glib/gatomic.c

   1 /*
   2  * Copyright © 2011 Ryan Lortie
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  16  *
  17  * Author: Ryan Lortie <desrt@desrt.ca>
  18  */
  19
  20 #include "config.h"
  21
  22 #include "gatomic.h"
  23
  24 /**
  25  * SECTION:atomic_operations
  26  * @title: Atomic Operations
  27  * @short_description: basic atomic integer and pointer operations
  28  * @see_also: #GMutex
  29  *
  30  * The following is a collection of compiler macros to provide atomic
  31  * access to integer and pointer-sized values.
  32  *
  33  * The macros that have 'int' in the name will operate on pointers to
  34  * #gint and #guint.  The macros with 'pointer' in the name will operate
  35  * on pointers to any pointer-sized value, including #gsize.  There is
  36  * no support for 64bit operations on platforms with 32bit pointers
  37  * because it is not generally possible to perform these operations
  38  * atomically.
  39  *
  40  * The get, set and exchange operations for integers and pointers
  41  * nominally operate on #gint and #gpointer, respectively.  Of the
  42  * arithmetic operations, the 'add' operation operates on (and returns)
  43  * signed integer values (#gint and #gssize) and the 'and', 'or', and
  44  * 'xor' operations operate on (and return) unsigned integer values
  45  * (#guint and #gsize).
  46  *
  47  * All of the operations act as a full compiler and (where appropriate)
  48  * hardware memory barrier.  Acquire and release or producer and
  49  * consumer barrier semantics are not available through this API.
  50  *
  51  * It is very important that all accesses to a particular integer or
  52  * pointer be performed using only this API and that different sizes of
  53  * operation are not mixed or used on overlapping memory regions.  Never
  54  * read or assign directly from or to a value -- always use this API.
  55  *
  56  * For simple reference counting purposes you should use
  57  * g_atomic_int_inc() and g_atomic_int_dec_and_test().  Other uses that
  58  * fall outside of simple reference counting patterns are prone to
  59  * subtle bugs and occasionally undefined behaviour.  It is also worth
  60  * noting that since all of these operations require global
  61  * synchronisation of the entire machine, they can be quite slow.  In
  62  * the case of performing multiple atomic operations it can often be
  63  * faster to simply acquire a mutex lock around the critical area,
  64  * perform the operations normally and then release the lock.
  65  **/
  66
  67 /**
  68  * G_ATOMIC_LOCK_FREE:
  69  *
  70  * This macro is defined if the atomic operations of GLib are
  71  * implemented using real hardware atomic operations.  This means that
  72  * the GLib atomic API can be used between processes and safely mixed
  73  * with other (hardware) atomic APIs.
  74  *
  75  * If this macro is not defined, the atomic operations may be
  76  * emulated using a mutex.  In that case, the GLib atomic operations are
  77  * only atomic relative to themselves and within a single process.
  78  **/
  79
  80 /* NOTE CAREFULLY:
  81  *
  82  * This file is the lowest-level part of GLib.
  83  *
  84  * Other lowlevel parts of GLib (threads, slice allocator, g_malloc,
  85  * messages, etc) call into these functions and macros to get work done.
  86  *
  87  * As such, these functions can not call back into any part of GLib
  88  * without risking recursion.
  89  */
  90
  91 #ifdef G_ATOMIC_LOCK_FREE
  92
  93 /* if G_ATOMIC_LOCK_FREE was defined by ./configure then we MUST
  94  * implement the atomic operations in a lock-free manner.
  95  */
  96
  97 #if defined (__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
  98
  99 #if defined(__ATOMIC_SEQ_CST) && !defined(__clang__)
 100 /* The implementation used in this code path in gatomic.h assumes
 101  * 4-byte int */
 102 G_STATIC_ASSERT (sizeof (gint) == 4);
 103
 104 /* The implementations in gatomic.h assume 4- or 8-byte pointers */
 105 G_STATIC_ASSERT (sizeof (void *) == 4 || sizeof (void *) == 8);
 106 #endif
 107
 108 /**
 109  * g_atomic_int_get:
 110  * @atomic: a pointer to a #gint or #guint
 111  *
 112  * Gets the current value of @atomic.
 113  *
 114  * This call acts as a full compiler and hardware
 115  * memory barrier (before the get).
 116  *
 117  * Returns: the value of the integer
 118  *
 119  * Since: 2.4
 120  **/
 121 gint
 122 (g_atomic_int_get) (const volatile gint *atomic)
 123 {
 124   return g_atomic_int_get (atomic);
 125 }
 126
 127 /**
 128  * g_atomic_int_set:
 129  * @atomic: a pointer to a #gint or #guint
 130  * @newval: a new value to store
 131  *
 132  * Sets the value of @atomic to @newval.
 133  *
 134  * This call acts as a full compiler and hardware
 135  * memory barrier (after the set).
 136  *
 137  * Since: 2.4
 138  */
 139 void
 140 (g_atomic_int_set) (volatile gint *atomic,
 141                     gint           newval)
 142 {
 143   g_atomic_int_set (atomic, newval);
 144 }
 145
 146 /**
 147  * g_atomic_int_inc:
 148  * @atomic: a pointer to a #gint or #guint
 149  *
 150  * Increments the value of @atomic by 1.
 151  *
 152  * Think of this operation as an atomic version of `{ *atomic += 1; }`.
 153  *
 154  * This call acts as a full compiler and hardware memory barrier.
 155  *
 156  * Since: 2.4
 157  **/
 158 void
 159 (g_atomic_int_inc) (volatile gint *atomic)
 160 {
 161   g_atomic_int_inc (atomic);
 162 }
 163
 164 /**
 165  * g_atomic_int_dec_and_test:
 166  * @atomic: a pointer to a #gint or #guint
 167  *
 168  * Decrements the value of @atomic by 1.
 169  *
 170  * Think of this operation as an atomic version of
 171  * `{ *atomic -= 1; return (*atomic == 0); }`.
 172  *
 173  * This call acts as a full compiler and hardware memory barrier.
 174  *
 175  * Returns: %TRUE if the resultant value is zero
 176  *
 177  * Since: 2.4
 178  **/
 179 gboolean
 180 (g_atomic_int_dec_and_test) (volatile gint *atomic)
 181 {
 182   return g_atomic_int_dec_and_test (atomic);
 183 }
 184
 185 /**
 186  * g_atomic_int_compare_and_exchange:
 187  * @atomic: a pointer to a #gint or #guint
 188  * @oldval: the value to compare with
 189  * @newval: the value to conditionally replace with
 190  *
 191  * Compares @atomic to @oldval and, if equal, sets it to @newval.
 192  * If @atomic was not equal to @oldval then no change occurs.
 193  *
 194  * This compare and exchange is done atomically.
 195  *
 196  * Think of this operation as an atomic version of
 197  * `{ if (*atomic == oldval) { *atomic = newval; return TRUE; } else return FALSE; }`.
 198  *
 199  * This call acts as a full compiler and hardware memory barrier.
 200  *
 201  * Returns: %TRUE if the exchange took place
 202  *
 203  * Since: 2.4
 204  **/
 205 gboolean
 206 (g_atomic_int_compare_and_exchange) (volatile gint *atomic,
 207                                      gint           oldval,
 208                                      gint           newval)
 209 {
 210   return g_atomic_int_compare_and_exchange (atomic, oldval, newval);
 211 }
 212
 213 /**
 214  * g_atomic_int_add:
 215  * @atomic: a pointer to a #gint or #guint
 216  * @val: the value to add
 217  *
 218  * Atomically adds @val to the value of @atomic.
 219  *
 220  * Think of this operation as an atomic version of
 221  * `{ tmp = *atomic; *atomic += val; return tmp; }`.
 222  *
 223  * This call acts as a full compiler and hardware memory barrier.
 224  *
 225  * Before version 2.30, this function did not return a value
 226  * (but g_atomic_int_exchange_and_add() did, and had the same meaning).
 227  *
 228  * Returns: the value of @atomic before the add, signed
 229  *
 230  * Since: 2.4
 231  **/
 232 gint
 233 (g_atomic_int_add) (volatile gint *atomic,
 234                     gint           val)
 235 {
 236   return g_atomic_int_add (atomic, val);
 237 }
 238
 239 /**
 240  * g_atomic_int_and:
 241  * @atomic: a pointer to a #gint or #guint
 242  * @val: the value to 'and'
 243  *
 244  * Performs an atomic bitwise 'and' of the value of @atomic and @val,
 245  * storing the result back in @atomic.
 246  *
 247  * This call acts as a full compiler and hardware memory barrier.
 248  *
 249  * Think of this operation as an atomic version of
 250  * `{ tmp = *atomic; *atomic &= val; return tmp; }`.
 251  *
 252  * Returns: the value of @atomic before the operation, unsigned
 253  *
 254  * Since: 2.30
 255  **/
 256 guint
 257 (g_atomic_int_and) (volatile guint *atomic,
 258                     guint           val)
 259 {
 260   return g_atomic_int_and (atomic, val);
 261 }
 262
 263 /**
 264  * g_atomic_int_or:
 265  * @atomic: a pointer to a #gint or #guint
 266  * @val: the value to 'or'
 267  *
 268  * Performs an atomic bitwise 'or' of the value of @atomic and @val,
 269  * storing the result back in @atomic.
 270  *
 271  * Think of this operation as an atomic version of
 272  * `{ tmp = *atomic; *atomic |= val; return tmp; }`.
 273  *
 274  * This call acts as a full compiler and hardware memory barrier.
 275  *
 276  * Returns: the value of @atomic before the operation, unsigned
 277  *
 278  * Since: 2.30
 279  **/
 280 guint
 281 (g_atomic_int_or) (volatile guint *atomic,
 282                    guint           val)
 283 {
 284   return g_atomic_int_or (atomic, val);
 285 }
 286
 287 /**
 288  * g_atomic_int_xor:
 289  * @atomic: a pointer to a #gint or #guint
 290  * @val: the value to 'xor'
 291  *
 292  * Performs an atomic bitwise 'xor' of the value of @atomic and @val,
 293  * storing the result back in @atomic.
 294  *
 295  * Think of this operation as an atomic version of
 296  * `{ tmp = *atomic; *atomic ^= val; return tmp; }`.
 297  *
 298  * This call acts as a full compiler and hardware memory barrier.
 299  *
 300  * Returns: the value of @atomic before the operation, unsigned
 301  *
 302  * Since: 2.30
 303  **/
 304 guint
 305 (g_atomic_int_xor) (volatile guint *atomic,
 306                     guint           val)
 307 {
 308   return g_atomic_int_xor (atomic, val);
 309 }
 310
 311
 312 /**
 313  * g_atomic_pointer_get:
 314  * @atomic: (not nullable): a pointer to a #gpointer-sized value
 315  *
 316  * Gets the current value of @atomic.
 317  *
 318  * This call acts as a full compiler and hardware
 319  * memory barrier (before the get).
 320  *
 321  * Returns: the value of the pointer
 322  *
 323  * Since: 2.4
 324  **/
 325 gpointer
 326 (g_atomic_pointer_get) (const volatile void *atomic)
 327 {
 328   return g_atomic_pointer_get ((const volatile gpointer *) atomic);
 329 }
 330
 331 /**
 332  * g_atomic_pointer_set:
 333  * @atomic: (not nullable): a pointer to a #gpointer-sized value
 334  * @newval: a new value to store
 335  *
 336  * Sets the value of @atomic to @newval.
 337  *
 338  * This call acts as a full compiler and hardware
 339  * memory barrier (after the set).
 340  *
 341  * Since: 2.4
 342  **/
 343 void
 344 (g_atomic_pointer_set) (volatile void *atomic,
 345                         gpointer       newval)
 346 {
 347   g_atomic_pointer_set ((volatile gpointer *) atomic, newval);
 348 }
 349
 350 /**
 351  * g_atomic_pointer_compare_and_exchange:
 352  * @atomic: (not nullable): a pointer to a #gpointer-sized value
 353  * @oldval: the value to compare with
 354  * @newval: the value to conditionally replace with
 355  *
 356  * Compares @atomic to @oldval and, if equal, sets it to @newval.
 357  * If @atomic was not equal to @oldval then no change occurs.
 358  *
 359  * This compare and exchange is done atomically.
 360  *
 361  * Think of this operation as an atomic version of
 362  * `{ if (*atomic == oldval) { *atomic = newval; return TRUE; } else return FALSE; }`.
 363  *
 364  * This call acts as a full compiler and hardware memory barrier.
 365  *
 366  * Returns: %TRUE if the exchange took place
 367  *
 368  * Since: 2.4
 369  **/
 370 gboolean
 371 (g_atomic_pointer_compare_and_exchange) (volatile void *atomic,
 372                                          gpointer       oldval,
 373                                          gpointer       newval)
 374 {
 375   return g_atomic_pointer_compare_and_exchange ((volatile gpointer *) atomic,
 376                                                 oldval, newval);
 377 }
 378
 379 /**
 380  * g_atomic_pointer_add:
 381  * @atomic: (not nullable): a pointer to a #gpointer-sized value
 382  * @val: the value to add
 383  *
 384  * Atomically adds @val to the value of @atomic.
 385  *
 386  * Think of this operation as an atomic version of
 387  * `{ tmp = *atomic; *atomic += val; return tmp; }`.
 388  *
 389  * This call acts as a full compiler and hardware memory barrier.
 390  *
 391  * Returns: the value of @atomic before the add, signed
 392  *
 393  * Since: 2.30
 394  **/
 395 gssize
 396 (g_atomic_pointer_add) (volatile void *atomic,
 397                         gssize         val)
 398 {
 399   return g_atomic_pointer_add ((volatile gpointer *) atomic, val);
 400 }
 401
 402 /**
 403  * g_atomic_pointer_and:
 404  * @atomic: (not nullable): a pointer to a #gpointer-sized value
 405  * @val: the value to 'and'
 406  *
 407  * Performs an atomic bitwise 'and' of the value of @atomic and @val,
 408  * storing the result back in @atomic.
 409  *
 410  * Think of this operation as an atomic version of
 411  * `{ tmp = *atomic; *atomic &= val; return tmp; }`.
 412  *
 413  * This call acts as a full compiler and hardware memory barrier.
 414  *
 415  * Returns: the value of @atomic before the operation, unsigned
 416  *
 417  * Since: 2.30
 418  **/
 419 gsize
 420 (g_atomic_pointer_and) (volatile void *atomic,
 421                         gsize          val)
 422 {
 423   return g_atomic_pointer_and ((volatile gpointer *) atomic, val);
 424 }
 425
 426 /**
 427  * g_atomic_pointer_or:
 428  * @atomic: (not nullable): a pointer to a #gpointer-sized value
 429  * @val: the value to 'or'
 430  *
 431  * Performs an atomic bitwise 'or' of the value of @atomic and @val,
 432  * storing the result back in @atomic.
 433  *
 434  * Think of this operation as an atomic version of
 435  * `{ tmp = *atomic; *atomic |= val; return tmp; }`.
 436  *
 437  * This call acts as a full compiler and hardware memory barrier.
 438  *
 439  * Returns: the value of @atomic before the operation, unsigned
 440  *
 441  * Since: 2.30
 442  **/
 443 gsize
 444 (g_atomic_pointer_or) (volatile void *atomic,
 445                        gsize          val)
 446 {
 447   return g_atomic_pointer_or ((volatile gpointer *) atomic, val);
 448 }
 449
 450 /**
 451  * g_atomic_pointer_xor:
 452  * @atomic: (not nullable): a pointer to a #gpointer-sized value
 453  * @val: the value to 'xor'
 454  *
 455  * Performs an atomic bitwise 'xor' of the value of @atomic and @val,
 456  * storing the result back in @atomic.
 457  *
 458  * Think of this operation as an atomic version of
 459  * `{ tmp = *atomic; *atomic ^= val; return tmp; }`.
 460  *
 461  * This call acts as a full compiler and hardware memory barrier.
 462  *
 463  * Returns: the value of @atomic before the operation, unsigned
 464  *
 465  * Since: 2.30
 466  **/
 467 gsize
 468 (g_atomic_pointer_xor) (volatile void *atomic,
 469                         gsize          val)
 470 {
 471   return g_atomic_pointer_xor ((volatile gpointer *) atomic, val);
 472 }
 473
 474 #elif defined (G_PLATFORM_WIN32)
 475
 476 #include <windows.h>
 477 #if !defined(_M_AMD64) && !defined (_M_IA64) && !defined(_M_X64) && !(defined _MSC_VER && _MSC_VER <= 1200)
 478 #define InterlockedAnd _InterlockedAnd
 479 #define InterlockedOr _InterlockedOr
 480 #define InterlockedXor _InterlockedXor
 481 #endif
 482
 483 #if !defined (_MSC_VER) || _MSC_VER <= 1200
 484 #include "gmessages.h"
 485 /* Inlined versions for older compiler */
 486 static LONG
 487 _gInterlockedAnd (volatile guint *atomic,
 488                   guint           val)
 489 {
 490   LONG i, j;
 491
 492   j = *atomic;
 493   do {
 494     i = j;
 495     j = InterlockedCompareExchange(atomic, i & val, i);
 496   } while (i != j);
 497
 498   return j;
 499 }
 500 #define InterlockedAnd(a,b) _gInterlockedAnd(a,b)
 501 static LONG
 502 _gInterlockedOr (volatile guint *atomic,
 503                  guint           val)
 504 {
 505   LONG i, j;
 506
 507   j = *atomic;
 508   do {
 509     i = j;
 510     j = InterlockedCompareExchange(atomic, i | val, i);
 511   } while (i != j);
 512
 513   return j;
 514 }
 515 #define InterlockedOr(a,b) _gInterlockedOr(a,b)
 516 static LONG
 517 _gInterlockedXor (volatile guint *atomic,
 518                   guint           val)
 519 {
 520   LONG i, j;
 521
 522   j = *atomic;
 523   do {
 524     i = j;
 525     j = InterlockedCompareExchange(atomic, i ^ val, i);
 526   } while (i != j);
 527
 528   return j;
 529 }
 530 #define InterlockedXor(a,b) _gInterlockedXor(a,b)
 531 #endif
 532
 533 /*
 534  * http://msdn.microsoft.com/en-us/library/ms684122(v=vs.85).aspx
 535  */
 536 gint
 537 (g_atomic_int_get) (const volatile gint *atomic)
 538 {
 539   MemoryBarrier ();
 540   return *atomic;
 541 }
 542
 543 void
 544 (g_atomic_int_set) (volatile gint *atomic,
 545                     gint           newval)
 546 {
 547   *atomic = newval;
 548   MemoryBarrier ();
 549 }
 550
 551 void
 552 (g_atomic_int_inc) (volatile gint *atomic)
 553 {
 554   InterlockedIncrement (atomic);
 555 }
 556
 557 gboolean
 558 (g_atomic_int_dec_and_test) (volatile gint *atomic)
 559 {
 560   return InterlockedDecrement (atomic) == 0;
 561 }
 562
 563 gboolean
 564 (g_atomic_int_compare_and_exchange) (volatile gint *atomic,
 565                                      gint           oldval,
 566                                      gint           newval)
 567 {
 568   return InterlockedCompareExchange (atomic, newval, oldval) == oldval;
 569 }
 570
 571 gint
 572 (g_atomic_int_add) (volatile gint *atomic,
 573                     gint           val)
 574 {
 575   return InterlockedExchangeAdd (atomic, val);
 576 }
 577
 578 guint
 579 (g_atomic_int_and) (volatile guint *atomic,
 580                     guint           val)
 581 {
 582   return InterlockedAnd (atomic, val);
 583 }
 584
 585 guint
 586 (g_atomic_int_or) (volatile guint *atomic,
 587                    guint           val)
 588 {
 589   return InterlockedOr (atomic, val);
 590 }
 591
 592 guint
 593 (g_atomic_int_xor) (volatile guint *atomic,
 594                     guint           val)
 595 {
 596   return InterlockedXor (atomic, val);
 597 }
 598
 599
 600 gpointer
 601 (g_atomic_pointer_get) (const volatile void *atomic)
 602 {
 603   const volatile gpointer *ptr = atomic;
 604
 605   MemoryBarrier ();
 606   return *ptr;
 607 }
 608
 609 void
 610 (g_atomic_pointer_set) (volatile void *atomic,
 611                         gpointer       newval)
 612 {
 613   volatile gpointer *ptr = atomic;
 614
 615   *ptr = newval;
 616   MemoryBarrier ();
 617 }
 618
 619 gboolean
 620 (g_atomic_pointer_compare_and_exchange) (volatile void *atomic,
 621                                          gpointer       oldval,
 622                                          gpointer       newval)
 623 {
 624   return InterlockedCompareExchangePointer (atomic, newval, oldval) == oldval;
 625 }
 626
 627 gssize
 628 (g_atomic_pointer_add) (volatile void *atomic,
 629                         gssize         val)
 630 {
 631 #if GLIB_SIZEOF_VOID_P == 8
 632   return InterlockedExchangeAdd64 (atomic, val);
 633 #else
 634   return InterlockedExchangeAdd (atomic, val);
 635 #endif
 636 }
 637
 638 gsize
 639 (g_atomic_pointer_and) (volatile void *atomic,
 640                         gsize          val)
 641 {
 642 #if GLIB_SIZEOF_VOID_P == 8
 643   return InterlockedAnd64 (atomic, val);
 644 #else
 645   return InterlockedAnd (atomic, val);
 646 #endif
 647 }
 648
 649 gsize
 650 (g_atomic_pointer_or) (volatile void *atomic,
 651                        gsize          val)
 652 {
 653 #if GLIB_SIZEOF_VOID_P == 8
 654   return InterlockedOr64 (atomic, val);
 655 #else
 656   return InterlockedOr (atomic, val);
 657 #endif
 658 }
 659
 660 gsize
 661 (g_atomic_pointer_xor) (volatile void *atomic,
 662                         gsize          val)
 663 {
 664 #if GLIB_SIZEOF_VOID_P == 8
 665   return InterlockedXor64 (atomic, val);
 666 #else
 667   return InterlockedXor (atomic, val);
 668 #endif
 669 }
 670 #else
 671
 672 /* This error occurs when ./configure decided that we should be capable
 673  * of lock-free atomics but we find at compile-time that we are not.
 674  */
 675 #error G_ATOMIC_LOCK_FREE defined, but incapable of lock-free atomics.
 676
 677 #endif /* defined (__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4) */
 678
 679 #else /* G_ATOMIC_LOCK_FREE */
 680
 681 /* We are not permitted to call into any GLib functions from here, so we
 682  * can not use GMutex.
 683  *
 684  * Fortunately, we already take care of the Windows case above, and all
 685  * non-Windows platforms on which glib runs have pthreads.  Use those.
 686  */
 687 #include <pthread.h>
 688
 689 static pthread_mutex_t g_atomic_lock = PTHREAD_MUTEX_INITIALIZER;
 690
 691 gint
 692 (g_atomic_int_get) (const volatile gint *atomic)
 693 {
 694   gint value;
 695
 696   pthread_mutex_lock (&g_atomic_lock);
 697   value = *atomic;
 698   pthread_mutex_unlock (&g_atomic_lock);
 699
 700   return value;
 701 }
 702
 703 void
 704 (g_atomic_int_set) (volatile gint *atomic,
 705                     gint           value)
 706 {
 707   pthread_mutex_lock (&g_atomic_lock);
 708   *atomic = value;
 709   pthread_mutex_unlock (&g_atomic_lock);
 710 }
 711
 712 void
 713 (g_atomic_int_inc) (volatile gint *atomic)
 714 {
 715   pthread_mutex_lock (&g_atomic_lock);
 716   (*atomic)++;
 717   pthread_mutex_unlock (&g_atomic_lock);
 718 }
 719
 720 gboolean
 721 (g_atomic_int_dec_and_test) (volatile gint *atomic)
 722 {
 723   gboolean is_zero;
 724
 725   pthread_mutex_lock (&g_atomic_lock);
 726   is_zero = --(*atomic) == 0;
 727   pthread_mutex_unlock (&g_atomic_lock);
 728
 729   return is_zero;
 730 }
 731
 732 gboolean
 733 (g_atomic_int_compare_and_exchange) (volatile gint *atomic,
 734                                      gint           oldval,
 735                                      gint           newval)
 736 {
 737   gboolean success;
 738
 739   pthread_mutex_lock (&g_atomic_lock);
 740
 741   if ((success = (*atomic == oldval)))
 742     *atomic = newval;
 743
 744   pthread_mutex_unlock (&g_atomic_lock);
 745
 746   return success;
 747 }
 748
 749 gint
 750 (g_atomic_int_add) (volatile gint *atomic,
 751                     gint           val)
 752 {
 753   gint oldval;
 754
 755   pthread_mutex_lock (&g_atomic_lock);
 756   oldval = *atomic;
 757   *atomic = oldval + val;
 758   pthread_mutex_unlock (&g_atomic_lock);
 759
 760   return oldval;
 761 }
 762
 763 guint
 764 (g_atomic_int_and) (volatile guint *atomic,
 765                     guint           val)
 766 {
 767   guint oldval;
 768
 769   pthread_mutex_lock (&g_atomic_lock);
 770   oldval = *atomic;
 771   *atomic = oldval & val;
 772   pthread_mutex_unlock (&g_atomic_lock);
 773
 774   return oldval;
 775 }
 776
 777 guint
 778 (g_atomic_int_or) (volatile guint *atomic,
 779                    guint           val)
 780 {
 781   guint oldval;
 782
 783   pthread_mutex_lock (&g_atomic_lock);
 784   oldval = *atomic;
 785   *atomic = oldval | val;
 786   pthread_mutex_unlock (&g_atomic_lock);
 787
 788   return oldval;
 789 }
 790
 791 guint
 792 (g_atomic_int_xor) (volatile guint *atomic,
 793                     guint           val)
 794 {
 795   guint oldval;
 796
 797   pthread_mutex_lock (&g_atomic_lock);
 798   oldval = *atomic;
 799   *atomic = oldval ^ val;
 800   pthread_mutex_unlock (&g_atomic_lock);
 801
 802   return oldval;
 803 }
 804
 805
 806 gpointer
 807 (g_atomic_pointer_get) (const volatile void *atomic)
 808 {
 809   const volatile gpointer *ptr = atomic;
 810   gpointer value;
 811
 812   pthread_mutex_lock (&g_atomic_lock);
 813   value = *ptr;
 814   pthread_mutex_unlock (&g_atomic_lock);
 815
 816   return value;
 817 }
 818
 819 void
 820 (g_atomic_pointer_set) (volatile void *atomic,
 821                         gpointer       newval)
 822 {
 823   volatile gpointer *ptr = atomic;
 824
 825   pthread_mutex_lock (&g_atomic_lock);
 826   *ptr = newval;
 827   pthread_mutex_unlock (&g_atomic_lock);
 828 }
 829
 830 gboolean
 831 (g_atomic_pointer_compare_and_exchange) (volatile void *atomic,
 832                                          gpointer       oldval,
 833                                          gpointer       newval)
 834 {
 835   volatile gpointer *ptr = atomic;
 836   gboolean success;
 837
 838   pthread_mutex_lock (&g_atomic_lock);
 839
 840   if ((success = (*ptr == oldval)))
 841     *ptr = newval;
 842
 843   pthread_mutex_unlock (&g_atomic_lock);
 844
 845   return success;
 846 }
 847
 848 gssize
 849 (g_atomic_pointer_add) (volatile void *atomic,
 850                         gssize         val)
 851 {
 852   volatile gssize *ptr = atomic;
 853   gssize oldval;
 854
 855   pthread_mutex_lock (&g_atomic_lock);
 856   oldval = *ptr;
 857   *ptr = oldval + val;
 858   pthread_mutex_unlock (&g_atomic_lock);
 859
 860   return oldval;
 861 }
 862
 863 gsize
 864 (g_atomic_pointer_and) (volatile void *atomic,
 865                         gsize          val)
 866 {
 867   volatile gsize *ptr = atomic;
 868   gsize oldval;
 869
 870   pthread_mutex_lock (&g_atomic_lock);
 871   oldval = *ptr;
 872   *ptr = oldval & val;
 873   pthread_mutex_unlock (&g_atomic_lock);
 874
 875   return oldval;
 876 }
 877
 878 gsize
 879 (g_atomic_pointer_or) (volatile void *atomic,
 880                        gsize          val)
 881 {
 882   volatile gsize *ptr = atomic;
 883   gsize oldval;
 884
 885   pthread_mutex_lock (&g_atomic_lock);
 886   oldval = *ptr;
 887   *ptr = oldval | val;
 888   pthread_mutex_unlock (&g_atomic_lock);
 889
 890   return oldval;
 891 }
 892
 893 gsize
 894 (g_atomic_pointer_xor) (volatile void *atomic,
 895                         gsize          val)
 896 {
 897   volatile gsize *ptr = atomic;
 898   gsize oldval;
 899
 900   pthread_mutex_lock (&g_atomic_lock);
 901   oldval = *ptr;
 902   *ptr = oldval ^ val;
 903   pthread_mutex_unlock (&g_atomic_lock);
 904
 905   return oldval;
 906 }
 907
 908 #endif
 909
 910 /**
 911  * g_atomic_int_exchange_and_add:
 912  * @atomic: a pointer to a #gint
 913  * @val: the value to add
 914  *
 915  * This function existed before g_atomic_int_add() returned the prior
 916  * value of the integer (which it now does).  It is retained only for
 917  * compatibility reasons.  Don't use this function in new code.
 918  *
 919  * Returns: the value of @atomic before the add, signed
 920  * Since: 2.4
 921  * Deprecated: 2.30: Use g_atomic_int_add() instead.
 922  **/
 923 gint
 924 g_atomic_int_exchange_and_add (volatile gint *atomic,
 925                                gint           val)
 926 {
 927   return (g_atomic_int_add) (atomic, val);
 928 }