1// -*- C++ -*- header.
2
3// Copyright (C) 2008-2013 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/** @file bits/atomic_base.h
26 *  This is an internal header file, included by other library headers.
27 *  Do not attempt to use it directly. @headername{atomic}
28 */
29
30#ifndef _GLIBCXX_ATOMIC_BASE_H
31#define _GLIBCXX_ATOMIC_BASE_H 1
32
33#pragma GCC system_header
34
35#include <bits/c++config.h>
36#include <stdbool.h>
37#include <stdint.h>
38#include <bits/atomic_lockfree_defines.h>
39
40namespace std _GLIBCXX_VISIBILITY(default)
41{
42_GLIBCXX_BEGIN_NAMESPACE_VERSION
43
44  /**
45   * @defgroup atomics Atomics
46   *
47   * Components for performing atomic operations.
48   * @{
49   */
50
51  /// Enumeration for memory_order
52  typedef enum memory_order
53    {
54      memory_order_relaxed,
55      memory_order_consume,
56      memory_order_acquire,
57      memory_order_release,
58      memory_order_acq_rel,
59      memory_order_seq_cst
60    } memory_order;
61
62  enum __memory_order_modifier
63    {
64      __memory_order_mask          = 0x0ffff,
65      __memory_order_modifier_mask = 0xffff0000,
66      __memory_order_hle_acquire   = 0x10000,
67      __memory_order_hle_release   = 0x20000
68    };
69
70  constexpr memory_order
71  operator|(memory_order __m, __memory_order_modifier __mod)
72  {
73    return memory_order(__m | int(__mod));
74  }
75
76  constexpr memory_order
77  operator&(memory_order __m, __memory_order_modifier __mod)
78  {
79    return memory_order(__m & int(__mod));
80  }
81
82  // Drop release ordering as per [atomics.types.operations.req]/21
83  constexpr memory_order
84  __cmpexch_failure_order2(memory_order __m) noexcept
85  {
86    return __m == memory_order_acq_rel ? memory_order_acquire
87      : __m == memory_order_release ? memory_order_relaxed : __m;
88  }
89
90  constexpr memory_order
91  __cmpexch_failure_order(memory_order __m) noexcept
92  {
93    return memory_order(__cmpexch_failure_order2(__m & __memory_order_mask)
94      | (__m & __memory_order_modifier_mask));
95  }
96
97  inline void
98  atomic_thread_fence(memory_order __m) noexcept
99  { __atomic_thread_fence(__m); }
100
101  inline void
102  atomic_signal_fence(memory_order __m) noexcept
103  { __atomic_signal_fence(__m); }
104
105  /// kill_dependency
106  template<typename _Tp>
107    inline _Tp
108    kill_dependency(_Tp __y) noexcept
109    {
110      _Tp __ret(__y);
111      return __ret;
112    }
113
114
115  // Base types for atomics.
116  template<typename _IntTp>
117    struct __atomic_base;
118
119  /// atomic_char
120  typedef __atomic_base<char>  	       		atomic_char;
121
122  /// atomic_schar
123  typedef __atomic_base<signed char>	     	atomic_schar;
124
125  /// atomic_uchar
126  typedef __atomic_base<unsigned char>		atomic_uchar;
127
128  /// atomic_short
129  typedef __atomic_base<short>			atomic_short;
130
131  /// atomic_ushort
132  typedef __atomic_base<unsigned short>	 	atomic_ushort;
133
134  /// atomic_int
135  typedef __atomic_base<int>  	       		atomic_int;
136
137  /// atomic_uint
138  typedef __atomic_base<unsigned int>	     	atomic_uint;
139
140  /// atomic_long
141  typedef __atomic_base<long>  	       		atomic_long;
142
143  /// atomic_ulong
144  typedef __atomic_base<unsigned long>		atomic_ulong;
145
146  /// atomic_llong
147  typedef __atomic_base<long long>  		atomic_llong;
148
149  /// atomic_ullong
150  typedef __atomic_base<unsigned long long> 	atomic_ullong;
151
152  /// atomic_wchar_t
153  typedef __atomic_base<wchar_t>  		atomic_wchar_t;
154
155  /// atomic_char16_t
156  typedef __atomic_base<char16_t>  		atomic_char16_t;
157
158  /// atomic_char32_t
159  typedef __atomic_base<char32_t>  		atomic_char32_t;
160
161  /// atomic_char32_t
162  typedef __atomic_base<char32_t>  		atomic_char32_t;
163
164
165  /// atomic_int_least8_t
166  typedef __atomic_base<int_least8_t>  		atomic_int_least8_t;
167
168  /// atomic_uint_least8_t
169  typedef __atomic_base<uint_least8_t>	       	atomic_uint_least8_t;
170
171  /// atomic_int_least16_t
172  typedef __atomic_base<int_least16_t>	       	atomic_int_least16_t;
173
174  /// atomic_uint_least16_t
175  typedef __atomic_base<uint_least16_t>	       	atomic_uint_least16_t;
176
177  /// atomic_int_least32_t
178  typedef __atomic_base<int_least32_t>	       	atomic_int_least32_t;
179
180  /// atomic_uint_least32_t
181  typedef __atomic_base<uint_least32_t>	       	atomic_uint_least32_t;
182
183  /// atomic_int_least64_t
184  typedef __atomic_base<int_least64_t>	       	atomic_int_least64_t;
185
186  /// atomic_uint_least64_t
187  typedef __atomic_base<uint_least64_t>	       	atomic_uint_least64_t;
188
189
190  /// atomic_int_fast8_t
191  typedef __atomic_base<int_fast8_t>  		atomic_int_fast8_t;
192
193  /// atomic_uint_fast8_t
194  typedef __atomic_base<uint_fast8_t>	      	atomic_uint_fast8_t;
195
196  /// atomic_int_fast16_t
197  typedef __atomic_base<int_fast16_t>	      	atomic_int_fast16_t;
198
199  /// atomic_uint_fast16_t
200  typedef __atomic_base<uint_fast16_t>	      	atomic_uint_fast16_t;
201
202  /// atomic_int_fast32_t
203  typedef __atomic_base<int_fast32_t>	      	atomic_int_fast32_t;
204
205  /// atomic_uint_fast32_t
206  typedef __atomic_base<uint_fast32_t>	      	atomic_uint_fast32_t;
207
208  /// atomic_int_fast64_t
209  typedef __atomic_base<int_fast64_t>	      	atomic_int_fast64_t;
210
211  /// atomic_uint_fast64_t
212  typedef __atomic_base<uint_fast64_t>	      	atomic_uint_fast64_t;
213
214
215  /// atomic_intptr_t
216  typedef __atomic_base<intptr_t>  	       	atomic_intptr_t;
217
218  /// atomic_uintptr_t
219  typedef __atomic_base<uintptr_t>  	       	atomic_uintptr_t;
220
221  /// atomic_size_t
222  typedef __atomic_base<size_t>	 	       	atomic_size_t;
223
224  /// atomic_intmax_t
225  typedef __atomic_base<intmax_t>  	       	atomic_intmax_t;
226
227  /// atomic_uintmax_t
228  typedef __atomic_base<uintmax_t>  	       	atomic_uintmax_t;
229
230  /// atomic_ptrdiff_t
231  typedef __atomic_base<ptrdiff_t>  	       	atomic_ptrdiff_t;
232
233
234#define ATOMIC_VAR_INIT(_VI) { _VI }
235
236  template<typename _Tp>
237    struct atomic;
238
239  template<typename _Tp>
240    struct atomic<_Tp*>;
241
242    /* The target's "set" value for test-and-set may not be exactly 1.  */
243#if __GCC_ATOMIC_TEST_AND_SET_TRUEVAL == 1
244    typedef bool __atomic_flag_data_type;
245#else
246    typedef unsigned char __atomic_flag_data_type;
247#endif
248
249  /**
250   *  @brief Base type for atomic_flag.
251   *
252   *  Base type is POD with data, allowing atomic_flag to derive from
253   *  it and meet the standard layout type requirement. In addition to
254   *  compatibilty with a C interface, this allows different
255   *  implementations of atomic_flag to use the same atomic operation
256   *  functions, via a standard conversion to the __atomic_flag_base
257   *  argument.
258  */
259  _GLIBCXX_BEGIN_EXTERN_C
260
261  struct __atomic_flag_base
262  {
263    __atomic_flag_data_type _M_i;
264  };
265
266  _GLIBCXX_END_EXTERN_C
267
268#define ATOMIC_FLAG_INIT { 0 }
269
270  /// atomic_flag
271  struct atomic_flag : public __atomic_flag_base
272  {
273    atomic_flag() noexcept = default;
274    ~atomic_flag() noexcept = default;
275    atomic_flag(const atomic_flag&) = delete;
276    atomic_flag& operator=(const atomic_flag&) = delete;
277    atomic_flag& operator=(const atomic_flag&) volatile = delete;
278
279    // Conversion to ATOMIC_FLAG_INIT.
280    constexpr atomic_flag(bool __i) noexcept
281      : __atomic_flag_base{ _S_init(__i) }
282    { }
283
284    bool
285    test_and_set(memory_order __m = memory_order_seq_cst) noexcept
286    {
287      return __atomic_test_and_set (&_M_i, __m);
288    }
289
290    bool
291    test_and_set(memory_order __m = memory_order_seq_cst) volatile noexcept
292    {
293      return __atomic_test_and_set (&_M_i, __m);
294    }
295
296    void
297    clear(memory_order __m = memory_order_seq_cst) noexcept
298    {
299      memory_order __b = __m & __memory_order_mask;
300      __glibcxx_assert(__b != memory_order_consume);
301      __glibcxx_assert(__b != memory_order_acquire);
302      __glibcxx_assert(__b != memory_order_acq_rel);
303
304      __atomic_clear (&_M_i, __m);
305    }
306
307    void
308    clear(memory_order __m = memory_order_seq_cst) volatile noexcept
309    {
310      memory_order __b = __m & __memory_order_mask;
311      __glibcxx_assert(__b != memory_order_consume);
312      __glibcxx_assert(__b != memory_order_acquire);
313      __glibcxx_assert(__b != memory_order_acq_rel);
314
315      __atomic_clear (&_M_i, __m);
316    }
317
318  private:
319    static constexpr __atomic_flag_data_type
320    _S_init(bool __i)
321    { return __i ? __GCC_ATOMIC_TEST_AND_SET_TRUEVAL : 0; }
322  };
323
324
325  /// Base class for atomic integrals.
326  //
327  // For each of the integral types, define atomic_[integral type] struct
328  //
329  // atomic_bool     bool
330  // atomic_char     char
331  // atomic_schar    signed char
332  // atomic_uchar    unsigned char
333  // atomic_short    short
334  // atomic_ushort   unsigned short
335  // atomic_int      int
336  // atomic_uint     unsigned int
337  // atomic_long     long
338  // atomic_ulong    unsigned long
339  // atomic_llong    long long
340  // atomic_ullong   unsigned long long
341  // atomic_char16_t char16_t
342  // atomic_char32_t char32_t
343  // atomic_wchar_t  wchar_t
344  //
345  // NB: Assuming _ITp is an integral scalar type that is 1, 2, 4, or
346  // 8 bytes, since that is what GCC built-in functions for atomic
347  // memory access expect.
348  template<typename _ITp>
349    struct __atomic_base
350    {
351    private:
352      typedef _ITp 	__int_type;
353
354      __int_type 	_M_i;
355
356    public:
357      __atomic_base() noexcept = default;
358      ~__atomic_base() noexcept = default;
359      __atomic_base(const __atomic_base&) = delete;
360      __atomic_base& operator=(const __atomic_base&) = delete;
361      __atomic_base& operator=(const __atomic_base&) volatile = delete;
362
363      // Requires __int_type convertible to _M_i.
364      constexpr __atomic_base(__int_type __i) noexcept : _M_i (__i) { }
365
366      operator __int_type() const noexcept
367      { return load(); }
368
369      operator __int_type() const volatile noexcept
370      { return load(); }
371
372      __int_type
373      operator=(__int_type __i) noexcept
374      {
375	store(__i);
376	return __i;
377      }
378
379      __int_type
380      operator=(__int_type __i) volatile noexcept
381      {
382	store(__i);
383	return __i;
384      }
385
386      __int_type
387      operator++(int) noexcept
388      { return fetch_add(1); }
389
390      __int_type
391      operator++(int) volatile noexcept
392      { return fetch_add(1); }
393
394      __int_type
395      operator--(int) noexcept
396      { return fetch_sub(1); }
397
398      __int_type
399      operator--(int) volatile noexcept
400      { return fetch_sub(1); }
401
402      __int_type
403      operator++() noexcept
404      { return __atomic_add_fetch(&_M_i, 1, memory_order_seq_cst); }
405
406      __int_type
407      operator++() volatile noexcept
408      { return __atomic_add_fetch(&_M_i, 1, memory_order_seq_cst); }
409
410      __int_type
411      operator--() noexcept
412      { return __atomic_sub_fetch(&_M_i, 1, memory_order_seq_cst); }
413
414      __int_type
415      operator--() volatile noexcept
416      { return __atomic_sub_fetch(&_M_i, 1, memory_order_seq_cst); }
417
418      __int_type
419      operator+=(__int_type __i) noexcept
420      { return __atomic_add_fetch(&_M_i, __i, memory_order_seq_cst); }
421
422      __int_type
423      operator+=(__int_type __i) volatile noexcept
424      { return __atomic_add_fetch(&_M_i, __i, memory_order_seq_cst); }
425
426      __int_type
427      operator-=(__int_type __i) noexcept
428      { return __atomic_sub_fetch(&_M_i, __i, memory_order_seq_cst); }
429
430      __int_type
431      operator-=(__int_type __i) volatile noexcept
432      { return __atomic_sub_fetch(&_M_i, __i, memory_order_seq_cst); }
433
434      __int_type
435      operator&=(__int_type __i) noexcept
436      { return __atomic_and_fetch(&_M_i, __i, memory_order_seq_cst); }
437
438      __int_type
439      operator&=(__int_type __i) volatile noexcept
440      { return __atomic_and_fetch(&_M_i, __i, memory_order_seq_cst); }
441
442      __int_type
443      operator|=(__int_type __i) noexcept
444      { return __atomic_or_fetch(&_M_i, __i, memory_order_seq_cst); }
445
446      __int_type
447      operator|=(__int_type __i) volatile noexcept
448      { return __atomic_or_fetch(&_M_i, __i, memory_order_seq_cst); }
449
450      __int_type
451      operator^=(__int_type __i) noexcept
452      { return __atomic_xor_fetch(&_M_i, __i, memory_order_seq_cst); }
453
454      __int_type
455      operator^=(__int_type __i) volatile noexcept
456      { return __atomic_xor_fetch(&_M_i, __i, memory_order_seq_cst); }
457
458      bool
459      is_lock_free() const noexcept
460      { return __atomic_is_lock_free(sizeof(_M_i), nullptr); }
461
462      bool
463      is_lock_free() const volatile noexcept
464      { return __atomic_is_lock_free(sizeof(_M_i), nullptr); }
465
466      void
467      store(__int_type __i, memory_order __m = memory_order_seq_cst) noexcept
468      {
469        memory_order __b = __m & __memory_order_mask;
470	__glibcxx_assert(__b != memory_order_acquire);
471	__glibcxx_assert(__b != memory_order_acq_rel);
472	__glibcxx_assert(__b != memory_order_consume);
473
474	__atomic_store_n(&_M_i, __i, __m);
475      }
476
477      void
478      store(__int_type __i,
479	    memory_order __m = memory_order_seq_cst) volatile noexcept
480      {
481        memory_order __b = __m & __memory_order_mask;
482	__glibcxx_assert(__b != memory_order_acquire);
483	__glibcxx_assert(__b != memory_order_acq_rel);
484	__glibcxx_assert(__b != memory_order_consume);
485
486	__atomic_store_n(&_M_i, __i, __m);
487      }
488
489      __int_type
490      load(memory_order __m = memory_order_seq_cst) const noexcept
491      {
492       memory_order __b = __m & __memory_order_mask;
493	__glibcxx_assert(__b != memory_order_release);
494	__glibcxx_assert(__b != memory_order_acq_rel);
495
496	return __atomic_load_n(&_M_i, __m);
497      }
498
499      __int_type
500      load(memory_order __m = memory_order_seq_cst) const volatile noexcept
501      {
502        memory_order __b = __m & __memory_order_mask;
503	__glibcxx_assert(__b != memory_order_release);
504	__glibcxx_assert(__b != memory_order_acq_rel);
505
506	return __atomic_load_n(&_M_i, __m);
507      }
508
509      __int_type
510      exchange(__int_type __i,
511	       memory_order __m = memory_order_seq_cst) noexcept
512      {
513	return __atomic_exchange_n(&_M_i, __i, __m);
514      }
515
516
517      __int_type
518      exchange(__int_type __i,
519	       memory_order __m = memory_order_seq_cst) volatile noexcept
520      {
521	return __atomic_exchange_n(&_M_i, __i, __m);
522      }
523
524      bool
525      compare_exchange_weak(__int_type& __i1, __int_type __i2,
526			    memory_order __m1, memory_order __m2) noexcept
527      {
528       memory_order __b2 = __m2 & __memory_order_mask;
529       memory_order __b1 = __m1 & __memory_order_mask;
530	__glibcxx_assert(__b2 != memory_order_release);
531	__glibcxx_assert(__b2 != memory_order_acq_rel);
532	__glibcxx_assert(__b2 <= __b1);
533
534	return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 1, __m1, __m2);
535      }
536
537      bool
538      compare_exchange_weak(__int_type& __i1, __int_type __i2,
539			    memory_order __m1,
540			    memory_order __m2) volatile noexcept
541      {
542       memory_order __b2 = __m2 & __memory_order_mask;
543       memory_order __b1 = __m1 & __memory_order_mask;
544	__glibcxx_assert(__b2 != memory_order_release);
545	__glibcxx_assert(__b2 != memory_order_acq_rel);
546	__glibcxx_assert(__b2 <= __b1);
547
548	return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 1, __m1, __m2);
549      }
550
551      bool
552      compare_exchange_weak(__int_type& __i1, __int_type __i2,
553			    memory_order __m = memory_order_seq_cst) noexcept
554      {
555	return compare_exchange_weak(__i1, __i2, __m,
556				     __cmpexch_failure_order(__m));
557      }
558
559      bool
560      compare_exchange_weak(__int_type& __i1, __int_type __i2,
561		   memory_order __m = memory_order_seq_cst) volatile noexcept
562      {
563	return compare_exchange_weak(__i1, __i2, __m,
564				     __cmpexch_failure_order(__m));
565      }
566
567      bool
568      compare_exchange_strong(__int_type& __i1, __int_type __i2,
569			      memory_order __m1, memory_order __m2) noexcept
570      {
571        memory_order __b2 = __m2 & __memory_order_mask;
572        memory_order __b1 = __m1 & __memory_order_mask;
573	__glibcxx_assert(__b2 != memory_order_release);
574	__glibcxx_assert(__b2 != memory_order_acq_rel);
575	__glibcxx_assert(__b2 <= __b1);
576
577	return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 0, __m1, __m2);
578      }
579
580      bool
581      compare_exchange_strong(__int_type& __i1, __int_type __i2,
582			      memory_order __m1,
583			      memory_order __m2) volatile noexcept
584      {
585        memory_order __b2 = __m2 & __memory_order_mask;
586        memory_order __b1 = __m1 & __memory_order_mask;
587
588	__glibcxx_assert(__b2 != memory_order_release);
589	__glibcxx_assert(__b2 != memory_order_acq_rel);
590	__glibcxx_assert(__b2 <= __b1);
591
592	return __atomic_compare_exchange_n(&_M_i, &__i1, __i2, 0, __m1, __m2);
593      }
594
595      bool
596      compare_exchange_strong(__int_type& __i1, __int_type __i2,
597			      memory_order __m = memory_order_seq_cst) noexcept
598      {
599	return compare_exchange_strong(__i1, __i2, __m,
600				       __cmpexch_failure_order(__m));
601      }
602
603      bool
604      compare_exchange_strong(__int_type& __i1, __int_type __i2,
605		 memory_order __m = memory_order_seq_cst) volatile noexcept
606      {
607	return compare_exchange_strong(__i1, __i2, __m,
608				       __cmpexch_failure_order(__m));
609      }
610
611      __int_type
612      fetch_add(__int_type __i,
613		memory_order __m = memory_order_seq_cst) noexcept
614      { return __atomic_fetch_add(&_M_i, __i, __m); }
615
616      __int_type
617      fetch_add(__int_type __i,
618		memory_order __m = memory_order_seq_cst) volatile noexcept
619      { return __atomic_fetch_add(&_M_i, __i, __m); }
620
621      __int_type
622      fetch_sub(__int_type __i,
623		memory_order __m = memory_order_seq_cst) noexcept
624      { return __atomic_fetch_sub(&_M_i, __i, __m); }
625
626      __int_type
627      fetch_sub(__int_type __i,
628		memory_order __m = memory_order_seq_cst) volatile noexcept
629      { return __atomic_fetch_sub(&_M_i, __i, __m); }
630
631      __int_type
632      fetch_and(__int_type __i,
633		memory_order __m = memory_order_seq_cst) noexcept
634      { return __atomic_fetch_and(&_M_i, __i, __m); }
635
636      __int_type
637      fetch_and(__int_type __i,
638		memory_order __m = memory_order_seq_cst) volatile noexcept
639      { return __atomic_fetch_and(&_M_i, __i, __m); }
640
641      __int_type
642      fetch_or(__int_type __i,
643	       memory_order __m = memory_order_seq_cst) noexcept
644      { return __atomic_fetch_or(&_M_i, __i, __m); }
645
646      __int_type
647      fetch_or(__int_type __i,
648	       memory_order __m = memory_order_seq_cst) volatile noexcept
649      { return __atomic_fetch_or(&_M_i, __i, __m); }
650
651      __int_type
652      fetch_xor(__int_type __i,
653		memory_order __m = memory_order_seq_cst) noexcept
654      { return __atomic_fetch_xor(&_M_i, __i, __m); }
655
656      __int_type
657      fetch_xor(__int_type __i,
658		memory_order __m = memory_order_seq_cst) volatile noexcept
659      { return __atomic_fetch_xor(&_M_i, __i, __m); }
660    };
661
662
663  /// Partial specialization for pointer types.
664  template<typename _PTp>
665    struct __atomic_base<_PTp*>
666    {
667    private:
668      typedef _PTp* 	__pointer_type;
669
670      __pointer_type 	_M_p;
671
672      // Factored out to facilitate explicit specialization.
673      constexpr ptrdiff_t
674      _M_type_size(ptrdiff_t __d) { return __d * sizeof(_PTp); }
675
676      constexpr ptrdiff_t
677      _M_type_size(ptrdiff_t __d) volatile { return __d * sizeof(_PTp); }
678
679    public:
680      __atomic_base() noexcept = default;
681      ~__atomic_base() noexcept = default;
682      __atomic_base(const __atomic_base&) = delete;
683      __atomic_base& operator=(const __atomic_base&) = delete;
684      __atomic_base& operator=(const __atomic_base&) volatile = delete;
685
686      // Requires __pointer_type convertible to _M_p.
687      constexpr __atomic_base(__pointer_type __p) noexcept : _M_p (__p) { }
688
689      operator __pointer_type() const noexcept
690      { return load(); }
691
692      operator __pointer_type() const volatile noexcept
693      { return load(); }
694
695      __pointer_type
696      operator=(__pointer_type __p) noexcept
697      {
698	store(__p);
699	return __p;
700      }
701
702      __pointer_type
703      operator=(__pointer_type __p) volatile noexcept
704      {
705	store(__p);
706	return __p;
707      }
708
709      __pointer_type
710      operator++(int) noexcept
711      { return fetch_add(1); }
712
713      __pointer_type
714      operator++(int) volatile noexcept
715      { return fetch_add(1); }
716
717      __pointer_type
718      operator--(int) noexcept
719      { return fetch_sub(1); }
720
721      __pointer_type
722      operator--(int) volatile noexcept
723      { return fetch_sub(1); }
724
725      __pointer_type
726      operator++() noexcept
727      { return __atomic_add_fetch(&_M_p, _M_type_size(1),
728				  memory_order_seq_cst); }
729
730      __pointer_type
731      operator++() volatile noexcept
732      { return __atomic_add_fetch(&_M_p, _M_type_size(1),
733				  memory_order_seq_cst); }
734
735      __pointer_type
736      operator--() noexcept
737      { return __atomic_sub_fetch(&_M_p, _M_type_size(1),
738				  memory_order_seq_cst); }
739
740      __pointer_type
741      operator--() volatile noexcept
742      { return __atomic_sub_fetch(&_M_p, _M_type_size(1),
743				  memory_order_seq_cst); }
744
745      __pointer_type
746      operator+=(ptrdiff_t __d) noexcept
747      { return __atomic_add_fetch(&_M_p, _M_type_size(__d),
748				  memory_order_seq_cst); }
749
750      __pointer_type
751      operator+=(ptrdiff_t __d) volatile noexcept
752      { return __atomic_add_fetch(&_M_p, _M_type_size(__d),
753				  memory_order_seq_cst); }
754
755      __pointer_type
756      operator-=(ptrdiff_t __d) noexcept
757      { return __atomic_sub_fetch(&_M_p, _M_type_size(__d),
758				  memory_order_seq_cst); }
759
760      __pointer_type
761      operator-=(ptrdiff_t __d) volatile noexcept
762      { return __atomic_sub_fetch(&_M_p, _M_type_size(__d),
763				  memory_order_seq_cst); }
764
765      bool
766      is_lock_free() const noexcept
767      { return __atomic_is_lock_free(sizeof(__pointer_type), nullptr); }
768
769      bool
770      is_lock_free() const volatile noexcept
771      { return __atomic_is_lock_free(sizeof(__pointer_type), nullptr); }
772
773      void
774      store(__pointer_type __p,
775	    memory_order __m = memory_order_seq_cst) noexcept
776      {
777        memory_order __b = __m & __memory_order_mask;
778
779	__glibcxx_assert(__b != memory_order_acquire);
780	__glibcxx_assert(__b != memory_order_acq_rel);
781	__glibcxx_assert(__b != memory_order_consume);
782
783	__atomic_store_n(&_M_p, __p, __m);
784      }
785
786      void
787      store(__pointer_type __p,
788	    memory_order __m = memory_order_seq_cst) volatile noexcept
789      {
790        memory_order __b = __m & __memory_order_mask;
791	__glibcxx_assert(__b != memory_order_acquire);
792	__glibcxx_assert(__b != memory_order_acq_rel);
793	__glibcxx_assert(__b != memory_order_consume);
794
795	__atomic_store_n(&_M_p, __p, __m);
796      }
797
798      __pointer_type
799      load(memory_order __m = memory_order_seq_cst) const noexcept
800      {
801        memory_order __b = __m & __memory_order_mask;
802	__glibcxx_assert(__b != memory_order_release);
803	__glibcxx_assert(__b != memory_order_acq_rel);
804
805	return __atomic_load_n(&_M_p, __m);
806      }
807
808      __pointer_type
809      load(memory_order __m = memory_order_seq_cst) const volatile noexcept
810      {
811        memory_order __b = __m & __memory_order_mask;
812	__glibcxx_assert(__b != memory_order_release);
813	__glibcxx_assert(__b != memory_order_acq_rel);
814
815	return __atomic_load_n(&_M_p, __m);
816      }
817
818      __pointer_type
819      exchange(__pointer_type __p,
820	       memory_order __m = memory_order_seq_cst) noexcept
821      {
822	return __atomic_exchange_n(&_M_p, __p, __m);
823      }
824
825
826      __pointer_type
827      exchange(__pointer_type __p,
828	       memory_order __m = memory_order_seq_cst) volatile noexcept
829      {
830	return __atomic_exchange_n(&_M_p, __p, __m);
831      }
832
833      bool
834      compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2,
835			      memory_order __m1,
836			      memory_order __m2) noexcept
837      {
838        memory_order __b2 = __m2 & __memory_order_mask;
839        memory_order __b1 = __m1 & __memory_order_mask;
840	__glibcxx_assert(__b2 != memory_order_release);
841	__glibcxx_assert(__b2 != memory_order_acq_rel);
842	__glibcxx_assert(__b2 <= __b1);
843
844	return __atomic_compare_exchange_n(&_M_p, &__p1, __p2, 0, __m1, __m2);
845      }
846
847      bool
848      compare_exchange_strong(__pointer_type& __p1, __pointer_type __p2,
849			      memory_order __m1,
850			      memory_order __m2) volatile noexcept
851      {
852        memory_order __b2 = __m2 & __memory_order_mask;
853        memory_order __b1 = __m1 & __memory_order_mask;
854
855	__glibcxx_assert(__b2 != memory_order_release);
856	__glibcxx_assert(__b2 != memory_order_acq_rel);
857	__glibcxx_assert(__b2 <= __b1);
858
859	return __atomic_compare_exchange_n(&_M_p, &__p1, __p2, 0, __m1, __m2);
860      }
861
862      __pointer_type
863      fetch_add(ptrdiff_t __d,
864		memory_order __m = memory_order_seq_cst) noexcept
865      { return __atomic_fetch_add(&_M_p, _M_type_size(__d), __m); }
866
867      __pointer_type
868      fetch_add(ptrdiff_t __d,
869		memory_order __m = memory_order_seq_cst) volatile noexcept
870      { return __atomic_fetch_add(&_M_p, _M_type_size(__d), __m); }
871
872      __pointer_type
873      fetch_sub(ptrdiff_t __d,
874		memory_order __m = memory_order_seq_cst) noexcept
875      { return __atomic_fetch_sub(&_M_p, _M_type_size(__d), __m); }
876
877      __pointer_type
878      fetch_sub(ptrdiff_t __d,
879		memory_order __m = memory_order_seq_cst) volatile noexcept
880      { return __atomic_fetch_sub(&_M_p, _M_type_size(__d), __m); }
881    };
882
883  // @} group atomics
884
885_GLIBCXX_END_NAMESPACE_VERSION
886} // namespace std
887
888#endif
889