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