On Mon, May 23, 2011 at 11:42 AM, 肖锋 <xfxyjwf@gmail.com> wrote:

On Mon, May 23, 2011 at 6:25 PM, Robert Jones <robertgbjones@gmail.com> wrote:

Hi All

I'm trying to use std::vector::push_back() within a Boost.Lambda expression, but am finding it impossible

to bind correctly. Can anyone tell me what I'm doing wrong in this code?

Thanks in advance,

- Rob.

#include <vector>

#include <boost/function.hpp>

#include <boost/lambda/bind.hpp>

void f( )

{

    namespace ll = boost::lambda;

    using boost::function;

    typedef unsigned char Id;

    typedef std::vector<Id> Ids;

    ll::placeholder1_type x;

    Ids ids;

    void ( Ids::* push_back )( const Ids::value_type & ) = & Ids::push_back;

    function<void(Id)> my_push = ll::bind( push_back, ids, x ); // Line 18

Change ids to ll:var(ids) because the operation 'push_back' needs a mutable object.

    (void)my_push;

}

> g++ ignore.cpp

[...lots of template instantiation errors, then...]

ignore.cpp:18:   instantiated from here

/usr/include/boost/lambda/detail/actions.hpp:96: error: no matching function for call to ‘boost::lambda::function_adaptor<void (std::vector<unsigned char, std::allocator<unsigned char> >::*)(const unsigned char&)>::apply(void (std::vector<unsigned char, std::allocator<unsigned char> >::* const&)(const unsigned char&), const std::vector<unsigned char, std::allocator<unsigned char> >&, unsigned char&)’

/usr/include/boost/lambda/detail/actions.hpp:96: error: return-statement with a value, in function returning 'void'

Ok, many thanks, that worked. But why isn't  "ids" mutable on its own?