[Boost-bugs] [Boost C++ Libraries] #7628: [signals2] Noisy g++ warning generated by 'unused' parameter

Subject: [Boost-bugs] [Boost C++ Libraries] #7628: [signals2] Noisy g++ warning generated by 'unused' parameter
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-11-02 12:43:39

#7628: [signals2] Noisy g++ warning generated by 'unused' parameter
---------------------------------+------------------------------------------
 Reporter:  boost@…              |       Owner:  fmhess  
     Type:  Feature Requests     |      Status:  new     
Milestone:  To Be Determined     |   Component:  signals2
  Version:  Boost 1.51.0         |    Severity:  Cosmetic
 Keywords:                       |  
---------------------------------+------------------------------------------
 An unused parameter (args) warning in
 .../signals2/details/variadic_slot_invoker.hpp:87

 I'm seeing the warning with g++ 4.6 for Linux x86 and g++ 4.5 for Linux
 Arm.  Not tried with 4.7.

 This may be an over-zealous compiler, but it would be nice if it could be
 suppressed because it generates a lot of noise.

 Perhaps a:

 {{{
 #if BOOST_WORKAROUND(__GNUC__, <= 4) && BOOST_WORKAROUND(__GNUC_MINOR__,
 <= 6)
           static_cast<void>(args);
 #endif
 }}}


 Here's the noise generated (g++ 4.6):

 (-std=c++0x -O2 -Wall -W)

 {{{
 In file include from ...<snip>

 .../boost/boost_1_51_0/boost/signals2/detail/variadic_slot_invoker.hpp: In
 member function ‘R
 boost::signals2::detail::call_with_tuple_args<R>::m_invoke(void*, Func&,
 boost::signals2::detail::unsigned_meta_array<indices ...>, std::tuple<Args
 ...>) const [with Func = boost::function<void()>, unsigned int ...indices
 = {}, Args = {}, R = boost::signals2::detail::void_type]’:
 .../boost/boost_1_51_0/boost/signals2/detail/variadic_slot_invoker.hpp:78:63:
 instantiated from ‘R
 boost::signals2::detail::call_with_tuple_args<R>::operator()(Func&,
 std::tuple<_Args2 ...>) const [with Func = boost::function<void()>, Args =
 {}, R = boost::signals2::detail::void_type]’
 .../boost/boost_1_51_0/boost/signals2/detail/variadic_slot_invoker.hpp:117:97:
 instantiated from ‘boost::signals2::detail::variadic_slot_invoker<R,
 Args>::result_type boost::signals2::detail::variadic_slot_invoker<R,
 Args>::m_invoke(const ConnectionBodyType&, const
 boost::signals2::detail::void_type*) const [with ConnectionBodyType =
 boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group,
 boost::optional<int> >, boost::signals2::slot<void(),
 boost::function<void()> >, boost::signals2::mutex> >, R =
 boost::signals2::detail::void_type, Args = {},
 boost::signals2::detail::variadic_slot_invoker<R, Args>::result_type =
 boost::signals2::detail::void_type]’
 .../boost/boost_1_51_0/boost/signals2/detail/variadic_slot_invoker.hpp:110:21:
 instantiated from ‘boost::signals2::detail::variadic_slot_invoker<R,
 Args>::result_type boost::signals2::detail::variadic_slot_invoker<R,
 Args>::operator()(const ConnectionBodyType&) const [with
 ConnectionBodyType =
 boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group,
 boost::optional<int> >, boost::signals2::slot<void(),
 boost::function<void()> >, boost::signals2::mutex> >, R =
 boost::signals2::detail::void_type, Args = {},
 boost::signals2::detail::variadic_slot_invoker<R, Args>::result_type =
 boost::signals2::detail::void_type]’
 .../boost/boost_1_51_0/boost/signals2/detail/slot_call_iterator.hpp:82:15:
 instantiated from ‘typename
 boost::signals2::detail::slot_call_iterator_t<Function, Iterator,
 ConnectionBody>::inherited::reference
 boost::signals2::detail::slot_call_iterator_t<Function, Iterator,
 ConnectionBody>::dereference() const [with Function =
 boost::signals2::detail::variadic_slot_invoker<boost::signals2::detail::void_type>,
 Iterator =
 std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group,
 boost::optional<int> >, boost::signals2::slot<void(),
 boost::function<void()> >, boost::signals2::mutex> > >, ConnectionBody =
 boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group,
 boost::optional<int> >, boost::signals2::slot<void(),
 boost::function<void()> >, boost::signals2::mutex>, typename
 boost::signals2::detail::slot_call_iterator_t<Function, Iterator,
 ConnectionBody>::inherited::reference = const
 boost::signals2::detail::void_type&]’
 .../boost/boost_1_51_0/boost/iterator/iterator_facade.hpp:514:32:
 instantiated from ‘static typename Facade::reference
 boost::iterator_core_access::dereference(const Facade&) [with Facade =
 boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<boost::signals2::detail::void_type>,
 std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group,
 boost::optional<int> >, boost::signals2::slot<void(),
 boost::function<void()> >, boost::signals2::mutex> > >,
 boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group,
 boost::optional<int> >, boost::signals2::slot<void(),
 boost::function<void()> >, boost::signals2::mutex> >, typename
 Facade::reference = const boost::signals2::detail::void_type&]’
 .../boost/boost_1_51_0/boost/iterator/iterator_facade.hpp:639:67:
 instantiated from ‘boost::iterator_facade<I, V, TC, R, D>::reference
 boost::iterator_facade<I, V, TC, R, D>::operator*() const [with Derived =
 boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<boost::signals2::detail::void_type>,
 std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group,
 boost::optional<int> >, boost::signals2::slot<void(),
 boost::function<void()> >, boost::signals2::mutex> > >,
 boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group,
 boost::optional<int> >, boost::signals2::slot<void(),
 boost::function<void()> >, boost::signals2::mutex> >, Value =
 boost::signals2::detail::void_type, CategoryOrTraversal =
 boost::single_pass_traversal_tag, Reference = const
 boost::signals2::detail::void_type&, Difference = int,
 boost::iterator_facade<I, V, TC, R, D>::reference = const
 boost::signals2::detail::void_type&]’
 .../boost/boost_1_51_0/boost/signals2/optional_last_value.hpp:55:13:
 instantiated from ‘boost::signals2::optional_last_value<void>::result_type
 boost::signals2::optional_last_value<void>::operator()(InputIterator,
 InputIterator) const [with InputIterator =
 boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<boost::signals2::detail::void_type>,
 std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group,
 boost::optional<int> >, boost::signals2::slot<void(),
 boost::function<void()> >, boost::signals2::mutex> > >,
 boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group,
 boost::optional<int> >, boost::signals2::slot<void(),
 boost::function<void()> >, boost::signals2::mutex> >,
 boost::signals2::optional_last_value<void>::result_type = void]’
 .../boost/boost_1_51_0/boost/signals2/detail/result_type_wrapper.hpp:64:11:
 instantiated from
 ‘boost::signals2::detail::combiner_invoker<void>::result_type
 boost::signals2::detail::combiner_invoker<void>::operator()(Combiner&,
 InputIterator, InputIterator) const [with Combiner =
 boost::signals2::optional_last_value<void>, InputIterator =
 boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::variadic_slot_invoker<boost::signals2::detail::void_type>,
 std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group,
 boost::optional<int> >, boost::signals2::slot<void(),
 boost::function<void()> >, boost::signals2::mutex> > >,
 boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group,
 boost::optional<int> >, boost::signals2::slot<void(),
 boost::function<void()> >, boost::signals2::mutex> >,
 boost::signals2::detail::combiner_invoker<void>::result_type = void]’
 .../boost/boost_1_51_0/boost/signals2/detail/signal_template.hpp:246:13:
 instantiated from ‘boost::signals2::detail::signal_impl<R(Args ...),
 Combiner, Group, GroupCompare, SlotFunction, ExtendedSlotFunction,
 Mutex>::result_type boost::signals2::detail::signal_impl<R(Args ...),
 Combiner, Group, GroupCompare, SlotFunction, ExtendedSlotFunction,
 Mutex>::operator()(Args ...) [with Combiner =
 boost::signals2::optional_last_value<void>, Group = int, GroupCompare =
 std::less<int>, SlotFunction = boost::function<void()>,
 ExtendedSlotFunction = boost::function<void(const
 boost::signals2::connection&)>, Mutex = boost::signals2::mutex, R = void,
 Args = {}, boost::signals2::detail::signal_impl<R(Args ...), Combiner,
 Group, GroupCompare, SlotFunction, ExtendedSlotFunction,
 Mutex>::result_type = void]’
 .../boost/boost_1_51_0/boost/signals2/detail/signal_template.hpp:695:85:
 instantiated from ‘boost::signals2::signal<R(Args ...), Combiner, Group,
 GroupCompare, SlotFunction, ExtendedSlotFunction, Mutex>::result_type
 boost::signals2::signal<R(Args ...), Combiner, Group, GroupCompare,
 SlotFunction, ExtendedSlotFunction, Mutex>::operator()(Args ...) [with
 Combiner = boost::signals2::optional_last_value<void>, Group = int,
 GroupCompare = std::less<int>, SlotFunction = boost::function<void()>,
 ExtendedSlotFunction = boost::function<void(const
 boost::signals2::connection&)>, Mutex = boost::signals2::mutex, R = void,
 Args = {}, boost::signals2::signal<R(Args ...), Combiner, Group,
 GroupCompare, SlotFunction, ExtendedSlotFunction, Mutex>::result_type =
 void]’
 privateFile.cpp:98:24:   instantiated from here
 .../boost/boost_1_51_0/boost/signals2/detail/variadic_slot_invoker.hpp:87:13:
 warning: parameter ‘args’ set but not used [-Wunused-but-set-parameter]
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/7628>
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