Use of boost coroutine2 without lambdas - c++

Question

I guess this is the first time I couldn't manage to find an already answered question in here, and I could really use some help if anyone have successfully used boost coroutine2 lib without lambdas.
My problem, sumarized:
class worker {
...
void import_data(boost::coroutines2::coroutine
<boost::variant<long, long long, double, std::string> >::push_type& sink) {
...
sink(stol(fieldbuffer));
...
sink(stod(fieldbuffer));
...
sink(fieldbuffer); //Fieldbuffer is a std::string
}
};
I intend to use this as a coroutine from inside another class, that has the task of putting each yielded value in its place, so I tried to instantiate an object:
worker _data_loader;
boost::coroutines2::coroutine<boost::variant<long, long long, double, string>>::pull_type _fieldloader
(boost::bind(&worker::import_data, &_data_loader));
but that wont compile:
/usr/include/boost/bind/mem_fn.hpp:342:23:
error: invalid use of non-static member function of type
‘void (worker::)(boost::coroutines2::detail::push_coroutine<boost::variant<long int, long long int, double, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > >&)’
Could someone shed any light in this problem?

Answer 1

This has nothing to do with Boost Coroutine.
It is just about bind with a member function. You forgot to expose the unbound parameter:
boost::bind(&worker::import_data, &_data_loader, _1)
Live On Coliru
#include <boost/coroutine2/all.hpp>
#include <boost/variant.hpp>
#include <boost/bind.hpp>
#include <string>
using V = boost::variant<long, long long, double, std::string>;
using Coro = boost::coroutines2::coroutine<V>;
class worker {
public:
void import_data(Coro::push_type &sink) {
sink(stol(fieldbuffer));
sink(stod(fieldbuffer));
sink(fieldbuffer); // Fieldbuffer is a std::string
}
std::string fieldbuffer = "+042.42";
};
#include <iostream>
int main()
{
worker _data_loader;
Coro::pull_type _fieldloader(boost::bind(&worker::import_data, &_data_loader, _1));
while (_fieldloader) {
std::cout << _fieldloader.get() << "\n";
_fieldloader();
}
}
Prints
42
42.42
+042.42