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 #define G_NSEC_PER_SEC 1000000000
 550
 551 static guint64
 552 gettime (void)
 553 {
 554 #ifdef G_OS_WIN32
 555   guint64 v;
 556
 557   GetSystemTimeAsFileTime ((FILETIME *)&v);
 558
 559   return v;
 560 #else
 561   struct timeval tv;
 562
 563   gettimeofday (&tv, NULL);
 564
 565   return (guint64) tv.tv_sec * G_NSEC_PER_SEC + tv.tv_usec * (G_NSEC_PER_SEC / G_USEC_PER_SEC);
 566 #endif
 567 }
 568
 569 static gpointer
 570 g_thread_create_proxy (gpointer data)
 571 {
 572   GRealThread* thread = data;
 573
 574   g_assert (data);
 575
 576   /* This has to happen before G_LOCK, as that might call g_thread_self */
 577   g_private_set (g_thread_specific_private, data);
 578
 579   /* the lock makes sure, that thread->system_thread is written,
 580      before thread->thread.func is called. See g_thread_create. */
 581   G_LOCK (g_thread);
 582   G_UNLOCK (g_thread);
 583
 584   thread->retval = thread->thread.func (thread->thread.data);
 585
 586   return NULL;
 587 }
 588
 589 GThread*
 590 g_thread_create_full (GThreadFunc                func,
 591                       gpointer           data,
 592                       gulong             stack_size,
 593                       gboolean           joinable,
 594                       gboolean           bound,
 595                       GThreadPriority    priority,
 596                       GError                **error)
 597 {
 598   GRealThread* result;
 599   GError *local_error = NULL;
 600   g_return_val_if_fail (func, NULL);
 601   g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL);
 602   g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL);
 603
 604   result = g_new0 (GRealThread, 1);
 605
 606   result->thread.joinable = joinable;
 607   result->thread.priority = priority;
 608   result->thread.func = func;
 609   result->thread.data = data;
 610   result->private_data = NULL;
 611   G_LOCK (g_thread);
 612   G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
 613                                stack_size, joinable, bound, priority,
 614                                &result->system_thread, &local_error));
 615   result->next = g_thread_all_threads;
 616   g_thread_all_threads = result;
 617   G_UNLOCK (g_thread);
 618
 619   if (local_error)
 620     {
 621       g_propagate_error (error, local_error);
 622       g_free (result);
 623       return NULL;
 624     }
 625
 626   return (GThread*) result;
 627 }
 628
 629 void
 630 g_thread_exit (gpointer retval)
 631 {
 632   GRealThread* real = (GRealThread*) g_thread_self ();
 633   real->retval = retval;
 634   G_THREAD_CF (thread_exit, (void)0, ());
 635 }
 636
 637 gpointer
 638 g_thread_join (GThread* thread)
 639 {
 640   GRealThread* real = (GRealThread*) thread;
 641   GRealThread *p, *t;
 642   gpointer retval;
 643
 644   g_return_val_if_fail (thread, NULL);
 645   g_return_val_if_fail (thread->joinable, NULL);
 646   g_return_val_if_fail (!g_system_thread_equal (real->system_thread,
 647                                                 zero_thread), NULL);
 648
 649   G_THREAD_UF (thread_join, (&real->system_thread));
 650
 651   retval = real->retval;
 652
 653   G_LOCK (g_thread);
 654   for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
 655     {
 656       if (t == (GRealThread*) thread)
 657         {
 658           if (p)
 659             p->next = t->next;
 660           else
 661             g_thread_all_threads = t->next;
 662           break;
 663         }
 664     }
 665   G_UNLOCK (g_thread);
 666
 667   /* Just to make sure, this isn't used any more */
 668   thread->joinable = 0;
 669   g_system_thread_assign (real->system_thread, zero_thread);
 670
 671   /* the thread structure for non-joinable threads is freed upon
 672      thread end. We free the memory here. This will leave a loose end,
 673      if a joinable thread is not joined. */
 674
 675   g_free (thread);
 676
 677   return retval;
 678 }
 679
 680 void
 681 g_thread_set_priority (GThread* thread,
 682                        GThreadPriority priority)
 683 {
 684   GRealThread* real = (GRealThread*) thread;
 685
 686   g_return_if_fail (thread);
 687   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 688   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 689   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 690
 691   thread->priority = priority;
 692
 693   G_THREAD_CF (thread_set_priority, (void)0,
 694                (&real->system_thread, priority));
 695 }
 696
 697 GThread*
 698 g_thread_self (void)
 699 {
 700   GRealThread* thread = g_private_get (g_thread_specific_private);
 701
 702   if (!thread)
 703     {
 704       /* If no thread data is available, provide and set one.  This
 705          can happen for the main thread and for threads, that are not
 706          created by GLib. */
 707       thread = g_new0 (GRealThread, 1);
 708       thread->thread.joinable = FALSE; /* This is a save guess */
 709       thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
 710                                                              just a guess */
 711       thread->thread.func = NULL;
 712       thread->thread.data = NULL;
 713       thread->private_data = NULL;
 714
 715       if (g_thread_supported ())
 716         G_THREAD_UF (thread_self, (&thread->system_thread));
 717
 718       g_private_set (g_thread_specific_private, thread);
 719
 720       G_LOCK (g_thread);
 721       thread->next = g_thread_all_threads;
 722       g_thread_all_threads = thread;
 723       G_UNLOCK (g_thread);
 724     }
 725
 726   return (GThread*)thread;
 727 }
 728
 729 void
 730 g_static_rw_lock_init (GStaticRWLock* lock)
 731 {
 732   static const GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
 733
 734   g_return_if_fail (lock);
 735
 736   *lock = init_lock;
 737 }
 738
 739 inline static void
 740 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
 741 {
 742   if (!*cond)
 743       *cond = g_cond_new ();
 744   g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
 745 }
 746
 747 inline static void
 748 g_static_rw_lock_signal (GStaticRWLock* lock)
 749 {
 750   if (lock->want_to_write && lock->write_cond)
 751     g_cond_signal (lock->write_cond);
 752   else if (lock->want_to_read && lock->read_cond)
 753     g_cond_broadcast (lock->read_cond);
 754 }
 755
 756 void
 757 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
 758 {
 759   g_return_if_fail (lock);
 760
 761   if (!g_threads_got_initialized)
 762     return;
 763
 764   g_static_mutex_lock (&lock->mutex);
 765   lock->want_to_read++;
 766   while (lock->have_writer || lock->want_to_write)
 767     g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
 768   lock->want_to_read--;
 769   lock->read_counter++;
 770   g_static_mutex_unlock (&lock->mutex);
 771 }
 772
 773 gboolean
 774 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
 775 {
 776   gboolean ret_val = FALSE;
 777
 778   g_return_val_if_fail (lock, FALSE);
 779
 780   if (!g_threads_got_initialized)
 781     return TRUE;
 782
 783   g_static_mutex_lock (&lock->mutex);
 784   if (!lock->have_writer && !lock->want_to_write)
 785     {
 786       lock->read_counter++;
 787       ret_val = TRUE;
 788     }
 789   g_static_mutex_unlock (&lock->mutex);
 790   return ret_val;
 791 }
 792
 793 void
 794 g_static_rw_lock_reader_unlock  (GStaticRWLock* lock)
 795 {
 796   g_return_if_fail (lock);
 797
 798   if (!g_threads_got_initialized)
 799     return;
 800
 801   g_static_mutex_lock (&lock->mutex);
 802   lock->read_counter--;
 803   if (lock->read_counter == 0)
 804     g_static_rw_lock_signal (lock);
 805   g_static_mutex_unlock (&lock->mutex);
 806 }
 807
 808 void
 809 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
 810 {
 811   g_return_if_fail (lock);
 812
 813   if (!g_threads_got_initialized)
 814     return;
 815
 816   g_static_mutex_lock (&lock->mutex);
 817   lock->want_to_write++;
 818   while (lock->have_writer || lock->read_counter)
 819     g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
 820   lock->want_to_write--;
 821   lock->have_writer = TRUE;
 822   g_static_mutex_unlock (&lock->mutex);
 823 }
 824
 825 gboolean
 826 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
 827 {
 828   gboolean ret_val = FALSE;
 829
 830   g_return_val_if_fail (lock, FALSE);
 831
 832   if (!g_threads_got_initialized)
 833     return TRUE;
 834
 835   g_static_mutex_lock (&lock->mutex);
 836   if (!lock->have_writer && !lock->read_counter)
 837     {
 838       lock->have_writer = TRUE;
 839       ret_val = TRUE;
 840     }
 841   g_static_mutex_unlock (&lock->mutex);
 842   return ret_val;
 843 }
 844
 845 void
 846 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
 847 {
 848   g_return_if_fail (lock);
 849
 850   if (!g_threads_got_initialized)
 851     return;
 852
 853   g_static_mutex_lock (&lock->mutex);
 854   lock->have_writer = FALSE;
 855   g_static_rw_lock_signal (lock);
 856   g_static_mutex_unlock (&lock->mutex);
 857 }
 858
 859 void
 860 g_static_rw_lock_free (GStaticRWLock* lock)
 861 {
 862   g_return_if_fail (lock);
 863
 864   if (lock->read_cond)
 865     {
 866       g_cond_free (lock->read_cond);
 867       lock->read_cond = NULL;
 868     }
 869   if (lock->write_cond)
 870     {
 871       g_cond_free (lock->write_cond);
 872       lock->write_cond = NULL;
 873     }
 874   g_static_mutex_free (&lock->mutex);
 875 }
 876
 877 /**
 878  * g_thread_foreach
 879  * @thread_func: function to call for all GThread structures
 880  * @user_data:   second argument to @thread_func
 881  *
 882  * Call @thread_func on all existing #GThread structures. Note that
 883  * threads may decide to exit while @thread_func is running, so
 884  * without intimate knowledge about the lifetime of foreign threads,
 885  * @thread_func shouldn't access the GThread* pointer passed in as
 886  * first argument. However, @thread_func will not be called for threads
 887  * which are known to have exited already.
 888  *
 889  * Due to thread lifetime checks, this function has an execution complexity
 890  * which is quadratic in the number of existing threads.
 891  *
 892  * Since: 2.10
 893  */
 894 void
 895 g_thread_foreach (GFunc    thread_func,
 896                   gpointer user_data)
 897 {
 898   GSList *slist = NULL;
 899   GRealThread *thread;
 900   g_return_if_fail (thread_func != NULL);
 901   /* snapshot the list of threads for iteration */
 902   G_LOCK (g_thread);
 903   for (thread = g_thread_all_threads; thread; thread = thread->next)
 904     slist = g_slist_prepend (slist, thread);
 905   G_UNLOCK (g_thread);
 906   /* walk the list, skipping non-existant threads */
 907   while (slist)
 908     {
 909       GSList *node = slist;
 910       slist = node->next;
 911       /* check whether the current thread still exists */
 912       G_LOCK (g_thread);
 913       for (thread = g_thread_all_threads; thread; thread = thread->next)
 914         if (thread == node->data)
 915           break;
 916       G_UNLOCK (g_thread);
 917       if (thread)
 918         thread_func (thread, user_data);
 919       g_slist_free_1 (node);
 920     }
 921 }
 922
 923 #define __G_THREAD_C__
 924 #include "galiasdef.c"