glib/gthread.c

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * gthread.c: MT safety related functions
   5  * Copyright 1998 Sebastian Wilhelmi; University of Karlsruhe
   6  *                Owen Taylor
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the
  20  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21  * Boston, MA 02111-1307, USA.
  22  */
  23
  24 /*
  25  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  26  * file for a list of people on the GLib Team.  See the ChangeLog
  27  * files for a list of changes.  These files are distributed with
  28  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  29  */
  30
  31 /*
  32  * MT safe
  33  */
  34
  35 /* implement gthread.h's inline functions */
  36 #define G_IMPLEMENT_INLINES 1
  37 #define __G_THREAD_C__
  38
  39 #include "config.h"
  40
  41 #include "glib.h"
  42 #include "gthreadprivate.h"
  43
  44 #ifdef HAVE_UNISTD_H
  45 #include <unistd.h>
  46 #endif
  47
  48 #ifndef G_OS_WIN32
  49 #include <sys/time.h>
  50 #include <time.h>
  51 #else
  52 #include <windows.h>
  53 #endif /* G_OS_WIN32 */
  54
  55 #include <string.h>
  56
  57 #include "galias.h"
  58
  59 GQuark
  60 g_thread_error_quark (void)
  61 {
  62   return g_quark_from_static_string ("g_thread_error");
  63 }
  64
  65 /* Keep this in sync with GRealThread in gmain.c! */
  66 typedef struct _GRealThread GRealThread;
  67 struct  _GRealThread
  68 {
  69   GThread thread;
  70   gpointer private_data;
  71   GRealThread *next;
  72   gpointer retval;
  73   GSystemThread system_thread;
  74 };
  75
  76 typedef struct _GStaticPrivateNode GStaticPrivateNode;
  77 struct _GStaticPrivateNode
  78 {
  79   gpointer       data;
  80   GDestroyNotify destroy;
  81 };
  82
  83 static void    g_thread_cleanup (gpointer data);
  84 static void    g_thread_fail (void);
  85 static guint64 gettime (void);
  86
  87 guint64        (*g_thread_gettime) (void) = gettime;
  88
  89 /* Global variables */
  90
  91 static GSystemThread zero_thread; /* This is initialized to all zero */
  92 gboolean g_thread_use_default_impl = TRUE;
  93 gboolean g_threads_got_initialized = FALSE;
  94
  95 GThreadFunctions g_thread_functions_for_glib_use = {
  96   (GMutex*(*)())g_thread_fail,                 /* mutex_new */
  97   NULL,                                        /* mutex_lock */
  98   NULL,                                        /* mutex_trylock */
  99   NULL,                                        /* mutex_unlock */
 100   NULL,                                        /* mutex_free */
 101   (GCond*(*)())g_thread_fail,                  /* cond_new */
 102   NULL,                                        /* cond_signal */
 103   NULL,                                        /* cond_broadcast */
 104   NULL,                                        /* cond_wait */
 105   NULL,                                        /* cond_timed_wait  */
 106   NULL,                                        /* cond_free */
 107   (GPrivate*(*)(GDestroyNotify))g_thread_fail, /* private_new */
 108   NULL,                                        /* private_get */
 109   NULL,                                        /* private_set */
 110   (void(*)(GThreadFunc, gpointer, gulong,
 111            gboolean, gboolean, GThreadPriority,
 112            gpointer, GError**))g_thread_fail,  /* thread_create */
 113   NULL,                                        /* thread_yield */
 114   NULL,                                        /* thread_join */
 115   NULL,                                        /* thread_exit */
 116   NULL,                                        /* thread_set_priority */
 117   NULL,                                        /* thread_self */
 118   NULL                                         /* thread_equal */
 119 };
 120
 121 /* Local data */
 122
 123 static GMutex   *g_once_mutex = NULL;
 124 static GCond    *g_once_cond = NULL;
 125 static GPrivate *g_thread_specific_private = NULL;
 126 static GRealThread *g_thread_all_threads = NULL;
 127 static GSList   *g_thread_free_indeces = NULL;
 128 static GSList*   g_once_init_list = NULL;
 129
 130 G_LOCK_DEFINE_STATIC (g_thread);
 131
 132 #ifdef G_THREADS_ENABLED
 133 /* This must be called only once, before any threads are created.
 134  * It will only be called from g_thread_init() in -lgthread.
 135  */
 136 void
 137 g_thread_init_glib (void)
 138 {
 139   /* We let the main thread (the one that calls g_thread_init) inherit
 140    * the static_private data set before calling g_thread_init
 141    */
 142   GRealThread* main_thread = (GRealThread*) g_thread_self ();
 143
 144   /* mutex and cond creation works without g_threads_got_initialized */
 145   g_once_mutex = g_mutex_new ();
 146   g_once_cond = g_cond_new ();
 147
 148   /* we may only create mutex and cond in here */
 149   _g_mem_thread_init_noprivate_nomessage ();
 150
 151   /* setup the basic threading system */
 152   g_threads_got_initialized = TRUE;
 153   g_thread_specific_private = g_private_new (g_thread_cleanup);
 154   g_private_set (g_thread_specific_private, main_thread);
 155   G_THREAD_UF (thread_self, (&main_thread->system_thread));
 156
 157   /* complete memory system initialization, g_private_*() works now */
 158   _g_slice_thread_init_nomessage ();
 159
 160   /* accomplish log system initialization to enable messaging */
 161   _g_messages_thread_init_nomessage ();
 162
 163   /* we may run full-fledged initializers from here */
 164   _g_atomic_thread_init ();
 165   _g_convert_thread_init ();
 166   _g_rand_thread_init ();
 167   _g_main_thread_init ();
 168   _g_utils_thread_init ();
 169 #ifdef G_OS_WIN32
 170   _g_win32_thread_init ();
 171 #endif
 172 }
 173 #endif /* G_THREADS_ENABLED */
 174
 175 gpointer
 176 g_once_impl (GOnce       *once,
 177              GThreadFunc  func,
 178              gpointer     arg)
 179 {
 180   g_mutex_lock (g_once_mutex);
 181
 182   while (once->status == G_ONCE_STATUS_PROGRESS)
 183     g_cond_wait (g_once_cond, g_once_mutex);
 184
 185   if (once->status != G_ONCE_STATUS_READY)
 186     {
 187       once->status = G_ONCE_STATUS_PROGRESS;
 188       g_mutex_unlock (g_once_mutex);
 189
 190       once->retval = func (arg);
 191
 192       g_mutex_lock (g_once_mutex);
 193       once->status = G_ONCE_STATUS_READY;
 194       g_cond_broadcast (g_once_cond);
 195     }
 196
 197   g_mutex_unlock (g_once_mutex);
 198
 199   return once->retval;
 200 }
 201
 202 gboolean
 203 g_once_init_enter_impl (volatile gsize *value_location)
 204 {
 205   gboolean need_init = FALSE;
 206   g_mutex_lock (g_once_mutex);
 207   if (g_atomic_pointer_get ((void**) value_location) == NULL)
 208     {
 209       if (!g_slist_find (g_once_init_list, (void*) value_location))
 210         {
 211           need_init = TRUE;
 212           g_once_init_list = g_slist_prepend (g_once_init_list, (void*) value_location);
 213         }
 214       else
 215         do
 216           g_cond_wait (g_once_cond, g_once_mutex);
 217         while (g_slist_find (g_once_init_list, (void*) value_location));
 218     }
 219   g_mutex_unlock (g_once_mutex);
 220   return need_init;
 221 }
 222
 223 void
 224 g_once_init_leave (volatile gsize *value_location,
 225                    gsize           initialization_value)
 226 {
 227   g_return_if_fail (g_atomic_pointer_get ((void**) value_location) == NULL);
 228   g_return_if_fail (initialization_value != 0);
 229   g_return_if_fail (g_once_init_list != NULL);
 230
 231   g_atomic_pointer_set ((void**) value_location, (void*) initialization_value);
 232   g_mutex_lock (g_once_mutex);
 233   g_once_init_list = g_slist_remove (g_once_init_list, (void*) value_location);
 234   g_cond_broadcast (g_once_cond);
 235   g_mutex_unlock (g_once_mutex);
 236 }
 237
 238 void
 239 g_static_mutex_init (GStaticMutex *mutex)
 240 {
 241   static const GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
 242
 243   g_return_if_fail (mutex);
 244
 245   *mutex = init_mutex;
 246 }
 247
 248 GMutex *
 249 g_static_mutex_get_mutex_impl (GMutex** mutex)
 250 {
 251   if (!g_thread_supported ())
 252     return NULL;
 253
 254   g_assert (g_once_mutex);
 255
 256   g_mutex_lock (g_once_mutex);
 257
 258   if (!(*mutex))
 259     g_atomic_pointer_set ((void**) mutex, g_mutex_new());
 260
 261   g_mutex_unlock (g_once_mutex);
 262
 263   return *mutex;
 264 }
 265
 266 void
 267 g_static_mutex_free (GStaticMutex* mutex)
 268 {
 269   GMutex **runtime_mutex;
 270
 271   g_return_if_fail (mutex);
 272
 273   /* The runtime_mutex is the first (or only) member of GStaticMutex,
 274    * see both versions (of glibconfig.h) in configure.in. Note, that
 275    * this variable is NULL, if g_thread_init() hasn't been called or
 276    * if we're using the default thread implementation and it provides
 277    * static mutexes. */
 278   runtime_mutex = ((GMutex**)mutex);
 279
 280   if (*runtime_mutex)
 281     g_mutex_free (*runtime_mutex);
 282
 283   *runtime_mutex = NULL;
 284 }
 285
 286 void
 287 g_static_rec_mutex_init (GStaticRecMutex *mutex)
 288 {
 289   static const GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
 290
 291   g_return_if_fail (mutex);
 292
 293   *mutex = init_mutex;
 294 }
 295
 296 void
 297 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
 298 {
 299   GSystemThread self;
 300
 301   g_return_if_fail (mutex);
 302
 303   if (!g_thread_supported ())
 304     return;
 305
 306   G_THREAD_UF (thread_self, (&self));
 307
 308   if (g_system_thread_equal (self, mutex->owner))
 309     {
 310       mutex->depth++;
 311       return;
 312     }
 313   g_static_mutex_lock (&mutex->mutex);
 314   g_system_thread_assign (mutex->owner, self);
 315   mutex->depth = 1;
 316 }
 317
 318 gboolean
 319 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
 320 {
 321   GSystemThread self;
 322
 323   g_return_val_if_fail (mutex, FALSE);
 324
 325   if (!g_thread_supported ())
 326     return TRUE;
 327
 328   G_THREAD_UF (thread_self, (&self));
 329
 330   if (g_system_thread_equal (self, mutex->owner))
 331     {
 332       mutex->depth++;
 333       return TRUE;
 334     }
 335
 336   if (!g_static_mutex_trylock (&mutex->mutex))
 337     return FALSE;
 338
 339   g_system_thread_assign (mutex->owner, self);
 340   mutex->depth = 1;
 341   return TRUE;
 342 }
 343
 344 void
 345 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
 346 {
 347   g_return_if_fail (mutex);
 348
 349   if (!g_thread_supported ())
 350     return;
 351
 352   if (mutex->depth > 1)
 353     {
 354       mutex->depth--;
 355       return;
 356     }
 357   g_system_thread_assign (mutex->owner, zero_thread);
 358   g_static_mutex_unlock (&mutex->mutex);
 359 }
 360
 361 void
 362 g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
 363                                 guint            depth)
 364 {
 365   GSystemThread self;
 366   g_return_if_fail (mutex);
 367
 368   if (!g_thread_supported ())
 369     return;
 370
 371   if (depth == 0)
 372     return;
 373
 374   G_THREAD_UF (thread_self, (&self));
 375
 376   if (g_system_thread_equal (self, mutex->owner))
 377     {
 378       mutex->depth += depth;
 379       return;
 380     }
 381   g_static_mutex_lock (&mutex->mutex);
 382   g_system_thread_assign (mutex->owner, self);
 383   mutex->depth = depth;
 384 }
 385
 386 guint
 387 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
 388 {
 389   guint depth;
 390
 391   g_return_val_if_fail (mutex, 0);
 392
 393   if (!g_thread_supported ())
 394     return 1;
 395
 396   depth = mutex->depth;
 397
 398   g_system_thread_assign (mutex->owner, zero_thread);
 399   mutex->depth = 0;
 400   g_static_mutex_unlock (&mutex->mutex);
 401
 402   return depth;
 403 }
 404
 405 void
 406 g_static_rec_mutex_free (GStaticRecMutex *mutex)
 407 {
 408   g_return_if_fail (mutex);
 409
 410   g_static_mutex_free (&mutex->mutex);
 411 }
 412
 413 void
 414 g_static_private_init (GStaticPrivate *private_key)
 415 {
 416   private_key->index = 0;
 417 }
 418
 419 gpointer
 420 g_static_private_get (GStaticPrivate *private_key)
 421 {
 422   GRealThread *self = (GRealThread*) g_thread_self ();
 423   GArray *array;
 424
 425   array = self->private_data;
 426   if (!array)
 427     return NULL;
 428
 429   if (!private_key->index)
 430     return NULL;
 431   else if (private_key->index <= array->len)
 432     return g_array_index (array, GStaticPrivateNode,
 433                           private_key->index - 1).data;
 434   else
 435     return NULL;
 436 }
 437
 438 void
 439 g_static_private_set (GStaticPrivate *private_key,
 440                       gpointer        data,
 441                       GDestroyNotify  notify)
 442 {
 443   GRealThread *self = (GRealThread*) g_thread_self ();
 444   GArray *array;
 445   static guint next_index = 0;
 446   GStaticPrivateNode *node;
 447
 448   array = self->private_data;
 449   if (!array)
 450     {
 451       array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
 452       self->private_data = array;
 453     }
 454
 455   if (!private_key->index)
 456     {
 457       G_LOCK (g_thread);
 458
 459       if (!private_key->index)
 460         {
 461           if (g_thread_free_indeces)
 462             {
 463               private_key->index =
 464                 GPOINTER_TO_UINT (g_thread_free_indeces->data);
 465               g_thread_free_indeces =
 466                 g_slist_delete_link (g_thread_free_indeces,
 467                                      g_thread_free_indeces);
 468             }
 469           else
 470             private_key->index = ++next_index;
 471         }
 472
 473       G_UNLOCK (g_thread);
 474     }
 475
 476   if (private_key->index > array->len)
 477     g_array_set_size (array, private_key->index);
 478
 479   node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
 480   if (node->destroy)
 481     {
 482       gpointer ddata = node->data;
 483       GDestroyNotify ddestroy = node->destroy;
 484
 485       node->data = data;
 486       node->destroy = notify;
 487
 488       ddestroy (ddata);
 489     }
 490   else
 491     {
 492       node->data = data;
 493       node->destroy = notify;
 494     }
 495 }
 496
 497 void
 498 g_static_private_free (GStaticPrivate *private_key)
 499 {
 500   guint index = private_key->index;
 501   GRealThread *thread;
 502
 503   if (!index)
 504     return;
 505
 506   private_key->index = 0;
 507
 508   G_LOCK (g_thread);
 509
 510   thread = g_thread_all_threads;
 511   while (thread)
 512     {
 513       GArray *array = thread->private_data;
 514       thread = thread->next;
 515
 516       if (array && index <= array->len)
 517         {
 518           GStaticPrivateNode *node = &g_array_index (array,
 519                                                      GStaticPrivateNode,
 520                                                      index - 1);
 521           gpointer ddata = node->data;
 522           GDestroyNotify ddestroy = node->destroy;
 523
 524           node->data = NULL;
 525           node->destroy = NULL;
 526
 527           if (ddestroy)
 528             {
 529               G_UNLOCK (g_thread);
 530               ddestroy (ddata);
 531               G_LOCK (g_thread);
 532               }
 533         }
 534     }
 535   g_thread_free_indeces = g_slist_prepend (g_thread_free_indeces,
 536                                            GUINT_TO_POINTER (index));
 537   G_UNLOCK (g_thread);
 538 }
 539
 540 static void
 541 g_thread_cleanup (gpointer data)
 542 {
 543   if (data)
 544     {
 545       GRealThread* thread = data;
 546       if (thread->private_data)
 547         {
 548           GArray* array = thread->private_data;
 549           guint i;
 550
 551           for (i = 0; i < array->len; i++ )
 552             {
 553               GStaticPrivateNode *node =
 554                 &g_array_index (array, GStaticPrivateNode, i);
 555               if (node->destroy)
 556                 node->destroy (node->data);
 557             }
 558           g_array_free (array, TRUE);
 559         }
 560
 561       /* We only free the thread structure, if it isn't joinable. If
 562          it is, the structure is freed in g_thread_join */
 563       if (!thread->thread.joinable)
 564         {
 565           GRealThread *t, *p;
 566
 567           G_LOCK (g_thread);
 568           for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
 569             {
 570               if (t == thread)
 571                 {
 572                   if (p)
 573                     p->next = t->next;
 574                   else
 575                     g_thread_all_threads = t->next;
 576                   break;
 577                 }
 578             }
 579           G_UNLOCK (g_thread);
 580
 581           /* Just to make sure, this isn't used any more */
 582           g_system_thread_assign (thread->system_thread, zero_thread);
 583           g_free (thread);
 584         }
 585     }
 586 }
 587
 588 static void
 589 g_thread_fail (void)
 590 {
 591   g_error ("The thread system is not yet initialized.");
 592 }
 593
 594 #define G_NSEC_PER_SEC 1000000000
 595
 596 static guint64
 597 gettime (void)
 598 {
 599 #ifdef G_OS_WIN32
 600   guint64 v;
 601
 602   /* Returns 100s of nanoseconds since start of 1601 */
 603   GetSystemTimeAsFileTime ((FILETIME *)&v);
 604
 605   /* Offset to Unix epoch */
 606   v -= G_GINT64_CONSTANT (116444736000000000);
 607   /* Convert to nanoseconds */
 608   v *= 100;
 609
 610   return v;
 611 #else
 612   struct timeval tv;
 613
 614   gettimeofday (&tv, NULL);
 615
 616   return (guint64) tv.tv_sec * G_NSEC_PER_SEC + tv.tv_usec * (G_NSEC_PER_SEC / G_USEC_PER_SEC);
 617 #endif
 618 }
 619
 620 static gpointer
 621 g_thread_create_proxy (gpointer data)
 622 {
 623   GRealThread* thread = data;
 624
 625   g_assert (data);
 626
 627   /* This has to happen before G_LOCK, as that might call g_thread_self */
 628   g_private_set (g_thread_specific_private, data);
 629
 630   /* the lock makes sure, that thread->system_thread is written,
 631      before thread->thread.func is called. See g_thread_create. */
 632   G_LOCK (g_thread);
 633   G_UNLOCK (g_thread);
 634
 635   thread->retval = thread->thread.func (thread->thread.data);
 636
 637   return NULL;
 638 }
 639
 640 GThread*
 641 g_thread_create_full (GThreadFunc                func,
 642                       gpointer           data,
 643                       gulong             stack_size,
 644                       gboolean           joinable,
 645                       gboolean           bound,
 646                       GThreadPriority    priority,
 647                       GError                **error)
 648 {
 649   GRealThread* result;
 650   GError *local_error = NULL;
 651   g_return_val_if_fail (func, NULL);
 652   g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL);
 653   g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL);
 654
 655   result = g_new0 (GRealThread, 1);
 656
 657   result->thread.joinable = joinable;
 658   result->thread.priority = priority;
 659   result->thread.func = func;
 660   result->thread.data = data;
 661   result->private_data = NULL;
 662   G_LOCK (g_thread);
 663   G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
 664                                stack_size, joinable, bound, priority,
 665                                &result->system_thread, &local_error));
 666   if (!local_error)
 667     {
 668       result->next = g_thread_all_threads;
 669       g_thread_all_threads = result;
 670     }
 671   G_UNLOCK (g_thread);
 672
 673   if (local_error)
 674     {
 675       g_propagate_error (error, local_error);
 676       g_free (result);
 677       return NULL;
 678     }
 679
 680   return (GThread*) result;
 681 }
 682
 683 void
 684 g_thread_exit (gpointer retval)
 685 {
 686   GRealThread* real = (GRealThread*) g_thread_self ();
 687   real->retval = retval;
 688   G_THREAD_CF (thread_exit, (void)0, ());
 689 }
 690
 691 gpointer
 692 g_thread_join (GThread* thread)
 693 {
 694   GRealThread* real = (GRealThread*) thread;
 695   GRealThread *p, *t;
 696   gpointer retval;
 697
 698   g_return_val_if_fail (thread, NULL);
 699   g_return_val_if_fail (thread->joinable, NULL);
 700   g_return_val_if_fail (!g_system_thread_equal (real->system_thread,
 701                                                 zero_thread), NULL);
 702
 703   G_THREAD_UF (thread_join, (&real->system_thread));
 704
 705   retval = real->retval;
 706
 707   G_LOCK (g_thread);
 708   for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
 709     {
 710       if (t == (GRealThread*) thread)
 711         {
 712           if (p)
 713             p->next = t->next;
 714           else
 715             g_thread_all_threads = t->next;
 716           break;
 717         }
 718     }
 719   G_UNLOCK (g_thread);
 720
 721   /* Just to make sure, this isn't used any more */
 722   thread->joinable = 0;
 723   g_system_thread_assign (real->system_thread, zero_thread);
 724
 725   /* the thread structure for non-joinable threads is freed upon
 726      thread end. We free the memory here. This will leave a loose end,
 727      if a joinable thread is not joined. */
 728
 729   g_free (thread);
 730
 731   return retval;
 732 }
 733
 734 void
 735 g_thread_set_priority (GThread* thread,
 736                        GThreadPriority priority)
 737 {
 738   GRealThread* real = (GRealThread*) thread;
 739
 740   g_return_if_fail (thread);
 741   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 742   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 743   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 744
 745   thread->priority = priority;
 746
 747   G_THREAD_CF (thread_set_priority, (void)0,
 748                (&real->system_thread, priority));
 749 }
 750
 751 GThread*
 752 g_thread_self (void)
 753 {
 754   GRealThread* thread = g_private_get (g_thread_specific_private);
 755
 756   if (!thread)
 757     {
 758       /* If no thread data is available, provide and set one.  This
 759          can happen for the main thread and for threads, that are not
 760          created by GLib. */
 761       thread = g_new0 (GRealThread, 1);
 762       thread->thread.joinable = FALSE; /* This is a save guess */
 763       thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
 764                                                              just a guess */
 765       thread->thread.func = NULL;
 766       thread->thread.data = NULL;
 767       thread->private_data = NULL;
 768
 769       if (g_thread_supported ())
 770         G_THREAD_UF (thread_self, (&thread->system_thread));
 771
 772       g_private_set (g_thread_specific_private, thread);
 773
 774       G_LOCK (g_thread);
 775       thread->next = g_thread_all_threads;
 776       g_thread_all_threads = thread;
 777       G_UNLOCK (g_thread);
 778     }
 779
 780   return (GThread*)thread;
 781 }
 782
 783 void
 784 g_static_rw_lock_init (GStaticRWLock* lock)
 785 {
 786   static const GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
 787
 788   g_return_if_fail (lock);
 789
 790   *lock = init_lock;
 791 }
 792
 793 inline static void
 794 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
 795 {
 796   if (!*cond)
 797       *cond = g_cond_new ();
 798   g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
 799 }
 800
 801 inline static void
 802 g_static_rw_lock_signal (GStaticRWLock* lock)
 803 {
 804   if (lock->want_to_write && lock->write_cond)
 805     g_cond_signal (lock->write_cond);
 806   else if (lock->want_to_read && lock->read_cond)
 807     g_cond_broadcast (lock->read_cond);
 808 }
 809
 810 void
 811 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
 812 {
 813   g_return_if_fail (lock);
 814
 815   if (!g_threads_got_initialized)
 816     return;
 817
 818   g_static_mutex_lock (&lock->mutex);
 819   lock->want_to_read++;
 820   while (lock->have_writer || lock->want_to_write)
 821     g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
 822   lock->want_to_read--;
 823   lock->read_counter++;
 824   g_static_mutex_unlock (&lock->mutex);
 825 }
 826
 827 gboolean
 828 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
 829 {
 830   gboolean ret_val = FALSE;
 831
 832   g_return_val_if_fail (lock, FALSE);
 833
 834   if (!g_threads_got_initialized)
 835     return TRUE;
 836
 837   g_static_mutex_lock (&lock->mutex);
 838   if (!lock->have_writer && !lock->want_to_write)
 839     {
 840       lock->read_counter++;
 841       ret_val = TRUE;
 842     }
 843   g_static_mutex_unlock (&lock->mutex);
 844   return ret_val;
 845 }
 846
 847 void
 848 g_static_rw_lock_reader_unlock  (GStaticRWLock* lock)
 849 {
 850   g_return_if_fail (lock);
 851
 852   if (!g_threads_got_initialized)
 853     return;
 854
 855   g_static_mutex_lock (&lock->mutex);
 856   lock->read_counter--;
 857   if (lock->read_counter == 0)
 858     g_static_rw_lock_signal (lock);
 859   g_static_mutex_unlock (&lock->mutex);
 860 }
 861
 862 void
 863 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
 864 {
 865   g_return_if_fail (lock);
 866
 867   if (!g_threads_got_initialized)
 868     return;
 869
 870   g_static_mutex_lock (&lock->mutex);
 871   lock->want_to_write++;
 872   while (lock->have_writer || lock->read_counter)
 873     g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
 874   lock->want_to_write--;
 875   lock->have_writer = TRUE;
 876   g_static_mutex_unlock (&lock->mutex);
 877 }
 878
 879 gboolean
 880 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
 881 {
 882   gboolean ret_val = FALSE;
 883
 884   g_return_val_if_fail (lock, FALSE);
 885
 886   if (!g_threads_got_initialized)
 887     return TRUE;
 888
 889   g_static_mutex_lock (&lock->mutex);
 890   if (!lock->have_writer && !lock->read_counter)
 891     {
 892       lock->have_writer = TRUE;
 893       ret_val = TRUE;
 894     }
 895   g_static_mutex_unlock (&lock->mutex);
 896   return ret_val;
 897 }
 898
 899 void
 900 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
 901 {
 902   g_return_if_fail (lock);
 903
 904   if (!g_threads_got_initialized)
 905     return;
 906
 907   g_static_mutex_lock (&lock->mutex);
 908   lock->have_writer = FALSE;
 909   g_static_rw_lock_signal (lock);
 910   g_static_mutex_unlock (&lock->mutex);
 911 }
 912
 913 void
 914 g_static_rw_lock_free (GStaticRWLock* lock)
 915 {
 916   g_return_if_fail (lock);
 917
 918   if (lock->read_cond)
 919     {
 920       g_cond_free (lock->read_cond);
 921       lock->read_cond = NULL;
 922     }
 923   if (lock->write_cond)
 924     {
 925       g_cond_free (lock->write_cond);
 926       lock->write_cond = NULL;
 927     }
 928   g_static_mutex_free (&lock->mutex);
 929 }
 930
 931 /**
 932  * g_thread_foreach
 933  * @thread_func: function to call for all GThread structures
 934  * @user_data:   second argument to @thread_func
 935  *
 936  * Call @thread_func on all existing #GThread structures. Note that
 937  * threads may decide to exit while @thread_func is running, so
 938  * without intimate knowledge about the lifetime of foreign threads,
 939  * @thread_func shouldn't access the GThread* pointer passed in as
 940  * first argument. However, @thread_func will not be called for threads
 941  * which are known to have exited already.
 942  *
 943  * Due to thread lifetime checks, this function has an execution complexity
 944  * which is quadratic in the number of existing threads.
 945  *
 946  * Since: 2.10
 947  */
 948 void
 949 g_thread_foreach (GFunc    thread_func,
 950                   gpointer user_data)
 951 {
 952   GSList *slist = NULL;
 953   GRealThread *thread;
 954   g_return_if_fail (thread_func != NULL);
 955   /* snapshot the list of threads for iteration */
 956   G_LOCK (g_thread);
 957   for (thread = g_thread_all_threads; thread; thread = thread->next)
 958     slist = g_slist_prepend (slist, thread);
 959   G_UNLOCK (g_thread);
 960   /* walk the list, skipping non-existant threads */
 961   while (slist)
 962     {
 963       GSList *node = slist;
 964       slist = node->next;
 965       /* check whether the current thread still exists */
 966       G_LOCK (g_thread);
 967       for (thread = g_thread_all_threads; thread; thread = thread->next)
 968         if (thread == node->data)
 969           break;
 970       G_UNLOCK (g_thread);
 971       if (thread)
 972         thread_func (thread, user_data);
 973       g_slist_free_1 (node);
 974     }
 975 }
 976
 977 #define __G_THREAD_C__
 978 #include "galiasdef.c"