File: lock.h

package info (click to toggle)
lpe 1.2.8-2
  • links: PTS
  • area: main
  • in suites: bullseye, buster, sid, stretch
  • size: 4,244 kB
  • ctags: 2,848
  • sloc: ansic: 27,612; sh: 12,468; makefile: 689; yacc: 291; cs: 137; perl: 111; sed: 16
file content (927 lines) | stat: -rw-r--r-- 36,311 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
/* Locking in multithreaded situations.
   Copyright (C) 2005-2008, 2015 Free Software Foundation, Inc.

   This program 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 program 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 program.  If not, see <http://www.gnu.org/licenses/>.  */

/* Written by Bruno Haible <bruno@clisp.org>, 2005.
   Based on GCC's gthr-posix.h, gthr-posix95.h, gthr-solaris.h,
   gthr-win32.h.  */

/* This file contains locking primitives for use with a given thread library.
   It does not contain primitives for creating threads or for other
   synchronization primitives.

   Normal (non-recursive) locks:
     Type:                gl_lock_t
     Declaration:         gl_lock_define(extern, name)
     Initializer:         gl_lock_define_initialized(, name)
     Initialization:      gl_lock_init (name);
     Taking the lock:     gl_lock_lock (name);
     Releasing the lock:  gl_lock_unlock (name);
     De-initialization:   gl_lock_destroy (name);
   Equivalent functions with control of error handling:
     Initialization:      err = glthread_lock_init (&name);
     Taking the lock:     err = glthread_lock_lock (&name);
     Releasing the lock:  err = glthread_lock_unlock (&name);
     De-initialization:   err = glthread_lock_destroy (&name);

   Read-Write (non-recursive) locks:
     Type:                gl_rwlock_t
     Declaration:         gl_rwlock_define(extern, name)
     Initializer:         gl_rwlock_define_initialized(, name)
     Initialization:      gl_rwlock_init (name);
     Taking the lock:     gl_rwlock_rdlock (name);
                          gl_rwlock_wrlock (name);
     Releasing the lock:  gl_rwlock_unlock (name);
     De-initialization:   gl_rwlock_destroy (name);
   Equivalent functions with control of error handling:
     Initialization:      err = glthread_rwlock_init (&name);
     Taking the lock:     err = glthread_rwlock_rdlock (&name);
                          err = glthread_rwlock_wrlock (&name);
     Releasing the lock:  err = glthread_rwlock_unlock (&name);
     De-initialization:   err = glthread_rwlock_destroy (&name);

   Recursive locks:
     Type:                gl_recursive_lock_t
     Declaration:         gl_recursive_lock_define(extern, name)
     Initializer:         gl_recursive_lock_define_initialized(, name)
     Initialization:      gl_recursive_lock_init (name);
     Taking the lock:     gl_recursive_lock_lock (name);
     Releasing the lock:  gl_recursive_lock_unlock (name);
     De-initialization:   gl_recursive_lock_destroy (name);
   Equivalent functions with control of error handling:
     Initialization:      err = glthread_recursive_lock_init (&name);
     Taking the lock:     err = glthread_recursive_lock_lock (&name);
     Releasing the lock:  err = glthread_recursive_lock_unlock (&name);
     De-initialization:   err = glthread_recursive_lock_destroy (&name);

  Once-only execution:
     Type:                gl_once_t
     Initializer:         gl_once_define(extern, name)
     Execution:           gl_once (name, initfunction);
   Equivalent functions with control of error handling:
     Execution:           err = glthread_once (&name, initfunction);
*/


#ifndef _LOCK_H
#define _LOCK_H

#include <errno.h>
#include <stdlib.h>

/* ========================================================================= */

#if USE_POSIX_THREADS

/* Use the POSIX threads library.  */

# include <pthread.h>

# ifdef __cplusplus
extern "C" {
# endif

# if PTHREAD_IN_USE_DETECTION_HARD

/* The pthread_in_use() detection needs to be done at runtime.  */
#  define pthread_in_use() \
     glthread_in_use ()
extern int glthread_in_use (void);

# endif

# if USE_POSIX_THREADS_WEAK

/* Use weak references to the POSIX threads library.  */

/* Weak references avoid dragging in external libraries if the other parts
   of the program don't use them.  Here we use them, because we don't want
   every program that uses libintl to depend on libpthread.  This assumes
   that libpthread would not be loaded after libintl; i.e. if libintl is
   loaded first, by an executable that does not depend on libpthread, and
   then a module is dynamically loaded that depends on libpthread, libintl
   will not be multithread-safe.  */

/* The way to test at runtime whether libpthread is present is to test
   whether a function pointer's value, such as &pthread_mutex_init, is
   non-NULL.  However, some versions of GCC have a bug through which, in
   PIC mode, &foo != NULL always evaluates to true if there is a direct
   call to foo(...) in the same function.  To avoid this, we test the
   address of a function in libpthread that we don't use.  */

#  pragma weak pthread_mutex_init
#  pragma weak pthread_mutex_lock
#  pragma weak pthread_mutex_unlock
#  pragma weak pthread_mutex_destroy
#  pragma weak pthread_rwlock_init
#  pragma weak pthread_rwlock_rdlock
#  pragma weak pthread_rwlock_wrlock
#  pragma weak pthread_rwlock_unlock
#  pragma weak pthread_rwlock_destroy
#  pragma weak pthread_once
#  pragma weak pthread_cond_init
#  pragma weak pthread_cond_wait
#  pragma weak pthread_cond_signal
#  pragma weak pthread_cond_broadcast
#  pragma weak pthread_cond_destroy
#  pragma weak pthread_mutexattr_init
#  pragma weak pthread_mutexattr_settype
#  pragma weak pthread_mutexattr_destroy
#  ifndef pthread_self
#   pragma weak pthread_self
#  endif

#  if !PTHREAD_IN_USE_DETECTION_HARD
#   pragma weak pthread_cancel
#   define pthread_in_use() (pthread_cancel != NULL)
#  endif

# else

#  if !PTHREAD_IN_USE_DETECTION_HARD
#   define pthread_in_use() 1
#  endif

# endif

/* -------------------------- gl_lock_t datatype -------------------------- */

typedef pthread_mutex_t gl_lock_t;
# define gl_lock_define(STORAGECLASS, NAME) \
    STORAGECLASS pthread_mutex_t NAME;
# define gl_lock_define_initialized(STORAGECLASS, NAME) \
    STORAGECLASS pthread_mutex_t NAME = gl_lock_initializer;
# define gl_lock_initializer \
    PTHREAD_MUTEX_INITIALIZER
# define glthread_lock_init(LOCK) \
    (pthread_in_use () ? pthread_mutex_init (LOCK, NULL) : 0)
# define glthread_lock_lock(LOCK) \
    (pthread_in_use () ? pthread_mutex_lock (LOCK) : 0)
# define glthread_lock_unlock(LOCK) \
    (pthread_in_use () ? pthread_mutex_unlock (LOCK) : 0)
# define glthread_lock_destroy(LOCK) \
    (pthread_in_use () ? pthread_mutex_destroy (LOCK) : 0)

/* ------------------------- gl_rwlock_t datatype ------------------------- */

# if HAVE_PTHREAD_RWLOCK

#  ifdef PTHREAD_RWLOCK_INITIALIZER

typedef pthread_rwlock_t gl_rwlock_t;
#   define gl_rwlock_define(STORAGECLASS, NAME) \
      STORAGECLASS pthread_rwlock_t NAME;
#   define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
      STORAGECLASS pthread_rwlock_t NAME = gl_rwlock_initializer;
#   define gl_rwlock_initializer \
      PTHREAD_RWLOCK_INITIALIZER
#   define glthread_rwlock_init(LOCK) \
      (pthread_in_use () ? pthread_rwlock_init (LOCK, NULL) : 0)
#   define glthread_rwlock_rdlock(LOCK) \
      (pthread_in_use () ? pthread_rwlock_rdlock (LOCK) : 0)
#   define glthread_rwlock_wrlock(LOCK) \
      (pthread_in_use () ? pthread_rwlock_wrlock (LOCK) : 0)
#   define glthread_rwlock_unlock(LOCK) \
      (pthread_in_use () ? pthread_rwlock_unlock (LOCK) : 0)
#   define glthread_rwlock_destroy(LOCK) \
      (pthread_in_use () ? pthread_rwlock_destroy (LOCK) : 0)

#  else

typedef struct
        {
          int initialized;
          pthread_mutex_t guard;   /* protects the initialization */
          pthread_rwlock_t rwlock; /* read-write lock */
        }
        gl_rwlock_t;
#   define gl_rwlock_define(STORAGECLASS, NAME) \
      STORAGECLASS gl_rwlock_t NAME;
#   define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
      STORAGECLASS gl_rwlock_t NAME = gl_rwlock_initializer;
#   define gl_rwlock_initializer \
      { 0, PTHREAD_MUTEX_INITIALIZER }
#   define glthread_rwlock_init(LOCK) \
      (pthread_in_use () ? glthread_rwlock_init_multithreaded (LOCK) : 0)
#   define glthread_rwlock_rdlock(LOCK) \
      (pthread_in_use () ? glthread_rwlock_rdlock_multithreaded (LOCK) : 0)
#   define glthread_rwlock_wrlock(LOCK) \
      (pthread_in_use () ? glthread_rwlock_wrlock_multithreaded (LOCK) : 0)
#   define glthread_rwlock_unlock(LOCK) \
      (pthread_in_use () ? glthread_rwlock_unlock_multithreaded (LOCK) : 0)
#   define glthread_rwlock_destroy(LOCK) \
      (pthread_in_use () ? glthread_rwlock_destroy_multithreaded (LOCK) : 0)
extern int glthread_rwlock_init_multithreaded (gl_rwlock_t *lock);
extern int glthread_rwlock_rdlock_multithreaded (gl_rwlock_t *lock);
extern int glthread_rwlock_wrlock_multithreaded (gl_rwlock_t *lock);
extern int glthread_rwlock_unlock_multithreaded (gl_rwlock_t *lock);
extern int glthread_rwlock_destroy_multithreaded (gl_rwlock_t *lock);

#  endif

# else

typedef struct
        {
          pthread_mutex_t lock; /* protects the remaining fields */
          pthread_cond_t waiting_readers; /* waiting readers */
          pthread_cond_t waiting_writers; /* waiting writers */
          unsigned int waiting_writers_count; /* number of waiting writers */
          int runcount; /* number of readers running, or -1 when a writer runs */
        }
        gl_rwlock_t;
# define gl_rwlock_define(STORAGECLASS, NAME) \
    STORAGECLASS gl_rwlock_t NAME;
# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
    STORAGECLASS gl_rwlock_t NAME = gl_rwlock_initializer;
# define gl_rwlock_initializer \
    { PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER, PTHREAD_COND_INITIALIZER, 0, 0 }
# define glthread_rwlock_init(LOCK) \
    (pthread_in_use () ? glthread_rwlock_init_multithreaded (LOCK) : 0)
# define glthread_rwlock_rdlock(LOCK) \
    (pthread_in_use () ? glthread_rwlock_rdlock_multithreaded (LOCK) : 0)
# define glthread_rwlock_wrlock(LOCK) \
    (pthread_in_use () ? glthread_rwlock_wrlock_multithreaded (LOCK) : 0)
# define glthread_rwlock_unlock(LOCK) \
    (pthread_in_use () ? glthread_rwlock_unlock_multithreaded (LOCK) : 0)
# define glthread_rwlock_destroy(LOCK) \
    (pthread_in_use () ? glthread_rwlock_destroy_multithreaded (LOCK) : 0)
extern int glthread_rwlock_init_multithreaded (gl_rwlock_t *lock);
extern int glthread_rwlock_rdlock_multithreaded (gl_rwlock_t *lock);
extern int glthread_rwlock_wrlock_multithreaded (gl_rwlock_t *lock);
extern int glthread_rwlock_unlock_multithreaded (gl_rwlock_t *lock);
extern int glthread_rwlock_destroy_multithreaded (gl_rwlock_t *lock);

# endif

/* --------------------- gl_recursive_lock_t datatype --------------------- */

# if HAVE_PTHREAD_MUTEX_RECURSIVE

#  if defined PTHREAD_RECURSIVE_MUTEX_INITIALIZER || defined PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP

typedef pthread_mutex_t gl_recursive_lock_t;
#   define gl_recursive_lock_define(STORAGECLASS, NAME) \
      STORAGECLASS pthread_mutex_t NAME;
#   define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \
      STORAGECLASS pthread_mutex_t NAME = gl_recursive_lock_initializer;
#   ifdef PTHREAD_RECURSIVE_MUTEX_INITIALIZER
#    define gl_recursive_lock_initializer \
       PTHREAD_RECURSIVE_MUTEX_INITIALIZER
#   else
#    define gl_recursive_lock_initializer \
       PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP
#   endif
#   define glthread_recursive_lock_init(LOCK) \
      (pthread_in_use () ? glthread_recursive_lock_init_multithreaded (LOCK) : 0)
#   define glthread_recursive_lock_lock(LOCK) \
      (pthread_in_use () ? pthread_mutex_lock (LOCK) : 0)
#   define glthread_recursive_lock_unlock(LOCK) \
      (pthread_in_use () ? pthread_mutex_unlock (LOCK) : 0)
#   define glthread_recursive_lock_destroy(LOCK) \
      (pthread_in_use () ? pthread_mutex_destroy (LOCK) : 0)
extern int glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock);

#  else

typedef struct
        {
          pthread_mutex_t recmutex; /* recursive mutex */
          pthread_mutex_t guard;    /* protects the initialization */
          int initialized;
        }
        gl_recursive_lock_t;
#   define gl_recursive_lock_define(STORAGECLASS, NAME) \
      STORAGECLASS gl_recursive_lock_t NAME;
#   define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \
      STORAGECLASS gl_recursive_lock_t NAME = gl_recursive_lock_initializer;
#   define gl_recursive_lock_initializer \
      { PTHREAD_MUTEX_INITIALIZER, PTHREAD_MUTEX_INITIALIZER, 0 }
#   define glthread_recursive_lock_init(LOCK) \
      (pthread_in_use () ? glthread_recursive_lock_init_multithreaded (LOCK) : 0)
#   define glthread_recursive_lock_lock(LOCK) \
      (pthread_in_use () ? glthread_recursive_lock_lock_multithreaded (LOCK) : 0)
#   define glthread_recursive_lock_unlock(LOCK) \
      (pthread_in_use () ? glthread_recursive_lock_unlock_multithreaded (LOCK) : 0)
#   define glthread_recursive_lock_destroy(LOCK) \
      (pthread_in_use () ? glthread_recursive_lock_destroy_multithreaded (LOCK) : 0)
extern int glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock);
extern int glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock);
extern int glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock);
extern int glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock);

#  endif

# else

/* Old versions of POSIX threads on Solaris did not have recursive locks.
   We have to implement them ourselves.  */

typedef struct
        {
          pthread_mutex_t mutex;
          pthread_t owner;
          unsigned long depth;
        }
        gl_recursive_lock_t;
#  define gl_recursive_lock_define(STORAGECLASS, NAME) \
     STORAGECLASS gl_recursive_lock_t NAME;
#  define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \
     STORAGECLASS gl_recursive_lock_t NAME = gl_recursive_lock_initializer;
#  define gl_recursive_lock_initializer \
     { PTHREAD_MUTEX_INITIALIZER, (pthread_t) 0, 0 }
#  define glthread_recursive_lock_init(LOCK) \
     (pthread_in_use () ? glthread_recursive_lock_init_multithreaded (LOCK) : 0)
#  define glthread_recursive_lock_lock(LOCK) \
     (pthread_in_use () ? glthread_recursive_lock_lock_multithreaded (LOCK) : 0)
#  define glthread_recursive_lock_unlock(LOCK) \
     (pthread_in_use () ? glthread_recursive_lock_unlock_multithreaded (LOCK) : 0)
#  define glthread_recursive_lock_destroy(LOCK) \
     (pthread_in_use () ? glthread_recursive_lock_destroy_multithreaded (LOCK) : 0)
extern int glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock);
extern int glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock);
extern int glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock);
extern int glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock);

# endif

/* -------------------------- gl_once_t datatype -------------------------- */

typedef pthread_once_t gl_once_t;
# define gl_once_define(STORAGECLASS, NAME) \
    STORAGECLASS pthread_once_t NAME = PTHREAD_ONCE_INIT;
# define glthread_once(ONCE_CONTROL, INITFUNCTION) \
    (pthread_in_use ()                                                         \
     ? pthread_once (ONCE_CONTROL, INITFUNCTION)                               \
     : (glthread_once_singlethreaded (ONCE_CONTROL) ? (INITFUNCTION (), 0) : 0))
extern int glthread_once_singlethreaded (pthread_once_t *once_control);

# ifdef __cplusplus
}
# endif

#endif

/* ========================================================================= */

#if USE_PTH_THREADS

/* Use the GNU Pth threads library.  */

# include <pth.h>

# ifdef __cplusplus
extern "C" {
# endif

# if USE_PTH_THREADS_WEAK

/* Use weak references to the GNU Pth threads library.  */

#  pragma weak pth_mutex_init
#  pragma weak pth_mutex_acquire
#  pragma weak pth_mutex_release
#  pragma weak pth_rwlock_init
#  pragma weak pth_rwlock_acquire
#  pragma weak pth_rwlock_release
#  pragma weak pth_once

#  pragma weak pth_cancel
#  define pth_in_use() (pth_cancel != NULL)

# else

#  define pth_in_use() 1

# endif

/* -------------------------- gl_lock_t datatype -------------------------- */

typedef pth_mutex_t gl_lock_t;
# define gl_lock_define(STORAGECLASS, NAME) \
    STORAGECLASS pth_mutex_t NAME;
# define gl_lock_define_initialized(STORAGECLASS, NAME) \
    STORAGECLASS pth_mutex_t NAME = gl_lock_initializer;
# define gl_lock_initializer \
    PTH_MUTEX_INIT
# define glthread_lock_init(LOCK) \
    (pth_in_use () && !pth_mutex_init (LOCK) ? errno : 0)
# define glthread_lock_lock(LOCK) \
    (pth_in_use () && !pth_mutex_acquire (LOCK, 0, NULL) ? errno : 0)
# define glthread_lock_unlock(LOCK) \
    (pth_in_use () && !pth_mutex_release (LOCK) ? errno : 0)
# define glthread_lock_destroy(LOCK) \
    ((void)(LOCK), 0)

/* ------------------------- gl_rwlock_t datatype ------------------------- */

typedef pth_rwlock_t gl_rwlock_t;
#  define gl_rwlock_define(STORAGECLASS, NAME) \
     STORAGECLASS pth_rwlock_t NAME;
#  define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
     STORAGECLASS pth_rwlock_t NAME = gl_rwlock_initializer;
#  define gl_rwlock_initializer \
     PTH_RWLOCK_INIT
#  define glthread_rwlock_init(LOCK) \
     (pth_in_use () && !pth_rwlock_init (LOCK) ? errno : 0)
#  define glthread_rwlock_rdlock(LOCK) \
     (pth_in_use () && !pth_rwlock_acquire (LOCK, PTH_RWLOCK_RD, 0, NULL) ? errno : 0)
#  define glthread_rwlock_wrlock(LOCK) \
     (pth_in_use () && !pth_rwlock_acquire (LOCK, PTH_RWLOCK_RW, 0, NULL) ? errno : 0)
#  define glthread_rwlock_unlock(LOCK) \
     (pth_in_use () && !pth_rwlock_release (LOCK) ? errno : 0)
#  define glthread_rwlock_destroy(LOCK) \
     ((void)(LOCK), 0)

/* --------------------- gl_recursive_lock_t datatype --------------------- */

/* In Pth, mutexes are recursive by default.  */
typedef pth_mutex_t gl_recursive_lock_t;
#  define gl_recursive_lock_define(STORAGECLASS, NAME) \
     STORAGECLASS pth_mutex_t NAME;
#  define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \
     STORAGECLASS pth_mutex_t NAME = gl_recursive_lock_initializer;
#  define gl_recursive_lock_initializer \
     PTH_MUTEX_INIT
#  define glthread_recursive_lock_init(LOCK) \
     (pth_in_use () && !pth_mutex_init (LOCK) ? errno : 0)
#  define glthread_recursive_lock_lock(LOCK) \
     (pth_in_use () && !pth_mutex_acquire (LOCK, 0, NULL) ? errno : 0)
#  define glthread_recursive_lock_unlock(LOCK) \
     (pth_in_use () && !pth_mutex_release (LOCK) ? errno : 0)
#  define glthread_recursive_lock_destroy(LOCK) \
     ((void)(LOCK), 0)

/* -------------------------- gl_once_t datatype -------------------------- */

typedef pth_once_t gl_once_t;
# define gl_once_define(STORAGECLASS, NAME) \
    STORAGECLASS pth_once_t NAME = PTH_ONCE_INIT;
# define glthread_once(ONCE_CONTROL, INITFUNCTION) \
    (pth_in_use ()                                                             \
     ? glthread_once_multithreaded (ONCE_CONTROL, INITFUNCTION)                \
     : (glthread_once_singlethreaded (ONCE_CONTROL) ? (INITFUNCTION (), 0) : 0))
extern int glthread_once_multithreaded (pth_once_t *once_control, void (*initfunction) (void));
extern int glthread_once_singlethreaded (pth_once_t *once_control);

# ifdef __cplusplus
}
# endif

#endif

/* ========================================================================= */

#if USE_SOLARIS_THREADS

/* Use the old Solaris threads library.  */

# include <thread.h>
# include <synch.h>

# ifdef __cplusplus
extern "C" {
# endif

# if USE_SOLARIS_THREADS_WEAK

/* Use weak references to the old Solaris threads library.  */

#  pragma weak mutex_init
#  pragma weak mutex_lock
#  pragma weak mutex_unlock
#  pragma weak mutex_destroy
#  pragma weak rwlock_init
#  pragma weak rw_rdlock
#  pragma weak rw_wrlock
#  pragma weak rw_unlock
#  pragma weak rwlock_destroy
#  pragma weak thr_self

#  pragma weak thr_suspend
#  define thread_in_use() (thr_suspend != NULL)

# else

#  define thread_in_use() 1

# endif

/* -------------------------- gl_lock_t datatype -------------------------- */

typedef mutex_t gl_lock_t;
# define gl_lock_define(STORAGECLASS, NAME) \
    STORAGECLASS mutex_t NAME;
# define gl_lock_define_initialized(STORAGECLASS, NAME) \
    STORAGECLASS mutex_t NAME = gl_lock_initializer;
# define gl_lock_initializer \
    DEFAULTMUTEX
# define glthread_lock_init(LOCK) \
    (thread_in_use () ? mutex_init (LOCK, USYNC_THREAD, NULL) : 0)
# define glthread_lock_lock(LOCK) \
    (thread_in_use () ? mutex_lock (LOCK) : 0)
# define glthread_lock_unlock(LOCK) \
    (thread_in_use () ? mutex_unlock (LOCK) : 0)
# define glthread_lock_destroy(LOCK) \
    (thread_in_use () ? mutex_destroy (LOCK) : 0)

/* ------------------------- gl_rwlock_t datatype ------------------------- */

typedef rwlock_t gl_rwlock_t;
# define gl_rwlock_define(STORAGECLASS, NAME) \
    STORAGECLASS rwlock_t NAME;
# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
    STORAGECLASS rwlock_t NAME = gl_rwlock_initializer;
# define gl_rwlock_initializer \
    DEFAULTRWLOCK
# define glthread_rwlock_init(LOCK) \
    (thread_in_use () ? rwlock_init (LOCK, USYNC_THREAD, NULL) : 0)
# define glthread_rwlock_rdlock(LOCK) \
    (thread_in_use () ? rw_rdlock (LOCK) : 0)
# define glthread_rwlock_wrlock(LOCK) \
    (thread_in_use () ? rw_wrlock (LOCK) : 0)
# define glthread_rwlock_unlock(LOCK) \
    (thread_in_use () ? rw_unlock (LOCK) : 0)
# define glthread_rwlock_destroy(LOCK) \
    (thread_in_use () ? rwlock_destroy (LOCK) : 0)

/* --------------------- gl_recursive_lock_t datatype --------------------- */

/* Old Solaris threads did not have recursive locks.
   We have to implement them ourselves.  */

typedef struct
        {
          mutex_t mutex;
          thread_t owner;
          unsigned long depth;
        }
        gl_recursive_lock_t;
# define gl_recursive_lock_define(STORAGECLASS, NAME) \
    STORAGECLASS gl_recursive_lock_t NAME;
# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \
    STORAGECLASS gl_recursive_lock_t NAME = gl_recursive_lock_initializer;
# define gl_recursive_lock_initializer \
    { DEFAULTMUTEX, (thread_t) 0, 0 }
# define glthread_recursive_lock_init(LOCK) \
    (thread_in_use () ? glthread_recursive_lock_init_multithreaded (LOCK) : 0)
# define glthread_recursive_lock_lock(LOCK) \
    (thread_in_use () ? glthread_recursive_lock_lock_multithreaded (LOCK) : 0)
# define glthread_recursive_lock_unlock(LOCK) \
    (thread_in_use () ? glthread_recursive_lock_unlock_multithreaded (LOCK) : 0)
# define glthread_recursive_lock_destroy(LOCK) \
    (thread_in_use () ? glthread_recursive_lock_destroy_multithreaded (LOCK) : 0)
extern int glthread_recursive_lock_init_multithreaded (gl_recursive_lock_t *lock);
extern int glthread_recursive_lock_lock_multithreaded (gl_recursive_lock_t *lock);
extern int glthread_recursive_lock_unlock_multithreaded (gl_recursive_lock_t *lock);
extern int glthread_recursive_lock_destroy_multithreaded (gl_recursive_lock_t *lock);

/* -------------------------- gl_once_t datatype -------------------------- */

typedef struct
        {
          volatile int inited;
          mutex_t mutex;
        }
        gl_once_t;
# define gl_once_define(STORAGECLASS, NAME) \
    STORAGECLASS gl_once_t NAME = { 0, DEFAULTMUTEX };
# define glthread_once(ONCE_CONTROL, INITFUNCTION) \
    (thread_in_use ()                                                          \
     ? glthread_once_multithreaded (ONCE_CONTROL, INITFUNCTION)                \
     : (glthread_once_singlethreaded (ONCE_CONTROL) ? (INITFUNCTION (), 0) : 0))
extern int glthread_once_multithreaded (gl_once_t *once_control, void (*initfunction) (void));
extern int glthread_once_singlethreaded (gl_once_t *once_control);

# ifdef __cplusplus
}
# endif

#endif

/* ========================================================================= */

#if USE_WINDOWS_THREADS

# define WIN32_LEAN_AND_MEAN  /* avoid including junk */
# include <windows.h>

# ifdef __cplusplus
extern "C" {
# endif

/* We can use CRITICAL_SECTION directly, rather than the native Windows Event,
   Mutex, Semaphore types, because
     - we need only to synchronize inside a single process (address space),
       not inter-process locking,
     - we don't need to support trylock operations.  (TryEnterCriticalSection
       does not work on Windows 95/98/ME.  Packages that need trylock usually
       define their own mutex type.)  */

/* There is no way to statically initialize a CRITICAL_SECTION.  It needs
   to be done lazily, once only.  For this we need spinlocks.  */

typedef struct { volatile int done; volatile long started; } gl_spinlock_t;

/* -------------------------- gl_lock_t datatype -------------------------- */

typedef struct
        {
          gl_spinlock_t guard; /* protects the initialization */
          CRITICAL_SECTION lock;
        }
        gl_lock_t;
# define gl_lock_define(STORAGECLASS, NAME) \
    STORAGECLASS gl_lock_t NAME;
# define gl_lock_define_initialized(STORAGECLASS, NAME) \
    STORAGECLASS gl_lock_t NAME = gl_lock_initializer;
# define gl_lock_initializer \
    { { 0, -1 } }
# define glthread_lock_init(LOCK) \
    (glthread_lock_init_func (LOCK), 0)
# define glthread_lock_lock(LOCK) \
    glthread_lock_lock_func (LOCK)
# define glthread_lock_unlock(LOCK) \
    glthread_lock_unlock_func (LOCK)
# define glthread_lock_destroy(LOCK) \
    glthread_lock_destroy_func (LOCK)
extern void glthread_lock_init_func (gl_lock_t *lock);
extern int glthread_lock_lock_func (gl_lock_t *lock);
extern int glthread_lock_unlock_func (gl_lock_t *lock);
extern int glthread_lock_destroy_func (gl_lock_t *lock);

/* ------------------------- gl_rwlock_t datatype ------------------------- */

/* It is impossible to implement read-write locks using plain locks, without
   introducing an extra thread dedicated to managing read-write locks.
   Therefore here we need to use the low-level Event type.  */

typedef struct
        {
          HANDLE *array; /* array of waiting threads, each represented by an event */
          unsigned int count; /* number of waiting threads */
          unsigned int alloc; /* length of allocated array */
          unsigned int offset; /* index of first waiting thread in array */
        }
        gl_carray_waitqueue_t;
typedef struct
        {
          gl_spinlock_t guard; /* protects the initialization */
          CRITICAL_SECTION lock; /* protects the remaining fields */
          gl_carray_waitqueue_t waiting_readers; /* waiting readers */
          gl_carray_waitqueue_t waiting_writers; /* waiting writers */
          int runcount; /* number of readers running, or -1 when a writer runs */
        }
        gl_rwlock_t;
# define gl_rwlock_define(STORAGECLASS, NAME) \
    STORAGECLASS gl_rwlock_t NAME;
# define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
    STORAGECLASS gl_rwlock_t NAME = gl_rwlock_initializer;
# define gl_rwlock_initializer \
    { { 0, -1 } }
# define glthread_rwlock_init(LOCK) \
    (glthread_rwlock_init_func (LOCK), 0)
# define glthread_rwlock_rdlock(LOCK) \
    glthread_rwlock_rdlock_func (LOCK)
# define glthread_rwlock_wrlock(LOCK) \
    glthread_rwlock_wrlock_func (LOCK)
# define glthread_rwlock_unlock(LOCK) \
    glthread_rwlock_unlock_func (LOCK)
# define glthread_rwlock_destroy(LOCK) \
    glthread_rwlock_destroy_func (LOCK)
extern void glthread_rwlock_init_func (gl_rwlock_t *lock);
extern int glthread_rwlock_rdlock_func (gl_rwlock_t *lock);
extern int glthread_rwlock_wrlock_func (gl_rwlock_t *lock);
extern int glthread_rwlock_unlock_func (gl_rwlock_t *lock);
extern int glthread_rwlock_destroy_func (gl_rwlock_t *lock);

/* --------------------- gl_recursive_lock_t datatype --------------------- */

/* The native Windows documentation says that CRITICAL_SECTION already
   implements a recursive lock.  But we need not rely on it: It's easy to
   implement a recursive lock without this assumption.  */

typedef struct
        {
          gl_spinlock_t guard; /* protects the initialization */
          DWORD owner;
          unsigned long depth;
          CRITICAL_SECTION lock;
        }
        gl_recursive_lock_t;
# define gl_recursive_lock_define(STORAGECLASS, NAME) \
    STORAGECLASS gl_recursive_lock_t NAME;
# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME) \
    STORAGECLASS gl_recursive_lock_t NAME = gl_recursive_lock_initializer;
# define gl_recursive_lock_initializer \
    { { 0, -1 }, 0, 0 }
# define glthread_recursive_lock_init(LOCK) \
    (glthread_recursive_lock_init_func (LOCK), 0)
# define glthread_recursive_lock_lock(LOCK) \
    glthread_recursive_lock_lock_func (LOCK)
# define glthread_recursive_lock_unlock(LOCK) \
    glthread_recursive_lock_unlock_func (LOCK)
# define glthread_recursive_lock_destroy(LOCK) \
    glthread_recursive_lock_destroy_func (LOCK)
extern void glthread_recursive_lock_init_func (gl_recursive_lock_t *lock);
extern int glthread_recursive_lock_lock_func (gl_recursive_lock_t *lock);
extern int glthread_recursive_lock_unlock_func (gl_recursive_lock_t *lock);
extern int glthread_recursive_lock_destroy_func (gl_recursive_lock_t *lock);

/* -------------------------- gl_once_t datatype -------------------------- */

typedef struct
        {
          volatile int inited;
          volatile long started;
          CRITICAL_SECTION lock;
        }
        gl_once_t;
# define gl_once_define(STORAGECLASS, NAME) \
    STORAGECLASS gl_once_t NAME = { -1, -1 };
# define glthread_once(ONCE_CONTROL, INITFUNCTION) \
    (glthread_once_func (ONCE_CONTROL, INITFUNCTION), 0)
extern void glthread_once_func (gl_once_t *once_control, void (*initfunction) (void));

# ifdef __cplusplus
}
# endif

#endif

/* ========================================================================= */

#if !(USE_POSIX_THREADS || USE_PTH_THREADS || USE_SOLARIS_THREADS || USE_WINDOWS_THREADS)

/* Provide dummy implementation if threads are not supported.  */

/* -------------------------- gl_lock_t datatype -------------------------- */

typedef int gl_lock_t;
# define gl_lock_define(STORAGECLASS, NAME)
# define gl_lock_define_initialized(STORAGECLASS, NAME)
# define glthread_lock_init(NAME) 0
# define glthread_lock_lock(NAME) 0
# define glthread_lock_unlock(NAME) 0
# define glthread_lock_destroy(NAME) 0

/* ------------------------- gl_rwlock_t datatype ------------------------- */

typedef int gl_rwlock_t;
# define gl_rwlock_define(STORAGECLASS, NAME)
# define gl_rwlock_define_initialized(STORAGECLASS, NAME)
# define glthread_rwlock_init(NAME) 0
# define glthread_rwlock_rdlock(NAME) 0
# define glthread_rwlock_wrlock(NAME) 0
# define glthread_rwlock_unlock(NAME) 0
# define glthread_rwlock_destroy(NAME) 0

/* --------------------- gl_recursive_lock_t datatype --------------------- */

typedef int gl_recursive_lock_t;
# define gl_recursive_lock_define(STORAGECLASS, NAME)
# define gl_recursive_lock_define_initialized(STORAGECLASS, NAME)
# define glthread_recursive_lock_init(NAME) 0
# define glthread_recursive_lock_lock(NAME) 0
# define glthread_recursive_lock_unlock(NAME) 0
# define glthread_recursive_lock_destroy(NAME) 0

/* -------------------------- gl_once_t datatype -------------------------- */

typedef int gl_once_t;
# define gl_once_define(STORAGECLASS, NAME) \
    STORAGECLASS gl_once_t NAME = 0;
# define glthread_once(ONCE_CONTROL, INITFUNCTION) \
    (*(ONCE_CONTROL) == 0 ? (*(ONCE_CONTROL) = ~ 0, INITFUNCTION (), 0) : 0)

#endif

/* ========================================================================= */

/* Macros with built-in error handling.  */

/* -------------------------- gl_lock_t datatype -------------------------- */

#define gl_lock_init(NAME) \
   do                                  \
     {                                 \
       if (glthread_lock_init (&NAME)) \
         abort ();                     \
     }                                 \
   while (0)
#define gl_lock_lock(NAME) \
   do                                  \
     {                                 \
       if (glthread_lock_lock (&NAME)) \
         abort ();                     \
     }                                 \
   while (0)
#define gl_lock_unlock(NAME) \
   do                                    \
     {                                   \
       if (glthread_lock_unlock (&NAME)) \
         abort ();                       \
     }                                   \
   while (0)
#define gl_lock_destroy(NAME) \
   do                                     \
     {                                    \
       if (glthread_lock_destroy (&NAME)) \
         abort ();                        \
     }                                    \
   while (0)

/* ------------------------- gl_rwlock_t datatype ------------------------- */

#define gl_rwlock_init(NAME) \
   do                                    \
     {                                   \
       if (glthread_rwlock_init (&NAME)) \
         abort ();                       \
     }                                   \
   while (0)
#define gl_rwlock_rdlock(NAME) \
   do                                      \
     {                                     \
       if (glthread_rwlock_rdlock (&NAME)) \
         abort ();                         \
     }                                     \
   while (0)
#define gl_rwlock_wrlock(NAME) \
   do                                      \
     {                                     \
       if (glthread_rwlock_wrlock (&NAME)) \
         abort ();                         \
     }                                     \
   while (0)
#define gl_rwlock_unlock(NAME) \
   do                                      \
     {                                     \
       if (glthread_rwlock_unlock (&NAME)) \
         abort ();                         \
     }                                     \
   while (0)
#define gl_rwlock_destroy(NAME) \
   do                                       \
     {                                      \
       if (glthread_rwlock_destroy (&NAME)) \
         abort ();                          \
     }                                      \
   while (0)

/* --------------------- gl_recursive_lock_t datatype --------------------- */

#define gl_recursive_lock_init(NAME) \
   do                                            \
     {                                           \
       if (glthread_recursive_lock_init (&NAME)) \
         abort ();                               \
     }                                           \
   while (0)
#define gl_recursive_lock_lock(NAME) \
   do                                            \
     {                                           \
       if (glthread_recursive_lock_lock (&NAME)) \
         abort ();                               \
     }                                           \
   while (0)
#define gl_recursive_lock_unlock(NAME) \
   do                                              \
     {                                             \
       if (glthread_recursive_lock_unlock (&NAME)) \
         abort ();                                 \
     }                                             \
   while (0)
#define gl_recursive_lock_destroy(NAME) \
   do                                               \
     {                                              \
       if (glthread_recursive_lock_destroy (&NAME)) \
         abort ();                                  \
     }                                              \
   while (0)

/* -------------------------- gl_once_t datatype -------------------------- */

#define gl_once(NAME, INITFUNCTION) \
   do                                           \
     {                                          \
       if (glthread_once (&NAME, INITFUNCTION)) \
         abort ();                              \
     }                                          \
   while (0)

/* ========================================================================= */

#endif /* _LOCK_H */