Re: [Boost-users] boost::bind used with boost shared_ptr

4 Mar 2009

      Hi,

This is with RHEL, gcc version 3.4.6. I *think* the boost version is 1.32.0.

-bash-3.00$ gcc -v
Reading specs from /usr/lib/gcc/i386-redhat-linux/3.4.6/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --enable-shared --enable-threads=posix
--disable-checking --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-java-awt=gtk
--host=i386-redhat-linux
Thread model: posix
gcc version 3.4.6 20060404 (Red Hat 3.4.6-8)
-bash-3.00$

The complete mini program I use is:
[code]
#include <map>

#include 
#include 

class A {
  public:
  void reset() {}
};

typedef boost::shared_ptr<A> ptr_type;

typedef std::map map_type;

map_type m;

int main()
{
    m[1] = ptr_type(new A());
    m[2] = ptr_type(new A());

    for_each (m.begin(), m.end(),
        boost::bind(&A::reset,
        boost::bind(&map_type::value_type::second, _1)));

    return 0;
}

[/code]

The following is the compiler error received:

[output]
-bash-3.00$ g++ -o tc tc.cpp
/usr/include/boost/bind.hpp: In member function `void
boost::_bi::list1<A1>::operator()(boost::_bi::type<void>, F&, A&, int) [with
F = boost::_mfi::mf0, A = boost::_bi::list1&>, A1 = boost::_bi::bind_t >, boost::_bi::list1 > >]':
/usr/include/boost/bind/bind_template.hpp:32:   instantiated from `typename
boost::_bi::result_traits::type boost::_bi::bind_t::operator()(A1&) [with A1 = std::pair, R = void, F =
boost::_mfi::mf0, L =
boost::_bi::list1 >, boost::_bi::list1 > > >]'
/usr/lib/gcc/i386-redhat-linux/3.4.6/../../../../include/c++/3.4.6/bits/stl_algo.h:158:
instantiated from `_Function std::for_each(_InputIterator, _InputIterator,
_Function) [with _InputIterator = std::_Rb_tree_iterator >, _Function = boost::_bi::bind_t, boost::_bi::list1 >,
boost::_bi::list1 > > > >]'
tc.cpp:24:   instantiated from here
/usr/include/boost/bind.hpp:228: error: no match for call to
`(boost::_mfi::mf0) (ptr_type)'
/usr/include/boost/bind/mem_fn_template.hpp:44: note: candidates are: R
boost::_mfi::mf0::operator()(T*) const [with R = void, T = A]
/usr/include/boost/bind/mem_fn_template.hpp:49: note:                 R
boost::_mfi::mf0::operator()(U&) const [with U = ptr_type, R = void, T
= A]
/usr/include/boost/bind/mem_fn_template.hpp:54: note:                 R
boost::_mfi::mf0::operator()(T&) const [with R = void, T = A]
-bash-3.00$
[/output]

Anyway, since it works on VC7.1 I imagine that it was fixed in some later
version of the library.

Thanks,
--Kevin

On Wed, Mar 4, 2009 at 11:49 AM, Peter Dimov  wrote:
...
Kevin Ludwig:
...
Hi,
I've recently been making more use of boost::bind, and I coded the
following, which I thought would work:
class A {
  public:
  void reset () {}
};
typedef std::map map_type;
map_type m;
std::for_each (m.begin(), m.end(),
  boost::bind(&A::reset,
  boost::bind(&map_type::value_type::second, _1)));
but fails to compile.
This compiles for me with MSVC 7.1. What compiler and Boost version do you
use? What errors do you get?
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-- 
Kevin