boost::bind for member functions

27 Jun 2002

      Hi,

I'd like to be able to bind an object to to a member function argument, 
like the example below. NB: if I make not_ok()'s first argument an int 
and pass an int variable to bind, gcc will buy it. I've tried this every 
way that makes any sense to me and I have not been able to get it to work.

I'm using gcc 2.95.3.

Thanks,
Bill

#include 
#include 

class D
{
private:
   int _d;
public:
   D()
     :_d(0)
   {}

   int d() const { return _d; }
   void d(int i) { _d = i; }
};

typedef boost::function Foo;

class A
{
private:
   Foo _f;

public:
   A(Foo f)
     :_f(f)
   {}

   int doit(int i) { return _f(i); }
};

class B
{
public:
   int not_ok(const D *d, int j) { return d->d() + j; }
};

class C
{
public:
   int ok(int i) { return i * i; }
};

int fooBar(int j);

static Foo g = fooBar;

int fooBar(int j)
{
   B *b = new B;
   C *c = new C;

   Foo f1 = boost::bind(&C::ok, c, _1);
   A a1(f1);

   int i = 5;
   D *d = new D;
   d->d(3);
   Foo f2 = boost::bind(&B::not_ok, b, _1, d); //<-----
   A a2(f2);

   return a1.doit(i) +  a2.doit(2);
}

/usr/local/devl/src/incl/boost/bind.hpp: In method `int 
boost::_bi::list3,boost::arg<1>,boost::_bi::value >::operator (), boost::_bi::list1
...
(boost::_bi::type<int>, boost::_mfi::mf2, 
boost::_bi::list1 &) const':
/usr/local/devl/src/incl/boost/bind/bind_template.hpp:33:   instantiated 
from `boost::_bi::bind_t,boost::_bi::list3,boost::arg<1>,boost::_bi::value > >::operator ()<int>(int &)'
/usr/local/devl/src/incl/boost/function/function_template.hpp:110: 
instantiated from 
`boost::detail::function::function_obj_invoker1,boost::_bi::list3,boost::arg<1>,boost::_bi::value > 
,int,int>::invoke(boost::detail::function::any_pointer, int)'
/usr/local/devl/src/incl/boost/function/function_template.hpp:437: 
instantiated from 
`boost::function1boost::function_base 
::assign_to,boost::_bi::list3,boost::arg<1>,boost::_bi::value > > 
(boost::_bi::bind_t,boost::_bi::list3,boost::arg<1>,boost::_bi::value > >, 
boost::detail::function::function_obj_tag)'
/usr/local/devl/src/incl/boost/function/function_template.hpp:388: 
instantiated from 
`boost::function1boost::function_base 
::assign_to,boost::_bi::list3,boost::arg<1>,boost::_bi::value > > 
(boost::_bi::bind_t,boost::_bi::list3,boost::arg<1>,boost::_bi::value > >)'
/usr/local/devl/src/incl/boost/function/function_template.hpp:274: 
instantiated from 
`boost::function1boost::function_base 
::function1,boost::_bi::list3,boost::arg<1>,boost::_bi::value > > 
(boost::_bi::bind_t,boost::_bi::list3,boost::arg<1>,boost::_bi::value > >)'
/usr/local/devl/src/incl/boost/function.hpp:459:   instantiated from 
`boost::function::function,boost::_bi::list3,boost::arg<1>,boost::_bi::value > > 
(boost::_bi::bind_t,boost::_bi::list3,boost::arg<1>,boost::_bi::value > >)'
testBoost.C:61:   instantiated from here
/usr/local/devl/src/incl/boost/bind.hpp:263: no match for call to 
`(boost::_mfi::mf2) (B *const &, int &, D *const &)'
/usr/local/devl/src/incl/boost/bind/mem_fn_template.hpp:212: candidates 
are: int boost::_mfi::mf2::operator ()(B *, const D 
*, int) const
/usr/local/devl/src/incl/boost/bind/mem_fn_template.hpp:217: 
      int boost::_mfi::mf2::operator ()(B 
*const &, const D *, int) const
/usr/local/devl/src/incl/boost/bind/mem_fn_template.hpp:222: 
      int boost::_mfi::mf2::operator ()(B &, const 
D *, int) const
/usr/local/devl/src/incl/boost/bind.hpp:263: warning: control reaches 
end of non-void function `boost::_bi::list3,boost::arg<1>,boost::_bi::value >::operator (), boost::_bi::list1 
(boost::_bi::type<int>, boost::_mfi::mf2, 
boost::_bi::list1 &) const'

boost::bind for member functions

Bill Dozier