Re: [Boost-users] boost::function/boost::bind compilation error

6 Sep 2009


      AMDG

Ahmed Badran wrote:
...
I was trying to use boost function/bind to bind the first argument of 
a member function that takes two arguments, when I got into a 
compilation error that I can't quite decipher or understand, below is 
a sample representation of the problem, and then there's the 
compilation error, am I doing something incorrectly here?
I have tried removing the boost::mem_fn instantiation with no difference.
#include <boost/function.hpp>
#include <boost/bind.hpp>
#include <boost/mem_fn.hpp>
#include <iostream>
using namespace std;
using namespace boost;
class my_class
{
    public:
    void test(bool b)
    {
        cout << "got " << b << endl;
    }
    private:
};
int main()
{
    my_class c;
    boost::function1<void, bool> test_fn;
    boost::bind(&my_class::test, &c, _2);
/* causes a compilation error */
    test_fn = boost::bind<void>(boost::mem_fn(&my_class::test), &c, _2);
Use _1 instead of _2.  The placeholder number indicates
the first argument to the function object created by bind.
You're only passing a single bool argument in, so only _1
is a valid placeholder.

In Christ,
Steven Watanabe