99bf3a817b
The std::function code now uses std::type_info* even when RTTI is disabled, so it should include <typeinfo> unconditionally. Without this, Clang can't compile <functional> with -fno-rtti (it works with GCC because std::type_info gets declared automatically by the compiler). libstdc++-v3/ChangeLog: PR libstdc++/97758 * include/bits/std_function.h [!__cpp_rtti]: Include <typeinfo>.
750 lines
22 KiB
C++
750 lines
22 KiB
C++
// Implementation of std::function -*- C++ -*-
|
|
|
|
// Copyright (C) 2004-2020 Free Software Foundation, Inc.
|
|
//
|
|
// This file is part of the GNU ISO C++ Library. This library is free
|
|
// software; you can redistribute it and/or modify it under the
|
|
// terms of the GNU General Public License as published by the
|
|
// Free Software Foundation; either version 3, 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 General Public License for more details.
|
|
|
|
// Under Section 7 of GPL version 3, you are granted additional
|
|
// permissions described in the GCC Runtime Library Exception, version
|
|
// 3.1, as published by the Free Software Foundation.
|
|
|
|
// You should have received a copy of the GNU General Public License and
|
|
// a copy of the GCC Runtime Library Exception along with this program;
|
|
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
// <http://www.gnu.org/licenses/>.
|
|
|
|
/** @file include/bits/std_function.h
|
|
* This is an internal header file, included by other library headers.
|
|
* Do not attempt to use it directly. @headername{functional}
|
|
*/
|
|
|
|
#ifndef _GLIBCXX_STD_FUNCTION_H
|
|
#define _GLIBCXX_STD_FUNCTION_H 1
|
|
|
|
#pragma GCC system_header
|
|
|
|
#if __cplusplus < 201103L
|
|
# include <bits/c++0x_warning.h>
|
|
#else
|
|
|
|
#include <typeinfo>
|
|
#include <bits/stl_function.h>
|
|
#include <bits/invoke.h>
|
|
#include <bits/refwrap.h>
|
|
#include <bits/functexcept.h>
|
|
|
|
namespace std _GLIBCXX_VISIBILITY(default)
|
|
{
|
|
_GLIBCXX_BEGIN_NAMESPACE_VERSION
|
|
|
|
/**
|
|
* @brief Exception class thrown when class template function's
|
|
* operator() is called with an empty target.
|
|
* @ingroup exceptions
|
|
*/
|
|
class bad_function_call : public std::exception
|
|
{
|
|
public:
|
|
virtual ~bad_function_call() noexcept;
|
|
|
|
const char* what() const noexcept;
|
|
};
|
|
|
|
/**
|
|
* Trait identifying "location-invariant" types, meaning that the
|
|
* address of the object (or any of its members) will not escape.
|
|
* Trivially copyable types are location-invariant and users can
|
|
* specialize this trait for other types.
|
|
*/
|
|
template<typename _Tp>
|
|
struct __is_location_invariant
|
|
: is_trivially_copyable<_Tp>::type
|
|
{ };
|
|
|
|
class _Undefined_class;
|
|
|
|
union _Nocopy_types
|
|
{
|
|
void* _M_object;
|
|
const void* _M_const_object;
|
|
void (*_M_function_pointer)();
|
|
void (_Undefined_class::*_M_member_pointer)();
|
|
};
|
|
|
|
union [[gnu::may_alias]] _Any_data
|
|
{
|
|
void* _M_access() { return &_M_pod_data[0]; }
|
|
const void* _M_access() const { return &_M_pod_data[0]; }
|
|
|
|
template<typename _Tp>
|
|
_Tp&
|
|
_M_access()
|
|
{ return *static_cast<_Tp*>(_M_access()); }
|
|
|
|
template<typename _Tp>
|
|
const _Tp&
|
|
_M_access() const
|
|
{ return *static_cast<const _Tp*>(_M_access()); }
|
|
|
|
_Nocopy_types _M_unused;
|
|
char _M_pod_data[sizeof(_Nocopy_types)];
|
|
};
|
|
|
|
enum _Manager_operation
|
|
{
|
|
__get_type_info,
|
|
__get_functor_ptr,
|
|
__clone_functor,
|
|
__destroy_functor
|
|
};
|
|
|
|
template<typename _Signature>
|
|
class function;
|
|
|
|
/// Base class of all polymorphic function object wrappers.
|
|
class _Function_base
|
|
{
|
|
public:
|
|
static const size_t _M_max_size = sizeof(_Nocopy_types);
|
|
static const size_t _M_max_align = __alignof__(_Nocopy_types);
|
|
|
|
template<typename _Functor>
|
|
class _Base_manager
|
|
{
|
|
protected:
|
|
static const bool __stored_locally =
|
|
(__is_location_invariant<_Functor>::value
|
|
&& sizeof(_Functor) <= _M_max_size
|
|
&& __alignof__(_Functor) <= _M_max_align
|
|
&& (_M_max_align % __alignof__(_Functor) == 0));
|
|
|
|
typedef integral_constant<bool, __stored_locally> _Local_storage;
|
|
|
|
// Retrieve a pointer to the function object
|
|
static _Functor*
|
|
_M_get_pointer(const _Any_data& __source)
|
|
{
|
|
if _GLIBCXX17_CONSTEXPR (__stored_locally)
|
|
{
|
|
const _Functor& __f = __source._M_access<_Functor>();
|
|
return const_cast<_Functor*>(std::__addressof(__f));
|
|
}
|
|
else // have stored a pointer
|
|
return __source._M_access<_Functor*>();
|
|
}
|
|
|
|
// Clone a location-invariant function object that fits within
|
|
// an _Any_data structure.
|
|
static void
|
|
_M_clone(_Any_data& __dest, const _Any_data& __source, true_type)
|
|
{
|
|
::new (__dest._M_access()) _Functor(__source._M_access<_Functor>());
|
|
}
|
|
|
|
// Clone a function object that is not location-invariant or
|
|
// that cannot fit into an _Any_data structure.
|
|
static void
|
|
_M_clone(_Any_data& __dest, const _Any_data& __source, false_type)
|
|
{
|
|
__dest._M_access<_Functor*>() =
|
|
new _Functor(*__source._M_access<const _Functor*>());
|
|
}
|
|
|
|
// Destroying a location-invariant object may still require
|
|
// destruction.
|
|
static void
|
|
_M_destroy(_Any_data& __victim, true_type)
|
|
{
|
|
__victim._M_access<_Functor>().~_Functor();
|
|
}
|
|
|
|
// Destroying an object located on the heap.
|
|
static void
|
|
_M_destroy(_Any_data& __victim, false_type)
|
|
{
|
|
delete __victim._M_access<_Functor*>();
|
|
}
|
|
|
|
public:
|
|
static bool
|
|
_M_manager(_Any_data& __dest, const _Any_data& __source,
|
|
_Manager_operation __op)
|
|
{
|
|
switch (__op)
|
|
{
|
|
case __get_type_info:
|
|
#if __cpp_rtti
|
|
__dest._M_access<const type_info*>() = &typeid(_Functor);
|
|
#else
|
|
__dest._M_access<const type_info*>() = nullptr;
|
|
#endif
|
|
break;
|
|
case __get_functor_ptr:
|
|
__dest._M_access<_Functor*>() = _M_get_pointer(__source);
|
|
break;
|
|
|
|
case __clone_functor:
|
|
_M_clone(__dest, __source, _Local_storage());
|
|
break;
|
|
|
|
case __destroy_functor:
|
|
_M_destroy(__dest, _Local_storage());
|
|
break;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
static void
|
|
_M_init_functor(_Any_data& __functor, _Functor&& __f)
|
|
{ _M_init_functor(__functor, std::move(__f), _Local_storage()); }
|
|
|
|
template<typename _Signature>
|
|
static bool
|
|
_M_not_empty_function(const function<_Signature>& __f)
|
|
{ return static_cast<bool>(__f); }
|
|
|
|
template<typename _Tp>
|
|
static bool
|
|
_M_not_empty_function(_Tp* __fp)
|
|
{ return __fp != nullptr; }
|
|
|
|
template<typename _Class, typename _Tp>
|
|
static bool
|
|
_M_not_empty_function(_Tp _Class::* __mp)
|
|
{ return __mp != nullptr; }
|
|
|
|
template<typename _Tp>
|
|
static bool
|
|
_M_not_empty_function(const _Tp&)
|
|
{ return true; }
|
|
|
|
private:
|
|
static void
|
|
_M_init_functor(_Any_data& __functor, _Functor&& __f, true_type)
|
|
{ ::new (__functor._M_access()) _Functor(std::move(__f)); }
|
|
|
|
static void
|
|
_M_init_functor(_Any_data& __functor, _Functor&& __f, false_type)
|
|
{ __functor._M_access<_Functor*>() = new _Functor(std::move(__f)); }
|
|
};
|
|
|
|
_Function_base() : _M_manager(nullptr) { }
|
|
|
|
~_Function_base()
|
|
{
|
|
if (_M_manager)
|
|
_M_manager(_M_functor, _M_functor, __destroy_functor);
|
|
}
|
|
|
|
bool _M_empty() const { return !_M_manager; }
|
|
|
|
typedef bool (*_Manager_type)(_Any_data&, const _Any_data&,
|
|
_Manager_operation);
|
|
|
|
_Any_data _M_functor;
|
|
_Manager_type _M_manager;
|
|
};
|
|
|
|
template<typename _Signature, typename _Functor>
|
|
class _Function_handler;
|
|
|
|
template<typename _Res, typename _Functor, typename... _ArgTypes>
|
|
class _Function_handler<_Res(_ArgTypes...), _Functor>
|
|
: public _Function_base::_Base_manager<_Functor>
|
|
{
|
|
typedef _Function_base::_Base_manager<_Functor> _Base;
|
|
|
|
public:
|
|
static bool
|
|
_M_manager(_Any_data& __dest, const _Any_data& __source,
|
|
_Manager_operation __op)
|
|
{
|
|
switch (__op)
|
|
{
|
|
#if __cpp_rtti
|
|
case __get_type_info:
|
|
__dest._M_access<const type_info*>() = &typeid(_Functor);
|
|
break;
|
|
#endif
|
|
case __get_functor_ptr:
|
|
__dest._M_access<_Functor*>() = _Base::_M_get_pointer(__source);
|
|
break;
|
|
|
|
default:
|
|
_Base::_M_manager(__dest, __source, __op);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
static _Res
|
|
_M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
|
|
{
|
|
return std::__invoke_r<_Res>(*_Base::_M_get_pointer(__functor),
|
|
std::forward<_ArgTypes>(__args)...);
|
|
}
|
|
};
|
|
|
|
// Specialization for invalid types
|
|
template<>
|
|
class _Function_handler<void, void>
|
|
{
|
|
public:
|
|
static bool
|
|
_M_manager(_Any_data&, const _Any_data&, _Manager_operation)
|
|
{ return false; }
|
|
};
|
|
|
|
// Avoids instantiating ill-formed specializations of _Function_handler
|
|
// in std::function<_Signature>::target<_Functor>().
|
|
// e.g. _Function_handler<Sig, void()> and _Function_handler<Sig, void>
|
|
// would be ill-formed.
|
|
template<typename _Signature, typename _Functor,
|
|
bool __valid = is_object<_Functor>::value>
|
|
struct _Target_handler
|
|
: _Function_handler<_Signature, typename remove_cv<_Functor>::type>
|
|
{ };
|
|
|
|
template<typename _Signature, typename _Functor>
|
|
struct _Target_handler<_Signature, _Functor, false>
|
|
: _Function_handler<void, void>
|
|
{ };
|
|
|
|
/**
|
|
* @brief Primary class template for std::function.
|
|
* @ingroup functors
|
|
*
|
|
* Polymorphic function wrapper.
|
|
*/
|
|
template<typename _Res, typename... _ArgTypes>
|
|
class function<_Res(_ArgTypes...)>
|
|
: public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
|
|
private _Function_base
|
|
{
|
|
template<typename _Func,
|
|
typename _Res2 = __invoke_result<_Func&, _ArgTypes...>>
|
|
struct _Callable
|
|
: __is_invocable_impl<_Res2, _Res>::type
|
|
{ };
|
|
|
|
// Used so the return type convertibility checks aren't done when
|
|
// performing overload resolution for copy construction/assignment.
|
|
template<typename _Tp>
|
|
struct _Callable<function, _Tp> : false_type { };
|
|
|
|
template<typename _Cond, typename _Tp>
|
|
using _Requires = typename enable_if<_Cond::value, _Tp>::type;
|
|
|
|
public:
|
|
typedef _Res result_type;
|
|
|
|
// [3.7.2.1] construct/copy/destroy
|
|
|
|
/**
|
|
* @brief Default construct creates an empty function call wrapper.
|
|
* @post @c !(bool)*this
|
|
*/
|
|
function() noexcept
|
|
: _Function_base() { }
|
|
|
|
/**
|
|
* @brief Creates an empty function call wrapper.
|
|
* @post @c !(bool)*this
|
|
*/
|
|
function(nullptr_t) noexcept
|
|
: _Function_base() { }
|
|
|
|
/**
|
|
* @brief %Function copy constructor.
|
|
* @param __x A %function object with identical call signature.
|
|
* @post @c bool(*this) == bool(__x)
|
|
*
|
|
* The newly-created %function contains a copy of the target of @a
|
|
* __x (if it has one).
|
|
*/
|
|
function(const function& __x)
|
|
: _Function_base()
|
|
{
|
|
if (static_cast<bool>(__x))
|
|
{
|
|
__x._M_manager(_M_functor, __x._M_functor, __clone_functor);
|
|
_M_invoker = __x._M_invoker;
|
|
_M_manager = __x._M_manager;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @brief %Function move constructor.
|
|
* @param __x A %function object rvalue with identical call signature.
|
|
*
|
|
* The newly-created %function contains the target of @a __x
|
|
* (if it has one).
|
|
*/
|
|
function(function&& __x) noexcept
|
|
: _Function_base()
|
|
{ __x.swap(*this); }
|
|
|
|
/**
|
|
* @brief Builds a %function that targets a copy of the incoming
|
|
* function object.
|
|
* @param __f A %function object that is callable with parameters of
|
|
* type @c T1, @c T2, ..., @c TN and returns a value convertible
|
|
* to @c Res.
|
|
*
|
|
* The newly-created %function object will target a copy of
|
|
* @a __f. If @a __f is @c reference_wrapper<F>, then this function
|
|
* object will contain a reference to the function object @c
|
|
* __f.get(). If @a __f is a NULL function pointer or NULL
|
|
* pointer-to-member, the newly-created object will be empty.
|
|
*
|
|
* If @a __f is a non-NULL function pointer or an object of type @c
|
|
* reference_wrapper<F>, this function will not throw.
|
|
*/
|
|
template<typename _Functor,
|
|
typename = _Requires<__not_<is_same<_Functor, function>>, void>,
|
|
typename = _Requires<_Callable<_Functor>, void>>
|
|
function(_Functor __f)
|
|
: _Function_base()
|
|
{
|
|
typedef _Function_handler<_Res(_ArgTypes...), _Functor> _My_handler;
|
|
|
|
if (_My_handler::_M_not_empty_function(__f))
|
|
{
|
|
_My_handler::_M_init_functor(_M_functor, std::move(__f));
|
|
_M_invoker = &_My_handler::_M_invoke;
|
|
_M_manager = &_My_handler::_M_manager;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @brief %Function assignment operator.
|
|
* @param __x A %function with identical call signature.
|
|
* @post @c (bool)*this == (bool)x
|
|
* @returns @c *this
|
|
*
|
|
* The target of @a __x is copied to @c *this. If @a __x has no
|
|
* target, then @c *this will be empty.
|
|
*
|
|
* If @a __x targets a function pointer or a reference to a function
|
|
* object, then this operation will not throw an %exception.
|
|
*/
|
|
function&
|
|
operator=(const function& __x)
|
|
{
|
|
function(__x).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
/**
|
|
* @brief %Function move-assignment operator.
|
|
* @param __x A %function rvalue with identical call signature.
|
|
* @returns @c *this
|
|
*
|
|
* The target of @a __x is moved to @c *this. If @a __x has no
|
|
* target, then @c *this will be empty.
|
|
*
|
|
* If @a __x targets a function pointer or a reference to a function
|
|
* object, then this operation will not throw an %exception.
|
|
*/
|
|
function&
|
|
operator=(function&& __x) noexcept
|
|
{
|
|
function(std::move(__x)).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
/**
|
|
* @brief %Function assignment to zero.
|
|
* @post @c !(bool)*this
|
|
* @returns @c *this
|
|
*
|
|
* The target of @c *this is deallocated, leaving it empty.
|
|
*/
|
|
function&
|
|
operator=(nullptr_t) noexcept
|
|
{
|
|
if (_M_manager)
|
|
{
|
|
_M_manager(_M_functor, _M_functor, __destroy_functor);
|
|
_M_manager = nullptr;
|
|
_M_invoker = nullptr;
|
|
}
|
|
return *this;
|
|
}
|
|
|
|
/**
|
|
* @brief %Function assignment to a new target.
|
|
* @param __f A %function object that is callable with parameters of
|
|
* type @c T1, @c T2, ..., @c TN and returns a value convertible
|
|
* to @c Res.
|
|
* @return @c *this
|
|
*
|
|
* This %function object wrapper will target a copy of @a
|
|
* __f. If @a __f is @c reference_wrapper<F>, then this function
|
|
* object will contain a reference to the function object @c
|
|
* __f.get(). If @a __f is a NULL function pointer or NULL
|
|
* pointer-to-member, @c this object will be empty.
|
|
*
|
|
* If @a __f is a non-NULL function pointer or an object of type @c
|
|
* reference_wrapper<F>, this function will not throw.
|
|
*/
|
|
template<typename _Functor>
|
|
_Requires<_Callable<typename decay<_Functor>::type>, function&>
|
|
operator=(_Functor&& __f)
|
|
{
|
|
function(std::forward<_Functor>(__f)).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
/// @overload
|
|
template<typename _Functor>
|
|
function&
|
|
operator=(reference_wrapper<_Functor> __f) noexcept
|
|
{
|
|
function(__f).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
// [3.7.2.2] function modifiers
|
|
|
|
/**
|
|
* @brief Swap the targets of two %function objects.
|
|
* @param __x A %function with identical call signature.
|
|
*
|
|
* Swap the targets of @c this function object and @a __f. This
|
|
* function will not throw an %exception.
|
|
*/
|
|
void swap(function& __x) noexcept
|
|
{
|
|
std::swap(_M_functor, __x._M_functor);
|
|
std::swap(_M_manager, __x._M_manager);
|
|
std::swap(_M_invoker, __x._M_invoker);
|
|
}
|
|
|
|
// [3.7.2.3] function capacity
|
|
|
|
/**
|
|
* @brief Determine if the %function wrapper has a target.
|
|
*
|
|
* @return @c true when this %function object contains a target,
|
|
* or @c false when it is empty.
|
|
*
|
|
* This function will not throw an %exception.
|
|
*/
|
|
explicit operator bool() const noexcept
|
|
{ return !_M_empty(); }
|
|
|
|
// [3.7.2.4] function invocation
|
|
|
|
/**
|
|
* @brief Invokes the function targeted by @c *this.
|
|
* @returns the result of the target.
|
|
* @throws bad_function_call when @c !(bool)*this
|
|
*
|
|
* The function call operator invokes the target function object
|
|
* stored by @c this.
|
|
*/
|
|
_Res
|
|
operator()(_ArgTypes... __args) const
|
|
{
|
|
if (_M_empty())
|
|
__throw_bad_function_call();
|
|
return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
|
|
}
|
|
|
|
#if __cpp_rtti
|
|
// [3.7.2.5] function target access
|
|
/**
|
|
* @brief Determine the type of the target of this function object
|
|
* wrapper.
|
|
*
|
|
* @returns the type identifier of the target function object, or
|
|
* @c typeid(void) if @c !(bool)*this.
|
|
*
|
|
* This function will not throw an %exception.
|
|
*/
|
|
const type_info&
|
|
target_type() const noexcept
|
|
{
|
|
if (_M_manager)
|
|
{
|
|
_Any_data __typeinfo_result;
|
|
_M_manager(__typeinfo_result, _M_functor, __get_type_info);
|
|
if (auto __ti = __typeinfo_result._M_access<const type_info*>())
|
|
return *__ti;
|
|
}
|
|
return typeid(void);
|
|
}
|
|
#endif
|
|
|
|
/**
|
|
* @brief Access the stored target function object.
|
|
*
|
|
* @return Returns a pointer to the stored target function object,
|
|
* if @c typeid(_Functor).equals(target_type()); otherwise, a null
|
|
* pointer.
|
|
*
|
|
* This function does not throw exceptions.
|
|
*
|
|
* @{
|
|
*/
|
|
template<typename _Functor>
|
|
_Functor*
|
|
target() noexcept
|
|
{
|
|
const function* __const_this = this;
|
|
const _Functor* __func = __const_this->template target<_Functor>();
|
|
// If is_function_v<_Functor> is true then const_cast<_Functor*>
|
|
// would be ill-formed, so use *const_cast<_Functor**> instead.
|
|
return *const_cast<_Functor**>(&__func);
|
|
}
|
|
|
|
template<typename _Functor>
|
|
const _Functor*
|
|
target() const noexcept
|
|
{
|
|
if _GLIBCXX17_CONSTEXPR (is_object<_Functor>::value)
|
|
{
|
|
// For C++11 and C++14 if-constexpr is not used above, so
|
|
// _Target_handler avoids ill-formed _Function_handler types.
|
|
using _Handler = _Target_handler<_Res(_ArgTypes...), _Functor>;
|
|
|
|
if (_M_manager == &_Handler::_M_manager
|
|
#if __cpp_rtti
|
|
|| (_M_manager && typeid(_Functor) == target_type())
|
|
#endif
|
|
)
|
|
{
|
|
_Any_data __ptr;
|
|
_M_manager(__ptr, _M_functor, __get_functor_ptr);
|
|
return __ptr._M_access<const _Functor*>();
|
|
}
|
|
}
|
|
return nullptr;
|
|
}
|
|
// @}
|
|
|
|
private:
|
|
using _Invoker_type = _Res (*)(const _Any_data&, _ArgTypes&&...);
|
|
_Invoker_type _M_invoker;
|
|
};
|
|
|
|
#if __cpp_deduction_guides >= 201606
|
|
template<typename>
|
|
struct __function_guide_helper
|
|
{ };
|
|
|
|
template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
|
|
struct __function_guide_helper<
|
|
_Res (_Tp::*) (_Args...) noexcept(_Nx)
|
|
>
|
|
{ using type = _Res(_Args...); };
|
|
|
|
template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
|
|
struct __function_guide_helper<
|
|
_Res (_Tp::*) (_Args...) & noexcept(_Nx)
|
|
>
|
|
{ using type = _Res(_Args...); };
|
|
|
|
template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
|
|
struct __function_guide_helper<
|
|
_Res (_Tp::*) (_Args...) const noexcept(_Nx)
|
|
>
|
|
{ using type = _Res(_Args...); };
|
|
|
|
template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
|
|
struct __function_guide_helper<
|
|
_Res (_Tp::*) (_Args...) const & noexcept(_Nx)
|
|
>
|
|
{ using type = _Res(_Args...); };
|
|
|
|
template<typename _Res, typename... _ArgTypes>
|
|
function(_Res(*)(_ArgTypes...)) -> function<_Res(_ArgTypes...)>;
|
|
|
|
template<typename _Functor, typename _Signature = typename
|
|
__function_guide_helper<decltype(&_Functor::operator())>::type>
|
|
function(_Functor) -> function<_Signature>;
|
|
#endif
|
|
|
|
// [20.7.15.2.6] null pointer comparisons
|
|
|
|
/**
|
|
* @brief Compares a polymorphic function object wrapper against 0
|
|
* (the NULL pointer).
|
|
* @returns @c true if the wrapper has no target, @c false otherwise
|
|
*
|
|
* This function will not throw an %exception.
|
|
*/
|
|
template<typename _Res, typename... _Args>
|
|
inline bool
|
|
operator==(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
|
|
{ return !static_cast<bool>(__f); }
|
|
|
|
#if __cpp_impl_three_way_comparison < 201907L
|
|
/// @overload
|
|
template<typename _Res, typename... _Args>
|
|
inline bool
|
|
operator==(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
|
|
{ return !static_cast<bool>(__f); }
|
|
|
|
/**
|
|
* @brief Compares a polymorphic function object wrapper against 0
|
|
* (the NULL pointer).
|
|
* @returns @c false if the wrapper has no target, @c true otherwise
|
|
*
|
|
* This function will not throw an %exception.
|
|
*/
|
|
template<typename _Res, typename... _Args>
|
|
inline bool
|
|
operator!=(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
|
|
{ return static_cast<bool>(__f); }
|
|
|
|
/// @overload
|
|
template<typename _Res, typename... _Args>
|
|
inline bool
|
|
operator!=(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
|
|
{ return static_cast<bool>(__f); }
|
|
#endif
|
|
|
|
// [20.7.15.2.7] specialized algorithms
|
|
|
|
/**
|
|
* @brief Swap the targets of two polymorphic function object wrappers.
|
|
*
|
|
* This function will not throw an %exception.
|
|
*/
|
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS
|
|
// 2062. Effect contradictions w/o no-throw guarantee of std::function swaps
|
|
template<typename _Res, typename... _Args>
|
|
inline void
|
|
swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y) noexcept
|
|
{ __x.swap(__y); }
|
|
|
|
#if __cplusplus >= 201703L
|
|
namespace __detail::__variant
|
|
{
|
|
template<typename> struct _Never_valueless_alt; // see <variant>
|
|
|
|
// Provide the strong exception-safety guarantee when emplacing a
|
|
// function into a variant.
|
|
template<typename _Signature>
|
|
struct _Never_valueless_alt<std::function<_Signature>>
|
|
: std::true_type
|
|
{ };
|
|
} // namespace __detail::__variant
|
|
#endif // C++17
|
|
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace std
|
|
|
|
#endif // C++11
|
|
#endif // _GLIBCXX_STD_FUNCTION_H
|