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 #include "glib.h"
  38 #include "gthreadprivate.h"
  39
  40 #ifdef HAVE_UNISTD_H
  41 #include <unistd.h>
  42 #endif
  43
  44 #ifndef G_OS_WIN32
  45 #include <sys/time.h>
  46 #include <time.h>
  47 #else
  48 #include <windows.h>
  49 #endif /* G_OS_WIN32 */
  50
  51 #include <string.h>
  52
  53 #include "galias.h"
  54
  55 GQuark
  56 g_thread_error_quark (void)
  57 {
  58   return g_quark_from_static_string ("g_thread_error");
  59 }
  60
  61 /* Keep this in sync with GRealThread in gmain.c! */
  62 typedef struct _GRealThread GRealThread;
  63 struct  _GRealThread
  64 {
  65   GThread thread;
  66   gpointer private_data;
  67   GRealThread *next;
  68   gpointer retval;
  69   GSystemThread system_thread;
  70 };
  71
  72 typedef struct _GStaticPrivateNode GStaticPrivateNode;
  73 struct _GStaticPrivateNode
  74 {
  75   gpointer       data;
  76   GDestroyNotify destroy;
  77 };
  78
  79 static void    g_thread_cleanup (gpointer data);
  80 static void    g_thread_fail (void);
  81 static guint64 gettime (void);
  82
  83 /* Global variables */
  84
  85 static GSystemThread zero_thread; /* This is initialized to all zero */
  86 gboolean g_thread_use_default_impl = TRUE;
  87 gboolean g_threads_got_initialized = FALSE;
  88
  89 GThreadFunctions g_thread_functions_for_glib_use = {
  90   (GMutex*(*)())g_thread_fail,                 /* mutex_new */
  91   NULL,                                        /* mutex_lock */
  92   NULL,                                        /* mutex_trylock */
  93   NULL,                                        /* mutex_unlock */
  94   NULL,                                        /* mutex_free */
  95   (GCond*(*)())g_thread_fail,                  /* cond_new */
  96   NULL,                                        /* cond_signal */
  97   NULL,                                        /* cond_broadcast */
  98   NULL,                                        /* cond_wait */
  99   NULL,                                        /* cond_timed_wait  */
 100   NULL,                                        /* cond_free */
 101   (GPrivate*(*)(GDestroyNotify))g_thread_fail, /* private_new */
 102   NULL,                                        /* private_get */
 103   NULL,                                        /* private_set */
 104   (void(*)(GThreadFunc, gpointer, gulong,
 105            gboolean, gboolean, GThreadPriority,
 106            gpointer, GError**))g_thread_fail,  /* thread_create */
 107   NULL,                                        /* thread_yield */
 108   NULL,                                        /* thread_join */
 109   NULL,                                        /* thread_exit */
 110   NULL,                                        /* thread_set_priority */
 111   NULL,                                         /* thread_self */
 112   NULL,                                         /* thread_equal */
 113   gettime                                      /* gettime */
 114 };
 115
 116 /* Local data */
 117
 118 static GMutex   *g_once_mutex = NULL;
 119 static GCond    *g_once_cond = NULL;
 120 static GPrivate *g_thread_specific_private = NULL;
 121 static GRealThread *g_thread_all_threads = NULL;
 122 static GSList   *g_thread_free_indeces = NULL;
 123
 124 G_LOCK_DEFINE_STATIC (g_thread);
 125
 126 #ifdef G_THREADS_ENABLED
 127 /* This must be called only once, before any threads are created.
 128  * It will only be called from g_thread_init() in -lgthread.
 129  */
 130 void
 131 g_thread_init_glib (void)
 132 {
 133   /* We let the main thread (the one that calls g_thread_init) inherit
 134    * the static_private data set before calling g_thread_init
 135    */
 136   GRealThread* main_thread = (GRealThread*) g_thread_self ();
 137
 138   /* mutex and cond creation works without g_threads_got_initialized */
 139   g_once_mutex = g_mutex_new ();
 140   g_once_cond = g_cond_new ();
 141
 142   /* we may only create mutex and cond in here */
 143   _g_mem_thread_init_noprivate_nomessage ();
 144
 145   /* setup the basic threading system */
 146   g_threads_got_initialized = TRUE;
 147   g_thread_specific_private = g_private_new (g_thread_cleanup);
 148   g_private_set (g_thread_specific_private, main_thread);
 149   G_THREAD_UF (thread_self, (&main_thread->system_thread));
 150
 151   /* complete memory system initialization, g_private_*() works now */
 152   _g_slice_thread_init_nomessage ();
 153
 154   /* accomplish log system initialization to enable messaging */
 155   _g_messages_thread_init_nomessage ();
 156
 157   /* we may run full-fledged initializers from here */
 158   _g_atomic_thread_init ();
 159   _g_convert_thread_init ();
 160   _g_rand_thread_init ();
 161   _g_main_thread_init ();
 162   _g_utils_thread_init ();
 163 #ifdef G_OS_WIN32
 164   _g_win32_thread_init ();
 165 #endif
 166 }
 167 #endif /* G_THREADS_ENABLED */
 168
 169 gpointer
 170 g_once_impl (GOnce       *once,
 171              GThreadFunc  func,
 172              gpointer     arg)
 173 {
 174   g_mutex_lock (g_once_mutex);
 175
 176   while (once->status == G_ONCE_STATUS_PROGRESS)
 177     g_cond_wait (g_once_cond, g_once_mutex);
 178
 179   if (once->status != G_ONCE_STATUS_READY)
 180     {
 181       once->status = G_ONCE_STATUS_PROGRESS;
 182       g_mutex_unlock (g_once_mutex);
 183
 184       once->retval = func (arg);
 185
 186       g_mutex_lock (g_once_mutex);
 187       once->status = G_ONCE_STATUS_READY;
 188       g_cond_broadcast (g_once_cond);
 189     }
 190
 191   g_mutex_unlock (g_once_mutex);
 192
 193   return once->retval;
 194 }
 195
 196 void
 197 g_static_mutex_init (GStaticMutex *mutex)
 198 {
 199   static const GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
 200
 201   g_return_if_fail (mutex);
 202
 203   *mutex = init_mutex;
 204 }
 205
 206 GMutex *
 207 g_static_mutex_get_mutex_impl (GMutex** mutex)
 208 {
 209   if (!g_thread_supported ())
 210     return NULL;
 211
 212   g_assert (g_once_mutex);
 213
 214   g_mutex_lock (g_once_mutex);
 215
 216   if (!(*mutex))
 217     g_atomic_pointer_set (mutex, g_mutex_new());
 218
 219   g_mutex_unlock (g_once_mutex);
 220
 221   return *mutex;
 222 }
 223
 224 void
 225 g_static_mutex_free (GStaticMutex* mutex)
 226 {
 227   GMutex **runtime_mutex;
 228
 229   g_return_if_fail (mutex);
 230
 231   /* The runtime_mutex is the first (or only) member of GStaticMutex,
 232    * see both versions (of glibconfig.h) in configure.in */
 233   runtime_mutex = ((GMutex**)mutex);
 234
 235   if (*runtime_mutex)
 236     g_mutex_free (*runtime_mutex);
 237
 238   *runtime_mutex = NULL;
 239 }
 240
 241 void
 242 g_static_rec_mutex_init (GStaticRecMutex *mutex)
 243 {
 244   static const GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
 245
 246   g_return_if_fail (mutex);
 247
 248   *mutex = init_mutex;
 249 }
 250
 251 void
 252 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
 253 {
 254   GSystemThread self;
 255
 256   g_return_if_fail (mutex);
 257
 258   if (!g_thread_supported ())
 259     return;
 260
 261   G_THREAD_UF (thread_self, (&self));
 262
 263   if (g_system_thread_equal (self, mutex->owner))
 264     {
 265       mutex->depth++;
 266       return;
 267     }
 268   g_static_mutex_lock (&mutex->mutex);
 269   g_system_thread_assign (mutex->owner, self);
 270   mutex->depth = 1;
 271 }
 272
 273 gboolean
 274 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
 275 {
 276   GSystemThread self;
 277
 278   g_return_val_if_fail (mutex, FALSE);
 279
 280   if (!g_thread_supported ())
 281     return TRUE;
 282
 283   G_THREAD_UF (thread_self, (&self));
 284
 285   if (g_system_thread_equal (self, mutex->owner))
 286     {
 287       mutex->depth++;
 288       return TRUE;
 289     }
 290
 291   if (!g_static_mutex_trylock (&mutex->mutex))
 292     return FALSE;
 293
 294   g_system_thread_assign (mutex->owner, self);
 295   mutex->depth = 1;
 296   return TRUE;
 297 }
 298
 299 void
 300 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
 301 {
 302   g_return_if_fail (mutex);
 303
 304   if (!g_thread_supported ())
 305     return;
 306
 307   if (mutex->depth > 1)
 308     {
 309       mutex->depth--;
 310       return;
 311     }
 312   g_system_thread_assign (mutex->owner, zero_thread);
 313   g_static_mutex_unlock (&mutex->mutex);
 314 }
 315
 316 void
 317 g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
 318                                 guint            depth)
 319 {
 320   GSystemThread self;
 321   g_return_if_fail (mutex);
 322
 323   if (!g_thread_supported ())
 324     return;
 325
 326   if (depth == 0)
 327     return;
 328
 329   G_THREAD_UF (thread_self, (&self));
 330
 331   if (g_system_thread_equal (self, mutex->owner))
 332     {
 333       mutex->depth += depth;
 334       return;
 335     }
 336   g_static_mutex_lock (&mutex->mutex);
 337   g_system_thread_assign (mutex->owner, self);
 338   mutex->depth = depth;
 339 }
 340
 341 guint
 342 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
 343 {
 344   guint depth;
 345
 346   g_return_val_if_fail (mutex, 0);
 347
 348   if (!g_thread_supported ())
 349     return 1;
 350
 351   depth = mutex->depth;
 352
 353   g_system_thread_assign (mutex->owner, zero_thread);
 354   mutex->depth = 0;
 355   g_static_mutex_unlock (&mutex->mutex);
 356
 357   return depth;
 358 }
 359
 360 void
 361 g_static_rec_mutex_free (GStaticRecMutex *mutex)
 362 {
 363   g_return_if_fail (mutex);
 364
 365   g_static_mutex_free (&mutex->mutex);
 366 }
 367
 368 void
 369 g_static_private_init (GStaticPrivate *private_key)
 370 {
 371   private_key->index = 0;
 372 }
 373
 374 gpointer
 375 g_static_private_get (GStaticPrivate *private_key)
 376 {
 377   GRealThread *self = (GRealThread*) g_thread_self ();
 378   GArray *array;
 379
 380   array = self->private_data;
 381   if (!array)
 382     return NULL;
 383
 384   if (!private_key->index)
 385     return NULL;
 386   else if (private_key->index <= array->len)
 387     return g_array_index (array, GStaticPrivateNode,
 388                           private_key->index - 1).data;
 389   else
 390     return NULL;
 391 }
 392
 393 void
 394 g_static_private_set (GStaticPrivate *private_key,
 395                       gpointer        data,
 396                       GDestroyNotify  notify)
 397 {
 398   GRealThread *self = (GRealThread*) g_thread_self ();
 399   GArray *array;
 400   static guint next_index = 0;
 401   GStaticPrivateNode *node;
 402
 403   array = self->private_data;
 404   if (!array)
 405     {
 406       array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
 407       self->private_data = array;
 408     }
 409
 410   if (!private_key->index)
 411     {
 412       G_LOCK (g_thread);
 413
 414       if (!private_key->index)
 415         {
 416           if (g_thread_free_indeces)
 417             {
 418               private_key->index =
 419                 GPOINTER_TO_UINT (g_thread_free_indeces->data);
 420               g_thread_free_indeces =
 421                 g_slist_delete_link (g_thread_free_indeces,
 422                                      g_thread_free_indeces);
 423             }
 424           else
 425             private_key->index = ++next_index;
 426         }
 427
 428       G_UNLOCK (g_thread);
 429     }
 430
 431   if (private_key->index > array->len)
 432     g_array_set_size (array, private_key->index);
 433
 434   node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
 435   if (node->destroy)
 436     {
 437       gpointer ddata = node->data;
 438       GDestroyNotify ddestroy = node->destroy;
 439
 440       node->data = data;
 441       node->destroy = notify;
 442
 443       ddestroy (ddata);
 444     }
 445   else
 446     {
 447       node->data = data;
 448       node->destroy = notify;
 449     }
 450 }
 451
 452 void
 453 g_static_private_free (GStaticPrivate *private_key)
 454 {
 455   guint index = private_key->index;
 456   GRealThread *thread;
 457
 458   if (!index)
 459     return;
 460
 461   private_key->index = 0;
 462
 463   G_LOCK (g_thread);
 464
 465   thread = g_thread_all_threads;
 466   while (thread)
 467     {
 468       GArray *array = thread->private_data;
 469       thread = thread->next;
 470
 471       if (array && index <= array->len)
 472         {
 473           GStaticPrivateNode *node = &g_array_index (array,
 474                                                      GStaticPrivateNode,
 475                                                      index - 1);
 476           gpointer ddata = node->data;
 477           GDestroyNotify ddestroy = node->destroy;
 478
 479           node->data = NULL;
 480           node->destroy = NULL;
 481
 482           if (ddestroy)
 483             {
 484               G_UNLOCK (g_thread);
 485               ddestroy (ddata);
 486               G_LOCK (g_thread);
 487               }
 488         }
 489     }
 490   g_thread_free_indeces = g_slist_prepend (g_thread_free_indeces,
 491                                            GUINT_TO_POINTER (index));
 492   G_UNLOCK (g_thread);
 493 }
 494
 495 static void
 496 g_thread_cleanup (gpointer data)
 497 {
 498   if (data)
 499     {
 500       GRealThread* thread = data;
 501       if (thread->private_data)
 502         {
 503           GArray* array = thread->private_data;
 504           guint i;
 505
 506           for (i = 0; i < array->len; i++ )
 507             {
 508               GStaticPrivateNode *node =
 509                 &g_array_index (array, GStaticPrivateNode, i);
 510               if (node->destroy)
 511                 node->destroy (node->data);
 512             }
 513           g_array_free (array, TRUE);
 514         }
 515
 516       /* We only free the thread structure, if it isn't joinable. If
 517          it is, the structure is freed in g_thread_join */
 518       if (!thread->thread.joinable)
 519         {
 520           GRealThread *t, *p;
 521
 522           G_LOCK (g_thread);
 523           for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
 524             {
 525               if (t == thread)
 526                 {
 527                   if (p)
 528                     p->next = t->next;
 529                   else
 530                     g_thread_all_threads = t->next;
 531                   break;
 532                 }
 533             }
 534           G_UNLOCK (g_thread);
 535
 536           /* Just to make sure, this isn't used any more */
 537           g_system_thread_assign (thread->system_thread, zero_thread);
 538           g_free (thread);
 539         }
 540     }
 541 }
 542
 543 static void
 544 g_thread_fail (void)
 545 {
 546   g_error ("The thread system is not yet initialized.");
 547 }
 548
 549 static guint64
 550 gettime (void)
 551 {
 552 #ifdef G_OS_WIN32
 553   guint64 v;
 554
 555   GetSystemTimeAsFileTime ((FILETIME *)&v);
 556
 557   return v;
 558 #else
 559   struct timeval tv;
 560
 561   gettimeofday (&tv, NULL);
 562
 563   return (guint64) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
 564 #endif
 565 }
 566
 567 static gpointer
 568 g_thread_create_proxy (gpointer data)
 569 {
 570   GRealThread* thread = data;
 571
 572   g_assert (data);
 573
 574   /* This has to happen before G_LOCK, as that might call g_thread_self */
 575   g_private_set (g_thread_specific_private, data);
 576
 577   /* the lock makes sure, that thread->system_thread is written,
 578      before thread->thread.func is called. See g_thread_create. */
 579   G_LOCK (g_thread);
 580   G_UNLOCK (g_thread);
 581
 582   thread->retval = thread->thread.func (thread->thread.data);
 583
 584   return NULL;
 585 }
 586
 587 GThread*
 588 g_thread_create_full (GThreadFunc                func,
 589                       gpointer           data,
 590                       gulong             stack_size,
 591                       gboolean           joinable,
 592                       gboolean           bound,
 593                       GThreadPriority    priority,
 594                       GError                **error)
 595 {
 596   GRealThread* result;
 597   GError *local_error = NULL;
 598   g_return_val_if_fail (func, NULL);
 599   g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL);
 600   g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL);
 601
 602   result = g_new0 (GRealThread, 1);
 603
 604   result->thread.joinable = joinable;
 605   result->thread.priority = priority;
 606   result->thread.func = func;
 607   result->thread.data = data;
 608   result->private_data = NULL;
 609   G_LOCK (g_thread);
 610   G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
 611                                stack_size, joinable, bound, priority,
 612                                &result->system_thread, &local_error));
 613   result->next = g_thread_all_threads;
 614   g_thread_all_threads = result;
 615   G_UNLOCK (g_thread);
 616
 617   if (local_error)
 618     {
 619       g_propagate_error (error, local_error);
 620       g_free (result);
 621       return NULL;
 622     }
 623
 624   return (GThread*) result;
 625 }
 626
 627 void
 628 g_thread_exit (gpointer retval)
 629 {
 630   GRealThread* real = (GRealThread*) g_thread_self ();
 631   real->retval = retval;
 632   G_THREAD_CF (thread_exit, (void)0, ());
 633 }
 634
 635 gpointer
 636 g_thread_join (GThread* thread)
 637 {
 638   GRealThread* real = (GRealThread*) thread;
 639   GRealThread *p, *t;
 640   gpointer retval;
 641
 642   g_return_val_if_fail (thread, NULL);
 643   g_return_val_if_fail (thread->joinable, NULL);
 644   g_return_val_if_fail (!g_system_thread_equal (real->system_thread,
 645                                                 zero_thread), NULL);
 646
 647   G_THREAD_UF (thread_join, (&real->system_thread));
 648
 649   retval = real->retval;
 650
 651   G_LOCK (g_thread);
 652   for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
 653     {
 654       if (t == (GRealThread*) thread)
 655         {
 656           if (p)
 657             p->next = t->next;
 658           else
 659             g_thread_all_threads = t->next;
 660           break;
 661         }
 662     }
 663   G_UNLOCK (g_thread);
 664
 665   /* Just to make sure, this isn't used any more */
 666   thread->joinable = 0;
 667   g_system_thread_assign (real->system_thread, zero_thread);
 668
 669   /* the thread structure for non-joinable threads is freed upon
 670      thread end. We free the memory here. This will leave a loose end,
 671      if a joinable thread is not joined. */
 672
 673   g_free (thread);
 674
 675   return retval;
 676 }
 677
 678 void
 679 g_thread_set_priority (GThread* thread,
 680                        GThreadPriority priority)
 681 {
 682   GRealThread* real = (GRealThread*) thread;
 683
 684   g_return_if_fail (thread);
 685   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 686   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 687   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 688
 689   thread->priority = priority;
 690
 691   G_THREAD_CF (thread_set_priority, (void)0,
 692                (&real->system_thread, priority));
 693 }
 694
 695 GThread*
 696 g_thread_self (void)
 697 {
 698   GRealThread* thread = g_private_get (g_thread_specific_private);
 699
 700   if (!thread)
 701     {
 702       /* If no thread data is available, provide and set one.  This
 703          can happen for the main thread and for threads, that are not
 704          created by GLib. */
 705       thread = g_new0 (GRealThread, 1);
 706       thread->thread.joinable = FALSE; /* This is a save guess */
 707       thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
 708                                                              just a guess */
 709       thread->thread.func = NULL;
 710       thread->thread.data = NULL;
 711       thread->private_data = NULL;
 712
 713       if (g_thread_supported ())
 714         G_THREAD_UF (thread_self, (&thread->system_thread));
 715
 716       g_private_set (g_thread_specific_private, thread);
 717
 718       G_LOCK (g_thread);
 719       thread->next = g_thread_all_threads;
 720       g_thread_all_threads = thread;
 721       G_UNLOCK (g_thread);
 722     }
 723
 724   return (GThread*)thread;
 725 }
 726
 727 void
 728 g_static_rw_lock_init (GStaticRWLock* lock)
 729 {
 730   static const GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
 731
 732   g_return_if_fail (lock);
 733
 734   *lock = init_lock;
 735 }
 736
 737 inline static void
 738 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
 739 {
 740   if (!*cond)
 741       *cond = g_cond_new ();
 742   g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
 743 }
 744
 745 inline static void
 746 g_static_rw_lock_signal (GStaticRWLock* lock)
 747 {
 748   if (lock->want_to_write && lock->write_cond)
 749     g_cond_signal (lock->write_cond);
 750   else if (lock->want_to_read && lock->read_cond)
 751     g_cond_broadcast (lock->read_cond);
 752 }
 753
 754 void
 755 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
 756 {
 757   g_return_if_fail (lock);
 758
 759   if (!g_threads_got_initialized)
 760     return;
 761
 762   g_static_mutex_lock (&lock->mutex);
 763   lock->want_to_read++;
 764   while (lock->have_writer || lock->want_to_write)
 765     g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
 766   lock->want_to_read--;
 767   lock->read_counter++;
 768   g_static_mutex_unlock (&lock->mutex);
 769 }
 770
 771 gboolean
 772 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
 773 {
 774   gboolean ret_val = FALSE;
 775
 776   g_return_val_if_fail (lock, FALSE);
 777
 778   if (!g_threads_got_initialized)
 779     return TRUE;
 780
 781   g_static_mutex_lock (&lock->mutex);
 782   if (!lock->have_writer && !lock->want_to_write)
 783     {
 784       lock->read_counter++;
 785       ret_val = TRUE;
 786     }
 787   g_static_mutex_unlock (&lock->mutex);
 788   return ret_val;
 789 }
 790
 791 void
 792 g_static_rw_lock_reader_unlock  (GStaticRWLock* lock)
 793 {
 794   g_return_if_fail (lock);
 795
 796   if (!g_threads_got_initialized)
 797     return;
 798
 799   g_static_mutex_lock (&lock->mutex);
 800   lock->read_counter--;
 801   if (lock->read_counter == 0)
 802     g_static_rw_lock_signal (lock);
 803   g_static_mutex_unlock (&lock->mutex);
 804 }
 805
 806 void
 807 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
 808 {
 809   g_return_if_fail (lock);
 810
 811   if (!g_threads_got_initialized)
 812     return;
 813
 814   g_static_mutex_lock (&lock->mutex);
 815   lock->want_to_write++;
 816   while (lock->have_writer || lock->read_counter)
 817     g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
 818   lock->want_to_write--;
 819   lock->have_writer = TRUE;
 820   g_static_mutex_unlock (&lock->mutex);
 821 }
 822
 823 gboolean
 824 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
 825 {
 826   gboolean ret_val = FALSE;
 827
 828   g_return_val_if_fail (lock, FALSE);
 829
 830   if (!g_threads_got_initialized)
 831     return TRUE;
 832
 833   g_static_mutex_lock (&lock->mutex);
 834   if (!lock->have_writer && !lock->read_counter)
 835     {
 836       lock->have_writer = TRUE;
 837       ret_val = TRUE;
 838     }
 839   g_static_mutex_unlock (&lock->mutex);
 840   return ret_val;
 841 }
 842
 843 void
 844 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
 845 {
 846   g_return_if_fail (lock);
 847
 848   if (!g_threads_got_initialized)
 849     return;
 850
 851   g_static_mutex_lock (&lock->mutex);
 852   lock->have_writer = FALSE;
 853   g_static_rw_lock_signal (lock);
 854   g_static_mutex_unlock (&lock->mutex);
 855 }
 856
 857 void
 858 g_static_rw_lock_free (GStaticRWLock* lock)
 859 {
 860   g_return_if_fail (lock);
 861
 862   if (lock->read_cond)
 863     {
 864       g_cond_free (lock->read_cond);
 865       lock->read_cond = NULL;
 866     }
 867   if (lock->write_cond)
 868     {
 869       g_cond_free (lock->write_cond);
 870       lock->write_cond = NULL;
 871     }
 872   g_static_mutex_free (&lock->mutex);
 873 }
 874
 875 /**
 876  * g_thread_foreach
 877  * @thread_func: function to call for all GThread structures
 878  * @user_data:   second argument to @thread_func
 879  *
 880  * Call @thread_func on all existing #GThread structures. Note that
 881  * threads may decide to exit while @thread_func is running, so
 882  * without intimate knowledge about the lifetime of foreign threads,
 883  * @thread_func shouldn't access the GThread* pointer passed in as
 884  * first argument. However, @thread_func will not be called for threads
 885  * which are known to have exited already.
 886  *
 887  * Due to thread lifetime checks, this function has an execution complexity
 888  * which is quadratic in the number of existing threads.
 889  *
 890  * Since: 2.10
 891  */
 892 void
 893 g_thread_foreach (GFunc    thread_func,
 894                   gpointer user_data)
 895 {
 896   GSList *slist = NULL;
 897   GRealThread *thread;
 898   g_return_if_fail (thread_func != NULL);
 899   /* snapshot the list of threads for iteration */
 900   G_LOCK (g_thread);
 901   for (thread = g_thread_all_threads; thread; thread = thread->next)
 902     slist = g_slist_prepend (slist, thread);
 903   G_UNLOCK (g_thread);
 904   /* walk the list, skipping non-existant threads */
 905   while (slist)
 906     {
 907       GSList *node = slist;
 908       slist = node->next;
 909       /* check whether the current thread still exists */
 910       G_LOCK (g_thread);
 911       for (thread = g_thread_all_threads; thread; thread = thread->next)
 912         if (thread == node->data)
 913           break;
 914       G_UNLOCK (g_thread);
 915       if (thread)
 916         thread_func (thread, user_data);
 917       g_slist_free_1 (node);
 918     }
 919 }
 920
 921 #define __G_THREAD_C__
 922 #include "galiasdef.c"