[Boost-users] packaged_task returning boost::any with BOOST_THREAD_VERSION>=3

Subject: [Boost-users] packaged_task returning boost::any with BOOST_THREAD_VERSION>=3
From: Nicolas P (nicolasph_at_[hidden])
Date: 2013-07-22 11:49:13

Hello,

I'm trying to enable boost (1.54) thread version >=3 with my code and i run
into a package_task compilation issue

I reduced my issue to a minimal test program that compiles fine on windows
7, but fails to compile on osx and linux (compilers info bellow) with
BOOST_THREAD_VERSION = 3 or 4  (fine with boost thread version 2)

test succeded on
 - Windows 7 with Visual 2010 Express sp1 with SDK 7.1 ok

test failed on
 - Mac os x 10.6 Xcode 4.2 : gcc 4.2.1 and clang 3.0
 - Mac os x 10.7 Xcode 4.4 : gcc and clang 4.0
 - Ubuntu 13.04 gcc 4.7.4

The minimal test program :

#define BOOST_THREAD_PROVIDES_SIGNATURE_PACKAGED_TASK
#define BOOST_THREAD_VERSION 4

#include <boost/any.hpp>
#include <boost/thread.hpp>
#include <boost/function.hpp>

boost::any process()
{
    return 1;
}

int main()
{
    boost::function< boost::any () > f =  &process ;
    //boost::packaged_task< boost::any () > task(&process); // Works fine
    boost::packaged_task< boost::any () > task(f);
    return 0;
}

// Replacing 'boost::any' with 'int' make it compile.

Error log with clang on os x 10.6 :

In file included from /tmp/packaged_task_test/main.cpp:5:
In file included from boost/thread.hpp:24:
boost/thread/future.hpp:2298:27: error: no matching
      member function for call to 'set_value_at_thread_exit'
                    this->set_value_at_thread_exit(f());
                    ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
boost/thread/future.hpp:2857:33: note: in instantiation
      of member function
'boost::detail::task_object<boost::function<boost::any ()>, boost::any
()>::do_apply' requested here
            task = task_ptr(new task_object_type(f));
                                ^
/tmp/packaged_task_test/main.cpp:17:43: note: in instantiation of function
template specialization
      'boost::packaged_task<boost::any
()>::packaged_task<boost::function<boost::any ()> >' requested here
    boost::packaged_task< boost::any () > task(f);
                                          ^
boost/thread/future.hpp:673:18: note: candidate function
      not viable: no known conversion from 'result_type' (aka 'boost::any')
to 'source_reference_type' (aka 'boost::any &') for 1st argument
            void set_value_at_thread_exit(source_reference_type result_)
                 ^
boost/thread/future.hpp:687:18: note: candidate function
      not viable: no known conversion from 'result_type' (aka 'boost::any')
to 'rvalue_source_type' (aka 'rv<boost::any> &') for 1st argument
            void set_value_at_thread_exit(rvalue_source_type result_)
                 ^
boost/thread/future.hpp:2329:25: error: no matching
      member function for call to 'mark_finished_with_result'
                  this->mark_finished_with_result(f());
                  ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
boost/thread/future.hpp:2857:33: note: in instantiation
      of member function
'boost::detail::task_object<boost::function<boost::any ()>, boost::any
()>::do_run' requested here
            task = task_ptr(new task_object_type(f));
                                ^
/tmp/packaged_task_test/main.cpp:17:43: note: in instantiation of function
template specialization
      'boost::packaged_task<boost::any
()>::packaged_task<boost::function<boost::any ()> >' requested here
    boost::packaged_task< boost::any () > task(f);
                                          ^
boost/thread/future.hpp:627:18: note: candidate function
      not viable: no known conversion from 'result_type' (aka 'boost::any')
to 'source_reference_type' (aka 'boost::any &') for 1st argument
            void mark_finished_with_result(source_reference_type result_)
                 ^
boost/thread/future.hpp:633:18: note: candidate function
      not viable: no known conversion from 'result_type' (aka 'boost::any')
to 'rvalue_source_type' (aka 'rv<boost::any> &') for 1st argument
            void mark_finished_with_result(rvalue_source_type result_)
                 ^
2 errors generated.

Am i missing something ?

Regards,
Nicolas