id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
10963	future<future<T>>::then Has No Implementation	code@…	viboes	"Linker errors when using .then() on a future<future<T>>

{{{
Undefined symbols for architecture x86_64:
  ""boost::future<boost::result_of<TestCallback (boost::future<boost::future<void> >)>::type> boost::future<boost::future<void> >::then<TestCallback>(TestCallback&&)"", referenced from:
      _main in test_100000.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
}}}

Example:

{{{
struct TestCallback
{
    typedef boost::future<void> result_type;

    result_type operator()(boost::future<void> future) const
    {
        future.get();
        return boost::make_ready_future();
    }

    result_type operator()(boost::future<boost::future<void>> future) const
    {
       future.get();
       return boost::make_ready_future();
    }
};

int main()
{
    boost::promise<void> test_promise;
    boost::future<void> test_future(test_promise.get_future());
    test_future.then(TestCallback()).then(TestCallback());
    return 0;
}
}}}"	Bugs	closed	Boost 1.58.0	thread	Boost 1.57.0	Problem	fixed