Problem with std::packaged_task

[Jamaika1]

I use GCC 11 with library mingw.
https://github.com/meganz/mingw-std-threads

In file included from c:\msys1101\include\c++\11.0.1\unordered_map:42,
                 from c:\msys1101\include\c++\11.0.1\functional:61,
                 from c:\msys1101\include\c++\11.0.1\pstl\glue_algorithm_defs.h:13,
                 from c:\msys1101\include\c++\11.0.1\algorithm:74,
                 from grk_includes.h:42,
                 from CodeStreamCompress.cpp:22:
c:\msys1101\include\c++\11.0.1\ext\aligned_buffer.h: In instantiation of 'struct __gnu_cxx::__aligned_buffer<std::packaged_task<int()> >':
c:\msys1101\include\c++\11.0.1\bits\shared_ptr_base.h:506:35:   required from 'class std::_Sp_counted_ptr_inplace<std::packaged_task<int()>, std::allocator<std::packaged_task<int()> >, __gnu_cxx::_S_atomic>::_Impl'
c:\msys1101\include\c++\11.0.1\bits\shared_ptr_base.h:567:13:   required from 'class std::_Sp_counted_ptr_inplace<std::packaged_task<int()>, std::allocator<std::packaged_task<int()> >, __gnu_cxx::_S_atomic>'
c:\msys1101\include\c++\11.0.1\bits\shared_ptr_base.h:647:43:   required from 'std::__shared_count<_Lp>::__shared_count(_Tp*&, std::_Sp_alloc_shared_tag<_Alloc>, _Args&& ...) [with _Tp = std::packaged_task<int()>; _Alloc = std::allocator<std::packaged_task<int()> >; _Args = {std::_Bind<grk::CodeStreamCompress::compress(grk_plugin_tile*)::<lambda()>()>}; __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]'
c:\msys1101\include\c++\11.0.1\bits\shared_ptr_base.h:1337:14:   required from 'std::__shared_ptr<_Tp, _Lp>::__shared_ptr(std::_Sp_alloc_shared_tag<_Tp>, _Args&& ...) [with _Alloc = std::allocator<std::packaged_task<int()> >; _Args = {std::_Bind<grk::CodeStreamCompress::compress(grk_plugin_tile*)::<lambda()>()>}; _Tp = std::packaged_task<int()>; __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic]'
c:\msys1101\include\c++\11.0.1\bits\shared_ptr.h:409:59:   required from 'std::shared_ptr<_Tp>::shared_ptr(std::_Sp_alloc_shared_tag<_Tp>, _Args&& ...) [with _Alloc = std::allocator<std::packaged_task<int()> >; _Args = {std::_Bind<grk::CodeStreamCompress::compress(grk_plugin_tile*)::<lambda()>()>}; _Tp = std::packaged_task<int()>]'
c:\msys1101\include\c++\11.0.1\bits\shared_ptr.h:860:14:   required from 'std::shared_ptr<_Tp> std::allocate_shared(const _Alloc&, _Args&& ...) [with _Tp = std::packaged_task<int()>; _Alloc = std::allocator<std::packaged_task<int()> >; _Args = {std::_Bind<grk::CodeStreamCompress::compress(grk_plugin_tile*)::<lambda()>()>}]'
c:\msys1101\include\c++\11.0.1\bits\shared_ptr.h:876:39:   required from 'std::shared_ptr<_Tp> std::make_shared(_Args&& ...) [with _Tp = std::packaged_task<int()>; _Args = {std::_Bind<grk::CodeStreamCompress::compress(grk_plugin_tile*)::<lambda()>()>}]'
ThreadPool.hpp:174:65:   required from 'std::future<typename std::result_of<_Functor(_ArgTypes ...)>::type> ThreadPool::enqueue(F&&, Args&& ...) [with F = grk::CodeStreamCompress::compress(grk_plugin_tile*)::<lambda()>; Args = {}; typename std::result_of<_Functor(_ArgTypes ...)>::type = int]'
CodeStreamCompress.cpp:639:37:   required from here
c:\msys1101\include\c++\11.0.1\ext\aligned_buffer.h:91:28: error: invalid application of 'sizeof' to incomplete type 'std::packaged_task<int()>'
   91 |     : std::aligned_storage<sizeof(_Tp), __alignof__(_Tp)>
      |                            ^~~~~~~~~~~
c:\msys1101\include\c++\11.0.1\ext\aligned_buffer.h:91:28: error: invalid application of 'sizeof' to incomplete type 'std::packaged_task<int()>'

[wilx]

This is unlikely to be problem in ThreadPool. It properly includes <future>.

[Jamaika1]

That's right. I have a problem with functions under C++17 in mingw.future.h.
meganz/mingw-std-threads#75

/*#if (__cplusplus < 201703L)
std::future<std::result_of<std::decay<Function>::type(std::decay<Args>::type...)>::type>
#else
#if (__cplusplus > 201703L)
[[nodiscard]]
#endif
std::future<std::invoke_result_t<std::decay_t<Function>, std::decay_t<Args>...>>
#endif*/
#if (__cplusplus > 201703L)
[[nodiscard]]
#endif
std::future<__async_result_of<Function, Args...> >
  async(Function&& f, Args&&... args)
{
  return async(launch::async | launch::deferred, std::forward<Function>(f), std::forward<Args>(args)...);
}
template< class Function, class... Args >
/*#if (__cplusplus < 201703L)
std::future<std::result_of<std::decay<Function>::type(std::decay<Args>::type...)>::type>
#else
#if (__cplusplus > 201703L)
[[nodiscard]]
#endif
std::future<std::invoke_result_t<std::decay_t<Function>, std::decay_t<Args>...> >
#endif*/
#if (__cplusplus > 201703L)
[[nodiscard]]
#endif
std::future<__async_result_of<Function, Args...> >
  async(std::launch policy, Function&& f, Args&&... args)
{
  typedef __async_result_of<Function, Args...> result_type;
/*#if (__cplusplus < 201703L)
  typedef std::result_of<std::decay<Function>::type(std::decay<Args>::type...)>::type result_type;
#else
  typedef std::invoke_result_t<std::decay_t<Function>, std::decay_t<Args>...> result_type;
#endif*/
  typedef future<result_type> future_type;
  typedef typename future_type::state_type state_type;

  //auto setter = []

  state_type * state_ptr = nullptr;
  /*if ((policy & std::launch::async) == std::launch::async)
    state_ptr = new state_type ();
  else
    state_ptr = new state_type (std::function<result_type(void)>(std::bind(std::forward<Function>(f), std::forward<Args>(args)...)));*/