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88e17b57 | 1 | /* GNU Objective C Runtime Thread Interface |
a945c346 | 2 | Copyright (C) 1996-2024 Free Software Foundation, Inc. |
88e17b57 BE |
3 | Contributed by Galen C. Hunt (gchunt@cs.rochester.edu) |
4 | ||
38709cad | 5 | This file is part of GCC. |
88e17b57 | 6 | |
38709cad | 7 | GCC is free software; you can redistribute it and/or modify it under the |
88e17b57 | 8 | terms of the GNU General Public License as published by the Free Software |
748086b7 | 9 | Foundation; either version 3, or (at your option) any later version. |
88e17b57 | 10 | |
38709cad | 11 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
88e17b57 BE |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
13 | FOR A PARTICULAR PURPOSE. See the GNU General Public License for more | |
14 | details. | |
15 | ||
748086b7 JJ |
16 | Under Section 7 of GPL version 3, you are granted additional |
17 | permissions described in the GCC Runtime Library Exception, version | |
18 | 3.1, as published by the Free Software Foundation. | |
19 | ||
20 | You should have received a copy of the GNU General Public License and | |
21 | a copy of the GCC Runtime Library Exception along with this program; | |
22 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 | <http://www.gnu.org/licenses/>. */ | |
88e17b57 | 24 | |
6dead247 | 25 | #include "objc-private/common.h" |
7b869986 | 26 | #include "objc-private/error.h" |
88a2722e | 27 | #define _LIBOBJC |
88a2722e NP |
28 | #include "config.h" |
29 | #include "tconfig.h" | |
30 | #include "coretypes.h" | |
31 | #include "tm.h" | |
32 | #include "defaults.h" | |
33 | #include "objc/thr.h" | |
5ec582f9 | 34 | #include "objc/message.h" /* For objc_msg_lookup(). */ |
718a8e53 | 35 | #include "objc/runtime.h" |
80e4b9e5 | 36 | #include "objc-private/module-abi-8.h" |
a19fac96 | 37 | #include "objc-private/runtime.h" |
88a2722e | 38 | #include <gthr.h> |
88e17b57 BE |
39 | |
40 | #include <stdlib.h> | |
88e17b57 BE |
41 | |
42 | /* Global exit status. */ | |
43 | int __objc_thread_exit_status = 0; | |
44 | ||
575584a9 | 45 | /* Flag which lets us know if we ever became multi threaded. */ |
88e17b57 BE |
46 | int __objc_is_multi_threaded = 0; |
47 | ||
575584a9 NP |
48 | /* The hook function called when the runtime becomes multi |
49 | threaded. */ | |
88e17b57 BE |
50 | objc_thread_callback _objc_became_multi_threaded = NULL; |
51 | ||
575584a9 NP |
52 | /* Use this to set the hook function that will be called when the |
53 | runtime initially becomes multi threaded. The hook function is | |
54 | only called once, meaning only when the 2nd thread is spawned, not | |
55 | for each and every thread. | |
88e17b57 | 56 | |
575584a9 | 57 | It returns the previous hook function or NULL if there is none. |
88e17b57 | 58 | |
575584a9 NP |
59 | A program outside of the runtime could set this to some function so |
60 | it can be informed; for example, the GNUstep Base Library sets it | |
61 | so it can implement the NSBecomingMultiThreaded notification. */ | |
40165636 | 62 | objc_thread_callback objc_set_thread_callback (objc_thread_callback func) |
88e17b57 BE |
63 | { |
64 | objc_thread_callback temp = _objc_became_multi_threaded; | |
65 | _objc_became_multi_threaded = func; | |
66 | return temp; | |
67 | } | |
68 | ||
575584a9 NP |
69 | /* Private functions. |
70 | ||
71 | These functions are utilized by the runtime, but they are not | |
72 | considered part of the public interface. */ | |
88e17b57 | 73 | |
575584a9 | 74 | /* Initialize the threads subsystem. */ |
88a2722e NP |
75 | int |
76 | __objc_init_thread_system(void) | |
77 | { | |
78 | return __gthread_objc_init_thread_system (); | |
79 | } | |
80 | ||
575584a9 | 81 | /* First function called in a thread, starts everything else. |
88e17b57 | 82 | |
575584a9 NP |
83 | This function is passed to the backend by objc_thread_detach as the |
84 | starting function for a new thread. */ | |
88e17b57 BE |
85 | struct __objc_thread_start_state |
86 | { | |
87 | SEL selector; | |
88 | id object; | |
89 | id argument; | |
90 | }; | |
91 | ||
bc012a44 AP |
92 | static void __attribute__((noreturn)) |
93 | __objc_thread_detach_function (struct __objc_thread_start_state *istate) | |
88e17b57 BE |
94 | { |
95 | /* Valid state? */ | |
575584a9 NP |
96 | if (istate) |
97 | { | |
98 | id (*imp) (id, SEL, id); | |
99 | SEL selector = istate->selector; | |
100 | id object = istate->object; | |
101 | id argument = istate->argument; | |
102 | ||
103 | /* Don't need anymore so free it. */ | |
104 | objc_free (istate); | |
105 | ||
106 | /* Clear out the thread local storage. */ | |
107 | objc_thread_set_data (NULL); | |
108 | ||
109 | /* Check to see if we just became multi threaded. */ | |
110 | if (! __objc_is_multi_threaded) | |
111 | { | |
112 | __objc_is_multi_threaded = 1; | |
113 | ||
114 | /* Call the hook function. */ | |
115 | if (_objc_became_multi_threaded != NULL) | |
116 | (*_objc_became_multi_threaded) (); | |
117 | } | |
118 | ||
119 | /* Call the method. */ | |
120 | if ((imp = (id (*) (id, SEL, id))objc_msg_lookup (object, selector))) | |
40165636 | 121 | (*imp) (object, selector, argument); |
575584a9 NP |
122 | else |
123 | { | |
124 | /* FIXME: Should we abort here ? */ | |
125 | _objc_abort ("objc_thread_detach called with bad selector.\n"); | |
126 | } | |
127 | } | |
88e17b57 | 128 | else |
7b869986 NP |
129 | { |
130 | /* FIXME: Should we abort here ? */ | |
131 | _objc_abort ("objc_thread_detach called with NULL state.\n"); | |
132 | } | |
575584a9 NP |
133 | |
134 | /* Exit the thread. */ | |
40165636 | 135 | objc_thread_exit (); |
b15b7ef8 KT |
136 | |
137 | /* Make sure compiler detects no return. */ | |
138 | __builtin_trap (); | |
88e17b57 BE |
139 | } |
140 | ||
575584a9 | 141 | /* Public functions. |
88e17b57 | 142 | |
575584a9 NP |
143 | These functions constitute the public interface to the Objective-C |
144 | thread and mutex functionality. */ | |
88e17b57 | 145 | |
575584a9 NP |
146 | /* Detach a new thread of execution and return its id. Returns NULL |
147 | if fails. Thread is started by sending message with selector to | |
148 | object. Message takes a single argument. */ | |
88e17b57 | 149 | objc_thread_t |
40165636 | 150 | objc_thread_detach (SEL selector, id object, id argument) |
88e17b57 BE |
151 | { |
152 | struct __objc_thread_start_state *istate; | |
153 | objc_thread_t thread_id = NULL; | |
154 | ||
575584a9 NP |
155 | /* Allocate the state structure. */ |
156 | if (!(istate = (struct __objc_thread_start_state *)objc_malloc | |
157 | (sizeof (*istate)))) | |
88e17b57 | 158 | return NULL; |
575584a9 NP |
159 | |
160 | /* Initialize the state structure. */ | |
88e17b57 BE |
161 | istate->selector = selector; |
162 | istate->object = object; | |
163 | istate->argument = argument; | |
164 | ||
575584a9 | 165 | /* Lock access. */ |
40165636 | 166 | objc_mutex_lock (__objc_runtime_mutex); |
88e17b57 | 167 | |
575584a9 | 168 | /* Call the backend to spawn the thread. */ |
88a2722e NP |
169 | if ((thread_id = __gthread_objc_thread_detach ((void *)__objc_thread_detach_function, |
170 | istate)) == NULL) | |
88e17b57 | 171 | { |
575584a9 | 172 | /* Failed! */ |
40165636 RB |
173 | objc_mutex_unlock (__objc_runtime_mutex); |
174 | objc_free (istate); | |
88e17b57 BE |
175 | return NULL; |
176 | } | |
177 | ||
575584a9 | 178 | /* Increment our thread counter. */ |
88e17b57 | 179 | __objc_runtime_threads_alive++; |
40165636 | 180 | objc_mutex_unlock (__objc_runtime_mutex); |
88e17b57 BE |
181 | |
182 | return thread_id; | |
183 | } | |
184 | ||
575584a9 | 185 | /* Set the current thread's priority. */ |
88e17b57 | 186 | int |
40165636 | 187 | objc_thread_set_priority (int priority) |
88e17b57 | 188 | { |
88a2722e | 189 | return __gthread_objc_thread_set_priority (priority); |
88e17b57 BE |
190 | } |
191 | ||
575584a9 | 192 | /* Return the current thread's priority. */ |
88e17b57 | 193 | int |
40165636 | 194 | objc_thread_get_priority (void) |
88e17b57 | 195 | { |
88a2722e | 196 | return __gthread_objc_thread_get_priority (); |
88e17b57 BE |
197 | } |
198 | ||
575584a9 NP |
199 | /* Yield our process time to another thread. Any BUSY waiting that is |
200 | done by a thread should use this function to make sure that other | |
201 | threads can make progress even on a lazy uniprocessor system. */ | |
88e17b57 | 202 | void |
40165636 | 203 | objc_thread_yield (void) |
88e17b57 | 204 | { |
88a2722e | 205 | __gthread_objc_thread_yield (); |
88e17b57 BE |
206 | } |
207 | ||
575584a9 NP |
208 | /* Terminate the current tread. Doesn't return. Actually, if it |
209 | failed returns -1. */ | |
88e17b57 | 210 | int |
40165636 | 211 | objc_thread_exit (void) |
88e17b57 | 212 | { |
575584a9 | 213 | /* Decrement our counter of the number of threads alive. */ |
40165636 | 214 | objc_mutex_lock (__objc_runtime_mutex); |
88e17b57 | 215 | __objc_runtime_threads_alive--; |
40165636 | 216 | objc_mutex_unlock (__objc_runtime_mutex); |
88e17b57 | 217 | |
575584a9 | 218 | /* Call the backend to terminate the thread. */ |
88a2722e | 219 | return __gthread_objc_thread_exit (); |
88e17b57 BE |
220 | } |
221 | ||
575584a9 NP |
222 | /* Returns an integer value which uniquely describes a thread. Must |
223 | not be NULL which is reserved as a marker for "no thread". */ | |
88e17b57 | 224 | objc_thread_t |
40165636 | 225 | objc_thread_id (void) |
88e17b57 | 226 | { |
88a2722e | 227 | return __gthread_objc_thread_id (); |
88e17b57 BE |
228 | } |
229 | ||
575584a9 NP |
230 | /* Sets the thread's local storage pointer. Returns 0 if successful |
231 | or -1 if failed. */ | |
88e17b57 | 232 | int |
40165636 | 233 | objc_thread_set_data (void *value) |
88e17b57 | 234 | { |
88a2722e | 235 | return __gthread_objc_thread_set_data (value); |
88e17b57 BE |
236 | } |
237 | ||
575584a9 NP |
238 | /* Returns the thread's local storage pointer. Returns NULL on |
239 | failure. */ | |
88e17b57 | 240 | void * |
40165636 | 241 | objc_thread_get_data (void) |
88e17b57 | 242 | { |
88a2722e | 243 | return __gthread_objc_thread_get_data (); |
88e17b57 BE |
244 | } |
245 | ||
575584a9 | 246 | /* Public mutex functions */ |
88e17b57 | 247 | |
575584a9 NP |
248 | /* Allocate a mutex. Return the mutex pointer if successful or NULL |
249 | if the allocation failed for any reason. */ | |
88e17b57 | 250 | objc_mutex_t |
40165636 | 251 | objc_mutex_allocate (void) |
88e17b57 BE |
252 | { |
253 | objc_mutex_t mutex; | |
254 | ||
575584a9 | 255 | /* Allocate the mutex structure. */ |
40165636 | 256 | if (! (mutex = (objc_mutex_t)objc_malloc (sizeof (struct objc_mutex)))) |
88e17b57 BE |
257 | return NULL; |
258 | ||
575584a9 | 259 | /* Call backend to create the mutex. */ |
88a2722e | 260 | if (__gthread_objc_mutex_allocate (mutex)) |
88e17b57 | 261 | { |
575584a9 | 262 | /* Failed! */ |
40165636 | 263 | objc_free (mutex); |
88e17b57 BE |
264 | return NULL; |
265 | } | |
266 | ||
575584a9 | 267 | /* Initialize mutex. */ |
88e17b57 BE |
268 | mutex->owner = NULL; |
269 | mutex->depth = 0; | |
270 | return mutex; | |
271 | } | |
272 | ||
575584a9 NP |
273 | /* Deallocate a mutex. Note that this includes an implicit mutex_lock |
274 | to insure that no one else is using the lock. It is legal to | |
275 | deallocate a lock if we have a lock on it, but illegal to | |
276 | deallocate a lock held by anyone else. Returns the number of locks | |
277 | on the thread. (1 for deallocate). */ | |
88e17b57 | 278 | int |
40165636 | 279 | objc_mutex_deallocate (objc_mutex_t mutex) |
88e17b57 BE |
280 | { |
281 | int depth; | |
282 | ||
575584a9 | 283 | /* Valid mutex? */ |
40165636 | 284 | if (! mutex) |
88e17b57 BE |
285 | return -1; |
286 | ||
575584a9 | 287 | /* Acquire lock on mutex. */ |
40165636 | 288 | depth = objc_mutex_lock (mutex); |
88e17b57 | 289 | |
575584a9 | 290 | /* Call backend to destroy mutex. */ |
88a2722e | 291 | if (__gthread_objc_mutex_deallocate (mutex)) |
88e17b57 BE |
292 | return -1; |
293 | ||
575584a9 | 294 | /* Free the mutex structure. */ |
40165636 | 295 | objc_free (mutex); |
88e17b57 | 296 | |
575584a9 | 297 | /* Return last depth. */ |
88e17b57 BE |
298 | return depth; |
299 | } | |
300 | ||
575584a9 NP |
301 | /* Grab a lock on a mutex. If this thread already has a lock on this |
302 | mutex then we increment the lock count. If another thread has a | |
303 | lock on the mutex we block and wait for the thread to release the | |
304 | lock. Returns the lock count on the mutex held by this thread. */ | |
88e17b57 | 305 | int |
40165636 | 306 | objc_mutex_lock (objc_mutex_t mutex) |
88e17b57 BE |
307 | { |
308 | objc_thread_t thread_id; | |
309 | int status; | |
310 | ||
575584a9 | 311 | /* Valid mutex? */ |
40165636 | 312 | if (! mutex) |
88e17b57 BE |
313 | return -1; |
314 | ||
575584a9 | 315 | /* If we already own the lock then increment depth. */ |
88a2722e | 316 | thread_id = __gthread_objc_thread_id (); |
88e17b57 BE |
317 | if (mutex->owner == thread_id) |
318 | return ++mutex->depth; | |
319 | ||
575584a9 | 320 | /* Call the backend to lock the mutex. */ |
88a2722e | 321 | status = __gthread_objc_mutex_lock (mutex); |
88e17b57 | 322 | |
575584a9 | 323 | /* Failed? */ |
88e17b57 BE |
324 | if (status) |
325 | return status; | |
326 | ||
575584a9 | 327 | /* Successfully locked the thread. */ |
88e17b57 BE |
328 | mutex->owner = thread_id; |
329 | return mutex->depth = 1; | |
330 | } | |
331 | ||
575584a9 NP |
332 | /* Try to grab a lock on a mutex. If this thread already has a lock |
333 | on this mutex then we increment the lock count and return it. If | |
334 | another thread has a lock on the mutex returns -1. */ | |
88e17b57 | 335 | int |
40165636 | 336 | objc_mutex_trylock (objc_mutex_t mutex) |
88e17b57 BE |
337 | { |
338 | objc_thread_t thread_id; | |
339 | int status; | |
340 | ||
575584a9 | 341 | /* Valid mutex? */ |
40165636 | 342 | if (! mutex) |
88e17b57 BE |
343 | return -1; |
344 | ||
575584a9 | 345 | /* If we already own the lock then increment depth. */ |
88a2722e | 346 | thread_id = __gthread_objc_thread_id (); |
88e17b57 BE |
347 | if (mutex->owner == thread_id) |
348 | return ++mutex->depth; | |
349 | ||
575584a9 | 350 | /* Call the backend to try to lock the mutex. */ |
88a2722e | 351 | status = __gthread_objc_mutex_trylock (mutex); |
88e17b57 | 352 | |
575584a9 | 353 | /* Failed? */ |
88e17b57 BE |
354 | if (status) |
355 | return status; | |
356 | ||
575584a9 | 357 | /* Successfully locked the thread. */ |
88e17b57 BE |
358 | mutex->owner = thread_id; |
359 | return mutex->depth = 1; | |
360 | } | |
361 | ||
575584a9 NP |
362 | /* Unlocks the mutex by one level. Decrements the lock count on this |
363 | mutex by one. If the lock count reaches zero, release the lock on | |
364 | the mutex. Returns the lock count on the mutex. It is an error to | |
365 | attempt to unlock a mutex which this thread doesn't hold in which | |
366 | case return -1 and the mutex is unaffected. */ | |
88e17b57 | 367 | int |
40165636 | 368 | objc_mutex_unlock (objc_mutex_t mutex) |
88e17b57 BE |
369 | { |
370 | objc_thread_t thread_id; | |
371 | int status; | |
372 | ||
575584a9 | 373 | /* Valid mutex? */ |
40165636 | 374 | if (! mutex) |
88e17b57 BE |
375 | return -1; |
376 | ||
575584a9 | 377 | /* If another thread owns the lock then abort. */ |
88a2722e | 378 | thread_id = __gthread_objc_thread_id (); |
88e17b57 BE |
379 | if (mutex->owner != thread_id) |
380 | return -1; | |
381 | ||
575584a9 | 382 | /* Decrement depth and return. */ |
88e17b57 BE |
383 | if (mutex->depth > 1) |
384 | return --mutex->depth; | |
385 | ||
575584a9 | 386 | /* Depth down to zero so we are no longer the owner. */ |
88e17b57 BE |
387 | mutex->depth = 0; |
388 | mutex->owner = NULL; | |
389 | ||
575584a9 | 390 | /* Have the backend unlock the mutex. */ |
88a2722e | 391 | status = __gthread_objc_mutex_unlock (mutex); |
88e17b57 | 392 | |
575584a9 | 393 | /* Failed? */ |
88e17b57 BE |
394 | if (status) |
395 | return status; | |
396 | ||
397 | return 0; | |
398 | } | |
399 | ||
575584a9 | 400 | /* Public condition mutex functions */ |
88e17b57 | 401 | |
575584a9 NP |
402 | /* Allocate a condition. Return the condition pointer if successful |
403 | or NULL if the allocation failed for any reason. */ | |
88e17b57 | 404 | objc_condition_t |
40165636 | 405 | objc_condition_allocate (void) |
88e17b57 BE |
406 | { |
407 | objc_condition_t condition; | |
408 | ||
575584a9 | 409 | /* Allocate the condition mutex structure. */ |
40165636 RB |
410 | if (! (condition = |
411 | (objc_condition_t) objc_malloc (sizeof (struct objc_condition)))) | |
88e17b57 BE |
412 | return NULL; |
413 | ||
575584a9 | 414 | /* Call the backend to create the condition mutex. */ |
88a2722e | 415 | if (__gthread_objc_condition_allocate (condition)) |
88e17b57 | 416 | { |
575584a9 | 417 | /* Failed! */ |
40165636 | 418 | objc_free (condition); |
88e17b57 BE |
419 | return NULL; |
420 | } | |
421 | ||
575584a9 | 422 | /* Success! */ |
88e17b57 BE |
423 | return condition; |
424 | } | |
425 | ||
575584a9 NP |
426 | /* Deallocate a condition. Note that this includes an implicit |
427 | condition_broadcast to insure that waiting threads have the | |
428 | opportunity to wake. It is legal to dealloc a condition only if no | |
429 | other thread is/will be using it. Here we do NOT check for other | |
430 | threads waiting but just wake them up. */ | |
88e17b57 | 431 | int |
40165636 | 432 | objc_condition_deallocate (objc_condition_t condition) |
88e17b57 | 433 | { |
575584a9 | 434 | /* Broadcast the condition. */ |
40165636 | 435 | if (objc_condition_broadcast (condition)) |
88e17b57 BE |
436 | return -1; |
437 | ||
575584a9 | 438 | /* Call the backend to destroy. */ |
88a2722e | 439 | if (__gthread_objc_condition_deallocate (condition)) |
88e17b57 BE |
440 | return -1; |
441 | ||
575584a9 | 442 | /* Free the condition mutex structure. */ |
40165636 | 443 | objc_free (condition); |
88e17b57 BE |
444 | |
445 | return 0; | |
446 | } | |
447 | ||
575584a9 NP |
448 | /* Wait on the condition unlocking the mutex until |
449 | objc_condition_signal () or objc_condition_broadcast () are called | |
450 | for the same condition. The given mutex *must* have the depth set | |
451 | to 1 so that it can be unlocked here, so that someone else can lock | |
452 | it and signal/broadcast the condition. The mutex is used to lock | |
453 | access to the shared data that make up the "condition" | |
454 | predicate. */ | |
88e17b57 | 455 | int |
40165636 | 456 | objc_condition_wait (objc_condition_t condition, objc_mutex_t mutex) |
88e17b57 BE |
457 | { |
458 | objc_thread_t thread_id; | |
459 | ||
575584a9 | 460 | /* Valid arguments? */ |
40165636 | 461 | if (! mutex || ! condition) |
88e17b57 BE |
462 | return -1; |
463 | ||
575584a9 | 464 | /* Make sure we are owner of mutex. */ |
88a2722e | 465 | thread_id = __gthread_objc_thread_id (); |
88e17b57 BE |
466 | if (mutex->owner != thread_id) |
467 | return -1; | |
468 | ||
575584a9 | 469 | /* Cannot be locked more than once. */ |
88e17b57 BE |
470 | if (mutex->depth > 1) |
471 | return -1; | |
472 | ||
575584a9 | 473 | /* Virtually unlock the mutex. */ |
88e17b57 BE |
474 | mutex->depth = 0; |
475 | mutex->owner = (objc_thread_t)NULL; | |
476 | ||
575584a9 | 477 | /* Call the backend to wait. */ |
88a2722e | 478 | __gthread_objc_condition_wait (condition, mutex); |
88e17b57 | 479 | |
575584a9 | 480 | /* Make ourselves owner of the mutex. */ |
88e17b57 BE |
481 | mutex->owner = thread_id; |
482 | mutex->depth = 1; | |
483 | ||
484 | return 0; | |
485 | } | |
486 | ||
575584a9 NP |
487 | /* Wake up all threads waiting on this condition. It is recommended |
488 | that the called would lock the same mutex as the threads in | |
489 | objc_condition_wait before changing the "condition predicate" and | |
490 | make this call and unlock it right away after this call. */ | |
88e17b57 | 491 | int |
40165636 | 492 | objc_condition_broadcast (objc_condition_t condition) |
88e17b57 | 493 | { |
575584a9 | 494 | /* Valid condition mutex? */ |
40165636 | 495 | if (! condition) |
88e17b57 BE |
496 | return -1; |
497 | ||
88a2722e | 498 | return __gthread_objc_condition_broadcast (condition); |
88e17b57 BE |
499 | } |
500 | ||
575584a9 NP |
501 | /* Wake up one thread waiting on this condition. It is recommended |
502 | that the called would lock the same mutex as the threads in | |
503 | objc_condition_wait before changing the "condition predicate" and | |
504 | make this call and unlock it right away after this call. */ | |
88e17b57 | 505 | int |
40165636 | 506 | objc_condition_signal (objc_condition_t condition) |
88e17b57 | 507 | { |
575584a9 | 508 | /* Valid condition mutex? */ |
40165636 | 509 | if (! condition) |
88e17b57 BE |
510 | return -1; |
511 | ||
88a2722e | 512 | return __gthread_objc_condition_signal (condition); |
88e17b57 BE |
513 | } |
514 | ||
b894530e NP |
515 | /* Make the objc thread system aware that a thread which is managed |
516 | (started, stopped) by external code could access objc facilities | |
517 | from now on. This is used when you are interfacing with some | |
518 | external non-objc-based environment/system - you must call | |
40165636 | 519 | objc_thread_add () before an alien thread makes any calls to |
b894530e NP |
520 | Objective-C. Do not cause the _objc_became_multi_threaded hook to |
521 | be executed. */ | |
522 | void | |
40165636 | 523 | objc_thread_add (void) |
b894530e | 524 | { |
40165636 | 525 | objc_mutex_lock (__objc_runtime_mutex); |
b894530e NP |
526 | __objc_is_multi_threaded = 1; |
527 | __objc_runtime_threads_alive++; | |
40165636 | 528 | objc_mutex_unlock (__objc_runtime_mutex); |
b894530e NP |
529 | } |
530 | ||
531 | /* Make the objc thread system aware that a thread managed (started, | |
532 | stopped) by some external code will no longer access objc and thus | |
533 | can be forgotten by the objc thread system. Call | |
40165636 | 534 | objc_thread_remove () when your alien thread is done with making |
b894530e NP |
535 | calls to Objective-C. */ |
536 | void | |
40165636 | 537 | objc_thread_remove (void) |
b894530e | 538 | { |
40165636 | 539 | objc_mutex_lock (__objc_runtime_mutex); |
b894530e | 540 | __objc_runtime_threads_alive--; |
40165636 | 541 | objc_mutex_unlock (__objc_runtime_mutex); |
b894530e NP |
542 | } |
543 |