32)
: see reference to function template instantiation 'R
boost::_bi::list2::operator
()::result_type,F,boost::_bi::list1
&>>(boost::_bi::type<T>,F &,A &,long)' being compiled
with
[
R=boost::_bi::bind_t,boost::_bi::list2>,boost::_bi::list1>::B1>>,Argument>::B1,boost::_bi::list_av_2>,boost::_bi::list1>::B1>>,Argument>::B2>>::result_type,
A1=boost::_bi::list_av_2>,boost::_bi::list1>::B1>>,Argument>::B1,
A2=boost::_bi::list_av_2>,boost::_bi::list1>::B1>>,Argument>::B2,
F=boost::_mfi::mf1,
L=boost::_bi::list2>,boost::_bi::list1>::B1>>,Argument>::B1,boost::_bi::list_av_2>,boost::_bi::list1>::B1>>,Argument>::B2>,
_T1=const int,
_T2=Operator,
T=boost::_bi::bind_t,boost::_bi::list2>,boost::_bi::list1>::B1>>,Argument>::B1,boost::_bi::list_av_2>,boost::_bi::list1>::B1>>,Argument>::B2>>::result_type,
A=boost::_bi::list1::value_type &>
]
..\..\..\STLport-5.0\stlport\stl\_algo.h(61) : see reference to
function template instantiation 'boost::_bi::bind_t::result_type
boost::_bi::bind_t::operator ()<_Tp>(A1 &)' being compiled
with
[
R=Operator &,
F=boost::_mfi::mf1,
L=boost::_bi::list2>,boost::_bi::list1>::B1>>,Argument>::B1,boost::_bi::list_av_2>,boost::_bi::list1>::B1>>,Argument>::B2>,
_Tp=stlp_std::map::value_type,
A1=stlp_std::map::value_type
]
\workspace\devel\RD3.0-vc71\Libraries\MkToolkit-3.0\src\core\test.cpp(35)
: see reference to function template instantiation '_Function
stlp_std::for_each::iterator,boost::_bi::bind_t>(_InputIter,_InputIter,_Function)'
being compiled
with
[
_Function=boost::_bi::bind_t,boost::_bi::list2>,boost::_bi::list1>::B1>>,Argument>::B1,boost::_bi::list_av_2>,boost::_bi::list1>::B1>>,Argument>::B2>>,
_Key=int,
_Tp=Operator,
R=Operator &,
F=boost::_mfi::mf1,
L=boost::_bi::list2>,boost::_bi::list1>::B1>>,Argument>::B1,boost::_bi::list_av_2>,boost::_bi::list1>::B1>>,Argument>::B2>,
_InputIter=stlp_std::map::iterator
]
=== snip ===
It seems that it is complaining about the const-ness of
Operator::compute() member function. May I know if there is anything I
can do to fix this problem? Or, is there any problem with my
understanding of Boost.Bind through the way I used it?
Cheers,
Freddie
--
Wu Yinghui, Freddie
Research & Development
Software Engineer
Volume Interactions Pte Ltd
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Peter Dimov
Wu Yinghui, Freddie