Import libsigc++ 2.10.8 sources

[ext/sigc++-2.0.git] / untracked / sigc++ / functors / slot.h

// -*- c++ -*-
/* Do not edit! -- generated file */
#ifndef _SIGC_FUNCTORS_SLOT_H_
#define _SIGC_FUNCTORS_SLOT_H_
#include <sigc++/trackable.h>
#include <sigc++/visit_each.h>
#include <sigc++/adaptors/adaptor_trait.h>
#include <sigc++/functors/slot_base.h>

//TODO: See comment in functor_trait.h.
#if defined(nil) && defined(SIGC_PRAGMA_PUSH_POP_MACRO)
  #define SIGC_NIL_HAS_BEEN_PUSHED 1
  #pragma push_macro("nil")
  #undef nil
#endif

namespace sigc {

namespace internal {

// Conversion between different types of function pointers with
// reinterpret_cast can make gcc8 print a warning.
// https://github.com/libsigcplusplus/libsigcplusplus/issues/1
// https://github.com/libsigcplusplus/libsigcplusplus/issues/8
/** Returns the supplied function pointer, cast to a pointer to another function type.
 *
 * When a single reinterpret_cast between function pointer types causes a
 * compiler warning or error, this function may work.
 *
 * Qualify calls with namespace names: sigc::internal::function_pointer_cast<>().
 * If you don't, indirect calls from another library that also contains a
 * function_pointer_cast<>() (perhaps glibmm), can be ambiguous due to ADL
 * (argument-dependent lookup).
 */
template <typename T_out, typename T_in>
inline T_out function_pointer_cast(T_in in)
{
  // The double reinterpret_cast suppresses a warning from gcc8 with the
  // -Wcast-function-type option.
  return reinterpret_cast<T_out>(reinterpret_cast<void (*)()>(in));
}

/** A typed slot_rep.
 * A typed slot_rep holds a functor that can be invoked from
 * slot::operator()(). visit_each() is used to visit the functor's
 * targets that inherit trackable recursively and register the
 * notification callback. Consequently the slot_rep object will be
 * notified when some referred object is destroyed or overwritten.
 */
template <class T_functor>
struct typed_slot_rep : public slot_rep
{
  typedef typed_slot_rep<T_functor> self;

  /* Use an adaptor type so that arguments can be passed as const references
   * through explicit template instantiation from slot_call#::call_it() */
  typedef typename adaptor_trait<T_functor>::adaptor_type adaptor_type;

  /** The functor contained by this slot_rep object. */
  adaptor_type functor_;

  /** Constructs an invalid typed slot_rep object.
   * The notification callback is registered using visit_each().
   * @param functor The functor contained by the new slot_rep object.
   */
  inline typed_slot_rep(const T_functor& functor)
    : slot_rep(nullptr, &destroy, &dup), functor_(functor)
    { sigc::visit_each_type<trackable*>(slot_do_bind(this), functor_); }

  inline typed_slot_rep(const typed_slot_rep& cl)
    : slot_rep(cl.call_, &destroy, &dup), functor_(cl.functor_)
    { sigc::visit_each_type<trackable*>(slot_do_bind(this), functor_); }

  typed_slot_rep& operator=(const typed_slot_rep& src) = delete;

  typed_slot_rep(typed_slot_rep&& src) = delete;
  typed_slot_rep& operator=(typed_slot_rep&& src) = delete;

  inline ~typed_slot_rep()
    {
      call_ = nullptr;
      destroy_ = nullptr;
      sigc::visit_each_type<trackable*>(slot_do_unbind(this), functor_);
    }

  /** Detaches the stored functor from the other referred trackables and destroys it.
   * This does not destroy the base slot_rep object.
   */
  static void* destroy(void* data)
    {
      self* self_ = static_cast<self*>(reinterpret_cast<slot_rep*>(data));
      self_->call_ = nullptr;
      self_->destroy_ = nullptr;
      sigc::visit_each_type<trackable*>(slot_do_unbind(self_), self_->functor_);
      self_->functor_.~adaptor_type();
      /* don't call disconnect() here: destroy() is either called
       * a) from the parent itself (in which case disconnect() leads to a segfault) or
       * b) from a parentless slot (in which case disconnect() does nothing)
       */
      return nullptr;
    }

  /** Makes a deep copy of the slot_rep object.
   * Deep copy means that the notification callback of the new
   * slot_rep object is registered in the referred trackables.
   * @return A deep copy of the slot_rep object.
   */
  static void* dup(void* data)
    {
      slot_rep* a_rep = reinterpret_cast<slot_rep*>(data);
      return static_cast<slot_rep*>(new self(*static_cast<self*>(a_rep)));
    }
};

/** Abstracts functor execution.
 * call_it() invokes a functor of type @e T_functor with a list of
 * parameters whose types are given by the template arguments.
 * address() forms a function pointer from call_it().
 *
 * The following template arguments are used:
 * - @e T_functor The functor type.
 * - @e T_return The return type of call_it().
 *
 */
template<class T_functor, class T_return>
struct slot_call0
{
  /** Invokes a functor of type @p T_functor.
   * @param rep slot_rep object that holds a functor of type @p T_functor.
   * @return The return values of the functor invocation.
   */
  static T_return call_it(slot_rep* rep)
    {
      typedef typed_slot_rep<T_functor> typed_slot;
      typed_slot *typed_rep = static_cast<typed_slot*>(rep);
      return (typed_rep->functor_)();
    }

  /** Forms a function pointer from call_it().
   * @return A function pointer formed from call_it().
   */
  static hook address()
  { return sigc::internal::function_pointer_cast<hook>(&call_it); }
};

/** Abstracts functor execution.
 * call_it() invokes a functor of type @e T_functor with a list of
 * parameters whose types are given by the template arguments.
 * address() forms a function pointer from call_it().
 *
 * The following template arguments are used:
 * - @e T_functor The functor type.
 * - @e T_return The return type of call_it().
 * - @e T_arg1 Argument type used in the definition of call_it().
 *
 */
template<class T_functor, class T_return, class T_arg1>
struct slot_call1
{
  /** Invokes a functor of type @p T_functor.
   * @param rep slot_rep object that holds a functor of type @p T_functor.
   * @param _A_a1 Argument to be passed on to the functor.
   * @return The return values of the functor invocation.
   */
  static T_return call_it(slot_rep* rep, type_trait_take_t<T_arg1> a_1)
    {
      typedef typed_slot_rep<T_functor> typed_slot;
      typed_slot *typed_rep = static_cast<typed_slot*>(rep);
      return (typed_rep->functor_).SIGC_WORKAROUND_OPERATOR_PARENTHESES<type_trait_take_t<T_arg1>>
               (a_1);
    }

  /** Forms a function pointer from call_it().
   * @return A function pointer formed from call_it().
   */
  static hook address()
  { return sigc::internal::function_pointer_cast<hook>(&call_it); }
};

/** Abstracts functor execution.
 * call_it() invokes a functor of type @e T_functor with a list of
 * parameters whose types are given by the template arguments.
 * address() forms a function pointer from call_it().
 *
 * The following template arguments are used:
 * - @e T_functor The functor type.
 * - @e T_return The return type of call_it().
 * - @e T_arg1 Argument type used in the definition of call_it().
 * - @e T_arg2 Argument type used in the definition of call_it().
 *
 */
template<class T_functor, class T_return, class T_arg1, class T_arg2>
struct slot_call2
{
  /** Invokes a functor of type @p T_functor.
   * @param rep slot_rep object that holds a functor of type @p T_functor.
   * @param _A_a1 Argument to be passed on to the functor.
   * @param _A_a2 Argument to be passed on to the functor.
   * @return The return values of the functor invocation.
   */
  static T_return call_it(slot_rep* rep, type_trait_take_t<T_arg1> a_1, type_trait_take_t<T_arg2> a_2)
    {
      typedef typed_slot_rep<T_functor> typed_slot;
      typed_slot *typed_rep = static_cast<typed_slot*>(rep);
      return (typed_rep->functor_).SIGC_WORKAROUND_OPERATOR_PARENTHESES<type_trait_take_t<T_arg1>, type_trait_take_t<T_arg2>>
               (a_1, a_2);
    }

  /** Forms a function pointer from call_it().
   * @return A function pointer formed from call_it().
   */
  static hook address()
  { return sigc::internal::function_pointer_cast<hook>(&call_it); }
};

/** Abstracts functor execution.
 * call_it() invokes a functor of type @e T_functor with a list of
 * parameters whose types are given by the template arguments.
 * address() forms a function pointer from call_it().
 *
 * The following template arguments are used:
 * - @e T_functor The functor type.
 * - @e T_return The return type of call_it().
 * - @e T_arg1 Argument type used in the definition of call_it().
 * - @e T_arg2 Argument type used in the definition of call_it().
 * - @e T_arg3 Argument type used in the definition of call_it().
 *
 */
template<class T_functor, class T_return, class T_arg1, class T_arg2, class T_arg3>
struct slot_call3
{
  /** Invokes a functor of type @p T_functor.
   * @param rep slot_rep object that holds a functor of type @p T_functor.
   * @param _A_a1 Argument to be passed on to the functor.
   * @param _A_a2 Argument to be passed on to the functor.
   * @param _A_a3 Argument to be passed on to the functor.
   * @return The return values of the functor invocation.
   */
  static T_return call_it(slot_rep* rep, type_trait_take_t<T_arg1> a_1, type_trait_take_t<T_arg2> a_2, type_trait_take_t<T_arg3> a_3)
    {
      typedef typed_slot_rep<T_functor> typed_slot;
      typed_slot *typed_rep = static_cast<typed_slot*>(rep);
      return (typed_rep->functor_).SIGC_WORKAROUND_OPERATOR_PARENTHESES<type_trait_take_t<T_arg1>, type_trait_take_t<T_arg2>, type_trait_take_t<T_arg3>>
               (a_1, a_2, a_3);
    }

  /** Forms a function pointer from call_it().
   * @return A function pointer formed from call_it().
   */
  static hook address()
  { return sigc::internal::function_pointer_cast<hook>(&call_it); }
};

/** Abstracts functor execution.
 * call_it() invokes a functor of type @e T_functor with a list of
 * parameters whose types are given by the template arguments.
 * address() forms a function pointer from call_it().
 *
 * The following template arguments are used:
 * - @e T_functor The functor type.
 * - @e T_return The return type of call_it().
 * - @e T_arg1 Argument type used in the definition of call_it().
 * - @e T_arg2 Argument type used in the definition of call_it().
 * - @e T_arg3 Argument type used in the definition of call_it().
 * - @e T_arg4 Argument type used in the definition of call_it().
 *
 */
template<class T_functor, class T_return, class T_arg1, class T_arg2, class T_arg3, class T_arg4>
struct slot_call4
{
  /** Invokes a functor of type @p T_functor.
   * @param rep slot_rep object that holds a functor of type @p T_functor.
   * @param _A_a1 Argument to be passed on to the functor.
   * @param _A_a2 Argument to be passed on to the functor.
   * @param _A_a3 Argument to be passed on to the functor.
   * @param _A_a4 Argument to be passed on to the functor.
   * @return The return values of the functor invocation.
   */
  static T_return call_it(slot_rep* rep, type_trait_take_t<T_arg1> a_1, type_trait_take_t<T_arg2> a_2, type_trait_take_t<T_arg3> a_3, type_trait_take_t<T_arg4> a_4)
    {
      typedef typed_slot_rep<T_functor> typed_slot;
      typed_slot *typed_rep = static_cast<typed_slot*>(rep);
      return (typed_rep->functor_).SIGC_WORKAROUND_OPERATOR_PARENTHESES<type_trait_take_t<T_arg1>, type_trait_take_t<T_arg2>, type_trait_take_t<T_arg3>, type_trait_take_t<T_arg4>>
               (a_1, a_2, a_3, a_4);
    }

  /** Forms a function pointer from call_it().
   * @return A function pointer formed from call_it().
   */
  static hook address()
  { return sigc::internal::function_pointer_cast<hook>(&call_it); }
};

/** Abstracts functor execution.
 * call_it() invokes a functor of type @e T_functor with a list of
 * parameters whose types are given by the template arguments.
 * address() forms a function pointer from call_it().
 *
 * The following template arguments are used:
 * - @e T_functor The functor type.
 * - @e T_return The return type of call_it().
 * - @e T_arg1 Argument type used in the definition of call_it().
 * - @e T_arg2 Argument type used in the definition of call_it().
 * - @e T_arg3 Argument type used in the definition of call_it().
 * - @e T_arg4 Argument type used in the definition of call_it().
 * - @e T_arg5 Argument type used in the definition of call_it().
 *
 */
template<class T_functor, class T_return, class T_arg1, class T_arg2, class T_arg3, class T_arg4, class T_arg5>
struct slot_call5
{
  /** Invokes a functor of type @p T_functor.
   * @param rep slot_rep object that holds a functor of type @p T_functor.
   * @param _A_a1 Argument to be passed on to the functor.
   * @param _A_a2 Argument to be passed on to the functor.
   * @param _A_a3 Argument to be passed on to the functor.
   * @param _A_a4 Argument to be passed on to the functor.
   * @param _A_a5 Argument to be passed on to the functor.
   * @return The return values of the functor invocation.
   */
  static T_return call_it(slot_rep* rep, type_trait_take_t<T_arg1> a_1, type_trait_take_t<T_arg2> a_2, type_trait_take_t<T_arg3> a_3, type_trait_take_t<T_arg4> a_4, type_trait_take_t<T_arg5> a_5)
    {
      typedef typed_slot_rep<T_functor> typed_slot;
      typed_slot *typed_rep = static_cast<typed_slot*>(rep);
      return (typed_rep->functor_).SIGC_WORKAROUND_OPERATOR_PARENTHESES<type_trait_take_t<T_arg1>, type_trait_take_t<T_arg2>, type_trait_take_t<T_arg3>, type_trait_take_t<T_arg4>, type_trait_take_t<T_arg5>>
               (a_1, a_2, a_3, a_4, a_5);
    }

  /** Forms a function pointer from call_it().
   * @return A function pointer formed from call_it().
   */
  static hook address()
  { return sigc::internal::function_pointer_cast<hook>(&call_it); }
};

/** Abstracts functor execution.
 * call_it() invokes a functor of type @e T_functor with a list of
 * parameters whose types are given by the template arguments.
 * address() forms a function pointer from call_it().
 *
 * The following template arguments are used:
 * - @e T_functor The functor type.
 * - @e T_return The return type of call_it().
 * - @e T_arg1 Argument type used in the definition of call_it().
 * - @e T_arg2 Argument type used in the definition of call_it().
 * - @e T_arg3 Argument type used in the definition of call_it().
 * - @e T_arg4 Argument type used in the definition of call_it().
 * - @e T_arg5 Argument type used in the definition of call_it().
 * - @e T_arg6 Argument type used in the definition of call_it().
 *
 */
template<class T_functor, class T_return, class T_arg1, class T_arg2, class T_arg3, class T_arg4, class T_arg5, class T_arg6>
struct slot_call6
{
  /** Invokes a functor of type @p T_functor.
   * @param rep slot_rep object that holds a functor of type @p T_functor.
   * @param _A_a1 Argument to be passed on to the functor.
   * @param _A_a2 Argument to be passed on to the functor.
   * @param _A_a3 Argument to be passed on to the functor.
   * @param _A_a4 Argument to be passed on to the functor.
   * @param _A_a5 Argument to be passed on to the functor.
   * @param _A_a6 Argument to be passed on to the functor.
   * @return The return values of the functor invocation.
   */
  static T_return call_it(slot_rep* rep, type_trait_take_t<T_arg1> a_1, type_trait_take_t<T_arg2> a_2, type_trait_take_t<T_arg3> a_3, type_trait_take_t<T_arg4> a_4, type_trait_take_t<T_arg5> a_5, type_trait_take_t<T_arg6> a_6)
    {
      typedef typed_slot_rep<T_functor> typed_slot;
      typed_slot *typed_rep = static_cast<typed_slot*>(rep);
      return (typed_rep->functor_).SIGC_WORKAROUND_OPERATOR_PARENTHESES<type_trait_take_t<T_arg1>, type_trait_take_t<T_arg2>, type_trait_take_t<T_arg3>, type_trait_take_t<T_arg4>, type_trait_take_t<T_arg5>, type_trait_take_t<T_arg6>>
               (a_1, a_2, a_3, a_4, a_5, a_6);
    }

  /** Forms a function pointer from call_it().
   * @return A function pointer formed from call_it().
   */
  static hook address()
  { return sigc::internal::function_pointer_cast<hook>(&call_it); }
};

/** Abstracts functor execution.
 * call_it() invokes a functor of type @e T_functor with a list of
 * parameters whose types are given by the template arguments.
 * address() forms a function pointer from call_it().
 *
 * The following template arguments are used:
 * - @e T_functor The functor type.
 * - @e T_return The return type of call_it().
 * - @e T_arg1 Argument type used in the definition of call_it().
 * - @e T_arg2 Argument type used in the definition of call_it().
 * - @e T_arg3 Argument type used in the definition of call_it().
 * - @e T_arg4 Argument type used in the definition of call_it().
 * - @e T_arg5 Argument type used in the definition of call_it().
 * - @e T_arg6 Argument type used in the definition of call_it().
 * - @e T_arg7 Argument type used in the definition of call_it().
 *
 */
template<class T_functor, class T_return, class T_arg1, class T_arg2, class T_arg3, class T_arg4, class T_arg5, class T_arg6, class T_arg7>
struct slot_call7
{
  /** Invokes a functor of type @p T_functor.
   * @param rep slot_rep object that holds a functor of type @p T_functor.
   * @param _A_a1 Argument to be passed on to the functor.
   * @param _A_a2 Argument to be passed on to the functor.
   * @param _A_a3 Argument to be passed on to the functor.
   * @param _A_a4 Argument to be passed on to the functor.
   * @param _A_a5 Argument to be passed on to the functor.
   * @param _A_a6 Argument to be passed on to the functor.
   * @param _A_a7 Argument to be passed on to the functor.
   * @return The return values of the functor invocation.
   */
  static T_return call_it(slot_rep* rep, type_trait_take_t<T_arg1> a_1, type_trait_take_t<T_arg2> a_2, type_trait_take_t<T_arg3> a_3, type_trait_take_t<T_arg4> a_4, type_trait_take_t<T_arg5> a_5, type_trait_take_t<T_arg6> a_6, type_trait_take_t<T_arg7> a_7)
    {
      typedef typed_slot_rep<T_functor> typed_slot;
      typed_slot *typed_rep = static_cast<typed_slot*>(rep);
      return (typed_rep->functor_).SIGC_WORKAROUND_OPERATOR_PARENTHESES<type_trait_take_t<T_arg1>, type_trait_take_t<T_arg2>, type_trait_take_t<T_arg3>, type_trait_take_t<T_arg4>, type_trait_take_t<T_arg5>, type_trait_take_t<T_arg6>, type_trait_take_t<T_arg7>>
               (a_1, a_2, a_3, a_4, a_5, a_6, a_7);
    }

  /** Forms a function pointer from call_it().
   * @return A function pointer formed from call_it().
   */
  static hook address()
  { return sigc::internal::function_pointer_cast<hook>(&call_it); }
};


/** Abstracts functor execution.
 * call_it() invokes a functor of type @e T_functor with a list of
 * parameters whose types are given by the template arguments.
 * address() forms a function pointer from call_it().
 *
 * The following template arguments are used:
 * - @e T_functor The functor type.
 * - @e T_return The return type of call_it().
 * - @e T_arg Argument types used in the definition of call_it().
 *
 */
template<class T_functor, class T_return, class... T_arg>
struct slot_call
{
  /** Invokes a functor of type @p T_functor.
   * @param rep slot_rep object that holds a functor of type @p T_functor.
   * @param _A_a Arguments to be passed on to the functor.
   * @return The return values of the functor invocation.
   */
  static T_return call_it(slot_rep* rep, type_trait_take_t<T_arg>... a_)
    {
      using typed_slot = typed_slot_rep<T_functor>;
      typed_slot *typed_rep = static_cast<typed_slot*>(rep);
      return (typed_rep->functor_).SIGC_WORKAROUND_OPERATOR_PARENTHESES<type_trait_take_t<T_arg>...>
               (a_...);
    }

  /** Forms a function pointer from call_it().
   * @return A function pointer formed from call_it().
   */
  static hook address()
  { return sigc::internal::function_pointer_cast<hook>(&call_it); }
};

/** Abstracts functor execution.
 * call_it() invokes a functor without parameters of type @e T_functor.
 * address() forms a function pointer from call_it().
 *
 * This is a specialization for functors without parameters.
 *
 * The following template arguments are used:
 * - @e T_functor The functor type.
 * - @e T_return The return type of call_it().
 *
 */
template<class T_functor, class T_return>
struct slot_call<T_functor, T_return>
{
  /** Invokes a functor of type @p T_functor.
   * @param rep slot_rep object that holds a functor of type @p T_functor.
   * @return The return values of the functor invocation.
   */
  static T_return call_it(slot_rep* rep)
    {
      using typed_slot = typed_slot_rep<T_functor>;
      typed_slot *typed_rep = static_cast<typed_slot*>(rep);
      return (typed_rep->functor_)();
    }

  /** Forms a function pointer from call_it().
   * @return A function pointer formed from call_it().
   */
  static hook address()
  { return sigc::internal::function_pointer_cast<hook>(&call_it); }
};

} /* namespace internal */


/** Converts an arbitrary functor to a unified type which is opaque.
 * sigc::slot itself is a functor or to be more precise a closure. It contains
 * a single, arbitrary functor (or closure) that is executed in operator()().
 *
 * The template arguments determine the function signature of operator()():
 * - @e T_return The return type of operator()().
 *
 * To use simply assign the desired functor to the slot. If the functor
 * is not compatible with the parameter list defined with the template
 * arguments compiler errors are triggered. When called the slot
 * will invoke the functor with minimal copies.
 * block() and unblock() can be used to block the functor's invocation
 * from operator()() temporarily.
 *
 * You should use the more convenient unnumbered sigc::slot template.
 *
 * @ingroup slot
 */
template <class T_return>
class slot0
  : public slot_base
{
public:
  typedef T_return result_type;


#ifndef DOXYGEN_SHOULD_SKIP_THIS
private:
  typedef internal::slot_rep rep_type;
public:
  typedef T_return (*call_type)(rep_type*);
#endif

  /** Invoke the contained functor unless slot is in blocking state.
   * @return The return value of the functor invocation.
   */
  inline T_return operator()() const
    {
      if (!empty() && !blocked())
        return (sigc::internal::function_pointer_cast<call_type>(slot_base::rep_->call_))(slot_base::rep_);
      return T_return();
    }

  inline slot0() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot0(const T_functor& _A_func)
    : slot_base(new internal::typed_slot_rep<T_functor>(_A_func))
    {
      //The slot_base:: is necessary to stop the HP-UX aCC compiler from being confused. murrayc.
      slot_base::rep_->call_ = internal::slot_call0<T_functor, T_return>::address();
    }

  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot0(const slot0& src)
    : slot_base(src)
    {}

  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot0(slot0&& src)
    : slot_base(std::move(src))
    {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot0& operator=(const slot0& src)
  {
    slot_base::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot0& operator=(slot0&& src)
  {
    slot_base::operator=(std::move(src));
    return *this;
  }
};

#ifndef DOXYGEN_SHOULD_SKIP_THIS
//template specialization of visitor<>::do_visit_each<>(action, functor):
/** Performs a functor on each of the targets of a functor.
 * The function overloads for sigc::slot0 are similar to the function
 * overloads for sigc::slot. See the description of those overloads.
 *
 * @ingroup slot
 */
template <typename T_return>
struct visitor<slot0<T_return>>
{
  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_bind>& _A_action,
                            const slot0<T_return>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == nullptr)
    _A_target.rep_->set_parent(_A_action.action_.rep_, &internal::slot_rep::notify);
  }

  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_unbind>& _A_action,
                            const slot0<T_return>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == _A_action.action_.rep_)
      _A_target.rep_->set_parent(nullptr, nullptr);
  }

  template <typename T_action>
  static void do_visit_each(const T_action& _A_action,
                            const slot0<T_return>& _A_target)
  {
    _A_action(_A_target);
  }
};
#endif // DOXYGEN_SHOULD_SKIP_THIS

/** Converts an arbitrary functor to a unified type which is opaque.
 * sigc::slot itself is a functor or to be more precise a closure. It contains
 * a single, arbitrary functor (or closure) that is executed in operator()().
 *
 * The template arguments determine the function signature of operator()():
 * - @e T_return The return type of operator()().
 * - @e T_arg1 Argument type used in the definition of operator()(). The default @p nil means no argument.
 *
 * To use simply assign the desired functor to the slot. If the functor
 * is not compatible with the parameter list defined with the template
 * arguments compiler errors are triggered. When called the slot
 * will invoke the functor with minimal copies.
 * block() and unblock() can be used to block the functor's invocation
 * from operator()() temporarily.
 *
 * You should use the more convenient unnumbered sigc::slot template.
 *
 * @ingroup slot
 */
template <class T_return, class T_arg1>
class slot1
  : public slot_base
{
public:
  typedef T_return result_type;
  typedef type_trait_take_t<T_arg1> arg1_type_;


#ifndef DOXYGEN_SHOULD_SKIP_THIS
private:
  typedef internal::slot_rep rep_type;
public:
  typedef T_return (*call_type)(rep_type*, arg1_type_);
#endif

  /** Invoke the contained functor unless slot is in blocking state.
   * @param _A_a1 Argument to be passed on to the functor.
   * @return The return value of the functor invocation.
   */
  inline T_return operator()(arg1_type_ _A_a1) const
    {
      if (!empty() && !blocked())
        return (sigc::internal::function_pointer_cast<call_type>(slot_base::rep_->call_))(slot_base::rep_, _A_a1);
      return T_return();
    }

  inline slot1() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot1(const T_functor& _A_func)
    : slot_base(new internal::typed_slot_rep<T_functor>(_A_func))
    {
      //The slot_base:: is necessary to stop the HP-UX aCC compiler from being confused. murrayc.
      slot_base::rep_->call_ = internal::slot_call1<T_functor, T_return, T_arg1>::address();
    }

  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot1(const slot1& src)
    : slot_base(src)
    {}

  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot1(slot1&& src)
    : slot_base(std::move(src))
    {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot1& operator=(const slot1& src)
  {
    slot_base::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot1& operator=(slot1&& src)
  {
    slot_base::operator=(std::move(src));
    return *this;
  }
};

#ifndef DOXYGEN_SHOULD_SKIP_THIS
//template specialization of visitor<>::do_visit_each<>(action, functor):
/** Performs a functor on each of the targets of a functor.
 * The function overloads for sigc::slot1 are similar to the function
 * overloads for sigc::slot. See the description of those overloads.
 *
 * @ingroup slot
 */
template <typename T_return, typename T_arg1>
struct visitor<slot1<T_return, T_arg1>>
{
  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_bind>& _A_action,
                            const slot1<T_return, T_arg1>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == nullptr)
    _A_target.rep_->set_parent(_A_action.action_.rep_, &internal::slot_rep::notify);
  }

  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_unbind>& _A_action,
                            const slot1<T_return, T_arg1>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == _A_action.action_.rep_)
      _A_target.rep_->set_parent(nullptr, nullptr);
  }

  template <typename T_action>
  static void do_visit_each(const T_action& _A_action,
                            const slot1<T_return, T_arg1>& _A_target)
  {
    _A_action(_A_target);
  }
};
#endif // DOXYGEN_SHOULD_SKIP_THIS

/** Converts an arbitrary functor to a unified type which is opaque.
 * sigc::slot itself is a functor or to be more precise a closure. It contains
 * a single, arbitrary functor (or closure) that is executed in operator()().
 *
 * The template arguments determine the function signature of operator()():
 * - @e T_return The return type of operator()().
 * - @e T_arg1 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg2 Argument type used in the definition of operator()(). The default @p nil means no argument.
 *
 * To use simply assign the desired functor to the slot. If the functor
 * is not compatible with the parameter list defined with the template
 * arguments compiler errors are triggered. When called the slot
 * will invoke the functor with minimal copies.
 * block() and unblock() can be used to block the functor's invocation
 * from operator()() temporarily.
 *
 * You should use the more convenient unnumbered sigc::slot template.
 *
 * @ingroup slot
 */
template <class T_return, class T_arg1, class T_arg2>
class slot2
  : public slot_base
{
public:
  typedef T_return result_type;
  typedef type_trait_take_t<T_arg1> arg1_type_;
  typedef type_trait_take_t<T_arg2> arg2_type_;


#ifndef DOXYGEN_SHOULD_SKIP_THIS
private:
  typedef internal::slot_rep rep_type;
public:
  typedef T_return (*call_type)(rep_type*, arg1_type_, arg2_type_);
#endif

  /** Invoke the contained functor unless slot is in blocking state.
   * @param _A_a1 Argument to be passed on to the functor.
   * @param _A_a2 Argument to be passed on to the functor.
   * @return The return value of the functor invocation.
   */
  inline T_return operator()(arg1_type_ _A_a1, arg2_type_ _A_a2) const
    {
      if (!empty() && !blocked())
        return (sigc::internal::function_pointer_cast<call_type>(slot_base::rep_->call_))(slot_base::rep_, _A_a1, _A_a2);
      return T_return();
    }

  inline slot2() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot2(const T_functor& _A_func)
    : slot_base(new internal::typed_slot_rep<T_functor>(_A_func))
    {
      //The slot_base:: is necessary to stop the HP-UX aCC compiler from being confused. murrayc.
      slot_base::rep_->call_ = internal::slot_call2<T_functor, T_return, T_arg1, T_arg2>::address();
    }

  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot2(const slot2& src)
    : slot_base(src)
    {}

  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot2(slot2&& src)
    : slot_base(std::move(src))
    {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot2& operator=(const slot2& src)
  {
    slot_base::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot2& operator=(slot2&& src)
  {
    slot_base::operator=(std::move(src));
    return *this;
  }
};

#ifndef DOXYGEN_SHOULD_SKIP_THIS
//template specialization of visitor<>::do_visit_each<>(action, functor):
/** Performs a functor on each of the targets of a functor.
 * The function overloads for sigc::slot2 are similar to the function
 * overloads for sigc::slot. See the description of those overloads.
 *
 * @ingroup slot
 */
template <typename T_return, typename T_arg1, typename T_arg2>
struct visitor<slot2<T_return, T_arg1, T_arg2>>
{
  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_bind>& _A_action,
                            const slot2<T_return, T_arg1, T_arg2>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == nullptr)
    _A_target.rep_->set_parent(_A_action.action_.rep_, &internal::slot_rep::notify);
  }

  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_unbind>& _A_action,
                            const slot2<T_return, T_arg1, T_arg2>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == _A_action.action_.rep_)
      _A_target.rep_->set_parent(nullptr, nullptr);
  }

  template <typename T_action>
  static void do_visit_each(const T_action& _A_action,
                            const slot2<T_return, T_arg1, T_arg2>& _A_target)
  {
    _A_action(_A_target);
  }
};
#endif // DOXYGEN_SHOULD_SKIP_THIS

/** Converts an arbitrary functor to a unified type which is opaque.
 * sigc::slot itself is a functor or to be more precise a closure. It contains
 * a single, arbitrary functor (or closure) that is executed in operator()().
 *
 * The template arguments determine the function signature of operator()():
 * - @e T_return The return type of operator()().
 * - @e T_arg1 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg2 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg3 Argument type used in the definition of operator()(). The default @p nil means no argument.
 *
 * To use simply assign the desired functor to the slot. If the functor
 * is not compatible with the parameter list defined with the template
 * arguments compiler errors are triggered. When called the slot
 * will invoke the functor with minimal copies.
 * block() and unblock() can be used to block the functor's invocation
 * from operator()() temporarily.
 *
 * You should use the more convenient unnumbered sigc::slot template.
 *
 * @ingroup slot
 */
template <class T_return, class T_arg1, class T_arg2, class T_arg3>
class slot3
  : public slot_base
{
public:
  typedef T_return result_type;
  typedef type_trait_take_t<T_arg1> arg1_type_;
  typedef type_trait_take_t<T_arg2> arg2_type_;
  typedef type_trait_take_t<T_arg3> arg3_type_;


#ifndef DOXYGEN_SHOULD_SKIP_THIS
private:
  typedef internal::slot_rep rep_type;
public:
  typedef T_return (*call_type)(rep_type*, arg1_type_, arg2_type_, arg3_type_);
#endif

  /** Invoke the contained functor unless slot is in blocking state.
   * @param _A_a1 Argument to be passed on to the functor.
   * @param _A_a2 Argument to be passed on to the functor.
   * @param _A_a3 Argument to be passed on to the functor.
   * @return The return value of the functor invocation.
   */
  inline T_return operator()(arg1_type_ _A_a1, arg2_type_ _A_a2, arg3_type_ _A_a3) const
    {
      if (!empty() && !blocked())
        return (sigc::internal::function_pointer_cast<call_type>(slot_base::rep_->call_))(slot_base::rep_, _A_a1, _A_a2, _A_a3);
      return T_return();
    }

  inline slot3() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot3(const T_functor& _A_func)
    : slot_base(new internal::typed_slot_rep<T_functor>(_A_func))
    {
      //The slot_base:: is necessary to stop the HP-UX aCC compiler from being confused. murrayc.
      slot_base::rep_->call_ = internal::slot_call3<T_functor, T_return, T_arg1, T_arg2, T_arg3>::address();
    }

  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot3(const slot3& src)
    : slot_base(src)
    {}

  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot3(slot3&& src)
    : slot_base(std::move(src))
    {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot3& operator=(const slot3& src)
  {
    slot_base::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot3& operator=(slot3&& src)
  {
    slot_base::operator=(std::move(src));
    return *this;
  }
};

#ifndef DOXYGEN_SHOULD_SKIP_THIS
//template specialization of visitor<>::do_visit_each<>(action, functor):
/** Performs a functor on each of the targets of a functor.
 * The function overloads for sigc::slot3 are similar to the function
 * overloads for sigc::slot. See the description of those overloads.
 *
 * @ingroup slot
 */
template <typename T_return, typename T_arg1, typename T_arg2, typename T_arg3>
struct visitor<slot3<T_return, T_arg1, T_arg2, T_arg3>>
{
  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_bind>& _A_action,
                            const slot3<T_return, T_arg1, T_arg2, T_arg3>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == nullptr)
    _A_target.rep_->set_parent(_A_action.action_.rep_, &internal::slot_rep::notify);
  }

  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_unbind>& _A_action,
                            const slot3<T_return, T_arg1, T_arg2, T_arg3>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == _A_action.action_.rep_)
      _A_target.rep_->set_parent(nullptr, nullptr);
  }

  template <typename T_action>
  static void do_visit_each(const T_action& _A_action,
                            const slot3<T_return, T_arg1, T_arg2, T_arg3>& _A_target)
  {
    _A_action(_A_target);
  }
};
#endif // DOXYGEN_SHOULD_SKIP_THIS

/** Converts an arbitrary functor to a unified type which is opaque.
 * sigc::slot itself is a functor or to be more precise a closure. It contains
 * a single, arbitrary functor (or closure) that is executed in operator()().
 *
 * The template arguments determine the function signature of operator()():
 * - @e T_return The return type of operator()().
 * - @e T_arg1 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg2 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg3 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg4 Argument type used in the definition of operator()(). The default @p nil means no argument.
 *
 * To use simply assign the desired functor to the slot. If the functor
 * is not compatible with the parameter list defined with the template
 * arguments compiler errors are triggered. When called the slot
 * will invoke the functor with minimal copies.
 * block() and unblock() can be used to block the functor's invocation
 * from operator()() temporarily.
 *
 * You should use the more convenient unnumbered sigc::slot template.
 *
 * @ingroup slot
 */
template <class T_return, class T_arg1, class T_arg2, class T_arg3, class T_arg4>
class slot4
  : public slot_base
{
public:
  typedef T_return result_type;
  typedef type_trait_take_t<T_arg1> arg1_type_;
  typedef type_trait_take_t<T_arg2> arg2_type_;
  typedef type_trait_take_t<T_arg3> arg3_type_;
  typedef type_trait_take_t<T_arg4> arg4_type_;


#ifndef DOXYGEN_SHOULD_SKIP_THIS
private:
  typedef internal::slot_rep rep_type;
public:
  typedef T_return (*call_type)(rep_type*, arg1_type_, arg2_type_, arg3_type_, arg4_type_);
#endif

  /** Invoke the contained functor unless slot is in blocking state.
   * @param _A_a1 Argument to be passed on to the functor.
   * @param _A_a2 Argument to be passed on to the functor.
   * @param _A_a3 Argument to be passed on to the functor.
   * @param _A_a4 Argument to be passed on to the functor.
   * @return The return value of the functor invocation.
   */
  inline T_return operator()(arg1_type_ _A_a1, arg2_type_ _A_a2, arg3_type_ _A_a3, arg4_type_ _A_a4) const
    {
      if (!empty() && !blocked())
        return (sigc::internal::function_pointer_cast<call_type>(slot_base::rep_->call_))(slot_base::rep_, _A_a1, _A_a2, _A_a3, _A_a4);
      return T_return();
    }

  inline slot4() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot4(const T_functor& _A_func)
    : slot_base(new internal::typed_slot_rep<T_functor>(_A_func))
    {
      //The slot_base:: is necessary to stop the HP-UX aCC compiler from being confused. murrayc.
      slot_base::rep_->call_ = internal::slot_call4<T_functor, T_return, T_arg1, T_arg2, T_arg3, T_arg4>::address();
    }

  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot4(const slot4& src)
    : slot_base(src)
    {}

  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot4(slot4&& src)
    : slot_base(std::move(src))
    {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot4& operator=(const slot4& src)
  {
    slot_base::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot4& operator=(slot4&& src)
  {
    slot_base::operator=(std::move(src));
    return *this;
  }
};

#ifndef DOXYGEN_SHOULD_SKIP_THIS
//template specialization of visitor<>::do_visit_each<>(action, functor):
/** Performs a functor on each of the targets of a functor.
 * The function overloads for sigc::slot4 are similar to the function
 * overloads for sigc::slot. See the description of those overloads.
 *
 * @ingroup slot
 */
template <typename T_return, typename T_arg1, typename T_arg2, typename T_arg3, typename T_arg4>
struct visitor<slot4<T_return, T_arg1, T_arg2, T_arg3, T_arg4>>
{
  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_bind>& _A_action,
                            const slot4<T_return, T_arg1, T_arg2, T_arg3, T_arg4>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == nullptr)
    _A_target.rep_->set_parent(_A_action.action_.rep_, &internal::slot_rep::notify);
  }

  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_unbind>& _A_action,
                            const slot4<T_return, T_arg1, T_arg2, T_arg3, T_arg4>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == _A_action.action_.rep_)
      _A_target.rep_->set_parent(nullptr, nullptr);
  }

  template <typename T_action>
  static void do_visit_each(const T_action& _A_action,
                            const slot4<T_return, T_arg1, T_arg2, T_arg3, T_arg4>& _A_target)
  {
    _A_action(_A_target);
  }
};
#endif // DOXYGEN_SHOULD_SKIP_THIS

/** Converts an arbitrary functor to a unified type which is opaque.
 * sigc::slot itself is a functor or to be more precise a closure. It contains
 * a single, arbitrary functor (or closure) that is executed in operator()().
 *
 * The template arguments determine the function signature of operator()():
 * - @e T_return The return type of operator()().
 * - @e T_arg1 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg2 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg3 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg4 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg5 Argument type used in the definition of operator()(). The default @p nil means no argument.
 *
 * To use simply assign the desired functor to the slot. If the functor
 * is not compatible with the parameter list defined with the template
 * arguments compiler errors are triggered. When called the slot
 * will invoke the functor with minimal copies.
 * block() and unblock() can be used to block the functor's invocation
 * from operator()() temporarily.
 *
 * You should use the more convenient unnumbered sigc::slot template.
 *
 * @ingroup slot
 */
template <class T_return, class T_arg1, class T_arg2, class T_arg3, class T_arg4, class T_arg5>
class slot5
  : public slot_base
{
public:
  typedef T_return result_type;
  typedef type_trait_take_t<T_arg1> arg1_type_;
  typedef type_trait_take_t<T_arg2> arg2_type_;
  typedef type_trait_take_t<T_arg3> arg3_type_;
  typedef type_trait_take_t<T_arg4> arg4_type_;
  typedef type_trait_take_t<T_arg5> arg5_type_;


#ifndef DOXYGEN_SHOULD_SKIP_THIS
private:
  typedef internal::slot_rep rep_type;
public:
  typedef T_return (*call_type)(rep_type*, arg1_type_, arg2_type_, arg3_type_, arg4_type_, arg5_type_);
#endif

  /** Invoke the contained functor unless slot is in blocking state.
   * @param _A_a1 Argument to be passed on to the functor.
   * @param _A_a2 Argument to be passed on to the functor.
   * @param _A_a3 Argument to be passed on to the functor.
   * @param _A_a4 Argument to be passed on to the functor.
   * @param _A_a5 Argument to be passed on to the functor.
   * @return The return value of the functor invocation.
   */
  inline T_return operator()(arg1_type_ _A_a1, arg2_type_ _A_a2, arg3_type_ _A_a3, arg4_type_ _A_a4, arg5_type_ _A_a5) const
    {
      if (!empty() && !blocked())
        return (sigc::internal::function_pointer_cast<call_type>(slot_base::rep_->call_))(slot_base::rep_, _A_a1, _A_a2, _A_a3, _A_a4, _A_a5);
      return T_return();
    }

  inline slot5() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot5(const T_functor& _A_func)
    : slot_base(new internal::typed_slot_rep<T_functor>(_A_func))
    {
      //The slot_base:: is necessary to stop the HP-UX aCC compiler from being confused. murrayc.
      slot_base::rep_->call_ = internal::slot_call5<T_functor, T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5>::address();
    }

  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot5(const slot5& src)
    : slot_base(src)
    {}

  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot5(slot5&& src)
    : slot_base(std::move(src))
    {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot5& operator=(const slot5& src)
  {
    slot_base::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot5& operator=(slot5&& src)
  {
    slot_base::operator=(std::move(src));
    return *this;
  }
};

#ifndef DOXYGEN_SHOULD_SKIP_THIS
//template specialization of visitor<>::do_visit_each<>(action, functor):
/** Performs a functor on each of the targets of a functor.
 * The function overloads for sigc::slot5 are similar to the function
 * overloads for sigc::slot. See the description of those overloads.
 *
 * @ingroup slot
 */
template <typename T_return, typename T_arg1, typename T_arg2, typename T_arg3, typename T_arg4, typename T_arg5>
struct visitor<slot5<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5>>
{
  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_bind>& _A_action,
                            const slot5<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == nullptr)
    _A_target.rep_->set_parent(_A_action.action_.rep_, &internal::slot_rep::notify);
  }

  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_unbind>& _A_action,
                            const slot5<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == _A_action.action_.rep_)
      _A_target.rep_->set_parent(nullptr, nullptr);
  }

  template <typename T_action>
  static void do_visit_each(const T_action& _A_action,
                            const slot5<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5>& _A_target)
  {
    _A_action(_A_target);
  }
};
#endif // DOXYGEN_SHOULD_SKIP_THIS

/** Converts an arbitrary functor to a unified type which is opaque.
 * sigc::slot itself is a functor or to be more precise a closure. It contains
 * a single, arbitrary functor (or closure) that is executed in operator()().
 *
 * The template arguments determine the function signature of operator()():
 * - @e T_return The return type of operator()().
 * - @e T_arg1 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg2 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg3 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg4 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg5 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg6 Argument type used in the definition of operator()(). The default @p nil means no argument.
 *
 * To use simply assign the desired functor to the slot. If the functor
 * is not compatible with the parameter list defined with the template
 * arguments compiler errors are triggered. When called the slot
 * will invoke the functor with minimal copies.
 * block() and unblock() can be used to block the functor's invocation
 * from operator()() temporarily.
 *
 * You should use the more convenient unnumbered sigc::slot template.
 *
 * @ingroup slot
 */
template <class T_return, class T_arg1, class T_arg2, class T_arg3, class T_arg4, class T_arg5, class T_arg6>
class slot6
  : public slot_base
{
public:
  typedef T_return result_type;
  typedef type_trait_take_t<T_arg1> arg1_type_;
  typedef type_trait_take_t<T_arg2> arg2_type_;
  typedef type_trait_take_t<T_arg3> arg3_type_;
  typedef type_trait_take_t<T_arg4> arg4_type_;
  typedef type_trait_take_t<T_arg5> arg5_type_;
  typedef type_trait_take_t<T_arg6> arg6_type_;


#ifndef DOXYGEN_SHOULD_SKIP_THIS
private:
  typedef internal::slot_rep rep_type;
public:
  typedef T_return (*call_type)(rep_type*, arg1_type_, arg2_type_, arg3_type_, arg4_type_, arg5_type_, arg6_type_);
#endif

  /** Invoke the contained functor unless slot is in blocking state.
   * @param _A_a1 Argument to be passed on to the functor.
   * @param _A_a2 Argument to be passed on to the functor.
   * @param _A_a3 Argument to be passed on to the functor.
   * @param _A_a4 Argument to be passed on to the functor.
   * @param _A_a5 Argument to be passed on to the functor.
   * @param _A_a6 Argument to be passed on to the functor.
   * @return The return value of the functor invocation.
   */
  inline T_return operator()(arg1_type_ _A_a1, arg2_type_ _A_a2, arg3_type_ _A_a3, arg4_type_ _A_a4, arg5_type_ _A_a5, arg6_type_ _A_a6) const
    {
      if (!empty() && !blocked())
        return (sigc::internal::function_pointer_cast<call_type>(slot_base::rep_->call_))(slot_base::rep_, _A_a1, _A_a2, _A_a3, _A_a4, _A_a5, _A_a6);
      return T_return();
    }

  inline slot6() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot6(const T_functor& _A_func)
    : slot_base(new internal::typed_slot_rep<T_functor>(_A_func))
    {
      //The slot_base:: is necessary to stop the HP-UX aCC compiler from being confused. murrayc.
      slot_base::rep_->call_ = internal::slot_call6<T_functor, T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6>::address();
    }

  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot6(const slot6& src)
    : slot_base(src)
    {}

  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot6(slot6&& src)
    : slot_base(std::move(src))
    {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot6& operator=(const slot6& src)
  {
    slot_base::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot6& operator=(slot6&& src)
  {
    slot_base::operator=(std::move(src));
    return *this;
  }
};

#ifndef DOXYGEN_SHOULD_SKIP_THIS
//template specialization of visitor<>::do_visit_each<>(action, functor):
/** Performs a functor on each of the targets of a functor.
 * The function overloads for sigc::slot6 are similar to the function
 * overloads for sigc::slot. See the description of those overloads.
 *
 * @ingroup slot
 */
template <typename T_return, typename T_arg1, typename T_arg2, typename T_arg3, typename T_arg4, typename T_arg5, typename T_arg6>
struct visitor<slot6<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6>>
{
  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_bind>& _A_action,
                            const slot6<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == nullptr)
    _A_target.rep_->set_parent(_A_action.action_.rep_, &internal::slot_rep::notify);
  }

  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_unbind>& _A_action,
                            const slot6<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == _A_action.action_.rep_)
      _A_target.rep_->set_parent(nullptr, nullptr);
  }

  template <typename T_action>
  static void do_visit_each(const T_action& _A_action,
                            const slot6<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6>& _A_target)
  {
    _A_action(_A_target);
  }
};
#endif // DOXYGEN_SHOULD_SKIP_THIS

/** Converts an arbitrary functor to a unified type which is opaque.
 * sigc::slot itself is a functor or to be more precise a closure. It contains
 * a single, arbitrary functor (or closure) that is executed in operator()().
 *
 * The template arguments determine the function signature of operator()():
 * - @e T_return The return type of operator()().
 * - @e T_arg1 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg2 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg3 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg4 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg5 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg6 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg7 Argument type used in the definition of operator()(). The default @p nil means no argument.
 *
 * To use simply assign the desired functor to the slot. If the functor
 * is not compatible with the parameter list defined with the template
 * arguments compiler errors are triggered. When called the slot
 * will invoke the functor with minimal copies.
 * block() and unblock() can be used to block the functor's invocation
 * from operator()() temporarily.
 *
 * You should use the more convenient unnumbered sigc::slot template.
 *
 * @ingroup slot
 */
template <class T_return, class T_arg1, class T_arg2, class T_arg3, class T_arg4, class T_arg5, class T_arg6, class T_arg7>
class slot7
  : public slot_base
{
public:
  typedef T_return result_type;
  typedef type_trait_take_t<T_arg1> arg1_type_;
  typedef type_trait_take_t<T_arg2> arg2_type_;
  typedef type_trait_take_t<T_arg3> arg3_type_;
  typedef type_trait_take_t<T_arg4> arg4_type_;
  typedef type_trait_take_t<T_arg5> arg5_type_;
  typedef type_trait_take_t<T_arg6> arg6_type_;
  typedef type_trait_take_t<T_arg7> arg7_type_;


#ifndef DOXYGEN_SHOULD_SKIP_THIS
private:
  typedef internal::slot_rep rep_type;
public:
  typedef T_return (*call_type)(rep_type*, arg1_type_, arg2_type_, arg3_type_, arg4_type_, arg5_type_, arg6_type_, arg7_type_);
#endif

  /** Invoke the contained functor unless slot is in blocking state.
   * @param _A_a1 Argument to be passed on to the functor.
   * @param _A_a2 Argument to be passed on to the functor.
   * @param _A_a3 Argument to be passed on to the functor.
   * @param _A_a4 Argument to be passed on to the functor.
   * @param _A_a5 Argument to be passed on to the functor.
   * @param _A_a6 Argument to be passed on to the functor.
   * @param _A_a7 Argument to be passed on to the functor.
   * @return The return value of the functor invocation.
   */
  inline T_return operator()(arg1_type_ _A_a1, arg2_type_ _A_a2, arg3_type_ _A_a3, arg4_type_ _A_a4, arg5_type_ _A_a5, arg6_type_ _A_a6, arg7_type_ _A_a7) const
    {
      if (!empty() && !blocked())
        return (sigc::internal::function_pointer_cast<call_type>(slot_base::rep_->call_))(slot_base::rep_, _A_a1, _A_a2, _A_a3, _A_a4, _A_a5, _A_a6, _A_a7);
      return T_return();
    }

  inline slot7() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot7(const T_functor& _A_func)
    : slot_base(new internal::typed_slot_rep<T_functor>(_A_func))
    {
      //The slot_base:: is necessary to stop the HP-UX aCC compiler from being confused. murrayc.
      slot_base::rep_->call_ = internal::slot_call7<T_functor, T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7>::address();
    }

  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot7(const slot7& src)
    : slot_base(src)
    {}

  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot7(slot7&& src)
    : slot_base(std::move(src))
    {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot7& operator=(const slot7& src)
  {
    slot_base::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot7& operator=(slot7&& src)
  {
    slot_base::operator=(std::move(src));
    return *this;
  }
};

#ifndef DOXYGEN_SHOULD_SKIP_THIS
//template specialization of visitor<>::do_visit_each<>(action, functor):
/** Performs a functor on each of the targets of a functor.
 * The function overloads for sigc::slot7 are similar to the function
 * overloads for sigc::slot. See the description of those overloads.
 *
 * @ingroup slot
 */
template <typename T_return, typename T_arg1, typename T_arg2, typename T_arg3, typename T_arg4, typename T_arg5, typename T_arg6, typename T_arg7>
struct visitor<slot7<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7>>
{
  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_bind>& _A_action,
                            const slot7<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == nullptr)
    _A_target.rep_->set_parent(_A_action.action_.rep_, &internal::slot_rep::notify);
  }

  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_unbind>& _A_action,
                            const slot7<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == _A_action.action_.rep_)
      _A_target.rep_->set_parent(nullptr, nullptr);
  }

  template <typename T_action>
  static void do_visit_each(const T_action& _A_action,
                            const slot7<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7>& _A_target)
  {
    _A_action(_A_target);
  }
};
#endif // DOXYGEN_SHOULD_SKIP_THIS


// Because slot is opaque, visit_each() will not visit its internal members.
// Those members are not reachable by visit_each() after the slot has been
// constructed. But when a slot contains another slot, the outer slot will become
// the parent of the inner slot, with similar results. See the description of
// slot's specialization of the visitor struct.
/** Convenience wrapper for the numbered sigc::slot# templates.
 * Slots convert arbitrary functors to unified types which are opaque.
 * sigc::slot itself is a functor or to be more precise a closure. It contains
 * a single, arbitrary functor (or closure) that is executed in operator()().
 *
 * The template arguments determine the function signature of operator()():
 * - @e T_return The return type of operator()().
 * - @e T_arg1 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg2 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg3 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg4 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg5 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg6 Argument type used in the definition of operator()(). The default @p nil means no argument.
 * - @e T_arg7 Argument type used in the definition of operator()(). The default @p nil means no argument.
 *
 * To use, simply assign the desired functor to the slot. If the functor
 * is not compatible with the parameter list defined with the template
 * arguments, compiler errors are triggered. When called, the slot
 * will invoke the functor with minimal copies.
 * block() and unblock() can be used to temporarily block the functor's
 * invocation from operator()().
 *
 * @par Example:
 * @code
 * void foo(int) {}
 * sigc::slot<void, int> s = sigc::ptr_fun(&foo);
 * s(19);
 * @endcode
 *
 * sigc::slot<> is similar to std::function<>. If you're going to assign the
 * resulting functor to a sigc::slot or connect it to a sigc::signal, it's better
 * not to use std::function. It would become an unnecessary extra wrapper.
 *
 * @deprecated Please use the syntax similar to that used by std::function<>:
 * @code
 * sigc::slot<void(bool, int)> some_slot;
 * @endcode
 *
 * @ingroup slot
 */
template <class T_return, class T_arg1 = nil, class T_arg2 = nil, class T_arg3 = nil, class T_arg4 = nil, class T_arg5 = nil, class T_arg6 = nil, class T_arg7 = nil>
class slot
  : public slot7<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7>
{
public:
  typedef slot7<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7> parent_type;

  inline slot() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot(const T_functor& _A_func)
    : parent_type(_A_func) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the copy constructor.
  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot(const slot& src)
    : parent_type(static_cast<const parent_type&>(src)) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the move constructor.
  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot(slot&& src)
    : parent_type(std::move(static_cast<parent_type&>(src))) {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot& operator=(const slot& src)
  {
    parent_type::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot& operator=(slot&& src)
  {
    parent_type::operator=(std::move(src));
    return *this;
  }
};

#ifndef DOXYGEN_SHOULD_SKIP_THIS
//template specialization of visitor<>::do_visit_each<>(action, functor):
/** Performs a functor on each of the targets of a functor.
 *
 * There are three function overloads for sigc::slot.
 *
 * The first two overloads are very specialized. They handle the (probably unusual)
 * case when the functor, stored in a slot, contains a slot. They are invoked from
 * the constructor, destructor or destroy() method of typed_slot_rep.
 * The first overload, called from the constructor of the outer slot, sets
 * the outer slot as the parent of the inner slot. The second overload, called from
 * the destructor or destroy() of the outer slot, unsets the parent of the inner slot.
 * When an object referenced from the inner slot is deleted, the inner slot calls
 * its slot_rep::disconnect(), which calls the outer slot's slot_rep::notify().
 * The outer slot is informed just as if one of its directly referenced objects
 * had been deleted. Result: The outer slot is disconnected from its parent,
 * if any (for instance a sigc::signal).
 * See https://bugzilla.gnome.org/show_bug.cgi?id=755003
 *
 * The third overload is identical to do_visit_each() in visitor's primary template.
 *
 * @ingroup slot
 */
template <typename T_return, typename T_arg1, typename T_arg2, typename T_arg3, typename T_arg4, typename T_arg5, typename T_arg6, typename T_arg7>
struct visitor<slot<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7>>
{
  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_bind>& _A_action,
                            const slot<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == nullptr)
      _A_target.rep_->set_parent(_A_action.action_.rep_, &internal::slot_rep::notify);
  }

  static void do_visit_each(const internal::limit_derived_target<trackable*, internal::slot_do_unbind>& _A_action,
                            const slot<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7>& _A_target)
  {
    if (_A_target.rep_ && _A_target.rep_->parent_ == _A_action.action_.rep_)
      _A_target.rep_->set_parent(nullptr, nullptr);
  }

  template <typename T_action>
  static void do_visit_each(const T_action& _A_action,
                            const slot<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7>& _A_target)
  {
    _A_action(_A_target);
  }
};
#endif // DOXYGEN_SHOULD_SKIP_THIS



/** Convenience wrapper for the numbered sigc::slot0 template.
 * See the base class for useful methods.
 * This is the template specialization of the unnumbered sigc::slot
 * template for 0 argument(s), specialized for different numbers of arguments
 * This is possible because the template has default (nil) template types.
 *
 * @deprecated Please use the syntax similar to that used by std::function<>:
 * @code
 * sigc::slot<void(bool, int)> some_slot;
 * @endcode
 *
 */
template <class T_return>
class slot <T_return, nil, nil, nil, nil, nil, nil, nil>
  : public slot0<T_return>
{
public:
  typedef slot0<T_return> parent_type;

  inline slot() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot(const T_functor& _A_func)
    : parent_type(_A_func) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the copy constructor.
  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot(const slot& src)
    : parent_type(static_cast<const parent_type&>(src)) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the move constructor.
  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot(slot&& src)
    : parent_type(std::move(static_cast<parent_type&>(src))) {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot& operator=(const slot& src)
  {
    parent_type::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot& operator=(slot&& src)
  {
    parent_type::operator=(std::move(src));
    return *this;
  }
};



/** Convenience wrapper for the numbered sigc::slot1 template.
 * See the base class for useful methods.
 * This is the template specialization of the unnumbered sigc::slot
 * template for 1 argument(s), specialized for different numbers of arguments
 * This is possible because the template has default (nil) template types.
 *
 * @deprecated Please use the syntax similar to that used by std::function<>:
 * @code
 * sigc::slot<void(bool, int)> some_slot;
 * @endcode
 *
 */
template <class T_return, class T_arg1>
class slot <T_return, T_arg1, nil, nil, nil, nil, nil, nil>
  : public slot1<T_return, T_arg1>
{
public:
  typedef slot1<T_return, T_arg1> parent_type;

  inline slot() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot(const T_functor& _A_func)
    : parent_type(_A_func) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the copy constructor.
  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot(const slot& src)
    : parent_type(static_cast<const parent_type&>(src)) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the move constructor.
  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot(slot&& src)
    : parent_type(std::move(static_cast<parent_type&>(src))) {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot& operator=(const slot& src)
  {
    parent_type::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot& operator=(slot&& src)
  {
    parent_type::operator=(std::move(src));
    return *this;
  }
};



/** Convenience wrapper for the numbered sigc::slot2 template.
 * See the base class for useful methods.
 * This is the template specialization of the unnumbered sigc::slot
 * template for 2 argument(s), specialized for different numbers of arguments
 * This is possible because the template has default (nil) template types.
 *
 * @deprecated Please use the syntax similar to that used by std::function<>:
 * @code
 * sigc::slot<void(bool, int)> some_slot;
 * @endcode
 *
 */
template <class T_return, class T_arg1, class T_arg2>
class slot <T_return, T_arg1, T_arg2, nil, nil, nil, nil, nil>
  : public slot2<T_return, T_arg1, T_arg2>
{
public:
  typedef slot2<T_return, T_arg1, T_arg2> parent_type;

  inline slot() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot(const T_functor& _A_func)
    : parent_type(_A_func) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the copy constructor.
  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot(const slot& src)
    : parent_type(static_cast<const parent_type&>(src)) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the move constructor.
  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot(slot&& src)
    : parent_type(std::move(static_cast<parent_type&>(src))) {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot& operator=(const slot& src)
  {
    parent_type::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot& operator=(slot&& src)
  {
    parent_type::operator=(std::move(src));
    return *this;
  }
};



/** Convenience wrapper for the numbered sigc::slot3 template.
 * See the base class for useful methods.
 * This is the template specialization of the unnumbered sigc::slot
 * template for 3 argument(s), specialized for different numbers of arguments
 * This is possible because the template has default (nil) template types.
 *
 * @deprecated Please use the syntax similar to that used by std::function<>:
 * @code
 * sigc::slot<void(bool, int)> some_slot;
 * @endcode
 *
 */
template <class T_return, class T_arg1, class T_arg2, class T_arg3>
class slot <T_return, T_arg1, T_arg2, T_arg3, nil, nil, nil, nil>
  : public slot3<T_return, T_arg1, T_arg2, T_arg3>
{
public:
  typedef slot3<T_return, T_arg1, T_arg2, T_arg3> parent_type;

  inline slot() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot(const T_functor& _A_func)
    : parent_type(_A_func) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the copy constructor.
  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot(const slot& src)
    : parent_type(static_cast<const parent_type&>(src)) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the move constructor.
  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot(slot&& src)
    : parent_type(std::move(static_cast<parent_type&>(src))) {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot& operator=(const slot& src)
  {
    parent_type::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot& operator=(slot&& src)
  {
    parent_type::operator=(std::move(src));
    return *this;
  }
};



/** Convenience wrapper for the numbered sigc::slot4 template.
 * See the base class for useful methods.
 * This is the template specialization of the unnumbered sigc::slot
 * template for 4 argument(s), specialized for different numbers of arguments
 * This is possible because the template has default (nil) template types.
 *
 * @deprecated Please use the syntax similar to that used by std::function<>:
 * @code
 * sigc::slot<void(bool, int)> some_slot;
 * @endcode
 *
 */
template <class T_return, class T_arg1, class T_arg2, class T_arg3, class T_arg4>
class slot <T_return, T_arg1, T_arg2, T_arg3, T_arg4, nil, nil, nil>
  : public slot4<T_return, T_arg1, T_arg2, T_arg3, T_arg4>
{
public:
  typedef slot4<T_return, T_arg1, T_arg2, T_arg3, T_arg4> parent_type;

  inline slot() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot(const T_functor& _A_func)
    : parent_type(_A_func) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the copy constructor.
  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot(const slot& src)
    : parent_type(static_cast<const parent_type&>(src)) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the move constructor.
  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot(slot&& src)
    : parent_type(std::move(static_cast<parent_type&>(src))) {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot& operator=(const slot& src)
  {
    parent_type::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot& operator=(slot&& src)
  {
    parent_type::operator=(std::move(src));
    return *this;
  }
};



/** Convenience wrapper for the numbered sigc::slot5 template.
 * See the base class for useful methods.
 * This is the template specialization of the unnumbered sigc::slot
 * template for 5 argument(s), specialized for different numbers of arguments
 * This is possible because the template has default (nil) template types.
 *
 * @deprecated Please use the syntax similar to that used by std::function<>:
 * @code
 * sigc::slot<void(bool, int)> some_slot;
 * @endcode
 *
 */
template <class T_return, class T_arg1, class T_arg2, class T_arg3, class T_arg4, class T_arg5>
class slot <T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, nil, nil>
  : public slot5<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5>
{
public:
  typedef slot5<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5> parent_type;

  inline slot() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot(const T_functor& _A_func)
    : parent_type(_A_func) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the copy constructor.
  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot(const slot& src)
    : parent_type(static_cast<const parent_type&>(src)) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the move constructor.
  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot(slot&& src)
    : parent_type(std::move(static_cast<parent_type&>(src))) {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot& operator=(const slot& src)
  {
    parent_type::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot& operator=(slot&& src)
  {
    parent_type::operator=(std::move(src));
    return *this;
  }
};



/** Convenience wrapper for the numbered sigc::slot6 template.
 * See the base class for useful methods.
 * This is the template specialization of the unnumbered sigc::slot
 * template for 6 argument(s), specialized for different numbers of arguments
 * This is possible because the template has default (nil) template types.
 *
 * @deprecated Please use the syntax similar to that used by std::function<>:
 * @code
 * sigc::slot<void(bool, int)> some_slot;
 * @endcode
 *
 */
template <class T_return, class T_arg1, class T_arg2, class T_arg3, class T_arg4, class T_arg5, class T_arg6>
class slot <T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, nil>
  : public slot6<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6>
{
public:
  typedef slot6<T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6> parent_type;

  inline slot() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot(const T_functor& _A_func)
    : parent_type(_A_func) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the copy constructor.
  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot(const slot& src)
    : parent_type(static_cast<const parent_type&>(src)) {}

  // Without static_cast parent_type(const T_functor& _A_func)
  // is called instead of the move constructor.
  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot(slot&& src)
    : parent_type(std::move(static_cast<parent_type&>(src))) {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot& operator=(const slot& src)
  {
    parent_type::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot& operator=(slot&& src)
  {
    parent_type::operator=(std::move(src));
    return *this;
  }
};




/** Converts an arbitrary functor to a unified type which is opaque.
 * sigc::slot itself is a functor or, to be more precise, a closure. It contains
 * a single, arbitrary functor (or closure) that is executed in operator()().
 *
 * The template arguments determine the function signature of operator()():
 * - @e T_return The return type of operator()().
 * - @e T_arg Argument types used in the definition of operator()().
 *
 * For instance, to declare a slot that returns void and takes two parameters
 * of bool and int:
 * @code
 * sigc::slot<void(bool, int)> some_slot;
 * @endcode
 *
 * Alternatively, you may use this syntax:
 * @code
 * sigc::slot<void, bool, int> some_slot;
 * @endcode
 *
 * To use, simply assign the desired functor to the slot. If the functor
 * is not compatible with the parameter list defined with the template
 * arguments then compiler errors are triggered. When called, the slot
 * will invoke the functor with minimal copies.
 * block() and unblock() can be used to block the functor's invocation
 * from operator()() temporarily.
 *
 * @ingroup slot
 */
template <class T_return, class... T_arg>
class slot<T_return(T_arg...)>
  : public slot_base
{
public:
  using result_type = T_return;
  //TODO: using arg_type_ = type_trait_take_t<T_arg>;

#ifndef DOXYGEN_SHOULD_SKIP_THIS
private:
  using rep_type = internal::slot_rep;
public:
  using call_type = T_return (*)(rep_type*, type_trait_take_t<T_arg>...);
#endif

  /** Invoke the contained functor unless slot is in blocking state.
   * @param _A_a Arguments to be passed on to the functor.
   * @return The return value of the functor invocation.
   */
  inline T_return operator()(type_trait_take_t<T_arg>... _A_a) const
    {
      if (!empty() && !blocked())
        return (sigc::internal::function_pointer_cast<call_type>(slot_base::rep_->call_))(slot_base::rep_, _A_a...);
      return T_return();
    }

  inline slot() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desired functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot(const T_functor& _A_func)
    : slot_base(new internal::typed_slot_rep<T_functor>(_A_func))
    {
      //The slot_base:: is necessary to stop the HP-UX aCC compiler from being confused. murrayc.
      slot_base::rep_->call_ = internal::slot_call<T_functor, T_return, T_arg...>::address();
    }

  /** Constructs a slot, copying an existing one.
   * @param src The existing slot to copy.
   */
  slot(const slot& src)
    : slot_base(src)
    {}

  /** Constructs a slot, moving an existing one.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The existing slot to move or copy.
   */
  slot(slot&& src)
    : slot_base(std::move(src))
    {}

  /** Overrides this slot, making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot& operator=(const slot& src)
  {
    slot_base::operator=(src);
    return *this;
  }

  /** Overrides this slot, making a move from another slot.
   * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
   * @param src The slot from which to move or copy.
   * @return @p this.
   */
  slot& operator=(slot&& src)
  {
    slot_base::operator=(std::move(src));
    return *this;
  }
};

} /* namespace sigc */

#ifdef SIGC_NIL_HAS_BEEN_PUSHED
  #undef SIGC_NIL_HAS_BEEN_PUSHED
  #pragma pop_macro("nil")
#endif
#endif /* _SIGC_FUNCTORS_SLOT_H_ */