1 // Functor implementations -*- C++ -*-
2
3 // Copyright (C) 2001-2013 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24
25 /*
26 *
27 * Copyright (c) 1994
28 * Hewlett-Packard Company
29 *
30 * Permission to use, copy, modify, distribute and sell this software
31 * and its documentation for any purpose is hereby granted without fee,
32 * provided that the above copyright notice appear in all copies and
33 * that both that copyright notice and this permission notice appear
34 * in supporting documentation. Hewlett-Packard Company makes no
35 * representations about the suitability of this software for any
36 * purpose. It is provided "as is" without express or implied warranty.
37 *
38 *
39 * Copyright (c) 1996-1998
40 * Silicon Graphics Computer Systems, Inc.
41 *
42 * Permission to use, copy, modify, distribute and sell this software
43 * and its documentation for any purpose is hereby granted without fee,
44 * provided that the above copyright notice appear in all copies and
45 * that both that copyright notice and this permission notice appear
46 * in supporting documentation. Silicon Graphics makes no
47 * representations about the suitability of this software for any
48 * purpose. It is provided "as is" without express or implied warranty.
49 */
50
51 /** @file bits/stl_function.h
52 * This is an internal header file, included by other library headers.
53 * Do not attempt to use it directly. @headername{functional}
54 */
55
56 #ifndef _STL_FUNCTION_H
57 #define _STL_FUNCTION_H 1
58
59 namespace std _GLIBCXX_VISIBILITY(default)
60 {
61 _GLIBCXX_BEGIN_NAMESPACE_VERSION
62
63 // 20.3.1 base classes
64 /** @defgroup functors Function Objects
65 * @ingroup utilities
66 *
67 * Function objects, or @e functors, are objects with an @c operator()
68 * defined and accessible. They can be passed as arguments to algorithm
69 * templates and used in place of a function pointer. Not only is the
70 * resulting expressiveness of the library increased, but the generated
71 * code can be more efficient than what you might write by hand. When we
72 * refer to @a functors, then, generally we include function pointers in
73 * the description as well.
74 *
75 * Often, functors are only created as temporaries passed to algorithm
76 * calls, rather than being created as named variables.
77 *
78 * Two examples taken from the standard itself follow. To perform a
79 * by-element addition of two vectors @c a and @c b containing @c double,
80 * and put the result in @c a, use
81 * \code
82 * transform (a.begin(), a.end(), b.begin(), a.begin(), plus<double>());
83 * \endcode
84 * To negate every element in @c a, use
85 * \code
86 * transform(a.begin(), a.end(), a.begin(), negate<double>());
87 * \endcode
88 * The addition and negation functions will be inlined directly.
89 *
90 * The standard functors are derived from structs named @c unary_function
91 * and @c binary_function. These two classes contain nothing but typedefs,
92 * to aid in generic (template) programming. If you write your own
93 * functors, you might consider doing the same.
94 *
95 * @{
96 */
97 /**
98 * This is one of the @link functors functor base classes@endlink.
99 */
100 template<typename _Arg, typename _Result>
101 struct unary_function
102 {
103 /// @c argument_type is the type of the argument
104 typedef _Arg argument_type;
105
106 /// @c result_type is the return type
107 typedef _Result result_type;
108 };
109
110 /**
111 * This is one of the @link functors functor base classes@endlink.
112 */
113 template<typename _Arg1, typename _Arg2, typename _Result>
114 struct binary_function
115 {
116 /// @c first_argument_type is the type of the first argument
117 typedef _Arg1 first_argument_type;
118
119 /// @c second_argument_type is the type of the second argument
120 typedef _Arg2 second_argument_type;
121
122 /// @c result_type is the return type
123 typedef _Result result_type;
124 };
125 /** @} */
126
127 // 20.3.2 arithmetic
128 /** @defgroup arithmetic_functors Arithmetic Classes
129 * @ingroup functors
130 *
131 * Because basic math often needs to be done during an algorithm,
132 * the library provides functors for those operations. See the
133 * documentation for @link functors the base classes@endlink
134 * for examples of their use.
135 *
136 * @{
137 */
138 /// One of the @link arithmetic_functors math functors@endlink.
139 template<typename _Tp>
140 struct plus : public binary_function<_Tp, _Tp, _Tp>
141 {
142 _Tp
143 operator()(const _Tp& __x, const _Tp& __y) const
144 { return __x + __y; }
145 };
146
147 /// One of the @link arithmetic_functors math functors@endlink.
148 template<typename _Tp>
149 struct minus : public binary_function<_Tp, _Tp, _Tp>
150 {
151 _Tp
152 operator()(const _Tp& __x, const _Tp& __y) const
153 { return __x - __y; }
154 };
155
156 /// One of the @link arithmetic_functors math functors@endlink.
157 template<typename _Tp>
158 struct multiplies : public binary_function<_Tp, _Tp, _Tp>
159 {
160 _Tp
161 operator()(const _Tp& __x, const _Tp& __y) const
162 { return __x * __y; }
163 };
164
165 /// One of the @link arithmetic_functors math functors@endlink.
166 template<typename _Tp>
167 struct divides : public binary_function<_Tp, _Tp, _Tp>
168 {
169 _Tp
170 operator()(const _Tp& __x, const _Tp& __y) const
171 { return __x / __y; }
172 };
173
174 /// One of the @link arithmetic_functors math functors@endlink.
175 template<typename _Tp>
176 struct modulus : public binary_function<_Tp, _Tp, _Tp>
177 {
178 _Tp
179 operator()(const _Tp& __x, const _Tp& __y) const
180 { return __x % __y; }
181 };
182
183 /// One of the @link arithmetic_functors math functors@endlink.
184 template<typename _Tp>
185 struct negate : public unary_function<_Tp, _Tp>
186 {
187 _Tp
188 operator()(const _Tp& __x) const
189 { return -__x; }
190 };
191 /** @} */
192
193 // 20.3.3 comparisons
194 /** @defgroup comparison_functors Comparison Classes
195 * @ingroup functors
196 *
197 * The library provides six wrapper functors for all the basic comparisons
198 * in C++, like @c <.
199 *
200 * @{
201 */
202 /// One of the @link comparison_functors comparison functors@endlink.
203 template<typename _Tp>
204 struct equal_to : public binary_function<_Tp, _Tp, bool>
205 {
206 bool
207 operator()(const _Tp& __x, const _Tp& __y) const
208 { return __x == __y; }
209 };
210
211 /// One of the @link comparison_functors comparison functors@endlink.
212 template<typename _Tp>
213 struct not_equal_to : public binary_function<_Tp, _Tp, bool>
214 {
215 bool
216 operator()(const _Tp& __x, const _Tp& __y) const
217 { return __x != __y; }
218 };
219
220 /// One of the @link comparison_functors comparison functors@endlink.
221 template<typename _Tp>
222 struct greater : public binary_function<_Tp, _Tp, bool>
223 {
224 bool
225 operator()(const _Tp& __x, const _Tp& __y) const
226 { return __x > __y; }
227 };
228
229 /// One of the @link comparison_functors comparison functors@endlink.
230 template<typename _Tp>
231 struct less : public binary_function<_Tp, _Tp, bool>
232 {
233 bool
234 operator()(const _Tp& __x, const _Tp& __y) const
235 { return __x < __y; }
236 };
237
238 /// One of the @link comparison_functors comparison functors@endlink.
239 template<typename _Tp>
240 struct greater_equal : public binary_function<_Tp, _Tp, bool>
241 {
242 bool
243 operator()(const _Tp& __x, const _Tp& __y) const
244 { return __x >= __y; }
245 };
246
247 /// One of the @link comparison_functors comparison functors@endlink.
248 template<typename _Tp>
249 struct less_equal : public binary_function<_Tp, _Tp, bool>
250 {
251 bool
252 operator()(const _Tp& __x, const _Tp& __y) const
253 { return __x <= __y; }
254 };
255 /** @} */
256
257 // 20.3.4 logical operations
258 /** @defgroup logical_functors Boolean Operations Classes
259 * @ingroup functors
260 *
261 * Here are wrapper functors for Boolean operations: @c &&, @c ||,
262 * and @c !.
263 *
264 * @{
265 */
266 /// One of the @link logical_functors Boolean operations functors@endlink.
267 template<typename _Tp>
268 struct logical_and : public binary_function<_Tp, _Tp, bool>
269 {
270 bool
271 operator()(const _Tp& __x, const _Tp& __y) const
272 { return __x && __y; }
273 };
274
275 /// One of the @link logical_functors Boolean operations functors@endlink.
276 template<typename _Tp>
277 struct logical_or : public binary_function<_Tp, _Tp, bool>
278 {
279 bool
280 operator()(const _Tp& __x, const _Tp& __y) const
281 { return __x || __y; }
282 };
283
284 /// One of the @link logical_functors Boolean operations functors@endlink.
285 template<typename _Tp>
286 struct logical_not : public unary_function<_Tp, bool>
287 {
288 bool
289 operator()(const _Tp& __x) const
290 { return !__x; }
291 };
292 /** @} */
293
294 // _GLIBCXX_RESOLVE_LIB_DEFECTS
295 // DR 660. Missing Bitwise Operations.
296 template<typename _Tp>
297 struct bit_and : public binary_function<_Tp, _Tp, _Tp>
298 {
299 _Tp
300 operator()(const _Tp& __x, const _Tp& __y) const
301 { return __x & __y; }
302 };
303
304 template<typename _Tp>
305 struct bit_or : public binary_function<_Tp, _Tp, _Tp>
306 {
307 _Tp
308 operator()(const _Tp& __x, const _Tp& __y) const
309 { return __x | __y; }
310 };
311
312 template<typename _Tp>
313 struct bit_xor : public binary_function<_Tp, _Tp, _Tp>
314 {
315 _Tp
316 operator()(const _Tp& __x, const _Tp& __y) const
317 { return __x ^ __y; }
318 };
319
320 // 20.3.5 negators
321 /** @defgroup negators Negators
322 * @ingroup functors
323 *
324 * The functions @c not1 and @c not2 each take a predicate functor
325 * and return an instance of @c unary_negate or
326 * @c binary_negate, respectively. These classes are functors whose
327 * @c operator() performs the stored predicate function and then returns
328 * the negation of the result.
329 *
330 * For example, given a vector of integers and a trivial predicate,
331 * \code
332 * struct IntGreaterThanThree
333 * : public std::unary_function<int, bool>
334 * {
335 * bool operator() (int x) { return x > 3; }
336 * };
337 *
338 * std::find_if (v.begin(), v.end(), not1(IntGreaterThanThree()));
339 * \endcode
340 * The call to @c find_if will locate the first index (i) of @c v for which
341 * <code>!(v[i] > 3)</code> is true.
342 *
343 * The not1/unary_negate combination works on predicates taking a single
344 * argument. The not2/binary_negate combination works on predicates which
345 * take two arguments.
346 *
347 * @{
348 */
349 /// One of the @link negators negation functors@endlink.
350 template<typename _Predicate>
351 class unary_negate
352 : public unary_function<typename _Predicate::argument_type, bool>
353 {
354 protected:
355 _Predicate _M_pred;
356
357 public:
358 explicit
359 unary_negate(const _Predicate& __x) : _M_pred(__x) { }
360
361 bool
362 operator()(const typename _Predicate::argument_type& __x) const
363 { return !_M_pred(__x); }
364 };
365
366 /// One of the @link negators negation functors@endlink.
367 template<typename _Predicate>
368 inline unary_negate<_Predicate>
369 not1(const _Predicate& __pred)
370 { return unary_negate<_Predicate>(__pred); }
371
372 /// One of the @link negators negation functors@endlink.
373 template<typename _Predicate>
374 class binary_negate
375 : public binary_function<typename _Predicate::first_argument_type,
376 typename _Predicate::second_argument_type, bool>
377 {
378 protected:
379 _Predicate _M_pred;
380
381 public:
382 explicit
383 binary_negate(const _Predicate& __x) : _M_pred(__x) { }
384
385 bool
386 operator()(const typename _Predicate::first_argument_type& __x,
387 const typename _Predicate::second_argument_type& __y) const
388 { return !_M_pred(__x, __y); }
389 };
390
391 /// One of the @link negators negation functors@endlink.
392 template<typename _Predicate>
393 inline binary_negate<_Predicate>
394 not2(const _Predicate& __pred)
395 { return binary_negate<_Predicate>(__pred); }
396 /** @} */
397
398 // 20.3.7 adaptors pointers functions
399 /** @defgroup pointer_adaptors Adaptors for pointers to functions
400 * @ingroup functors
401 *
402 * The advantage of function objects over pointers to functions is that
403 * the objects in the standard library declare nested typedefs describing
404 * their argument and result types with uniform names (e.g., @c result_type
405 * from the base classes @c unary_function and @c binary_function).
406 * Sometimes those typedefs are required, not just optional.
407 *
408 * Adaptors are provided to turn pointers to unary (single-argument) and
409 * binary (double-argument) functions into function objects. The
410 * long-winded functor @c pointer_to_unary_function is constructed with a
411 * function pointer @c f, and its @c operator() called with argument @c x
412 * returns @c f(x). The functor @c pointer_to_binary_function does the same
413 * thing, but with a double-argument @c f and @c operator().
414 *
415 * The function @c ptr_fun takes a pointer-to-function @c f and constructs
416 * an instance of the appropriate functor.
417 *
418 * @{
419 */
420 /// One of the @link pointer_adaptors adaptors for function pointers@endlink.
421 template<typename _Arg, typename _Result>
422 class pointer_to_unary_function : public unary_function<_Arg, _Result>
423 {
424 protected:
425 _Result (*_M_ptr)(_Arg);
426
427 public:
428 pointer_to_unary_function() { }
429
430 explicit
431 pointer_to_unary_function(_Result (*__x)(_Arg))
432 : _M_ptr(__x) { }
433
434 _Result
435 operator()(_Arg __x) const
436 { return _M_ptr(__x); }
437 };
438
439 /// One of the @link pointer_adaptors adaptors for function pointers@endlink.
440 template<typename _Arg, typename _Result>
441 inline pointer_to_unary_function<_Arg, _Result>
442 ptr_fun(_Result (*__x)(_Arg))
443 { return pointer_to_unary_function<_Arg, _Result>(__x); }
444
445 /// One of the @link pointer_adaptors adaptors for function pointers@endlink.
446 template<typename _Arg1, typename _Arg2, typename _Result>
447 class pointer_to_binary_function
448 : public binary_function<_Arg1, _Arg2, _Result>
449 {
450 protected:
451 _Result (*_M_ptr)(_Arg1, _Arg2);
452
453 public:
454 pointer_to_binary_function() { }
455
456 explicit
457 pointer_to_binary_function(_Result (*__x)(_Arg1, _Arg2))
458 : _M_ptr(__x) { }
459
460 _Result
461 operator()(_Arg1 __x, _Arg2 __y) const
462 { return _M_ptr(__x, __y); }
463 };
464
465 /// One of the @link pointer_adaptors adaptors for function pointers@endlink.
466 template<typename _Arg1, typename _Arg2, typename _Result>
467 inline pointer_to_binary_function<_Arg1, _Arg2, _Result>
468 ptr_fun(_Result (*__x)(_Arg1, _Arg2))
469 { return pointer_to_binary_function<_Arg1, _Arg2, _Result>(__x); }
470 /** @} */
471
472 template<typename _Tp>
473 struct _Identity
474 : public unary_function<_Tp,_Tp>
475 {
476 _Tp&
477 operator()(_Tp& __x) const
478 { return __x; }
479
480 const _Tp&
481 operator()(const _Tp& __x) const
482 { return __x; }
483 };
484
485 template<typename _Pair>
486 struct _Select1st
487 : public unary_function<_Pair, typename _Pair::first_type>
488 {
489 typename _Pair::first_type&
490 operator()(_Pair& __x) const
491 { return __x.first; }
492
493 const typename _Pair::first_type&
494 operator()(const _Pair& __x) const
495 { return __x.first; }
496
497 #if __cplusplus >= 201103L
498 template<typename _Pair2>
499 typename _Pair2::first_type&
500 operator()(_Pair2& __x) const
501 { return __x.first; }
502
503 template<typename _Pair2>
504 const typename _Pair2::first_type&
505 operator()(const _Pair2& __x) const
506 { return __x.first; }
507 #endif
508 };
509
510 template<typename _Pair>
511 struct _Select2nd
512 : public unary_function<_Pair, typename _Pair::second_type>
513 {
514 typename _Pair::second_type&
515 operator()(_Pair& __x) const
516 { return __x.second; }
517
518 const typename _Pair::second_type&
519 operator()(const _Pair& __x) const
520 { return __x.second; }
521 };
522
523 // 20.3.8 adaptors pointers members
524 /** @defgroup memory_adaptors Adaptors for pointers to members
525 * @ingroup functors
526 *
527 * There are a total of 8 = 2^3 function objects in this family.
528 * (1) Member functions taking no arguments vs member functions taking
529 * one argument.
530 * (2) Call through pointer vs call through reference.
531 * (3) Const vs non-const member function.
532 *
533 * All of this complexity is in the function objects themselves. You can
534 * ignore it by using the helper function mem_fun and mem_fun_ref,
535 * which create whichever type of adaptor is appropriate.
536 *
537 * @{
538 */
539 /// One of the @link memory_adaptors adaptors for member
540 /// pointers@endlink.
541 template<typename _Ret, typename _Tp>
542 class mem_fun_t : public unary_function<_Tp*, _Ret>
543 {
544 public:
545 explicit
546 mem_fun_t(_Ret (_Tp::*__pf)())
547 : _M_f(__pf) { }
548
549 _Ret
550 operator()(_Tp* __p) const
551 { return (__p->*_M_f)(); }
552
553 private:
554 _Ret (_Tp::*_M_f)();
555 };
556
557 /// One of the @link memory_adaptors adaptors for member
558 /// pointers@endlink.
559 template<typename _Ret, typename _Tp>
560 class const_mem_fun_t : public unary_function<const _Tp*, _Ret>
561 {
562 public:
563 explicit
564 const_mem_fun_t(_Ret (_Tp::*__pf)() const)
565 : _M_f(__pf) { }
566
567 _Ret
568 operator()(const _Tp* __p) const
569 { return (__p->*_M_f)(); }
570
571 private:
572 _Ret (_Tp::*_M_f)() const;
573 };
574
575 /// One of the @link memory_adaptors adaptors for member
576 /// pointers@endlink.
577 template<typename _Ret, typename _Tp>
578 class mem_fun_ref_t : public unary_function<_Tp, _Ret>
579 {
580 public:
581 explicit
582 mem_fun_ref_t(_Ret (_Tp::*__pf)())
583 : _M_f(__pf) { }
584
585 _Ret
586 operator()(_Tp& __r) const
587 { return (__r.*_M_f)(); }
588
589 private:
590 _Ret (_Tp::*_M_f)();
591 };
592
593 /// One of the @link memory_adaptors adaptors for member
594 /// pointers@endlink.
595 template<typename _Ret, typename _Tp>
596 class const_mem_fun_ref_t : public unary_function<_Tp, _Ret>
597 {
598 public:
599 explicit
600 const_mem_fun_ref_t(_Ret (_Tp::*__pf)() const)
601 : _M_f(__pf) { }
602
603 _Ret
604 operator()(const _Tp& __r) const
605 { return (__r.*_M_f)(); }
606
607 private:
608 _Ret (_Tp::*_M_f)() const;
609 };
610
611 /// One of the @link memory_adaptors adaptors for member
612 /// pointers@endlink.
613 template<typename _Ret, typename _Tp, typename _Arg>
614 class mem_fun1_t : public binary_function<_Tp*, _Arg, _Ret>
615 {
616 public:
617 explicit
618 mem_fun1_t(_Ret (_Tp::*__pf)(_Arg))
619 : _M_f(__pf) { }
620
621 _Ret
622 operator()(_Tp* __p, _Arg __x) const
623 { return (__p->*_M_f)(__x); }
624
625 private:
626 _Ret (_Tp::*_M_f)(_Arg);
627 };
628
629 /// One of the @link memory_adaptors adaptors for member
630 /// pointers@endlink.
631 template<typename _Ret, typename _Tp, typename _Arg>
632 class const_mem_fun1_t : public binary_function<const _Tp*, _Arg, _Ret>
633 {
634 public:
635 explicit
636 const_mem_fun1_t(_Ret (_Tp::*__pf)(_Arg) const)
637 : _M_f(__pf) { }
638
639 _Ret
640 operator()(const _Tp* __p, _Arg __x) const
641 { return (__p->*_M_f)(__x); }
642
643 private:
644 _Ret (_Tp::*_M_f)(_Arg) const;
645 };
646
647 /// One of the @link memory_adaptors adaptors for member
648 /// pointers@endlink.
649 template<typename _Ret, typename _Tp, typename _Arg>
650 class mem_fun1_ref_t : public binary_function<_Tp, _Arg, _Ret>
651 {
652 public:
653 explicit
654 mem_fun1_ref_t(_Ret (_Tp::*__pf)(_Arg))
655 : _M_f(__pf) { }
656
657 _Ret
658 operator()(_Tp& __r, _Arg __x) const
659 { return (__r.*_M_f)(__x); }
660
661 private:
662 _Ret (_Tp::*_M_f)(_Arg);
663 };
664
665 /// One of the @link memory_adaptors adaptors for member
666 /// pointers@endlink.
667 template<typename _Ret, typename _Tp, typename _Arg>
668 class const_mem_fun1_ref_t : public binary_function<_Tp, _Arg, _Ret>
669 {
670 public:
671 explicit
672 const_mem_fun1_ref_t(_Ret (_Tp::*__pf)(_Arg) const)
673 : _M_f(__pf) { }
674
675 _Ret
676 operator()(const _Tp& __r, _Arg __x) const
677 { return (__r.*_M_f)(__x); }
678
679 private:
680 _Ret (_Tp::*_M_f)(_Arg) const;
681 };
682
683 // Mem_fun adaptor helper functions. There are only two:
684 // mem_fun and mem_fun_ref.
685 template<typename _Ret, typename _Tp>
686 inline mem_fun_t<_Ret, _Tp>
687 mem_fun(_Ret (_Tp::*__f)())
688 { return mem_fun_t<_Ret, _Tp>(__f); }
689
690 template<typename _Ret, typename _Tp>
691 inline const_mem_fun_t<_Ret, _Tp>
692 mem_fun(_Ret (_Tp::*__f)() const)
693 { return const_mem_fun_t<_Ret, _Tp>(__f); }
694
695 template<typename _Ret, typename _Tp>
696 inline mem_fun_ref_t<_Ret, _Tp>
697 mem_fun_ref(_Ret (_Tp::*__f)())
698 { return mem_fun_ref_t<_Ret, _Tp>(__f); }
699
700 template<typename _Ret, typename _Tp>
701 inline const_mem_fun_ref_t<_Ret, _Tp>
702 mem_fun_ref(_Ret (_Tp::*__f)() const)
703 { return const_mem_fun_ref_t<_Ret, _Tp>(__f); }
704
705 template<typename _Ret, typename _Tp, typename _Arg>
706 inline mem_fun1_t<_Ret, _Tp, _Arg>
707 mem_fun(_Ret (_Tp::*__f)(_Arg))
708 { return mem_fun1_t<_Ret, _Tp, _Arg>(__f); }
709
710 template<typename _Ret, typename _Tp, typename _Arg>
711 inline const_mem_fun1_t<_Ret, _Tp, _Arg>
712 mem_fun(_Ret (_Tp::*__f)(_Arg) const)
713 { return const_mem_fun1_t<_Ret, _Tp, _Arg>(__f); }
714
715 template<typename _Ret, typename _Tp, typename _Arg>
716 inline mem_fun1_ref_t<_Ret, _Tp, _Arg>
717 mem_fun_ref(_Ret (_Tp::*__f)(_Arg))
718 { return mem_fun1_ref_t<_Ret, _Tp, _Arg>(__f); }
719
720 template<typename _Ret, typename _Tp, typename _Arg>
721 inline const_mem_fun1_ref_t<_Ret, _Tp, _Arg>
722 mem_fun_ref(_Ret (_Tp::*__f)(_Arg) const)
723 { return const_mem_fun1_ref_t<_Ret, _Tp, _Arg>(__f); }
724
725 /** @} */
726
727 _GLIBCXX_END_NAMESPACE_VERSION
728 } // namespace
729
730 #if (__cplusplus < 201103L) || _GLIBCXX_USE_DEPRECATED
731 # include <backward/binders.h>
732 #endif
733
734 #endif /* _STL_FUNCTION_H */
735