glib/gthread.c

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * gthread.c: MT safety related functions
   5  * Copyright 1998 Sebastian Wilhelmi; University of Karlsruhe
   6  *                Owen Taylor
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the
  20  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21  * Boston, MA 02111-1307, USA.
  22  */
  23
  24 /*
  25  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  26  * file for a list of people on the GLib Team.  See the ChangeLog
  27  * files for a list of changes.  These files are distributed with
  28  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  29  */
  30
  31 /*
  32  * MT safe
  33  */
  34
  35 #include "config.h"
  36
  37 #ifdef G_THREAD_USE_PID_SURROGATE
  38 #include <sys/types.h>
  39 #include <sys/time.h>
  40 #include <sys/resource.h>
  41 #include <errno.h>
  42 #endif /* G_THREAD_USE_PID_SURROGATE */
  43
  44 #ifdef HAVE_UNISTD_H
  45 #include <unistd.h>
  46 #endif
  47
  48 #include <string.h>
  49
  50 #include "glib.h"
  51 #include "gthreadinit.h"
  52
  53 #if GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P
  54 # define g_system_thread_equal_simple(thread1, thread2)                 \
  55    ((thread1).dummy_pointer == (thread2).dummy_pointer)
  56 # define g_system_thread_assign(dest, src)                              \
  57    ((dest).dummy_pointer = (src).dummy_pointer)
  58 #else /* GLIB_SIZEOF_SYSTEM_THREAD != SIZEOF_VOID_P */
  59 # define g_system_thread_equal_simple(thread1, thread2)                 \
  60    (memcmp (&(thread1), &(thread2), GLIB_SIZEOF_SYSTEM_THREAD) == 0)
  61 # define g_system_thread_assign(dest, src)                              \
  62    (memcpy (&(dest), &(src), GLIB_SIZEOF_SYSTEM_THREAD))
  63 #endif /* GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P */
  64
  65 #define g_system_thread_equal(thread1, thread2)                         \
  66   (g_thread_functions_for_glib_use.thread_equal ?                       \
  67    g_thread_functions_for_glib_use.thread_equal (&(thread1), &(thread2)) :\
  68    g_system_thread_equal_simple((thread1), (thread2)))
  69
  70 GQuark
  71 g_thread_error_quark (void)
  72 {
  73   static GQuark quark;
  74   if (!quark)
  75     quark = g_quark_from_static_string ("g_thread_error");
  76   return quark;
  77 }
  78
  79 /* Keep this in sync with GRealThread in gmain.c! */
  80 typedef struct _GRealThread GRealThread;
  81 struct  _GRealThread
  82 {
  83   GThread thread;
  84   gpointer private_data;
  85   gpointer retval;
  86   GSystemThread system_thread;
  87 #ifdef G_THREAD_USE_PID_SURROGATE
  88   pid_t pid;
  89 #endif /* G_THREAD_USE_PID_SURROGATE */
  90 };
  91
  92 #ifdef G_THREAD_USE_PID_SURROGATE
  93 static gint priority_map[4];
  94 static gboolean prio_warned = FALSE;
  95 # define SET_PRIO(pid, prio) G_STMT_START{                              \
  96   gint error = setpriority (PRIO_PROCESS, (pid), priority_map[prio]);   \
  97   if (error == -1 && errno == EACCES && !prio_warned)                   \
  98     {                                                                   \
  99       prio_warned = TRUE;                                               \
 100       g_warning ("Priorities can only be increased by root.");          \
 101     }                                                                   \
 102   }G_STMT_END
 103 #endif /* G_THREAD_USE_PID_SURROGATE */
 104
 105 typedef struct _GStaticPrivateNode GStaticPrivateNode;
 106 struct _GStaticPrivateNode
 107 {
 108   gpointer       data;
 109   GDestroyNotify destroy;
 110 };
 111
 112 static void g_thread_cleanup (gpointer data);
 113 static void g_thread_fail (void);
 114
 115 /* Global variables */
 116
 117 static GSystemThread zero_thread; /* This is initialized to all zero */
 118 gboolean g_thread_use_default_impl = TRUE;
 119 gboolean g_threads_got_initialized = FALSE;
 120
 121 #if defined(G_PLATFORM_WIN32) && defined(__GNUC__)
 122 __declspec(dllexport)
 123 #endif
 124 GThreadFunctions g_thread_functions_for_glib_use = {
 125   (GMutex*(*)())g_thread_fail,                 /* mutex_new */
 126   NULL,                                        /* mutex_lock */
 127   NULL,                                        /* mutex_trylock */
 128   NULL,                                        /* mutex_unlock */
 129   NULL,                                        /* mutex_free */
 130   (GCond*(*)())g_thread_fail,                  /* cond_new */
 131   NULL,                                        /* cond_signal */
 132   NULL,                                        /* cond_broadcast */
 133   NULL,                                        /* cond_wait */
 134   NULL,                                        /* cond_timed_wait  */
 135   NULL,                                        /* cond_free */
 136   (GPrivate*(*)(GDestroyNotify))g_thread_fail, /* private_new */
 137   NULL,                                        /* private_get */
 138   NULL,                                        /* private_set */
 139   (void(*)(GThreadFunc, gpointer, gulong,
 140            gboolean, gboolean, GThreadPriority,
 141            gpointer, GError**))g_thread_fail,  /* thread_create */
 142   NULL,                                        /* thread_yield */
 143   NULL,                                        /* thread_join */
 144   NULL,                                        /* thread_exit */
 145   NULL,                                        /* thread_set_priority */
 146   NULL                                         /* thread_self */
 147 };
 148
 149 /* Local data */
 150
 151 static GMutex   *g_once_mutex = NULL;
 152 static GCond    *g_once_cond = NULL;
 153 static GPrivate *g_thread_specific_private = NULL;
 154 static GSList   *g_thread_all_threads = NULL;
 155 static GSList   *g_thread_free_indeces = NULL;
 156
 157 G_LOCK_DEFINE_STATIC (g_thread);
 158
 159 #ifdef G_THREADS_ENABLED
 160 /* This must be called only once, before any threads are created.
 161  * It will only be called from g_thread_init() in -lgthread.
 162  */
 163 void
 164 g_thread_init_glib (void)
 165 {
 166   /* We let the main thread (the one that calls g_thread_init) inherit
 167    * the static_private data set before calling g_thread_init
 168    */
 169   GRealThread* main_thread = (GRealThread*) g_thread_self ();
 170
 171   g_once_mutex = g_mutex_new ();
 172   g_once_cond = g_cond_new ();
 173
 174   _g_convert_thread_init ();
 175   _g_rand_thread_init ();
 176   _g_main_thread_init ();
 177   _g_mem_thread_init ();
 178   _g_messages_thread_init ();
 179
 180 #ifdef G_THREAD_USE_PID_SURROGATE
 181   priority_map[G_THREAD_PRIORITY_NORMAL] =
 182     getpriority (PRIO_PROCESS, (getpid ()));
 183   priority_map[G_THREAD_PRIORITY_LOW] =
 184     MIN (20, priority_map[G_THREAD_PRIORITY_NORMAL] + 10);
 185   priority_map[G_THREAD_PRIORITY_HIGH] =
 186     MAX (-20, priority_map[G_THREAD_PRIORITY_NORMAL] - 10);
 187   priority_map[G_THREAD_PRIORITY_URGENT] =
 188     MAX (-20, priority_map[G_THREAD_PRIORITY_NORMAL] - 15);
 189 #endif /* G_THREAD_USE_PID_SURROGATE */
 190
 191   g_threads_got_initialized = TRUE;
 192
 193   g_thread_specific_private = g_private_new (g_thread_cleanup);
 194   g_private_set (g_thread_specific_private, main_thread);
 195   G_THREAD_UF (thread_self, (&main_thread->system_thread));
 196
 197   _g_mem_thread_private_init ();
 198   _g_messages_thread_private_init ();
 199
 200 }
 201 #endif /* G_THREADS_ENABLED */
 202
 203 gpointer
 204 g_once_impl (GOnce       *once,
 205              GThreadFunc  func,
 206              gpointer     arg)
 207 {
 208   g_mutex_lock (g_once_mutex);
 209
 210   while (once->status == G_ONCE_STATUS_PROGRESS)
 211     g_cond_wait (g_once_cond, g_once_mutex);
 212
 213   if (once->status != G_ONCE_STATUS_READY)
 214     {
 215       once->status = G_ONCE_STATUS_PROGRESS;
 216       g_mutex_unlock (g_once_mutex);
 217
 218       once->retval = func (arg);
 219
 220       g_mutex_lock (g_once_mutex);
 221       once->status = G_ONCE_STATUS_READY;
 222       g_cond_broadcast (g_once_cond);
 223     }
 224
 225   g_mutex_unlock (g_once_mutex);
 226
 227   return once->retval;
 228 }
 229
 230 void
 231 g_static_mutex_init (GStaticMutex *mutex)
 232 {
 233   static GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
 234
 235   g_return_if_fail (mutex);
 236
 237   *mutex = init_mutex;
 238 }
 239
 240 GMutex *
 241 g_static_mutex_get_mutex_impl (GMutex** mutex)
 242 {
 243   if (!g_thread_supported ())
 244     return NULL;
 245
 246   g_assert (g_once_mutex);
 247
 248   g_mutex_lock (g_once_mutex);
 249
 250   if (!(*mutex))
 251     {
 252       GMutex *new_mutex = g_mutex_new ();
 253
 254       /* The following is a memory barrier to avoid the write
 255        * to *new_mutex being reordered to after writing *mutex */
 256       g_mutex_lock (new_mutex);
 257       g_mutex_unlock (new_mutex);
 258
 259       *mutex = new_mutex;
 260     }
 261
 262   g_mutex_unlock (g_once_mutex);
 263
 264   return *mutex;
 265 }
 266
 267 void
 268 g_static_mutex_free (GStaticMutex* mutex)
 269 {
 270   GMutex **runtime_mutex;
 271
 272   g_return_if_fail (mutex);
 273
 274   /* The runtime_mutex is the first (or only) member of GStaticMutex,
 275    * see both versions (of glibconfig.h) in configure.in */
 276   runtime_mutex = ((GMutex**)mutex);
 277
 278   if (*runtime_mutex)
 279     g_mutex_free (*runtime_mutex);
 280
 281   *runtime_mutex = NULL;
 282 }
 283
 284 void
 285 g_static_rec_mutex_init (GStaticRecMutex *mutex)
 286 {
 287   static GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
 288
 289   g_return_if_fail (mutex);
 290
 291   *mutex = init_mutex;
 292 }
 293
 294 void
 295 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
 296 {
 297   GSystemThread self;
 298
 299   g_return_if_fail (mutex);
 300
 301   if (!g_thread_supported ())
 302     return;
 303
 304   G_THREAD_UF (thread_self, (&self));
 305
 306   if (g_system_thread_equal (self, mutex->owner))
 307     {
 308       mutex->depth++;
 309       return;
 310     }
 311   g_static_mutex_lock (&mutex->mutex);
 312   g_system_thread_assign (mutex->owner, self);
 313   mutex->depth = 1;
 314 }
 315
 316 gboolean
 317 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
 318 {
 319   GSystemThread self;
 320
 321   g_return_val_if_fail (mutex, FALSE);
 322
 323   if (!g_thread_supported ())
 324     return TRUE;
 325
 326   G_THREAD_UF (thread_self, (&self));
 327
 328   if (g_system_thread_equal (self, mutex->owner))
 329     {
 330       mutex->depth++;
 331       return TRUE;
 332     }
 333
 334   if (!g_static_mutex_trylock (&mutex->mutex))
 335     return FALSE;
 336
 337   g_system_thread_assign (mutex->owner, self);
 338   mutex->depth = 1;
 339   return TRUE;
 340 }
 341
 342 void
 343 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
 344 {
 345   g_return_if_fail (mutex);
 346
 347   if (!g_thread_supported ())
 348     return;
 349
 350   if (mutex->depth > 1)
 351     {
 352       mutex->depth--;
 353       return;
 354     }
 355   g_system_thread_assign (mutex->owner, zero_thread);
 356   g_static_mutex_unlock (&mutex->mutex);
 357 }
 358
 359 void
 360 g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
 361                                 guint            depth)
 362 {
 363   GSystemThread self;
 364   g_return_if_fail (mutex);
 365
 366   if (!g_thread_supported ())
 367     return;
 368
 369   G_THREAD_UF (thread_self, (&self));
 370
 371   if (g_system_thread_equal (self, mutex->owner))
 372     {
 373       mutex->depth += depth;
 374       return;
 375     }
 376   g_static_mutex_lock (&mutex->mutex);
 377   g_system_thread_assign (mutex->owner, self);
 378   mutex->depth = depth;
 379 }
 380
 381 guint
 382 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
 383 {
 384   guint depth;
 385
 386   g_return_val_if_fail (mutex, 0);
 387
 388   if (!g_thread_supported ())
 389     return 1;
 390
 391   depth = mutex->depth;
 392
 393   g_system_thread_assign (mutex->owner, zero_thread);
 394   mutex->depth = 0;
 395   g_static_mutex_unlock (&mutex->mutex);
 396
 397   return depth;
 398 }
 399
 400 void
 401 g_static_rec_mutex_free (GStaticRecMutex *mutex)
 402 {
 403   g_return_if_fail (mutex);
 404
 405   g_static_mutex_free (&mutex->mutex);
 406 }
 407
 408 void
 409 g_static_private_init (GStaticPrivate *private_key)
 410 {
 411   private_key->index = 0;
 412 }
 413
 414 gpointer
 415 g_static_private_get (GStaticPrivate *private_key)
 416 {
 417   GRealThread *self = (GRealThread*) g_thread_self ();
 418   GArray *array;
 419
 420   array = self->private_data;
 421   if (!array)
 422     return NULL;
 423
 424   if (!private_key->index)
 425     return NULL;
 426   else if (private_key->index <= array->len)
 427     return g_array_index (array, GStaticPrivateNode,
 428                           private_key->index - 1).data;
 429   else
 430     return NULL;
 431 }
 432
 433 void
 434 g_static_private_set (GStaticPrivate *private_key,
 435                       gpointer        data,
 436                       GDestroyNotify  notify)
 437 {
 438   GRealThread *self = (GRealThread*) g_thread_self ();
 439   GArray *array;
 440   static guint next_index = 0;
 441   GStaticPrivateNode *node;
 442
 443   array = self->private_data;
 444   if (!array)
 445     {
 446       array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
 447       self->private_data = array;
 448     }
 449
 450   if (!private_key->index)
 451     {
 452       G_LOCK (g_thread);
 453
 454       if (!private_key->index)
 455         {
 456           if (g_thread_free_indeces)
 457             {
 458               private_key->index =
 459                 GPOINTER_TO_UINT (g_thread_free_indeces->data);
 460               g_thread_free_indeces =
 461                 g_slist_delete_link (g_thread_free_indeces,
 462                                      g_thread_free_indeces);
 463             }
 464           else
 465             private_key->index = ++next_index;
 466         }
 467
 468       G_UNLOCK (g_thread);
 469     }
 470
 471   if (private_key->index > array->len)
 472     g_array_set_size (array, private_key->index);
 473
 474   node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
 475   if (node->destroy)
 476     {
 477       gpointer ddata = node->data;
 478       GDestroyNotify ddestroy = node->destroy;
 479
 480       node->data = data;
 481       node->destroy = notify;
 482
 483       ddestroy (ddata);
 484     }
 485   else
 486     {
 487       node->data = data;
 488       node->destroy = notify;
 489     }
 490 }
 491
 492 void
 493 g_static_private_free (GStaticPrivate *private_key)
 494 {
 495   guint index = private_key->index;
 496   GSList *list;
 497
 498   if (!index)
 499     return;
 500
 501   private_key->index = 0;
 502
 503   G_LOCK (g_thread);
 504   list =  g_thread_all_threads;
 505   while (list)
 506     {
 507       GRealThread *thread = list->data;
 508       GArray *array = thread->private_data;
 509       list = list->next;
 510
 511       if (array && index <= array->len)
 512         {
 513           GStaticPrivateNode *node = &g_array_index (array,
 514                                                      GStaticPrivateNode,
 515                                                      index - 1);
 516           gpointer ddata = node->data;
 517           GDestroyNotify ddestroy = node->destroy;
 518
 519           node->data = NULL;
 520           node->destroy = NULL;
 521
 522           if (ddestroy)
 523             {
 524               G_UNLOCK (g_thread);
 525               ddestroy (ddata);
 526               G_LOCK (g_thread);
 527               }
 528         }
 529     }
 530   g_thread_free_indeces = g_slist_prepend (g_thread_free_indeces,
 531                                            GUINT_TO_POINTER (index));
 532   G_UNLOCK (g_thread);
 533 }
 534
 535 static void
 536 g_thread_cleanup (gpointer data)
 537 {
 538   if (data)
 539     {
 540       GRealThread* thread = data;
 541       if (thread->private_data)
 542         {
 543           GArray* array = thread->private_data;
 544           guint i;
 545
 546           for (i = 0; i < array->len; i++ )
 547             {
 548               GStaticPrivateNode *node =
 549                 &g_array_index (array, GStaticPrivateNode, i);
 550               if (node->destroy)
 551                 node->destroy (node->data);
 552             }
 553           g_array_free (array, TRUE);
 554         }
 555
 556       /* We only free the thread structure, if it isn't joinable. If
 557          it is, the structure is freed in g_thread_join */
 558       if (!thread->thread.joinable)
 559         {
 560           G_LOCK (g_thread);
 561           g_thread_all_threads = g_slist_remove (g_thread_all_threads, data);
 562           G_UNLOCK (g_thread);
 563
 564           /* Just to make sure, this isn't used any more */
 565           g_system_thread_assign (thread->system_thread, zero_thread);
 566           g_free (thread);
 567         }
 568     }
 569 }
 570
 571 static void
 572 g_thread_fail (void)
 573 {
 574   g_error ("The thread system is not yet initialized.");
 575 }
 576
 577 static gpointer
 578 g_thread_create_proxy (gpointer data)
 579 {
 580   GRealThread* thread = data;
 581
 582   g_assert (data);
 583
 584 #ifdef G_THREAD_USE_PID_SURROGATE
 585   thread->pid = getpid ();
 586 #endif /* G_THREAD_USE_PID_SURROGATE */
 587
 588   /* This has to happen before G_LOCK, as that might call g_thread_self */
 589   g_private_set (g_thread_specific_private, data);
 590
 591   /* the lock makes sure, that thread->system_thread is written,
 592      before thread->thread.func is called. See g_thread_create. */
 593   G_LOCK (g_thread);
 594   G_UNLOCK (g_thread);
 595
 596 #ifdef G_THREAD_USE_PID_SURROGATE
 597   if (g_thread_use_default_impl)
 598     SET_PRIO (thread->pid, thread->thread.priority);
 599 #endif /* G_THREAD_USE_PID_SURROGATE */
 600
 601   thread->retval = thread->thread.func (thread->thread.data);
 602
 603   return NULL;
 604 }
 605
 606 GThread*
 607 g_thread_create_full (GThreadFunc                func,
 608                       gpointer           data,
 609                       gulong             stack_size,
 610                       gboolean           joinable,
 611                       gboolean           bound,
 612                       GThreadPriority    priority,
 613                       GError                **error)
 614 {
 615   GRealThread* result;
 616   GError *local_error = NULL;
 617   g_return_val_if_fail (func, NULL);
 618   g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL);
 619   g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL);
 620
 621   result = g_new (GRealThread, 1);
 622
 623   result->thread.joinable = joinable;
 624   result->thread.priority = priority;
 625   result->thread.func = func;
 626   result->thread.data = data;
 627   result->private_data = NULL;
 628   G_LOCK (g_thread);
 629   G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
 630                                stack_size, joinable, bound, priority,
 631                                &result->system_thread, &local_error));
 632   g_thread_all_threads = g_slist_prepend (g_thread_all_threads, result);
 633   G_UNLOCK (g_thread);
 634
 635   if (local_error)
 636     {
 637       g_propagate_error (error, local_error);
 638       g_free (result);
 639       return NULL;
 640     }
 641
 642   return (GThread*) result;
 643 }
 644
 645 void
 646 g_thread_exit (gpointer retval)
 647 {
 648   GRealThread* real = (GRealThread*) g_thread_self ();
 649   real->retval = retval;
 650   G_THREAD_CF (thread_exit, (void)0, ());
 651 }
 652
 653 gpointer
 654 g_thread_join (GThread* thread)
 655 {
 656   GRealThread* real = (GRealThread*) thread;
 657   gpointer retval;
 658
 659   g_return_val_if_fail (thread, NULL);
 660   g_return_val_if_fail (thread->joinable, NULL);
 661   g_return_val_if_fail (!g_system_thread_equal (real->system_thread,
 662                                                 zero_thread), NULL);
 663
 664   G_THREAD_UF (thread_join, (&real->system_thread));
 665
 666   retval = real->retval;
 667
 668   G_LOCK (g_thread);
 669   g_thread_all_threads = g_slist_remove (g_thread_all_threads, thread);
 670   G_UNLOCK (g_thread);
 671
 672   /* Just to make sure, this isn't used any more */
 673   thread->joinable = 0;
 674   g_system_thread_assign (real->system_thread, zero_thread);
 675
 676   /* the thread structure for non-joinable threads is freed upon
 677      thread end. We free the memory here. This will leave a loose end,
 678      if a joinable thread is not joined. */
 679
 680   g_free (thread);
 681
 682   return retval;
 683 }
 684
 685 void
 686 g_thread_set_priority (GThread* thread,
 687                        GThreadPriority priority)
 688 {
 689   GRealThread* real = (GRealThread*) thread;
 690
 691   g_return_if_fail (thread);
 692   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 693   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 694   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 695
 696   thread->priority = priority;
 697
 698 #ifdef G_THREAD_USE_PID_SURROGATE
 699   if (g_thread_use_default_impl)
 700     SET_PRIO (real->pid, priority);
 701   else
 702 #endif /* G_THREAD_USE_PID_SURROGATE */
 703     G_THREAD_CF (thread_set_priority, (void)0,
 704                  (&real->system_thread, priority));
 705 }
 706
 707 GThread*
 708 g_thread_self (void)
 709 {
 710   GRealThread* thread = g_private_get (g_thread_specific_private);
 711
 712   if (!thread)
 713     {
 714       /* If no thread data is available, provide and set one.  This
 715          can happen for the main thread and for threads, that are not
 716          created by GLib. */
 717       thread = g_new (GRealThread, 1);
 718       thread->thread.joinable = FALSE; /* This is a save guess */
 719       thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
 720                                                              just a guess */
 721       thread->thread.func = NULL;
 722       thread->thread.data = NULL;
 723       thread->private_data = NULL;
 724
 725       if (g_thread_supported ())
 726         G_THREAD_UF (thread_self, (&thread->system_thread));
 727
 728 #ifdef G_THREAD_USE_PID_SURROGATE
 729       thread->pid = getpid ();
 730 #endif /* G_THREAD_USE_PID_SURROGATE */
 731
 732       g_private_set (g_thread_specific_private, thread);
 733
 734       G_LOCK (g_thread);
 735       g_thread_all_threads = g_slist_prepend (g_thread_all_threads, thread);
 736       G_UNLOCK (g_thread);
 737     }
 738
 739   return (GThread*)thread;
 740 }
 741
 742 void
 743 g_static_rw_lock_init (GStaticRWLock* lock)
 744 {
 745   static GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
 746
 747   g_return_if_fail (lock);
 748
 749   *lock = init_lock;
 750 }
 751
 752 static void inline
 753 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
 754 {
 755   if (!*cond)
 756       *cond = g_cond_new ();
 757   g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
 758 }
 759
 760 static void inline
 761 g_static_rw_lock_signal (GStaticRWLock* lock)
 762 {
 763   if (lock->want_to_write && lock->write_cond)
 764     g_cond_signal (lock->write_cond);
 765   else if (lock->want_to_read && lock->read_cond)
 766     g_cond_broadcast (lock->read_cond);
 767 }
 768
 769 void
 770 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
 771 {
 772   g_return_if_fail (lock);
 773
 774   if (!g_threads_got_initialized)
 775     return;
 776
 777   g_static_mutex_lock (&lock->mutex);
 778   lock->want_to_read++;
 779   while (lock->have_writer || lock->want_to_write)
 780     g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
 781   lock->want_to_read--;
 782   lock->read_counter++;
 783   g_static_mutex_unlock (&lock->mutex);
 784 }
 785
 786 gboolean
 787 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
 788 {
 789   gboolean ret_val = FALSE;
 790
 791   g_return_val_if_fail (lock, FALSE);
 792
 793   if (!g_threads_got_initialized)
 794     return TRUE;
 795
 796   g_static_mutex_lock (&lock->mutex);
 797   if (!lock->have_writer && !lock->want_to_write)
 798     {
 799       lock->read_counter++;
 800       ret_val = TRUE;
 801     }
 802   g_static_mutex_unlock (&lock->mutex);
 803   return ret_val;
 804 }
 805
 806 void
 807 g_static_rw_lock_reader_unlock  (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->read_counter--;
 816   if (lock->read_counter == 0)
 817     g_static_rw_lock_signal (lock);
 818   g_static_mutex_unlock (&lock->mutex);
 819 }
 820
 821 void
 822 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
 823 {
 824   g_return_if_fail (lock);
 825
 826   if (!g_threads_got_initialized)
 827     return;
 828
 829   g_static_mutex_lock (&lock->mutex);
 830   lock->want_to_write++;
 831   while (lock->have_writer || lock->read_counter)
 832     g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
 833   lock->want_to_write--;
 834   lock->have_writer = TRUE;
 835   g_static_mutex_unlock (&lock->mutex);
 836 }
 837
 838 gboolean
 839 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
 840 {
 841   gboolean ret_val = FALSE;
 842
 843   g_return_val_if_fail (lock, FALSE);
 844
 845   if (!g_threads_got_initialized)
 846     return TRUE;
 847
 848   g_static_mutex_lock (&lock->mutex);
 849   if (!lock->have_writer && !lock->read_counter)
 850     {
 851       lock->have_writer = TRUE;
 852       ret_val = TRUE;
 853     }
 854   g_static_mutex_unlock (&lock->mutex);
 855   return ret_val;
 856 }
 857
 858 void
 859 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
 860 {
 861   g_return_if_fail (lock);
 862
 863   if (!g_threads_got_initialized)
 864     return;
 865
 866   g_static_mutex_lock (&lock->mutex);
 867   lock->have_writer = FALSE;
 868   g_static_rw_lock_signal (lock);
 869   g_static_mutex_unlock (&lock->mutex);
 870 }
 871
 872 void
 873 g_static_rw_lock_free (GStaticRWLock* lock)
 874 {
 875   g_return_if_fail (lock);
 876
 877   if (lock->read_cond)
 878     {
 879       g_cond_free (lock->read_cond);
 880       lock->read_cond = NULL;
 881     }
 882   if (lock->write_cond)
 883     {
 884       g_cond_free (lock->write_cond);
 885       lock->write_cond = NULL;
 886     }
 887   g_static_mutex_free (&lock->mutex);
 888 }