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/*
* Copyright 2003 - 2016, The libsigc++ Development Team
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef SIGC_FUNCTORS_FUNCTOR_TRAIT_H
#define SIGC_FUNCTORS_FUNCTOR_TRAIT_H
#include <sigc++/functors/mem_fun.h>
#include <sigc++/functors/ptr_fun.h>
#include <sigc++/type_traits.h>
#include <type_traits>
namespace sigc
{
/** @defgroup sigcfunctors Functors
* Functors are copyable types that define operator()().
*
* Types that define operator()() overloads with different return types are referred to
* as multi-type functors. Multi-type functors are only partially supported in libsigc++.
*
* Closures are functors that store all information needed to invoke a callback from operator()().
*
* Adaptors are functors that alter the signature of a functor's operator()().
*
* libsigc++ defines numerous functors, closures and adaptors.
* Since libsigc++ is a callback library, most functors are also closures.
* The documentation doesn't distinguish between functors and closures.
*
* The basic functor types libsigc++ provides are created with ptr_fun() and mem_fun()
* and can be converted into slots implicitly.
* The set of adaptors that ships with libsigc++ is documented in the @ref adaptors module.
*
*/
/** Trait that specifies the appropriate functor type of any callable type.
* Template specializations for function pointers and for class methods are provided.
*
* @tparam T_functor Functor type.
*
* @ingroup sigcfunctors
*/
template<typename T_functor>
struct functor_trait
{
using functor_type = T_functor;
};
#ifndef DOXYGEN_SHOULD_SKIP_THIS
// detect the functor version of non-functor types.
// functor ptr fun:
template<typename T_return, typename... T_arg>
struct functor_trait<T_return (*)(T_arg...)>
{
using functor_type = pointer_functor<T_return(T_arg...)>;
};
// functor mem fun:
template<typename T_return, typename T_obj, typename... T_arg>
struct functor_trait<T_return (T_obj::*)(T_arg...)>
{
using functor_type = mem_functor<T_return (T_obj::*)(T_arg...), T_arg...>;
};
template<typename T_return, typename T_obj, typename... T_arg>
struct functor_trait<T_return (T_obj::*)(T_arg...) const>
{
using functor_type = mem_functor<T_return (T_obj::*)(T_arg...) const, T_arg...>;
};
#endif // DOXYGEN_SHOULD_SKIP_THIS
} /* namespace sigc */
#endif /* SIGC_FUNCTORS_FUNCTOR_TRAIT_H */
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