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  * gmutex.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 #include "glib.h"
  37
  38 #ifdef G_THREAD_USE_PID_SURROGATE
  39 #include <sys/types.h>
  40 #include <sys/time.h>
  41 #include <sys/resource.h>
  42 #include <errno.h>
  43 #endif /* G_THREAD_USE_PID_SURROGATE */
  44
  45 #ifdef HAVE_UNISTD_H
  46 #include <unistd.h>
  47 #endif
  48
  49 #include <string.h>
  50
  51 #if GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P
  52 # define g_system_thread_equal(thread1, thread2)                        \
  53    (thread1.dummy_pointer == thread2.dummy_pointer)
  54 # define g_system_thread_assign(dest, src)                              \
  55    (dest.dummy_pointer = src.dummy_pointer)
  56 #else /* GLIB_SIZEOF_SYSTEM_THREAD != SIZEOF_VOID_P */
  57 # define g_system_thread_equal(thread1, thread2)                        \
  58    (memcmp (&thread1, &thread2, GLIB_SIZEOF_SYSTEM_THREAD) == 0)
  59 # define g_system_thread_assign(dest, src)                              \
  60    (memcpy (&dest, &src, GLIB_SIZEOF_SYSTEM_THREAD))
  61 #endif /* GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P */
  62
  63 GQuark
  64 g_thread_error_quark (void)
  65 {
  66   static GQuark quark;
  67   if (!quark)
  68     quark = g_quark_from_static_string ("g_thread_error");
  69   return quark;
  70 }
  71
  72 /* Keep this in sync with GRealThread in gmain.c! */
  73 typedef struct _GRealThread GRealThread;
  74 struct  _GRealThread
  75 {
  76   GThread thread;
  77   GThreadFunc func;
  78   gpointer arg;
  79   gpointer private_data;
  80   GMainContext *context;
  81   GSystemThread system_thread;
  82 #ifdef G_THREAD_USE_PID_SURROGATE
  83   pid_t pid;
  84 #endif /* G_THREAD_USE_PID_SURROGATE */
  85 };
  86
  87 #ifdef G_THREAD_USE_PID_SURROGATE
  88 static gint priority_map[] = { 15, 0, -15, -20 };
  89 static gboolean prio_warned = FALSE;
  90 # define SET_PRIO(pid, prio) G_STMT_START{                              \
  91   gint error = setpriority (PRIO_PROCESS, (pid), priority_map[prio]);   \
  92   if (error == -1 && errno == EACCES && !prio_warned)                   \
  93     {                                                                   \
  94       prio_warned = TRUE;                                               \
  95       g_warning ("Priorities can only be increased by root.");          \
  96     }                                                                   \
  97   }G_STMT_END
  98 #endif /* G_THREAD_USE_PID_SURROGATE */
  99
 100 typedef struct _GStaticPrivateNode GStaticPrivateNode;
 101 struct _GStaticPrivateNode
 102 {
 103   gpointer       data;
 104   GDestroyNotify destroy;
 105 };
 106
 107 static void g_thread_cleanup (gpointer data);
 108 static void g_thread_fail (void);
 109
 110 /* Global variables */
 111
 112 static GSystemThread zero_thread; /* This is initialized to all zero */
 113 gboolean g_thread_use_default_impl = TRUE;
 114 gboolean g_threads_got_initialized = FALSE;
 115
 116 #if defined(G_PLATFORM_WIN32) && defined(__GNUC__)
 117 __declspec(dllexport)
 118 #endif
 119 GThreadFunctions g_thread_functions_for_glib_use = {
 120   (GMutex*(*)())g_thread_fail,                 /* mutex_new */
 121   NULL,                                        /* mutex_lock */
 122   NULL,                                        /* mutex_trylock */
 123   NULL,                                        /* mutex_unlock */
 124   NULL,                                        /* mutex_free */
 125   (GCond*(*)())g_thread_fail,                  /* cond_new */
 126   NULL,                                        /* cond_signal */
 127   NULL,                                        /* cond_broadcast */
 128   NULL,                                        /* cond_wait */
 129   NULL,                                        /* cond_timed_wait  */
 130   NULL,                                        /* cond_free */
 131   (GPrivate*(*)(GDestroyNotify))g_thread_fail, /* private_new */
 132   NULL,                                        /* private_get */
 133   NULL,                                        /* private_set */
 134   (void(*)(GThreadFunc, gpointer, gulong,
 135            gboolean, gboolean, GThreadPriority,
 136            gpointer, GError**))g_thread_fail,  /* thread_create */
 137   NULL,                                        /* thread_yield */
 138   NULL,                                        /* thread_join */
 139   NULL,                                        /* thread_exit */
 140   NULL,                                        /* thread_set_priority */
 141   NULL                                         /* thread_self */
 142 };
 143
 144 /* Local data */
 145
 146 static GMutex   *g_mutex_protect_static_mutex_allocation = NULL;
 147 static GPrivate *g_thread_specific_private = NULL;
 148 static GSList   *g_thread_all_threads = NULL;
 149 static GSList   *g_thread_free_indeces = NULL;
 150
 151 G_LOCK_DEFINE_STATIC (g_thread);
 152
 153 /* This must be called only once, before any threads are created.
 154  * It will only be called from g_thread_init() in -lgthread.
 155  */
 156 void
 157 g_mutex_init (void)
 158 {
 159   GRealThread* main_thread;
 160
 161   /* We let the main thread (the one that calls g_thread_init) inherit
 162    * the data, that it set before calling g_thread_init
 163    */
 164   main_thread = (GRealThread*) g_thread_self ();
 165
 166   g_thread_specific_private = g_private_new (g_thread_cleanup);
 167   G_THREAD_UF (private_set, (g_thread_specific_private, main_thread));
 168   G_THREAD_UF (thread_self, (&main_thread->system_thread));
 169
 170   g_mutex_protect_static_mutex_allocation = g_mutex_new ();
 171 }
 172
 173 void
 174 g_static_mutex_init (GStaticMutex *mutex)
 175 {
 176   static GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
 177
 178   g_return_if_fail (mutex);
 179
 180   memcpy (mutex, &init_mutex, sizeof (GStaticMutex));
 181 }
 182
 183 GMutex *
 184 g_static_mutex_get_mutex_impl (GMutex** mutex)
 185 {
 186   if (!g_thread_supported ())
 187     return NULL;
 188
 189   g_assert (g_mutex_protect_static_mutex_allocation);
 190
 191   g_mutex_lock (g_mutex_protect_static_mutex_allocation);
 192
 193   if (!(*mutex))
 194     *mutex = g_mutex_new ();
 195
 196   g_mutex_unlock (g_mutex_protect_static_mutex_allocation);
 197
 198   return *mutex;
 199 }
 200
 201 void
 202 g_static_mutex_free (GStaticMutex* mutex)
 203 {
 204   GMutex **runtime_mutex;
 205
 206   g_return_if_fail (mutex);
 207
 208   /* The runtime_mutex is the first (or only) member of GStaticMutex,
 209    * see both versions (of glibconfig.h) in configure.in */
 210   runtime_mutex = ((GMutex**)mutex);
 211
 212   if (*runtime_mutex)
 213     g_mutex_free (*runtime_mutex);
 214
 215   *runtime_mutex = NULL;
 216 }
 217
 218 void
 219 g_static_rec_mutex_init (GStaticRecMutex *mutex)
 220 {
 221   static GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
 222
 223   g_return_if_fail (mutex);
 224
 225   memcpy (mutex, &init_mutex, sizeof (GStaticRecMutex));
 226 }
 227
 228 void
 229 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
 230 {
 231   GSystemThread self;
 232
 233   g_return_if_fail (mutex);
 234
 235   if (!g_thread_supported ())
 236     return;
 237
 238   G_THREAD_UF (thread_self, (&self));
 239
 240   if (g_system_thread_equal (self, mutex->owner))
 241     {
 242       mutex->depth++;
 243       return;
 244     }
 245   g_static_mutex_lock (&mutex->mutex);
 246   g_system_thread_assign (mutex->owner, self);
 247   mutex->depth = 1;
 248 }
 249
 250 gboolean
 251 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
 252 {
 253   GSystemThread self;
 254
 255   g_return_val_if_fail (mutex, FALSE);
 256
 257   if (!g_thread_supported ())
 258     return TRUE;
 259
 260   G_THREAD_UF (thread_self, (&self));
 261
 262   if (g_system_thread_equal (self, mutex->owner))
 263     {
 264       mutex->depth++;
 265       return TRUE;
 266     }
 267
 268   if (!g_static_mutex_trylock (&mutex->mutex))
 269     return FALSE;
 270
 271   g_system_thread_assign (mutex->owner, self);
 272   mutex->depth = 1;
 273   return TRUE;
 274 }
 275
 276 void
 277 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
 278 {
 279   g_return_if_fail (mutex);
 280
 281   if (!g_thread_supported ())
 282     return;
 283
 284   if (mutex->depth > 1)
 285     {
 286       mutex->depth--;
 287       return;
 288     }
 289   g_system_thread_assign (mutex->owner, zero_thread);
 290   g_static_mutex_unlock (&mutex->mutex);
 291 }
 292
 293 void
 294 g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
 295                                 guint            depth)
 296 {
 297   GSystemThread self;
 298   g_return_if_fail (mutex);
 299
 300   if (!g_thread_supported ())
 301     return;
 302
 303   G_THREAD_UF (thread_self, (&self));
 304
 305   if (g_system_thread_equal (self, mutex->owner))
 306     {
 307       mutex->depth += depth;
 308       return;
 309     }
 310   g_static_mutex_lock (&mutex->mutex);
 311   g_system_thread_assign (mutex->owner, self);
 312   mutex->depth = depth;
 313 }
 314
 315 guint
 316 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
 317 {
 318   gint depth;
 319
 320   g_return_val_if_fail (mutex, 0);
 321
 322   if (!g_thread_supported ())
 323     return 1;
 324
 325   depth = mutex->depth;
 326
 327   g_system_thread_assign (mutex->owner, zero_thread);
 328   mutex->depth = 0;
 329   g_static_mutex_unlock (&mutex->mutex);
 330
 331   return depth;
 332 }
 333
 334 void
 335 g_static_rec_mutex_free (GStaticRecMutex *mutex)
 336 {
 337   g_return_if_fail (mutex);
 338
 339   g_static_mutex_free (&mutex->mutex);
 340 }
 341
 342 void
 343 g_static_private_init (GStaticPrivate *private_key)
 344 {
 345   private_key->index = 0;
 346 }
 347
 348 gpointer
 349 g_static_private_get (GStaticPrivate *private_key)
 350 {
 351   GRealThread *self = (GRealThread*) g_thread_self ();
 352   GArray *array;
 353
 354   array = self->private_data;
 355   if (!array)
 356     return NULL;
 357
 358   if (!private_key->index)
 359     return NULL;
 360   else if (private_key->index <= array->len)
 361     return g_array_index (array, GStaticPrivateNode,
 362                           private_key->index - 1).data;
 363   else
 364     return NULL;
 365 }
 366
 367 void
 368 g_static_private_set (GStaticPrivate *private_key,
 369                       gpointer        data,
 370                       GDestroyNotify  notify)
 371 {
 372   GRealThread *self = (GRealThread*) g_thread_self ();
 373   GArray *array;
 374   static guint next_index = 0;
 375   GStaticPrivateNode *node;
 376
 377   array = self->private_data;
 378   if (!array)
 379     {
 380       array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
 381       self->private_data = array;
 382     }
 383
 384   if (!private_key->index)
 385     {
 386       G_LOCK (g_thread);
 387
 388       if (!private_key->index)
 389         {
 390           if (g_thread_free_indeces)
 391             {
 392               private_key->index =
 393                 GPOINTER_TO_UINT (g_thread_free_indeces->data);
 394               g_thread_free_indeces =
 395                 g_slist_delete_link (g_thread_free_indeces,
 396                                      g_thread_free_indeces);
 397             }
 398           else
 399             private_key->index = ++next_index;
 400         }
 401
 402       G_UNLOCK (g_thread);
 403     }
 404
 405   if (private_key->index > array->len)
 406     g_array_set_size (array, private_key->index);
 407
 408   node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
 409   if (node->destroy)
 410     {
 411       gpointer ddata = node->data;
 412       GDestroyNotify ddestroy = node->destroy;
 413
 414       node->data = data;
 415       node->destroy = notify;
 416
 417       ddestroy (ddata);
 418     }
 419   else
 420     {
 421       node->data = data;
 422       node->destroy = notify;
 423     }
 424 }
 425
 426 void
 427 g_static_private_free (GStaticPrivate *private_key)
 428 {
 429   guint index = private_key->index;
 430   GSList *list;
 431
 432   if (!index)
 433     return;
 434
 435   private_key->index = 0;
 436
 437   G_LOCK (g_thread);
 438   list =  g_thread_all_threads;
 439   while (list)
 440     {
 441       GRealThread *thread = list->data;
 442       GArray *array = thread->private_data;
 443       list = list->next;
 444
 445       if (array && index <= array->len)
 446         {
 447           GStaticPrivateNode *node = &g_array_index (array,
 448                                                      GStaticPrivateNode,
 449                                                      index - 1);
 450           gpointer ddata = node->data;
 451           GDestroyNotify ddestroy = node->destroy;
 452
 453           node->data = NULL;
 454           node->destroy = NULL;
 455
 456           if (ddestroy)
 457             {
 458               G_UNLOCK (g_thread);
 459               ddestroy (ddata);
 460               G_LOCK (g_thread);
 461               }
 462         }
 463     }
 464   g_thread_free_indeces = g_slist_prepend (g_thread_free_indeces,
 465                                            GUINT_TO_POINTER (index));
 466   G_UNLOCK (g_thread);
 467 }
 468
 469 void g_main_context_destroy (GMainContext *context);
 470
 471 static void
 472 g_thread_cleanup (gpointer data)
 473 {
 474   if (data)
 475     {
 476       GRealThread* thread = data;
 477       if (thread->private_data)
 478         {
 479           GArray* array = thread->private_data;
 480           guint i;
 481
 482           for (i = 0; i < array->len; i++ )
 483             {
 484               GStaticPrivateNode *node =
 485                 &g_array_index (array, GStaticPrivateNode, i);
 486               if (node->destroy)
 487                 node->destroy (node->data);
 488             }
 489           g_array_free (array, TRUE);
 490         }
 491       if (thread->context)
 492         g_main_context_destroy (thread->context);
 493
 494       /* We only free the thread structure, if it isn't joinable. If
 495          it is, the structure is freed in g_thread_join */
 496       if (!thread->thread.joinable)
 497         {
 498           G_LOCK (g_thread);
 499           g_thread_all_threads = g_slist_remove (g_thread_all_threads, data);
 500           G_UNLOCK (g_thread);
 501
 502           /* Just to make sure, this isn't used any more */
 503           g_system_thread_assign (thread->system_thread, zero_thread);
 504           g_free (thread);
 505         }
 506     }
 507 }
 508
 509 static void
 510 g_thread_fail (void)
 511 {
 512   g_error ("The thread system is not yet initialized.");
 513 }
 514
 515 static void
 516 g_thread_create_proxy (gpointer data)
 517 {
 518   GRealThread* thread = data;
 519
 520   g_assert (data);
 521
 522 #ifdef G_THREAD_USE_PID_SURROGATE
 523   thread->pid = getpid ();
 524 #endif /* G_THREAD_USE_PID_SURROGATE */
 525
 526   /* This has to happen before G_LOCK, as that might call g_thread_self */
 527   g_private_set (g_thread_specific_private, data);
 528
 529   /* the lock makes sure, that thread->system_thread is written,
 530      before thread->func is called. See g_thread_create. */
 531   G_LOCK (g_thread);
 532   G_UNLOCK (g_thread);
 533
 534 #ifdef G_THREAD_USE_PID_SURROGATE
 535   if (g_thread_use_default_impl)
 536     SET_PRIO (thread->pid, thread->thread.priority);
 537 #endif /* G_THREAD_USE_PID_SURROGATE */
 538
 539   thread->func (thread->arg);
 540 }
 541
 542 GThread*
 543 g_thread_create (GThreadFunc             thread_func,
 544                  gpointer                arg,
 545                  gulong                  stack_size,
 546                  gboolean                joinable,
 547                  gboolean                bound,
 548                  GThreadPriority         priority,
 549                  GError                **error)
 550 {
 551   GRealThread* result = g_new (GRealThread, 1);
 552   GError *local_error = NULL;
 553   g_return_val_if_fail (thread_func, NULL);
 554   g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL);
 555   g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL);
 556
 557   result->thread.joinable = joinable;
 558   result->thread.bound = bound;
 559   result->thread.priority = priority;
 560   result->func = thread_func;
 561   result->arg = arg;
 562   result->private_data = NULL;
 563   result->context = NULL;
 564   G_LOCK (g_thread);
 565   G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
 566                                stack_size, joinable, bound, priority,
 567                                &result->system_thread, &local_error));
 568   g_thread_all_threads = g_slist_prepend (g_thread_all_threads, result);
 569   G_UNLOCK (g_thread);
 570
 571   if (local_error)
 572     {
 573       g_propagate_error (error, local_error);
 574       g_free (result);
 575       return NULL;
 576     }
 577
 578   return (GThread*) result;
 579 }
 580
 581 void
 582 g_thread_join (GThread* thread)
 583 {
 584   GRealThread* real = (GRealThread*) thread;
 585
 586
 587   g_return_if_fail (thread);
 588   g_return_if_fail (thread->joinable);
 589   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 590
 591   G_THREAD_UF (thread_join, (&real->system_thread));
 592
 593   G_LOCK (g_thread);
 594   g_thread_all_threads = g_slist_remove (g_thread_all_threads, thread);
 595   G_UNLOCK (g_thread);
 596
 597   /* Just to make sure, this isn't used any more */
 598   thread->joinable = 0;
 599   g_system_thread_assign (real->system_thread, zero_thread);
 600
 601   /* the thread structure for non-joinable threads is freed upon
 602      thread end. We free the memory here. This will leave loose end,
 603      if a joinable thread is not joined. */
 604
 605   g_free (thread);
 606 }
 607
 608 void
 609 g_thread_set_priority (GThread* thread,
 610                        GThreadPriority priority)
 611 {
 612   GRealThread* real = (GRealThread*) thread;
 613
 614   g_return_if_fail (thread);
 615   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 616   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 617   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 618
 619   thread->priority = priority;
 620
 621 #ifdef G_THREAD_USE_PID_SURROGATE
 622   if (g_thread_use_default_impl)
 623     SET_PRIO (real->pid, priority);
 624   else
 625 #endif /* G_THREAD_USE_PID_SURROGATE */
 626     G_THREAD_CF (thread_set_priority, (void)0,
 627                  (&real->system_thread, priority));
 628 }
 629
 630 GThread*
 631 g_thread_self (void)
 632 {
 633   GRealThread* thread = g_private_get (g_thread_specific_private);
 634
 635   if (!thread)
 636     {
 637       /* If no thread data is available, provide and set one.  This
 638          can happen for the main thread and for threads, that are not
 639          created by GLib. */
 640       thread = g_new (GRealThread, 1);
 641       thread->thread.joinable = FALSE; /* This is a save guess */
 642       thread->thread.bound = TRUE; /* This isn't important at all */
 643       thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
 644                                                              just a guess */
 645       thread->func = NULL;
 646       thread->arg = NULL;
 647       thread->private_data = NULL;
 648       thread->context = NULL;
 649
 650       if (g_thread_supported ())
 651         G_THREAD_UF (thread_self, (&thread->system_thread));
 652
 653 #ifdef G_THREAD_USE_PID_SURROGATE
 654       thread->pid = getpid ();
 655 #endif /* G_THREAD_USE_PID_SURROGATE */
 656
 657       g_private_set (g_thread_specific_private, thread);
 658
 659       G_LOCK (g_thread);
 660       g_thread_all_threads = g_slist_prepend (g_thread_all_threads, thread);
 661       G_UNLOCK (g_thread);
 662     }
 663
 664   return (GThread*)thread;
 665 }
 666
 667 void
 668 g_static_rw_lock_init (GStaticRWLock* lock)
 669 {
 670   static GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
 671
 672   g_return_if_fail (lock);
 673
 674   memcpy (lock, &init_lock, sizeof (GStaticRWLock));
 675 }
 676
 677 static void inline
 678 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
 679 {
 680   if (!*cond)
 681       *cond = g_cond_new ();
 682   g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
 683 }
 684
 685 static void inline
 686 g_static_rw_lock_signal (GStaticRWLock* lock)
 687 {
 688   if (lock->want_to_write && lock->write_cond)
 689     g_cond_signal (lock->write_cond);
 690   else if (lock->read_cond)
 691     g_cond_broadcast (lock->read_cond);
 692 }
 693
 694 void
 695 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
 696 {
 697   g_return_if_fail (lock);
 698
 699   if (!g_threads_got_initialized)
 700     return;
 701
 702   g_static_mutex_lock (&lock->mutex);
 703   while (lock->write || lock->want_to_write)
 704     g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
 705   lock->read_counter++;
 706   g_static_mutex_unlock (&lock->mutex);
 707 }
 708
 709 gboolean
 710 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
 711 {
 712   gboolean ret_val = FALSE;
 713
 714   g_return_val_if_fail (lock, FALSE);
 715
 716   if (!g_threads_got_initialized)
 717     return TRUE;
 718
 719   g_static_mutex_lock (&lock->mutex);
 720   if (!lock->write && !lock->want_to_write)
 721     {
 722       lock->read_counter++;
 723       ret_val = TRUE;
 724     }
 725   g_static_mutex_unlock (&lock->mutex);
 726   return ret_val;
 727 }
 728
 729 void
 730 g_static_rw_lock_reader_unlock  (GStaticRWLock* lock)
 731 {
 732   g_return_if_fail (lock);
 733
 734   if (!g_threads_got_initialized)
 735     return;
 736
 737   g_static_mutex_lock (&lock->mutex);
 738   lock->read_counter--;
 739   if (lock->read_counter == 0)
 740     g_static_rw_lock_signal (lock);
 741   g_static_mutex_unlock (&lock->mutex);
 742 }
 743
 744 void
 745 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
 746 {
 747   g_return_if_fail (lock);
 748
 749   if (!g_threads_got_initialized)
 750     return;
 751
 752   g_static_mutex_lock (&lock->mutex);
 753   lock->want_to_write++;
 754   while (lock->write || lock->read_counter)
 755     g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
 756   lock->want_to_write--;
 757   lock->write = TRUE;
 758   g_static_mutex_unlock (&lock->mutex);
 759 }
 760
 761 gboolean
 762 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
 763 {
 764   gboolean ret_val = FALSE;
 765
 766   g_return_val_if_fail (lock, FALSE);
 767
 768   if (!g_threads_got_initialized)
 769     return TRUE;
 770
 771   g_static_mutex_lock (&lock->mutex);
 772   if (!lock->write && !lock->read_counter)
 773     {
 774       lock->write = TRUE;
 775       ret_val = TRUE;
 776     }
 777   g_static_mutex_unlock (&lock->mutex);
 778   return ret_val;
 779 }
 780
 781 void
 782 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
 783 {
 784   g_return_if_fail (lock);
 785
 786   if (!g_threads_got_initialized)
 787     return;
 788
 789   g_static_mutex_lock (&lock->mutex);
 790   lock->write = FALSE;
 791   g_static_rw_lock_signal (lock);
 792   g_static_mutex_unlock (&lock->mutex);
 793 }
 794
 795 void
 796 g_static_rw_lock_free (GStaticRWLock* lock)
 797 {
 798   g_return_if_fail (lock);
 799
 800   if (lock->read_cond)
 801     {
 802       g_cond_free (lock->read_cond);
 803       lock->read_cond = NULL;
 804     }
 805   if (lock->write_cond)
 806     {
 807       g_cond_free (lock->write_cond);
 808       lock->write_cond = NULL;
 809     }
 810   g_static_mutex_free (&lock->mutex);
 811 }