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