1 /*
2  * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3  * Copyright (c) 1991-1995 by Xerox Corporation.  All rights reserved.
4  * Copyright 1996-1999 by Silicon Graphics.  All rights reserved.
5  * Copyright 1999 by Hewlett-Packard Company.  All rights reserved.
6  * Copyright (C) 2007 Free Software Foundation, Inc
7  * Copyright (c) 2000-2011 by Hewlett-Packard Development Company.
8  * Copyright (c) 2009-2018 Ivan Maidanski
9  *
10  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
11  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
12  *
13  * Permission is hereby granted to use or copy this program
14  * for any purpose,  provided the above notices are retained on all copies.
15  * Permission to modify the code and to distribute modified code is granted,
16  * provided the above notices are retained, and a notice that the code was
17  * modified is included with the above copyright notice.
18  */
19 
20 /*
21  * Note that this defines a large number of tuning hooks, which can
22  * safely be ignored in nearly all cases.  For normal use it suffices
23  * to call only GC_MALLOC and perhaps GC_REALLOC.
24  * For better performance, also look at GC_MALLOC_ATOMIC, and
25  * GC_enable_incremental.  If you need an action to be performed
26  * immediately before an object is collected, look at GC_register_finalizer.
27  * Everything else is best ignored unless you encounter performance
28  * problems.
29  */
30 
31 #ifndef GC_H
32 #define GC_H
33 
34 /* Help debug mixed up preprocessor symbols.    */
35 #if (defined(WIN64) && !defined(_WIN64)) && defined(_MSC_VER)
36 #pragma message("Warning: Expecting _WIN64 for x64 targets! Notice the leading underscore!")
37 #endif
38 
39 #include "gc_version.h"
40         /* Define version numbers here to allow test on build machine   */
41         /* for cross-builds.  Note that this defines the header         */
42         /* version number, which may or may not match that of the       */
43         /* dynamic library.  GC_get_version() can be used to obtain     */
44         /* the latter.                                                  */
45 
46 #include "gc_config_macros.h"
47 
48 #ifdef __cplusplus
49   extern "C" {
50 #endif
51 
52 typedef void * GC_PTR;  /* preserved only for backward compatibility    */
53 
54 /* Define word and signed_word to be unsigned and signed types of the   */
55 /* size as char * or void *.  There seems to be no way to do this       */
56 /* even semi-portably.  The following is probably no better/worse       */
57 /* than almost anything else.                                           */
58 /* The ANSI standard suggests that size_t and ptrdiff_t might be        */
59 /* better choices.  But those had incorrect definitions on some older   */
60 /* systems.  Notably "typedef int size_t" is WRONG.                     */
61 #ifdef _WIN64
62 # if defined(__int64) && !defined(CPPCHECK)
63     typedef unsigned __int64 GC_word;
64     typedef __int64 GC_signed_word;
65 # else
66     typedef unsigned long long GC_word;
67     typedef long long GC_signed_word;
68 # endif
69 #else
70   typedef unsigned long GC_word;
71   typedef long GC_signed_word;
72 #endif
73 
74 /* Get the GC library version. The returned value is a constant in the  */
75 /* form: ((version_major<<16) | (version_minor<<8) | version_micro).    */
76 GC_API unsigned GC_CALL GC_get_version(void);
77 
78 /* Public read-only variables */
79 /* The supplied getter functions are preferred for new code.            */
80 
81 GC_API GC_ATTR_DEPRECATED GC_word GC_gc_no;
82                         /* Counter incremented per collection.          */
83                         /* Includes empty GCs at startup.               */
84 GC_API GC_word GC_CALL GC_get_gc_no(void);
85                         /* GC_get_gc_no() is unsynchronized, so         */
86                         /* it requires GC_call_with_alloc_lock() to     */
87                         /* avoid data races on multiprocessors.         */
88 
89 #ifdef GC_THREADS
90   GC_API GC_ATTR_DEPRECATED int GC_parallel;
91                         /* GC is parallelized for performance on        */
92                         /* multiprocessors.  Set to a non-zero value    */
93                         /* only implicitly if collector is built with   */
94                         /* PARALLEL_MARK defined, and if either         */
95                         /* GC_MARKERS (or GC_NPROCS) environment        */
96                         /* variable is set to > 1, or multiple cores    */
97                         /* (processors) are available.                  */
98                         /* If GC_parallel is on (non-zero), incremental */
99                         /* collection is only partially functional,     */
100                         /* and may not be desirable.  The getter does   */
101                         /* not use or need synchronization (i.e.        */
102                         /* acquiring the GC lock).  Starting from       */
103                         /* GC v7.3, GC_parallel value is equal to the   */
104                         /* number of marker threads minus one (i.e.     */
105                         /* number of existing parallel marker threads   */
106                         /* excluding the initiating one).               */
107   GC_API int GC_CALL GC_get_parallel(void);
108 #endif
109 
110 
111 /* Public R/W variables */
112 /* The supplied setter and getter functions are preferred for new code. */
113 
114 typedef void * (GC_CALLBACK * GC_oom_func)(size_t /* bytes_requested */);
115 GC_API GC_ATTR_DEPRECATED GC_oom_func GC_oom_fn;
116                         /* When there is insufficient memory to satisfy */
117                         /* an allocation request, we return             */
118                         /* (*GC_oom_fn)(size).  By default this just    */
119                         /* returns NULL.                                */
120                         /* If it returns, it must return 0 or a valid   */
121                         /* pointer to a previously allocated heap       */
122                         /* object.  GC_oom_fn must not be 0.            */
123                         /* Both the supplied setter and the getter      */
124                         /* acquire the GC lock (to avoid data races).   */
125 GC_API void GC_CALL GC_set_oom_fn(GC_oom_func) GC_ATTR_NONNULL(1);
126 GC_API GC_oom_func GC_CALL GC_get_oom_fn(void);
127 
128 typedef void (GC_CALLBACK * GC_on_heap_resize_proc)(GC_word /* new_size */);
129 GC_API GC_ATTR_DEPRECATED GC_on_heap_resize_proc GC_on_heap_resize;
130                         /* Invoked when the heap grows or shrinks.      */
131                         /* Called with the world stopped (and the       */
132                         /* allocation lock held).  May be 0.            */
133 GC_API void GC_CALL GC_set_on_heap_resize(GC_on_heap_resize_proc);
134 GC_API GC_on_heap_resize_proc GC_CALL GC_get_on_heap_resize(void);
135                         /* Both the supplied setter and the getter      */
136                         /* acquire the GC lock (to avoid data races).   */
137 
138 typedef enum {
139     GC_EVENT_START /* COLLECTION */,
140     GC_EVENT_MARK_START,
141     GC_EVENT_MARK_END,
142     GC_EVENT_RECLAIM_START,
143     GC_EVENT_RECLAIM_END,
144     GC_EVENT_END /* COLLECTION */,
145     GC_EVENT_PRE_STOP_WORLD /* STOPWORLD_BEGIN */,
146     GC_EVENT_POST_STOP_WORLD /* STOPWORLD_END */,
147     GC_EVENT_PRE_START_WORLD /* STARTWORLD_BEGIN */,
148     GC_EVENT_POST_START_WORLD /* STARTWORLD_END */,
149     GC_EVENT_THREAD_SUSPENDED,
150     GC_EVENT_THREAD_UNSUSPENDED
151 } GC_EventType;
152 
153 typedef void (GC_CALLBACK * GC_on_collection_event_proc)(GC_EventType);
154                         /* Invoked to indicate progress through the     */
155                         /* collection process.  Not used for thread     */
156                         /* suspend/resume notifications.  Called with   */
157                         /* the GC lock held (or, even, the world        */
158                         /* stopped).  May be 0 (means no notifier).     */
159 GC_API void GC_CALL GC_set_on_collection_event(GC_on_collection_event_proc);
160 GC_API GC_on_collection_event_proc GC_CALL GC_get_on_collection_event(void);
161                         /* Both the supplied setter and the getter      */
162                         /* acquire the GC lock (to avoid data races).   */
163 
164 #if defined(GC_THREADS) || (defined(GC_BUILD) && defined(NN_PLATFORM_CTR))
165   typedef void (GC_CALLBACK * GC_on_thread_event_proc)(GC_EventType,
166                                                 void * /* thread_id */);
167                         /* Invoked when a thread is suspended or        */
168                         /* resumed during collection.  Called with the  */
169                         /* GC lock held (and the world stopped          */
170                         /* partially).  May be 0 (means no notifier).   */
171   GC_API void GC_CALL GC_set_on_thread_event(GC_on_thread_event_proc);
172   GC_API GC_on_thread_event_proc GC_CALL GC_get_on_thread_event(void);
173                         /* Both the supplied setter and the getter      */
174                         /* acquire the GC lock (to avoid data races).   */
175 #endif
176 
177 GC_API GC_ATTR_DEPRECATED int GC_find_leak;
178                         /* Set to true to turn on the leak-finding mode */
179                         /* (do not actually garbage collect, but simply */
180                         /* report inaccessible memory that was not      */
181                         /* deallocated with GC_FREE).  Initial value    */
182                         /* is determined by FIND_LEAK macro.            */
183                         /* The value should not typically be modified   */
184                         /* after GC initialization (and, thus, it does  */
185                         /* not use or need synchronization).            */
186 GC_API void GC_CALL GC_set_find_leak(int);
187 GC_API int GC_CALL GC_get_find_leak(void);
188 
189 GC_API GC_ATTR_DEPRECATED int GC_all_interior_pointers;
190                         /* Arrange for pointers to object interiors to  */
191                         /* be recognized as valid.  Typically should    */
192                         /* not be changed after GC initialization (in   */
193                         /* case of calling it after the GC is           */
194                         /* initialized, the setter acquires the GC lock */
195                         /* (to avoid data races).  The initial value    */
196                         /* depends on whether the GC is built with      */
197                         /* ALL_INTERIOR_POINTERS macro defined or not.  */
198                         /* Unless DONT_ADD_BYTE_AT_END is defined, this */
199                         /* also affects whether sizes are increased by  */
200                         /* at least a byte to allow "off the end"       */
201                         /* pointer recognition.  Must be only 0 or 1.   */
202 GC_API void GC_CALL GC_set_all_interior_pointers(int);
203 GC_API int GC_CALL GC_get_all_interior_pointers(void);
204 
205 GC_API GC_ATTR_DEPRECATED int GC_finalize_on_demand;
206                         /* If nonzero, finalizers will only be run in   */
207                         /* response to an explicit GC_invoke_finalizers */
208                         /* call.  The default is determined by whether  */
209                         /* the FINALIZE_ON_DEMAND macro is defined      */
210                         /* when the collector is built.                 */
211                         /* The setter and getter are unsynchronized.    */
212 GC_API void GC_CALL GC_set_finalize_on_demand(int);
213 GC_API int GC_CALL GC_get_finalize_on_demand(void);
214 
215 GC_API GC_ATTR_DEPRECATED int GC_java_finalization;
216                         /* Mark objects reachable from finalizable      */
217                         /* objects in a separate post-pass.  This makes */
218                         /* it a bit safer to use non-topologically-     */
219                         /* ordered finalization.  Default value is      */
220                         /* determined by JAVA_FINALIZATION macro.       */
221                         /* Enables register_finalizer_unreachable to    */
222                         /* work correctly.                              */
223                         /* The setter and getter are unsynchronized.    */
224 GC_API void GC_CALL GC_set_java_finalization(int);
225 GC_API int GC_CALL GC_get_java_finalization(void);
226 
227 typedef void (GC_CALLBACK * GC_finalizer_notifier_proc)(void);
228 GC_API GC_ATTR_DEPRECATED GC_finalizer_notifier_proc GC_finalizer_notifier;
229                         /* Invoked by the collector when there are      */
230                         /* objects to be finalized.  Invoked at most    */
231                         /* once per GC cycle.  Never invoked unless     */
232                         /* GC_finalize_on_demand is set.                */
233                         /* Typically this will notify a finalization    */
234                         /* thread, which will call GC_invoke_finalizers */
235                         /* in response.  May be 0 (means no notifier).  */
236                         /* Both the supplied setter and the getter      */
237                         /* acquire the GC lock (to avoid data races).   */
238 GC_API void GC_CALL GC_set_finalizer_notifier(GC_finalizer_notifier_proc);
239 GC_API GC_finalizer_notifier_proc GC_CALL GC_get_finalizer_notifier(void);
240 
241 GC_API
242 # ifndef GC_DONT_GC
243     GC_ATTR_DEPRECATED
244 # endif
245   int GC_dont_gc;       /* != 0 ==> Don't collect.  In versions 6.2a1+, */
246                         /* this overrides explicit GC_gcollect() calls. */
247                         /* Used as a counter, so that nested enabling   */
248                         /* and disabling work correctly.  Should        */
249                         /* normally be updated with GC_enable() and     */
250                         /* GC_disable() calls.  Direct assignment to    */
251                         /* GC_dont_gc is deprecated.  To check whether  */
252                         /* GC is disabled, GC_is_disabled() is          */
253                         /* preferred for new code.                      */
254 
255 GC_API GC_ATTR_DEPRECATED int GC_dont_expand;
256                         /* Do not expand the heap unless explicitly     */
257                         /* requested or forced to.  The setter and      */
258                         /* getter are unsynchronized.                   */
259 GC_API void GC_CALL GC_set_dont_expand(int);
260 GC_API int GC_CALL GC_get_dont_expand(void);
261 
262 GC_API GC_ATTR_DEPRECATED int GC_use_entire_heap;
263                 /* Causes the non-incremental collector to use the      */
264                 /* entire heap before collecting.  This was the only    */
265                 /* option for GC versions < 5.0.  This sometimes        */
266                 /* results in more large block fragmentation, since     */
267                 /* very large blocks will tend to get broken up         */
268                 /* during each GC cycle.  It is likely to result in a   */
269                 /* larger working set, but lower collection             */
270                 /* frequencies, and hence fewer instructions executed   */
271                 /* in the collector.                                    */
272 
273 GC_API GC_ATTR_DEPRECATED int GC_full_freq;
274                             /* Number of partial collections between    */
275                             /* full collections.  Matters only if       */
276                             /* GC_is_incremental_mode().                */
277                             /* Full collections are also triggered if   */
278                             /* the collector detects a substantial      */
279                             /* increase in the number of in-use heap    */
280                             /* blocks.  Values in the tens are now      */
281                             /* perfectly reasonable, unlike for         */
282                             /* earlier GC versions.                     */
283                         /* The setter and getter are unsynchronized, so */
284                         /* GC_call_with_alloc_lock() is required to     */
285                         /* avoid data races (if the value is modified   */
286                         /* after the GC is put to multi-threaded mode). */
287 GC_API void GC_CALL GC_set_full_freq(int);
288 GC_API int GC_CALL GC_get_full_freq(void);
289 
290 GC_API GC_ATTR_DEPRECATED GC_word GC_non_gc_bytes;
291                         /* Bytes not considered candidates for          */
292                         /* collection.  Used only to control scheduling */
293                         /* of collections.  Updated by                  */
294                         /* GC_malloc_uncollectable and GC_free.         */
295                         /* Wizards only.                                */
296                         /* The setter and getter are unsynchronized, so */
297                         /* GC_call_with_alloc_lock() is required to     */
298                         /* avoid data races (if the value is modified   */
299                         /* after the GC is put to multi-threaded mode). */
300 GC_API void GC_CALL GC_set_non_gc_bytes(GC_word);
301 GC_API GC_word GC_CALL GC_get_non_gc_bytes(void);
302 
303 GC_API GC_ATTR_DEPRECATED int GC_no_dls;
304                         /* Don't register dynamic library data segments. */
305                         /* Wizards only.  Should be used only if the     */
306                         /* application explicitly registers all roots.   */
307                         /* (In some environments like Microsoft Windows  */
308                         /* and Apple's Darwin, this may also prevent     */
309                         /* registration of the main data segment as part */
310                         /* of the root set.)                             */
311                         /* The setter and getter are unsynchronized.     */
312 GC_API void GC_CALL GC_set_no_dls(int);
313 GC_API int GC_CALL GC_get_no_dls(void);
314 
315 GC_API GC_ATTR_DEPRECATED GC_word GC_free_space_divisor;
316                         /* We try to make sure that we allocate at      */
317                         /* least N/GC_free_space_divisor bytes between  */
318                         /* collections, where N is twice the number     */
319                         /* of traced bytes, plus the number of untraced */
320                         /* bytes (bytes in "atomic" objects), plus      */
321                         /* a rough estimate of the root set size.       */
322                         /* N approximates GC tracing work per GC.       */
323                         /* The initial value is GC_FREE_SPACE_DIVISOR.  */
324                         /* Increasing its value will use less space     */
325                         /* but more collection time.  Decreasing it     */
326                         /* will appreciably decrease collection time    */
327                         /* at the expense of space.                     */
328                         /* The setter and getter are unsynchronized, so */
329                         /* GC_call_with_alloc_lock() is required to     */
330                         /* avoid data races (if the value is modified   */
331                         /* after the GC is put to multi-threaded mode). */
332                         /* In version 7.1 (and before), the setter      */
333                         /* returned the old value.                      */
334 GC_API void GC_CALL GC_set_free_space_divisor(GC_word);
335 GC_API GC_word GC_CALL GC_get_free_space_divisor(void);
336 
337 GC_API GC_ATTR_DEPRECATED GC_word GC_max_retries;
338                         /* The maximum number of GCs attempted before   */
339                         /* reporting out of memory after heap           */
340                         /* expansion fails.  Initially 0.               */
341                         /* The setter and getter are unsynchronized, so */
342                         /* GC_call_with_alloc_lock() is required to     */
343                         /* avoid data races (if the value is modified   */
344                         /* after the GC is put to multi-threaded mode). */
345 GC_API void GC_CALL GC_set_max_retries(GC_word);
346 GC_API GC_word GC_CALL GC_get_max_retries(void);
347 
348 
349 GC_API GC_ATTR_DEPRECATED char *GC_stackbottom;
350                                 /* Cool end of user stack.              */
351                                 /* May be set in the client prior to    */
352                                 /* calling any GC_ routines.  This      */
353                                 /* avoids some overhead, and            */
354                                 /* potentially some signals that can    */
355                                 /* confuse debuggers.  Otherwise the    */
356                                 /* collector attempts to set it         */
357                                 /* automatically.                       */
358                                 /* For multi-threaded code, this is the */
359                                 /* cold end of the stack for the        */
360                                 /* primordial thread.  Portable clients */
361                                 /* should use GC_get_stack_base(),      */
362                                 /* GC_call_with_gc_active() and         */
363                                 /* GC_register_my_thread() instead.     */
364 
365 GC_API GC_ATTR_DEPRECATED int GC_dont_precollect;
366                                 /* Do not collect as part of GC         */
367                                 /* initialization.  Should be set only  */
368                                 /* if the client wants a chance to      */
369                                 /* manually initialize the root set     */
370                                 /* before the first collection.         */
371                                 /* Interferes with blacklisting.        */
372                                 /* Wizards only.  The setter and getter */
373                                 /* are unsynchronized (and no external  */
374                                 /* locking is needed since the value is */
375                                 /* accessed at GC initialization only). */
376 GC_API void GC_CALL GC_set_dont_precollect(int);
377 GC_API int GC_CALL GC_get_dont_precollect(void);
378 
379 GC_API GC_ATTR_DEPRECATED unsigned long GC_time_limit;
380                                /* If incremental collection is enabled, */
381                                /* We try to terminate collections       */
382                                /* after this many milliseconds.  Not a  */
383                                /* hard time bound.  Setting this to     */
384                                /* GC_TIME_UNLIMITED will essentially    */
385                                /* disable incremental collection while  */
386                                /* leaving generational collection       */
387                                /* enabled.                              */
388 #define GC_TIME_UNLIMITED 999999
389                                /* Setting GC_time_limit to this value   */
390                                /* will disable the "pause time exceeded"*/
391                                /* tests.                                */
392                         /* The setter and getter are unsynchronized, so */
393                         /* GC_call_with_alloc_lock() is required to     */
394                         /* avoid data races (if the value is modified   */
395                         /* after the GC is put to multi-threaded mode). */
396 GC_API void GC_CALL GC_set_time_limit(unsigned long);
397 GC_API unsigned long GC_CALL GC_get_time_limit(void);
398 
399 /* Public procedures */
400 
401 /* Tell the collector to start various performance measurements.        */
402 /* Only the total time taken by full collections is calculated, as      */
403 /* of now.  And, currently, there is no way to stop the measurements.   */
404 /* The function does not use any synchronization.  Defined only if the  */
405 /* library has been compiled without NO_CLOCK.                          */
406 GC_API void GC_CALL GC_start_performance_measurement(void);
407 
408 /* Get the total time of all full collections since the start of the    */
409 /* performance measurements.  The measurement unit is one millisecond.  */
410 /* Note that the returned value wraps around on overflow.               */
411 /* The function does not use any synchronization.  Defined only if the  */
412 /* library has been compiled without NO_CLOCK.                          */
413 GC_API unsigned long GC_CALL GC_get_full_gc_total_time(void);
414 
415 /* Set whether the GC will allocate executable memory pages or not.     */
416 /* A non-zero argument instructs the collector to allocate memory with  */
417 /* the executable flag on.  Must be called before the collector is      */
418 /* initialized.  May have no effect on some platforms.  The default     */
419 /* value is controlled by NO_EXECUTE_PERMISSION macro (if present then  */
420 /* the flag is off).  Portable clients should have                      */
421 /* GC_set_pages_executable(1) call (before GC_INIT) provided they are   */
422 /* going to execute code on any of the GC-allocated memory objects.     */
423 GC_API void GC_CALL GC_set_pages_executable(int);
424 
425 /* Returns non-zero value if the GC is set to the allocate-executable   */
426 /* mode.  The mode could be changed by GC_set_pages_executable (before  */
427 /* GC_INIT) unless the former has no effect on the platform.  Does not  */
428 /* use or need synchronization (i.e. acquiring the allocator lock).     */
429 GC_API int GC_CALL GC_get_pages_executable(void);
430 
431 /* The setter and getter of the minimum value returned by the internal  */
432 /* min_bytes_allocd().  The value should not be zero; the default value */
433 /* is one.  Not synchronized.                                           */
434 GC_API void GC_CALL GC_set_min_bytes_allocd(size_t);
435 GC_API size_t GC_CALL GC_get_min_bytes_allocd(void);
436 
437 /* Set/get the size in pages of units operated by GC_collect_a_little.  */
438 /* The value should not be zero.  Not synchronized.                     */
439 GC_API void GC_CALL GC_set_rate(int);
440 GC_API int GC_CALL GC_get_rate(void);
441 
442 /* Set/get the maximum number of prior attempts at the world-stop       */
443 /* marking.  Not synchronized.                                          */
444 GC_API void GC_CALL GC_set_max_prior_attempts(int);
445 GC_API int GC_CALL GC_get_max_prior_attempts(void);
446 
447 /* Overrides the default handle-fork mode.  Non-zero value means GC     */
448 /* should install proper pthread_atfork handlers.  Has effect only if   */
449 /* called before GC_INIT.  Clients should invoke GC_set_handle_fork     */
450 /* with non-zero argument if going to use fork with GC functions called */
451 /* in the forked child.  (Note that such client and atfork handlers     */
452 /* activities are not fully POSIX-compliant.)  GC_set_handle_fork       */
453 /* instructs GC_init to setup GC fork handlers using pthread_atfork,    */
454 /* the latter might fail (or, even, absent on some targets) causing     */
455 /* abort at GC initialization.  Starting from 7.3alpha3, problems with  */
456 /* missing (or failed) pthread_atfork() could be avoided by invocation  */
457 /* of GC_set_handle_fork(-1) at application start-up and surrounding    */
458 /* each fork() with the relevant GC_atfork_prepare/parent/child calls.  */
459 GC_API void GC_CALL GC_set_handle_fork(int);
460 
461 /* Routines to handle POSIX fork() manually (no-op if handled           */
462 /* automatically).  GC_atfork_prepare should be called immediately      */
463 /* before fork(); GC_atfork_parent should be invoked just after fork in */
464 /* the branch that corresponds to parent process (i.e., fork result is  */
465 /* non-zero); GC_atfork_child is to be called immediately in the child  */
466 /* branch (i.e., fork result is 0). Note that GC_atfork_child() call    */
467 /* should, of course, precede GC_start_mark_threads call (if any).      */
468 GC_API void GC_CALL GC_atfork_prepare(void);
469 GC_API void GC_CALL GC_atfork_parent(void);
470 GC_API void GC_CALL GC_atfork_child(void);
471 
472 /* Initialize the collector.  Portable clients should call GC_INIT()    */
473 /* from the main program instead.                                       */
474 GC_API void GC_CALL GC_init(void);
475 
476 /* Returns non-zero (TRUE) if and only if the collector is initialized  */
477 /* (or, at least, the initialization is in progress).                   */
478 GC_API int GC_CALL GC_is_init_called(void);
479 
480 /* Perform the collector shutdown.  (E.g. dispose critical sections on  */
481 /* Win32 target.)  A duplicate invocation is a no-op.  GC_INIT should   */
482 /* not be called after the shutdown.  See also GC_win32_free_heap().    */
483 GC_API void GC_CALL GC_deinit(void);
484 
485 /* General purpose allocation routines, with roughly malloc calling     */
486 /* conv.  The atomic versions promise that no relevant pointers are     */
487 /* contained in the object.  The non-atomic versions guarantee that the */
488 /* new object is cleared.  GC_malloc_uncollectable allocates            */
489 /* an object that is scanned for pointers to collectible                */
490 /* objects, but is not itself collectible.  The object is scanned even  */
491 /* if it does not appear to be reachable.  GC_malloc_uncollectable and  */
492 /* GC_free called on the resulting object implicitly update             */
493 /* GC_non_gc_bytes appropriately.                                       */
494 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
495         GC_malloc(size_t /* size_in_bytes */);
496 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
497         GC_malloc_atomic(size_t /* size_in_bytes */);
498 GC_API GC_ATTR_MALLOC char * GC_CALL GC_strdup(const char *);
499 GC_API GC_ATTR_MALLOC char * GC_CALL
500         GC_strndup(const char *, size_t) GC_ATTR_NONNULL(1);
501 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
502         GC_malloc_uncollectable(size_t /* size_in_bytes */);
503 GC_API GC_ATTR_DEPRECATED void * GC_CALL GC_malloc_stubborn(size_t);
504 
505 /* GC_memalign() is not well tested.                                    */
506 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(2) void * GC_CALL
507         GC_memalign(size_t /* align */, size_t /* lb */);
508 GC_API int GC_CALL GC_posix_memalign(void ** /* memptr */, size_t /* align */,
509                         size_t /* lb */) GC_ATTR_NONNULL(1);
510 
511 /* Explicitly deallocate an object.  Dangerous if used incorrectly.     */
512 /* Requires a pointer to the base of an object.                         */
513 /* An object should not be enabled for finalization (and it should not  */
514 /* contain registered disappearing links of any kind) when it is        */
515 /* explicitly deallocated.                                              */
516 /* GC_free(0) is a no-op, as required by ANSI C for free.               */
517 GC_API void GC_CALL GC_free(void *);
518 
519 /* The "stubborn" objects allocation is not supported anymore.  Exists  */
520 /* only for the backward compatibility.                                 */
521 #define GC_MALLOC_STUBBORN(sz)  GC_MALLOC(sz)
522 #define GC_NEW_STUBBORN(t)      GC_NEW(t)
523 #define GC_CHANGE_STUBBORN(p)   GC_change_stubborn(p)
524 GC_API GC_ATTR_DEPRECATED void GC_CALL GC_change_stubborn(const void *);
525 
526 /* Inform the collector that the object has been changed.               */
527 /* Only non-NULL pointer stores into the object are considered to be    */
528 /* changes.  Matters only if the incremental collection is enabled in   */
529 /* the manual VDB mode (otherwise the function does nothing).           */
530 /* Should be followed typically by GC_reachable_here called for each    */
531 /* of the stored pointers.                                              */
532 GC_API void GC_CALL GC_end_stubborn_change(const void *) GC_ATTR_NONNULL(1);
533 
534 /* Return a pointer to the base (lowest address) of an object given     */
535 /* a pointer to a location within the object.                           */
536 /* I.e., map an interior pointer to the corresponding base pointer.     */
537 /* Note that with debugging allocation, this returns a pointer to the   */
538 /* actual base of the object, i.e. the debug information, not to        */
539 /* the base of the user object.                                         */
540 /* Return 0 if displaced_pointer doesn't point to within a valid        */
541 /* object.                                                              */
542 /* Note that a deallocated object in the garbage collected heap         */
543 /* may be considered valid, even if it has been deallocated with        */
544 /* GC_free.                                                             */
545 GC_API void * GC_CALL GC_base(void * /* displaced_pointer */);
546 
547 /* Return non-zero (TRUE) if and only if the argument points to         */
548 /* somewhere in GC heap.  Primary use is as a fast alternative to       */
549 /* GC_base to check whether the pointed object is allocated by GC       */
550 /* or not.  It is assumed that the collector is already initialized.    */
551 GC_API int GC_CALL GC_is_heap_ptr(const void *);
552 
553 /* Given a pointer to the base of an object, return its size in bytes.  */
554 /* The returned size may be slightly larger than what was originally    */
555 /* requested.                                                           */
556 GC_API size_t GC_CALL GC_size(const void * /* obj_addr */) GC_ATTR_NONNULL(1);
557 
558 /* For compatibility with C library.  This is occasionally faster than  */
559 /* a malloc followed by a bcopy.  But if you rely on that, either here  */
560 /* or with the standard C library, your code is broken.  In my          */
561 /* opinion, it shouldn't have been invented, but now we're stuck. -HB   */
562 /* The resulting object has the same kind as the original.              */
563 /* It is an error to have changes enabled for the original object.      */
564 /* It does not change the content of the object from its beginning to   */
565 /* the minimum of old size and new_size_in_bytes; the content above in  */
566 /* case of object size growth is initialized to zero (not guaranteed    */
567 /* for atomic object type).  The function follows ANSI conventions for  */
568 /* NULL old_object (i.e., equivalent to GC_malloc regardless of new     */
569 /* size).  If new size is zero (and old_object is non-NULL) then the    */
570 /* call is equivalent to GC_free (and NULL is returned).  If old_object */
571 /* is non-NULL, it must have been returned by an earlier call to        */
572 /* GC_malloc* or GC_realloc.  In case of the allocation failure, the    */
573 /* memory pointed by old_object is untouched (and not freed).           */
574 /* If the returned pointer is not the same as old_object and both of    */
575 /* them are non-NULL then old_object is freed.  Returns either NULL (in */
576 /* case of the allocation failure or zero new size) or pointer to the   */
577 /* allocated memory.                                                    */
578 GC_API void * GC_CALL GC_realloc(void * /* old_object */,
579                                  size_t /* new_size_in_bytes */)
580                         /* 'realloc' attr */ GC_ATTR_ALLOC_SIZE(2);
581 
582 /* Explicitly increase the heap size.   */
583 /* Returns 0 on failure, 1 on success.  */
584 GC_API int GC_CALL GC_expand_hp(size_t /* number_of_bytes */);
585 
586 /* Limit the heap size to n bytes.  Useful when you're debugging,       */
587 /* especially on systems that don't handle running out of memory well.  */
588 /* n == 0 ==> unbounded.  This is the default.  This setter function is */
589 /* unsynchronized (so it might require GC_call_with_alloc_lock to avoid */
590 /* data races).                                                         */
591 GC_API void GC_CALL GC_set_max_heap_size(GC_word /* n */);
592 
593 /* Inform the collector that a certain section of statically allocated  */
594 /* memory contains no pointers to garbage collected memory.  Thus it    */
595 /* need not be scanned.  This is sometimes important if the application */
596 /* maps large read/write files into the address space, which could be   */
597 /* mistaken for dynamic library data segments on some systems.          */
598 /* Both section start and end are not needed to be pointer-aligned.     */
599 GC_API void GC_CALL GC_exclude_static_roots(void * /* low_address */,
600                                             void * /* high_address_plus_1 */);
601 
602 /* Clear the set of root segments.  Wizards only.                       */
603 GC_API void GC_CALL GC_clear_roots(void);
604 
605 /* Add a root segment.  Wizards only.                                   */
606 /* Both segment start and end are not needed to be pointer-aligned.     */
607 /* low_address must not be greater than high_address_plus_1.            */
608 GC_API void GC_CALL GC_add_roots(void * /* low_address */,
609                                  void * /* high_address_plus_1 */);
610 
611 /* Remove a root segment.  Wizards only.                                */
612 /* May be unimplemented on some platforms.                              */
613 GC_API void GC_CALL GC_remove_roots(void * /* low_address */,
614                                     void * /* high_address_plus_1 */);
615 
616 /* Add a displacement to the set of those considered valid by the       */
617 /* collector.  GC_register_displacement(n) means that if p was returned */
618 /* by GC_malloc, then (char *)p + n will be considered to be a valid    */
619 /* pointer to p.  N must be small and less than the size of p.          */
620 /* (All pointers to the interior of objects from the stack are          */
621 /* considered valid in any case.  This applies to heap objects and      */
622 /* static data.)                                                        */
623 /* Preferably, this should be called before any other GC procedures.    */
624 /* Calling it later adds to the probability of excess memory            */
625 /* retention.                                                           */
626 /* This is a no-op if the collector has recognition of                  */
627 /* arbitrary interior pointers enabled, which is now the default.       */
628 GC_API void GC_CALL GC_register_displacement(size_t /* n */);
629 
630 /* The following version should be used if any debugging allocation is  */
631 /* being done.                                                          */
632 GC_API void GC_CALL GC_debug_register_displacement(size_t /* n */);
633 
634 /* Explicitly trigger a full, world-stop collection.    */
635 GC_API void GC_CALL GC_gcollect(void);
636 
637 /* Same as above but ignores the default stop_func setting and tries to */
638 /* unmap as much memory as possible (regardless of the corresponding    */
639 /* switch setting).  The recommended usage: on receiving a system       */
640 /* low-memory event; before retrying a system call failed because of    */
641 /* the system is running out of resources.                              */
642 GC_API void GC_CALL GC_gcollect_and_unmap(void);
643 
644 /* Trigger a full world-stopped collection.  Abort the collection if    */
645 /* and when stop_func returns a nonzero value.  Stop_func will be       */
646 /* called frequently, and should be reasonably fast.  (stop_func is     */
647 /* called with the allocation lock held and the world might be stopped; */
648 /* it's not allowed for stop_func to manipulate pointers to the garbage */
649 /* collected heap or call most of GC functions.)  This works even       */
650 /* if virtual dirty bits, and hence incremental collection is not       */
651 /* available for this architecture.  Collections can be aborted faster  */
652 /* than normal pause times for incremental collection.  However,        */
653 /* aborted collections do no useful work; the next collection needs     */
654 /* to start from the beginning.  stop_func must not be 0.               */
655 /* GC_try_to_collect() returns 0 if the collection was aborted (or the  */
656 /* collections are disabled), 1 if it succeeded.                        */
657 typedef int (GC_CALLBACK * GC_stop_func)(void);
658 GC_API int GC_CALL GC_try_to_collect(GC_stop_func /* stop_func */)
659                                                         GC_ATTR_NONNULL(1);
660 
661 /* Set and get the default stop_func.  The default stop_func is used by */
662 /* GC_gcollect() and by implicitly trigged collections (except for the  */
663 /* case when handling out of memory).  Must not be 0.                   */
664 /* Both the setter and getter acquire the GC lock to avoid data races.  */
665 GC_API void GC_CALL GC_set_stop_func(GC_stop_func /* stop_func */)
666                                                         GC_ATTR_NONNULL(1);
667 GC_API GC_stop_func GC_CALL GC_get_stop_func(void);
668 
669 /* Return the number of bytes in the heap.  Excludes collector private  */
670 /* data structures.  Excludes the unmapped memory (returned to the OS). */
671 /* Includes empty blocks and fragmentation loss.  Includes some pages   */
672 /* that were allocated but never written.                               */
673 /* This is an unsynchronized getter, so it should be called typically   */
674 /* with the GC lock held to avoid data races on multiprocessors (the    */
675 /* alternative is to use GC_get_heap_usage_safe or GC_get_prof_stats    */
676 /* API calls instead).                                                  */
677 /* This getter remains lock-free (unsynchronized) for compatibility     */
678 /* reason since some existing clients call it from a GC callback        */
679 /* holding the allocator lock.  (This API function and the following    */
680 /* four ones below were made thread-safe in GC v7.2alpha1 and          */
681 /* reverted back in v7.2alpha7 for the reason described.)               */
682 GC_API size_t GC_CALL GC_get_heap_size(void);
683 
684 /* Return a lower bound on the number of free bytes in the heap         */
685 /* (excluding the unmapped memory space).  This is an unsynchronized    */
686 /* getter (see GC_get_heap_size comment regarding thread-safety).       */
687 GC_API size_t GC_CALL GC_get_free_bytes(void);
688 
689 /* Return the size (in bytes) of the unmapped memory (which is returned */
690 /* to the OS but could be remapped back by the collector later unless   */
691 /* the OS runs out of system/virtual memory). This is an unsynchronized */
692 /* getter (see GC_get_heap_size comment regarding thread-safety).       */
693 GC_API size_t GC_CALL GC_get_unmapped_bytes(void);
694 
695 /* Return the number of bytes allocated since the last collection.      */
696 /* This is an unsynchronized getter (see GC_get_heap_size comment       */
697 /* regarding thread-safety).                                            */
698 GC_API size_t GC_CALL GC_get_bytes_since_gc(void);
699 
700 /* Return the number of explicitly deallocated bytes of memory since    */
701 /* the recent collection.  This is an unsynchronized getter.            */
702 GC_API size_t GC_CALL GC_get_expl_freed_bytes_since_gc(void);
703 
704 /* Return the total number of bytes allocated in this process.          */
705 /* Never decreases, except due to wrapping.  This is an unsynchronized  */
706 /* getter (see GC_get_heap_size comment regarding thread-safety).       */
707 GC_API size_t GC_CALL GC_get_total_bytes(void);
708 
709 /* Return the heap usage information.  This is a thread-safe (atomic)   */
710 /* alternative for the five above getters.   (This function acquires    */
711 /* the allocator lock thus preventing data racing and returning the     */
712 /* consistent result.)  Passing NULL pointer is allowed for any         */
713 /* argument.  Returned (filled in) values are of word type.             */
714 /* (This API function was introduced in GC v7.2alpha7 at the same time  */
715 /* when GC_get_heap_size and the friends were made lock-free again.)    */
716 GC_API void GC_CALL GC_get_heap_usage_safe(GC_word * /* pheap_size */,
717                                            GC_word * /* pfree_bytes */,
718                                            GC_word * /* punmapped_bytes */,
719                                            GC_word * /* pbytes_since_gc */,
720                                            GC_word * /* ptotal_bytes */);
721 
722 /* Structure used to query GC statistics (profiling information).       */
723 /* More fields could be added in the future.  To preserve compatibility */
724 /* new fields should be added only to the end, and no deprecated fields */
725 /* should be removed from.                                              */
726 struct GC_prof_stats_s {
727   GC_word heapsize_full;
728             /* Heap size in bytes (including the area unmapped to OS).  */
729             /* Same as GC_get_heap_size() + GC_get_unmapped_bytes().    */
730   GC_word free_bytes_full;
731             /* Total bytes contained in free and unmapped blocks.       */
732             /* Same as GC_get_free_bytes() + GC_get_unmapped_bytes().   */
733   GC_word unmapped_bytes;
734             /* Amount of memory unmapped to OS.  Same as the value      */
735             /* returned by GC_get_unmapped_bytes().                     */
736   GC_word bytes_allocd_since_gc;
737             /* Number of bytes allocated since the recent collection.   */
738             /* Same as returned by GC_get_bytes_since_gc().             */
739   GC_word allocd_bytes_before_gc;
740             /* Number of bytes allocated before the recent garbage      */
741             /* collection.  The value may wrap.  Same as the result of  */
742             /* GC_get_total_bytes() - GC_get_bytes_since_gc().          */
743   GC_word non_gc_bytes;
744             /* Number of bytes not considered candidates for garbage    */
745             /* collection.  Same as returned by GC_get_non_gc_bytes().  */
746   GC_word gc_no;
747             /* Garbage collection cycle number.  The value may wrap     */
748             /* (and could be -1).  Same as returned by GC_get_gc_no().  */
749   GC_word markers_m1;
750             /* Number of marker threads (excluding the initiating one). */
751             /* Same as returned by GC_get_parallel (or 0 if the         */
752             /* collector is single-threaded).                           */
753   GC_word bytes_reclaimed_since_gc;
754             /* Approximate number of reclaimed bytes after recent GC.   */
755   GC_word reclaimed_bytes_before_gc;
756             /* Approximate number of bytes reclaimed before the recent  */
757             /* garbage collection.  The value may wrap.                 */
758   GC_word expl_freed_bytes_since_gc;
759             /* Number of bytes freed explicitly since the recent GC.    */
760             /* Same as returned by GC_get_expl_freed_bytes_since_gc().  */
761 };
762 
763 /* Atomically get GC statistics (various global counters).  Clients     */
764 /* should pass the size of the buffer (of GC_prof_stats_s type) to fill */
765 /* in the values - this is for interoperability between different GC    */
766 /* versions, an old client could have fewer fields, and vice versa,     */
767 /* client could use newer gc.h (with more entries declared in the       */
768 /* structure) than that of the linked libgc binary; in the latter case, */
769 /* unsupported (unknown) fields are filled in with -1.  Return the size */
770 /* (in bytes) of the filled in part of the structure (excluding all     */
771 /* unknown fields, if any).                                             */
772 GC_API size_t GC_CALL GC_get_prof_stats(struct GC_prof_stats_s *,
773                                         size_t /* stats_sz */);
774 #ifdef GC_THREADS
775   /* Same as above but unsynchronized (i.e., not holding the allocation */
776   /* lock).  Clients should call it using GC_call_with_alloc_lock to    */
777   /* avoid data races on multiprocessors.                               */
778   GC_API size_t GC_CALL GC_get_prof_stats_unsafe(struct GC_prof_stats_s *,
779                                                  size_t /* stats_sz */);
780 #endif
781 
782 /* Get the element value (converted to bytes) at a given index of       */
783 /* size_map table which provides requested-to-actual allocation size    */
784 /* mapping.  Assumes the collector is initialized.  Returns -1 if the   */
785 /* index is out of size_map table bounds. Does not use synchronization, */
786 /* thus clients should call it using GC_call_with_alloc_lock typically  */
787 /* to avoid data races on multiprocessors.                              */
788 GC_API size_t GC_CALL GC_get_size_map_at(int i);
789 
790 /* Count total memory use in bytes by all allocated blocks.  Acquires   */
791 /* the lock.                                                            */
792 GC_API size_t GC_CALL GC_get_memory_use(void);
793 
794 /* Disable garbage collection.  Even GC_gcollect calls will be          */
795 /* ineffective.                                                         */
796 GC_API void GC_CALL GC_disable(void);
797 
798 /* Return non-zero (TRUE) if and only if garbage collection is disabled */
799 /* (i.e., GC_dont_gc value is non-zero).  Does not acquire the lock.    */
800 GC_API int GC_CALL GC_is_disabled(void);
801 
802 /* Try to re-enable garbage collection.  GC_disable() and GC_enable()   */
803 /* calls nest.  Garbage collection is enabled if the number of calls to */
804 /* both functions is equal.                                             */
805 GC_API void GC_CALL GC_enable(void);
806 
807 /* Select whether to use the manual VDB mode for the incremental        */
808 /* collection.  Has no effect if called after enabling the incremental  */
809 /* collection.  The default value is off unless the collector is        */
810 /* compiled with MANUAL_VDB defined.  The manual VDB mode should be     */
811 /* used only if the client has the appropriate GC_END_STUBBORN_CHANGE   */
812 /* and GC_reachable_here (or, alternatively, GC_PTR_STORE_AND_DIRTY)    */
813 /* calls (to ensure proper write barriers).  Both the setter and getter */
814 /* are not synchronized, and are defined only if the library has been   */
815 /* compiled without SMALL_CONFIG.                                       */
816 GC_API void GC_CALL GC_set_manual_vdb_allowed(int);
817 GC_API int GC_CALL GC_get_manual_vdb_allowed(void);
818 
819 /* Enable incremental/generational collection.  Not advisable unless    */
820 /* dirty bits are available or most heap objects are pointer-free       */
821 /* (atomic) or immutable.  Don't use in leak finding mode.  Ignored if  */
822 /* GC_dont_gc is non-zero.  Only the generational piece of this is      */
823 /* functional if GC_parallel is non-zero or if GC_time_limit is         */
824 /* GC_TIME_UNLIMITED.  Causes thread-local variant of GC_gcj_malloc()   */
825 /* to revert to locked allocation.  Must be called before any such      */
826 /* GC_gcj_malloc() calls.  For best performance, should be called as    */
827 /* early as possible.  On some platforms, calling it later may have     */
828 /* adverse effects.                                                     */
829 /* Safe to call before GC_INIT().  Includes a  GC_init() call.          */
830 GC_API void GC_CALL GC_enable_incremental(void);
831 
832 /* Return non-zero (TRUE) if and only if the incremental mode is on.    */
833 /* Does not acquire the lock.                                           */
834 GC_API int GC_CALL GC_is_incremental_mode(void);
835 
836 /* Does incremental mode write-protect pages?  Returns zero or  */
837 /* more of the following, or'ed together:                       */
838 #define GC_PROTECTS_POINTER_HEAP  1 /* May protect non-atomic objects.  */
839 #define GC_PROTECTS_PTRFREE_HEAP  2
840 #define GC_PROTECTS_STATIC_DATA   4 /* Currently never.                 */
841 #define GC_PROTECTS_STACK         8 /* Probably impractical.            */
842 
843 #define GC_PROTECTS_NONE 0
844 /* The collector is assumed to be initialized before this call.         */
845 GC_API int GC_CALL GC_incremental_protection_needs(void);
846 
847 /* Perform some garbage collection work, if appropriate.        */
848 /* Return 0 if there is no more work to be done (including the  */
849 /* case when garbage collection is not appropriate).            */
850 /* Typically performs an amount of work corresponding roughly   */
851 /* to marking from one page.  May do more work if further       */
852 /* progress requires it, e.g. if incremental collection is      */
853 /* disabled.  It is reasonable to call this in a wait loop      */
854 /* until it returns 0.                                          */
855 GC_API int GC_CALL GC_collect_a_little(void);
856 
857 /* Allocate an object of size lb bytes.  The client guarantees that     */
858 /* as long as the object is live, it will be referenced by a pointer    */
859 /* that points to somewhere within the first 256 bytes of the object.   */
860 /* (This should normally be declared volatile to prevent the compiler   */
861 /* from invalidating this assertion.)  This routine is only useful      */
862 /* if a large array is being allocated.  It reduces the chance of       */
863 /* accidentally retaining such an array as a result of scanning an      */
864 /* integer that happens to be an address inside the array.  (Actually,  */
865 /* it reduces the chance of the allocator not finding space for such    */
866 /* an array, since it will try hard to avoid introducing such a false   */
867 /* reference.)  On a SunOS 4.X or MS Windows system this is recommended */
868 /* for arrays likely to be larger than 100K or so.  For other systems,  */
869 /* or if the collector is not configured to recognize all interior      */
870 /* pointers, the threshold is normally much higher.                     */
871 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
872         GC_malloc_ignore_off_page(size_t /* lb */);
873 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
874         GC_malloc_atomic_ignore_off_page(size_t /* lb */);
875 
876 #ifdef GC_ADD_CALLER
877 # define GC_EXTRAS GC_RETURN_ADDR, __FILE__, __LINE__
878 # define GC_EXTRA_PARAMS GC_word ra, const char * s, int i
879 #else
880 # define GC_EXTRAS __FILE__, __LINE__
881 # define GC_EXTRA_PARAMS const char * s, int i
882 #endif
883 
884 /* The following is only defined if the library has been suitably       */
885 /* compiled:                                                            */
886 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
887         GC_malloc_atomic_uncollectable(size_t /* size_in_bytes */);
888 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
889         GC_debug_malloc_atomic_uncollectable(size_t, GC_EXTRA_PARAMS);
890 
891 /* Debugging (annotated) allocation.  GC_gcollect will check            */
892 /* objects allocated in this way for overwrites, etc.                   */
893 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
894         GC_debug_malloc(size_t /* size_in_bytes */, GC_EXTRA_PARAMS);
895 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
896         GC_debug_malloc_atomic(size_t /* size_in_bytes */, GC_EXTRA_PARAMS);
897 GC_API GC_ATTR_MALLOC char * GC_CALL
898         GC_debug_strdup(const char *, GC_EXTRA_PARAMS);
899 GC_API GC_ATTR_MALLOC char * GC_CALL
900         GC_debug_strndup(const char *, size_t, GC_EXTRA_PARAMS)
901                                                         GC_ATTR_NONNULL(1);
902 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
903         GC_debug_malloc_uncollectable(size_t /* size_in_bytes */,
904                                       GC_EXTRA_PARAMS);
905 GC_API GC_ATTR_DEPRECATED void * GC_CALL
906         GC_debug_malloc_stubborn(size_t /* size_in_bytes */, GC_EXTRA_PARAMS);
907 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
908         GC_debug_malloc_ignore_off_page(size_t /* size_in_bytes */,
909                                         GC_EXTRA_PARAMS);
910 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
911         GC_debug_malloc_atomic_ignore_off_page(size_t /* size_in_bytes */,
912                                         GC_EXTRA_PARAMS);
913 GC_API void GC_CALL GC_debug_free(void *);
914 GC_API void * GC_CALL GC_debug_realloc(void * /* old_object */,
915                         size_t /* new_size_in_bytes */, GC_EXTRA_PARAMS)
916                         /* 'realloc' attr */ GC_ATTR_ALLOC_SIZE(2);
917 GC_API
918 #if !defined(CPPCHECK)
919   GC_ATTR_DEPRECATED
920 #endif
921 void GC_CALL GC_debug_change_stubborn(const void *);
922 GC_API void GC_CALL GC_debug_end_stubborn_change(const void *)
923                                                         GC_ATTR_NONNULL(1);
924 
925 /* Routines that allocate objects with debug information (like the      */
926 /* above), but just fill in dummy file and line number information.     */
927 /* Thus they can serve as drop-in malloc/realloc replacements.  This    */
928 /* can be useful for two reasons:                                       */
929 /* 1) It allows the collector to be built with DBG_HDRS_ALL defined     */
930 /*    even if some allocation calls come from 3rd party libraries       */
931 /*    that can't be recompiled.                                         */
932 /* 2) On some platforms, the file and line information is redundant,    */
933 /*    since it can be reconstructed from a stack trace.  On such        */
934 /*    platforms it may be more convenient not to recompile, e.g. for    */
935 /*    leak detection.  This can be accomplished by instructing the      */
936 /*    linker to replace malloc/realloc with these.                      */
937 GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
938         GC_debug_malloc_replacement(size_t /* size_in_bytes */);
939 GC_API /* 'realloc' attr */ GC_ATTR_ALLOC_SIZE(2) void * GC_CALL
940         GC_debug_realloc_replacement(void * /* object_addr */,
941                                      size_t /* size_in_bytes */);
942 
943 #ifdef GC_DEBUG_REPLACEMENT
944 # define GC_MALLOC(sz) GC_debug_malloc_replacement(sz)
945 # define GC_REALLOC(old, sz) GC_debug_realloc_replacement(old, sz)
946 #elif defined(GC_DEBUG)
947 # define GC_MALLOC(sz) GC_debug_malloc(sz, GC_EXTRAS)
948 # define GC_REALLOC(old, sz) GC_debug_realloc(old, sz, GC_EXTRAS)
949 #else
950 # define GC_MALLOC(sz) GC_malloc(sz)
951 # define GC_REALLOC(old, sz) GC_realloc(old, sz)
952 #endif /* !GC_DEBUG_REPLACEMENT && !GC_DEBUG */
953 
954 #ifdef GC_DEBUG
955 # define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, GC_EXTRAS)
956 # define GC_STRDUP(s) GC_debug_strdup(s, GC_EXTRAS)
957 # define GC_STRNDUP(s, sz) GC_debug_strndup(s, sz, GC_EXTRAS)
958 # define GC_MALLOC_ATOMIC_UNCOLLECTABLE(sz) \
959                         GC_debug_malloc_atomic_uncollectable(sz, GC_EXTRAS)
960 # define GC_MALLOC_UNCOLLECTABLE(sz) \
961                         GC_debug_malloc_uncollectable(sz, GC_EXTRAS)
962 # define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
963                         GC_debug_malloc_ignore_off_page(sz, GC_EXTRAS)
964 # define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
965                         GC_debug_malloc_atomic_ignore_off_page(sz, GC_EXTRAS)
966 # define GC_FREE(p) GC_debug_free(p)
967 # define GC_REGISTER_FINALIZER(p, f, d, of, od) \
968       GC_debug_register_finalizer(p, f, d, of, od)
969 # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
970       GC_debug_register_finalizer_ignore_self(p, f, d, of, od)
971 # define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
972       GC_debug_register_finalizer_no_order(p, f, d, of, od)
973 # define GC_REGISTER_FINALIZER_UNREACHABLE(p, f, d, of, od) \
974       GC_debug_register_finalizer_unreachable(p, f, d, of, od)
975 # define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p)
976 # define GC_PTR_STORE_AND_DIRTY(p, q) GC_debug_ptr_store_and_dirty(p, q)
977 # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
978       GC_general_register_disappearing_link(link, \
979                                         GC_base((/* no const */ void *)(obj)))
980 # define GC_REGISTER_LONG_LINK(link, obj) \
981       GC_register_long_link(link, GC_base((/* no const */ void *)(obj)))
982 # define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n)
983 #else
984 # define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz)
985 # define GC_STRDUP(s) GC_strdup(s)
986 # define GC_STRNDUP(s, sz) GC_strndup(s, sz)
987 # define GC_MALLOC_ATOMIC_UNCOLLECTABLE(sz) GC_malloc_atomic_uncollectable(sz)
988 # define GC_MALLOC_UNCOLLECTABLE(sz) GC_malloc_uncollectable(sz)
989 # define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
990                         GC_malloc_ignore_off_page(sz)
991 # define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
992                         GC_malloc_atomic_ignore_off_page(sz)
993 # define GC_FREE(p) GC_free(p)
994 # define GC_REGISTER_FINALIZER(p, f, d, of, od) \
995       GC_register_finalizer(p, f, d, of, od)
996 # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
997       GC_register_finalizer_ignore_self(p, f, d, of, od)
998 # define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
999       GC_register_finalizer_no_order(p, f, d, of, od)
1000 # define GC_REGISTER_FINALIZER_UNREACHABLE(p, f, d, of, od) \
1001       GC_register_finalizer_unreachable(p, f, d, of, od)
1002 # define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p)
1003 # define GC_PTR_STORE_AND_DIRTY(p, q) GC_ptr_store_and_dirty(p, q)
1004 # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
1005       GC_general_register_disappearing_link(link, obj)
1006 # define GC_REGISTER_LONG_LINK(link, obj) \
1007       GC_register_long_link(link, obj)
1008 # define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n)
1009 #endif /* !GC_DEBUG */
1010 
1011 /* The following are included because they are often convenient, and    */
1012 /* reduce the chance for a misspecified size argument.  But calls may   */
1013 /* expand to something syntactically incorrect if t is a complicated    */
1014 /* type expression.  Note that, unlike C++ new operator, these ones     */
1015 /* may return NULL (if out of memory).                                  */
1016 #define GC_NEW(t)               ((t*)GC_MALLOC(sizeof(t)))
1017 #define GC_NEW_ATOMIC(t)        ((t*)GC_MALLOC_ATOMIC(sizeof(t)))
1018 #define GC_NEW_UNCOLLECTABLE(t) ((t*)GC_MALLOC_UNCOLLECTABLE(sizeof(t)))
1019 
1020 #ifdef GC_REQUIRE_WCSDUP
1021   /* This might be unavailable on some targets (or not needed). */
1022   /* wchar_t should be defined in stddef.h */
1023   GC_API GC_ATTR_MALLOC wchar_t * GC_CALL
1024         GC_wcsdup(const wchar_t *) GC_ATTR_NONNULL(1);
1025   GC_API GC_ATTR_MALLOC wchar_t * GC_CALL
1026         GC_debug_wcsdup(const wchar_t *, GC_EXTRA_PARAMS) GC_ATTR_NONNULL(1);
1027 # ifdef GC_DEBUG
1028 #   define GC_WCSDUP(s) GC_debug_wcsdup(s, GC_EXTRAS)
1029 # else
1030 #   define GC_WCSDUP(s) GC_wcsdup(s)
1031 # endif
1032 #endif /* GC_REQUIRE_WCSDUP */
1033 
1034 /* Finalization.  Some of these primitives are grossly unsafe.          */
1035 /* The idea is to make them both cheap, and sufficient to build         */
1036 /* a safer layer, closer to Modula-3, Java, or PCedar finalization.     */
1037 /* The interface represents my conclusions from a long discussion       */
1038 /* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes,              */
1039 /* Christian Jacobi, and Russ Atkinson.  It's not perfect, and          */
1040 /* probably nobody else agrees with it.     Hans-J. Boehm  3/13/92      */
1041 typedef void (GC_CALLBACK * GC_finalization_proc)(void * /* obj */,
1042                                                   void * /* client_data */);
1043 
1044 GC_API void GC_CALL GC_register_finalizer(void * /* obj */,
1045                         GC_finalization_proc /* fn */, void * /* cd */,
1046                         GC_finalization_proc * /* ofn */, void ** /* ocd */)
1047                                                 GC_ATTR_NONNULL(1);
1048 GC_API void GC_CALL GC_debug_register_finalizer(void * /* obj */,
1049                         GC_finalization_proc /* fn */, void * /* cd */,
1050                         GC_finalization_proc * /* ofn */, void ** /* ocd */)
1051                                                 GC_ATTR_NONNULL(1);
1052         /* When obj is no longer accessible, invoke             */
1053         /* (*fn)(obj, cd).  If a and b are inaccessible, and    */
1054         /* a points to b (after disappearing links have been    */
1055         /* made to disappear), then only a will be              */
1056         /* finalized.  (If this does not create any new         */
1057         /* pointers to b, then b will be finalized after the    */
1058         /* next collection.)  Any finalizable object that       */
1059         /* is reachable from itself by following one or more    */
1060         /* pointers will not be finalized (or collected).       */
1061         /* Thus cycles involving finalizable objects should     */
1062         /* be avoided, or broken by disappearing links.         */
1063         /* All but the last finalizer registered for an object  */
1064         /* is ignored.                                          */
1065         /* No-op in the leak-finding mode.                      */
1066         /* Finalization may be removed by passing 0 as fn.      */
1067         /* Finalizers are implicitly unregistered when they are */
1068         /* enqueued for finalization (i.e. become ready to be   */
1069         /* finalized).                                          */
1070         /* The old finalizer and client data are stored in      */
1071         /* *ofn and *ocd.  (ofn and/or ocd may be NULL.         */
1072         /* The allocation lock is held while *ofn and *ocd are  */
1073         /* updated.  In case of error (no memory to register    */
1074         /* new finalizer), *ofn and *ocd remain unchanged.)     */
1075         /* Fn is never invoked on an accessible object,         */
1076         /* provided hidden pointers are converted to real       */
1077         /* pointers only if the allocation lock is held, and    */
1078         /* such conversions are not performed by finalization   */
1079         /* routines.                                            */
1080         /* If GC_register_finalizer is aborted as a result of   */
1081         /* a signal, the object may be left with no             */
1082         /* finalization, even if neither the old nor new        */
1083         /* finalizer were NULL.                                 */
1084         /* Obj should be the starting address of an object      */
1085         /* allocated by GC_malloc or friends. Obj may also be   */
1086         /* NULL or point to something outside GC heap (in this  */
1087         /* case, fn is ignored, *ofn and *ocd are set to NULL). */
1088         /* Note that any garbage collectible object referenced  */
1089         /* by cd will be considered accessible until the        */
1090         /* finalizer is invoked.                                */
1091 
1092 /* Another versions of the above follow.  It ignores            */
1093 /* self-cycles, i.e. pointers from a finalizable object to      */
1094 /* itself.  There is a stylistic argument that this is wrong,   */
1095 /* but it's unavoidable for C++, since the compiler may         */
1096 /* silently introduce these.  It's also benign in that specific */
1097 /* case.  And it helps if finalizable objects are split to      */
1098 /* avoid cycles.                                                */
1099 /* Note that cd will still be viewed as accessible, even if it  */
1100 /* refers to the object itself.                                 */
1101 GC_API void GC_CALL GC_register_finalizer_ignore_self(void * /* obj */,
1102                         GC_finalization_proc /* fn */, void * /* cd */,
1103                         GC_finalization_proc * /* ofn */, void ** /* ocd */)
1104                                                 GC_ATTR_NONNULL(1);
1105 GC_API void GC_CALL GC_debug_register_finalizer_ignore_self(void * /* obj */,
1106                         GC_finalization_proc /* fn */, void * /* cd */,
1107                         GC_finalization_proc * /* ofn */, void ** /* ocd */)
1108                                                 GC_ATTR_NONNULL(1);
1109 
1110 /* Another version of the above.  It ignores all cycles.        */
1111 /* It should probably only be used by Java implementations.     */
1112 /* Note that cd will still be viewed as accessible, even if it  */
1113 /* refers to the object itself.                                 */
1114 GC_API void GC_CALL GC_register_finalizer_no_order(void * /* obj */,
1115                         GC_finalization_proc /* fn */, void * /* cd */,
1116                         GC_finalization_proc * /* ofn */, void ** /* ocd */)
1117                                                 GC_ATTR_NONNULL(1);
1118 GC_API void GC_CALL GC_debug_register_finalizer_no_order(void * /* obj */,
1119                         GC_finalization_proc /* fn */, void * /* cd */,
1120                         GC_finalization_proc * /* ofn */, void ** /* ocd */)
1121                                                 GC_ATTR_NONNULL(1);
1122 
1123 /* This is a special finalizer that is useful when an object's  */
1124 /* finalizer must be run when the object is known to be no      */
1125 /* longer reachable, not even from other finalizable objects.   */
1126 /* It behaves like "normal" finalization, except that the       */
1127 /* finalizer is not run while the object is reachable from      */
1128 /* other objects specifying unordered finalization.             */
1129 /* Effectively it allows an object referenced, possibly         */
1130 /* indirectly, from an unordered finalizable object to override */
1131 /* the unordered finalization request.                          */
1132 /* This can be used in combination with finalizer_no_order so   */
1133 /* as to release resources that must not be released while an   */
1134 /* object can still be brought back to life by other            */
1135 /* finalizers.                                                  */
1136 /* Only works if GC_java_finalization is set.  Probably only    */
1137 /* of interest when implementing a language that requires       */
1138 /* unordered finalization (e.g. Java, C#).                      */
1139 GC_API void GC_CALL GC_register_finalizer_unreachable(void * /* obj */,
1140                         GC_finalization_proc /* fn */, void * /* cd */,
1141                         GC_finalization_proc * /* ofn */, void ** /* ocd */)
1142                                                 GC_ATTR_NONNULL(1);
1143 GC_API void GC_CALL GC_debug_register_finalizer_unreachable(void * /* obj */,
1144                         GC_finalization_proc /* fn */, void * /* cd */,
1145                         GC_finalization_proc * /* ofn */, void ** /* ocd */)
1146                                                 GC_ATTR_NONNULL(1);
1147 
1148 #define GC_NO_MEMORY 2  /* Failure due to lack of memory.       */
1149 
1150 /* The following routine may be used to break cycles between    */
1151 /* finalizable objects, thus causing cyclic finalizable         */
1152 /* objects to be finalized in the correct order.  Standard      */
1153 /* use involves calling GC_register_disappearing_link(&p),      */
1154 /* where p is a pointer that is not followed by finalization    */
1155 /* code, and should not be considered in determining            */
1156 /* finalization order.                                          */
1157 GC_API int GC_CALL GC_register_disappearing_link(void ** /* link */)
1158                                                 GC_ATTR_NONNULL(1);
1159         /* Link should point to a field of a heap allocated     */
1160         /* object obj.  *link will be cleared when obj is       */
1161         /* found to be inaccessible.  This happens BEFORE any   */
1162         /* finalization code is invoked, and BEFORE any         */
1163         /* decisions about finalization order are made.         */
1164         /* This is useful in telling the finalizer that         */
1165         /* some pointers are not essential for proper           */
1166         /* finalization.  This may avoid finalization cycles.   */
1167         /* Note that obj may be resurrected by another          */
1168         /* finalizer, and thus the clearing of *link may        */
1169         /* be visible to non-finalization code.                 */
1170         /* There's an argument that an arbitrary action should  */
1171         /* be allowed here, instead of just clearing a pointer. */
1172         /* But this causes problems if that action alters, or   */
1173         /* examines connectivity.  Returns GC_DUPLICATE if link */
1174         /* was already registered, GC_SUCCESS if registration   */
1175         /* succeeded, GC_NO_MEMORY if it failed for lack of     */
1176         /* memory, and GC_oom_fn did not handle the problem.    */
1177         /* Only exists for backward compatibility.  See below:  */
1178 
1179 GC_API int GC_CALL GC_general_register_disappearing_link(void ** /* link */,
1180                                                     const void * /* obj */)
1181                         GC_ATTR_NONNULL(1) GC_ATTR_NONNULL(2);
1182         /* A slight generalization of the above. *link is       */
1183         /* cleared when obj first becomes inaccessible.  This   */
1184         /* can be used to implement weak pointers easily and    */
1185         /* safely. Typically link will point to a location      */
1186         /* holding a disguised pointer to obj.  (A pointer      */
1187         /* inside an "atomic" object is effectively disguised.) */
1188         /* In this way, weak pointers are broken before any     */
1189         /* object reachable from them gets finalized.           */
1190         /* Each link may be registered only with one obj value, */
1191         /* i.e. all objects but the last one (link registered   */
1192         /* with) are ignored.  This was added after a long      */
1193         /* email discussion with John Ellis.                    */
1194         /* link must be non-NULL (and be properly aligned).     */
1195         /* obj must be a pointer to the first word of an object */
1196         /* allocated by GC_malloc or friends.   A link          */
1197         /* disappears when it is unregistered manually, or when */
1198         /* (*link) is cleared, or when the object containing    */
1199         /* this link is garbage collected.  It is unsafe to     */
1200         /* explicitly deallocate the object containing link.    */
1201         /* Explicit deallocation of obj may or may not cause    */
1202         /* link to eventually be cleared.                       */
1203         /* No-op in the leak-finding mode.                      */
1204         /* This function can be used to implement certain types */
1205         /* of weak pointers.  Note, however, this generally     */
1206         /* requires that the allocation lock is held (see       */
1207         /* GC_call_with_alloc_lock() below) when the disguised  */
1208         /* pointer is accessed.  Otherwise a strong pointer     */
1209         /* could be recreated between the time the collector    */
1210         /* decides to reclaim the object and the link is        */
1211         /* cleared.  Returns GC_SUCCESS if registration         */
1212         /* succeeded (a new link is registered), GC_DUPLICATE   */
1213         /* if link was already registered (with some object),   */
1214         /* GC_NO_MEMORY if registration failed for lack of      */
1215         /* memory (and GC_oom_fn did not handle the problem),   */
1216         /* GC_UNIMPLEMENTED if GC_find_leak is true.            */
1217 
1218 GC_API int GC_CALL GC_move_disappearing_link(void ** /* link */,
1219                                              void ** /* new_link */)
1220                         GC_ATTR_NONNULL(2);
1221         /* Moves a link previously registered via               */
1222         /* GC_general_register_disappearing_link (or            */
1223         /* GC_register_disappearing_link).  Does not change the */
1224         /* target object of the weak reference.  Does not       */
1225         /* change (*new_link) content.  May be called with      */
1226         /* new_link equal to link (to check whether link has    */
1227         /* been registered).  Returns GC_SUCCESS on success,    */
1228         /* GC_DUPLICATE if there is already another             */
1229         /* disappearing link at the new location (never         */
1230         /* returned if new_link is equal to link), GC_NOT_FOUND */
1231         /* if no link is registered at the original location.   */
1232 
1233 GC_API int GC_CALL GC_unregister_disappearing_link(void ** /* link */);
1234         /* Undoes a registration by either of the above two     */
1235         /* routines.  Returns 0 if link was not actually        */
1236         /* registered (otherwise returns 1).                    */
1237 
1238 GC_API int GC_CALL GC_register_long_link(void ** /* link */,
1239                                     const void * /* obj */)
1240                         GC_ATTR_NONNULL(1) GC_ATTR_NONNULL(2);
1241         /* Similar to GC_general_register_disappearing_link but */
1242         /* *link only gets cleared when obj becomes truly       */
1243         /* inaccessible.  An object becomes truly inaccessible  */
1244         /* when it can no longer be resurrected from its        */
1245         /* finalizer (e.g. by assigning itself to a pointer     */
1246         /* traceable from root).  This can be used to implement */
1247         /* long weak pointers easily and safely.                */
1248 
1249 GC_API int GC_CALL GC_move_long_link(void ** /* link */,
1250                                      void ** /* new_link */)
1251                         GC_ATTR_NONNULL(2);
1252         /* Similar to GC_move_disappearing_link but for a link  */
1253         /* previously registered via GC_register_long_link.     */
1254 
1255 GC_API int GC_CALL GC_unregister_long_link(void ** /* link */);
1256         /* Similar to GC_unregister_disappearing_link but for a */
1257         /* registration by either of the above two routines.    */
1258 
1259 /* Support of toggle-ref style of external memory management    */
1260 /* without hooking up to the host retain/release machinery.     */
1261 /* The idea of toggle-ref is that an external reference to      */
1262 /* an object is kept and it can be either a strong or weak      */
1263 /* reference; a weak reference is used when the external peer   */
1264 /* has no interest in the object, and a strong otherwise.       */
1265 typedef enum {
1266    GC_TOGGLE_REF_DROP,
1267    GC_TOGGLE_REF_STRONG,
1268    GC_TOGGLE_REF_WEAK
1269 } GC_ToggleRefStatus;
1270 
1271 /* The callback is to decide (return) the new state of a given  */
1272 /* object.  Invoked by the collector for all objects registered */
1273 /* for toggle-ref processing.  Invoked with the allocation lock */
1274 /* held (but the "world" is running).                           */
1275 typedef GC_ToggleRefStatus (GC_CALLBACK *GC_toggleref_func)(void * /* obj */);
1276 
1277 /* Set (register) a callback that decides the state of a given  */
1278 /* object (by, probably, inspecting its native state).          */
1279 /* The argument may be 0 (means no callback).  Both the setter  */
1280 /* and the getter acquire the allocation lock (to avoid data    */
1281 /* races).                                                      */
1282 GC_API void GC_CALL GC_set_toggleref_func(GC_toggleref_func);
1283 GC_API GC_toggleref_func GC_CALL GC_get_toggleref_func(void);
1284 
1285 /* Register a given object for toggle-ref processing.  It will  */
1286 /* be stored internally and the toggle-ref callback will be     */
1287 /* invoked on the object until the callback returns             */
1288 /* GC_TOGGLE_REF_DROP or the object is collected.  If is_strong */
1289 /* is true then the object is registered with a strong ref,     */
1290 /* a weak one otherwise.  Returns GC_SUCCESS if registration    */
1291 /* succeeded (or no callback registered yet), GC_NO_MEMORY if   */
1292 /* it failed for lack of memory.                                */
1293 GC_API int GC_CALL GC_toggleref_add(void * /* obj */, int /* is_strong */)
1294                                                 GC_ATTR_NONNULL(1);
1295 
1296 /* Finalizer callback support.  Invoked by the collector (with  */
1297 /* the allocation lock held) for each unreachable object        */
1298 /* enqueued for finalization.                                   */
1299 typedef void (GC_CALLBACK * GC_await_finalize_proc)(void * /* obj */);
1300 GC_API void GC_CALL GC_set_await_finalize_proc(GC_await_finalize_proc);
1301 GC_API GC_await_finalize_proc GC_CALL GC_get_await_finalize_proc(void);
1302                         /* Zero means no callback.  The setter  */
1303                         /* and getter acquire the lock too.     */
1304 
1305 /* Returns !=0 if GC_invoke_finalizers has something to do.     */
1306 /* Does not use any synchronization.                            */
1307 GC_API int GC_CALL GC_should_invoke_finalizers(void);
1308 
1309 GC_API int GC_CALL GC_invoke_finalizers(void);
1310         /* Run finalizers for all objects that are ready to     */
1311         /* be finalized.  Return the number of finalizers       */
1312         /* that were run.  Normally this is also called         */
1313         /* implicitly during some allocations.  If              */
1314         /* GC_finalize_on_demand is nonzero, it must be called  */
1315         /* explicitly.                                          */
1316 
1317 /* Explicitly tell the collector that an object is reachable    */
1318 /* at a particular program point.  This prevents the argument   */
1319 /* pointer from being optimized away, even it is otherwise no   */
1320 /* longer needed.  It should have no visible effect in the      */
1321 /* absence of finalizers or disappearing links.  But it may be  */
1322 /* needed to prevent finalizers from running while the          */
1323 /* associated external resource is still in use.                */
1324 /* The function is sometimes called keep_alive in other         */
1325 /* settings.                                                    */
1326 #if defined(__GNUC__) && !defined(__INTEL_COMPILER)
1327 # define GC_reachable_here(ptr) \
1328                 __asm__ __volatile__(" " : : "X"(ptr) : "memory")
1329 #else
1330   GC_API void GC_CALL GC_noop1(GC_word);
1331 # ifdef LINT2
1332 #   define GC_reachable_here(ptr) GC_noop1(~(GC_word)(ptr)^(~(GC_word)0))
1333                 /* The expression matches the one of COVERT_DATAFLOW(). */
1334 # else
1335 #   define GC_reachable_here(ptr) GC_noop1((GC_word)(ptr))
1336 # endif
1337 #endif
1338 
1339 /* GC_set_warn_proc can be used to redirect or filter warning messages. */
1340 /* p may not be a NULL pointer.  msg is printf format string (arg must  */
1341 /* match the format).  Both the setter and the getter acquire the GC    */
1342 /* lock (to avoid data races).  In version 7.1 (and before), the setter */
1343 /* returned the old warn_proc value.                                    */
1344 typedef void (GC_CALLBACK * GC_warn_proc)(char * /* msg */,
1345                                           GC_word /* arg */);
1346 GC_API void GC_CALL GC_set_warn_proc(GC_warn_proc /* p */) GC_ATTR_NONNULL(1);
1347 /* GC_get_warn_proc returns the current warn_proc.                      */
1348 GC_API GC_warn_proc GC_CALL GC_get_warn_proc(void);
1349 
1350 /* GC_ignore_warn_proc may be used as an argument for GC_set_warn_proc  */
1351 /* to suppress all warnings (unless statistics printing is turned on).  */
1352 GC_API void GC_CALLBACK GC_ignore_warn_proc(char *, GC_word);
1353 
1354 /* Change file descriptor of GC log.  Unavailable on some targets.      */
1355 GC_API void GC_CALL GC_set_log_fd(int);
1356 
1357 /* abort_func is invoked on GC fatal aborts (just before OS-dependent   */
1358 /* abort or exit(1) is called).  Must be non-NULL.  The default one     */
1359 /* outputs msg to stderr provided msg is non-NULL.  msg is NULL if      */
1360 /* invoked before exit(1) otherwise msg is non-NULL (i.e., if invoked   */
1361 /* before abort).  Both the setter and getter acquire the GC lock.      */
1362 /* Both the setter and getter are defined only if the library has been  */
1363 /* compiled without SMALL_CONFIG.                                       */
1364 typedef void (GC_CALLBACK * GC_abort_func)(const char * /* msg */);
1365 GC_API void GC_CALL GC_set_abort_func(GC_abort_func) GC_ATTR_NONNULL(1);
1366 GC_API GC_abort_func GC_CALL GC_get_abort_func(void);
1367 
1368 /* A portable way to abort the application because of not enough memory.*/
1369 GC_API void GC_CALL GC_abort_on_oom(void);
1370 
1371 /* The following is intended to be used by a higher level       */
1372 /* (e.g. Java-like) finalization facility.  It is expected      */
1373 /* that finalization code will arrange for hidden pointers to   */
1374 /* disappear.  Otherwise objects can be accessed after they     */
1375 /* have been collected.                                         */
1376 /* Should not be used in the leak-finding mode.                 */
1377 /* Note that putting pointers in atomic objects or in           */
1378 /* non-pointer slots of "typed" objects is equivalent to        */
1379 /* disguising them in this way, and may have other advantages.  */
1380 typedef GC_word GC_hidden_pointer;
1381 #define GC_HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
1382 /* Converting a hidden pointer to a real pointer requires verifying     */
1383 /* that the object still exists.  This involves acquiring the           */
1384 /* allocator lock to avoid a race with the collector.                   */
1385 #define GC_REVEAL_POINTER(p) ((void *)GC_HIDE_POINTER(p))
1386 
1387 #if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS)
1388   /* This exists only for compatibility (the GC-prefixed symbols are    */
1389   /* preferred for new code).                                           */
1390 # define HIDE_POINTER(p) GC_HIDE_POINTER(p)
1391 # define REVEAL_POINTER(p) GC_REVEAL_POINTER(p)
1392 #endif
1393 
1394 typedef void * (GC_CALLBACK * GC_fn_type)(void * /* client_data */);
1395 GC_API void * GC_CALL GC_call_with_alloc_lock(GC_fn_type /* fn */,
1396                                 void * /* client_data */) GC_ATTR_NONNULL(1);
1397 
1398 /* These routines are intended to explicitly notify the collector       */
1399 /* of new threads.  Often this is unnecessary because thread creation   */
1400 /* is implicitly intercepted by the collector, using header-file        */
1401 /* defines, or linker-based interception.  In the long run the intent   */
1402 /* is to always make redundant registration safe.  In the short run,    */
1403 /* this is being implemented a platform at a time.                      */
1404 /* The interface is complicated by the fact that we probably will not   */
1405 /* ever be able to automatically determine the stack base for thread    */
1406 /* stacks on all platforms.                                             */
1407 
1408 /* Structure representing the base of a thread stack.  On most          */
1409 /* platforms this contains just a single address.                       */
1410 struct GC_stack_base {
1411   void * mem_base; /* Base of memory stack. */
1412 # if defined(__ia64) || defined(__ia64__) || defined(_M_IA64)
1413     void * reg_base; /* Base of separate register stack. */
1414 # endif
1415 };
1416 
1417 typedef void * (GC_CALLBACK * GC_stack_base_func)(
1418                 struct GC_stack_base * /* sb */, void * /* arg */);
1419 
1420 /* Call a function with a stack base structure corresponding to         */
1421 /* somewhere in the GC_call_with_stack_base frame.  This often can      */
1422 /* be used to provide a sufficiently accurate stack base.  And we       */
1423 /* implement it everywhere.                                             */
1424 GC_API void * GC_CALL GC_call_with_stack_base(GC_stack_base_func /* fn */,
1425                                         void * /* arg */) GC_ATTR_NONNULL(1);
1426 
1427 #define GC_SUCCESS 0
1428 #define GC_DUPLICATE 1          /* Was already registered.              */
1429 #define GC_NO_THREADS 2         /* No thread support in GC.             */
1430         /* GC_NO_THREADS is not returned by any GC function anymore.    */
1431 #define GC_UNIMPLEMENTED 3 /* Not yet implemented on this platform.     */
1432 #define GC_NOT_FOUND 4          /* Requested link not found (returned   */
1433                                 /* by GC_move_disappearing_link).       */
1434 
1435 #if defined(GC_DARWIN_THREADS) || defined(GC_WIN32_THREADS)
1436   /* Use implicit thread registration and processing (via Win32 DllMain */
1437   /* or Darwin task_threads).  Deprecated.  Must be called before       */
1438   /* GC_INIT() and other GC routines.  Should be avoided if             */
1439   /* GC_pthread_create, GC_beginthreadex (or GC_CreateThread) could be  */
1440   /* called instead.  Disables parallelized GC on Win32.                */
1441   GC_API void GC_CALL GC_use_threads_discovery(void);
1442 #endif
1443 
1444 #ifdef GC_THREADS
1445   /* Suggest the GC to use the specific signal to suspend threads.      */
1446   /* Has no effect after GC_init and on non-POSIX systems.              */
1447   GC_API void GC_CALL GC_set_suspend_signal(int);
1448 
1449   /* Suggest the GC to use the specific signal to resume threads.       */
1450   /* Has no effect after GC_init and on non-POSIX systems.              */
1451   GC_API void GC_CALL GC_set_thr_restart_signal(int);
1452 
1453   /* Return the signal number (constant after initialization) used by   */
1454   /* the GC to suspend threads on POSIX systems.  Return -1 otherwise.  */
1455   GC_API int GC_CALL GC_get_suspend_signal(void);
1456 
1457   /* Return the signal number (constant after initialization) used by   */
1458   /* the garbage collector to restart (resume) threads on POSIX         */
1459   /* systems.  Return -1 otherwise.                                     */
1460   GC_API int GC_CALL GC_get_thr_restart_signal(void);
1461 
1462   /* Restart marker threads after POSIX fork in child.  Meaningless in  */
1463   /* other situations.  Should not be called if fork followed by exec.  */
1464   GC_API void GC_CALL GC_start_mark_threads(void);
1465 
1466   /* Explicitly enable GC_register_my_thread() invocation.              */
1467   /* Done implicitly if a GC thread-creation function is called (or     */
1468   /* implicit thread registration is activated, or the collector is     */
1469   /* compiled with GC_ALWAYS_MULTITHREADED defined).  Otherwise, it     */
1470   /* must be called from the main (or any previously registered) thread */
1471   /* between the collector initialization and the first explicit        */
1472   /* registering of a thread (it should be called as late as possible). */
1473   GC_API void GC_CALL GC_allow_register_threads(void);
1474 
1475   /* Register the current thread, with the indicated stack base, as     */
1476   /* a new thread whose stack(s) should be traced by the GC.  If it     */
1477   /* is not implicitly called by the GC, this must be called before a   */
1478   /* thread can allocate garbage collected memory, or assign pointers   */
1479   /* to the garbage collected heap.  Once registered, a thread will be  */
1480   /* stopped during garbage collections.                                */
1481   /* This call must be previously enabled (see above).                  */
1482   /* This should never be called from the main thread, where it is      */
1483   /* always done implicitly.  This is normally done implicitly if GC_   */
1484   /* functions are called to create the thread, e.g. by including gc.h  */
1485   /* (which redefines some system functions) before calling the system  */
1486   /* thread creation function.  Nonetheless, thread cleanup routines    */
1487   /* (e.g., pthread key destructor) typically require manual thread     */
1488   /* registering (and unregistering) if pointers to GC-allocated        */
1489   /* objects are manipulated inside.                                    */
1490   /* It is also always done implicitly on some platforms if             */
1491   /* GC_use_threads_discovery() is called at start-up.  Except for the  */
1492   /* latter case, the explicit call is normally required for threads    */
1493   /* created by third-party libraries.                                  */
1494   /* A manually registered thread requires manual unregistering.        */
1495   /* Returns GC_SUCCESS on success, GC_DUPLICATE if already registered. */
1496   GC_API int GC_CALL GC_register_my_thread(const struct GC_stack_base *)
1497                                                         GC_ATTR_NONNULL(1);
1498 
1499   /* Return non-zero (TRUE) if and only if the calling thread is        */
1500   /* registered with the garbage collector.                             */
1501   GC_API int GC_CALL GC_thread_is_registered(void);
1502 
1503   /* Notify the collector about the stack and the alt-stack of the      */
1504   /* current thread.  stack_start/size is used to determine the stack   */
1505   /* boundaries when a thread is suspended while it is on an alt-stack. */
1506   GC_API void GC_CALL GC_register_altstack(void * /* stack_start */,
1507                                            GC_word /* stack_size */,
1508                                            void * /* altstack_base */,
1509                                            GC_word /* altstack_size */);
1510 
1511   /* Unregister the current thread.  Only an explicitly registered      */
1512   /* thread (i.e. for which GC_register_my_thread() returns GC_SUCCESS) */
1513   /* is allowed (and required) to call this function.  (As a special    */
1514   /* exception, it is also allowed to once unregister the main thread.) */
1515   /* The thread may no longer allocate garbage collected memory or      */
1516   /* manipulate pointers to the garbage collected heap after making     */
1517   /* this call.  Specifically, if it wants to return or otherwise       */
1518   /* communicate a pointer to the garbage-collected heap to another     */
1519   /* thread, it must do this before calling GC_unregister_my_thread,    */
1520   /* most probably by saving it in a global data structure.  Must not   */
1521   /* be called inside a GC callback function (except for                */
1522   /* GC_call_with_stack_base() one).                                    */
1523   GC_API int GC_CALL GC_unregister_my_thread(void);
1524 
1525   /* Stop/start the world explicitly.  Not recommended for general use. */
1526   GC_API void GC_CALL GC_stop_world_external(void);
1527   GC_API void GC_CALL GC_start_world_external(void);
1528 #endif /* GC_THREADS */
1529 
1530 /* Wrapper for functions that are likely to block (or, at least, do not */
1531 /* allocate garbage collected memory and/or manipulate pointers to the  */
1532 /* garbage collected heap) for an appreciable length of time.  While fn */
1533 /* is running, the collector is said to be in the "inactive" state for  */
1534 /* the current thread (this means that the thread is not suspended and  */
1535 /* the thread's stack frames "belonging" to the functions in the        */
1536 /* "inactive" state are not scanned during garbage collections).  It is */
1537 /* assumed that the collector is already initialized and the current    */
1538 /* thread is registered.  It is allowed for fn to call                  */
1539 /* GC_call_with_gc_active() (even recursively), thus temporarily        */
1540 /* toggling the collector's state back to "active".  The latter         */
1541 /* technique might be used to make stack scanning more precise (i.e.    */
1542 /* scan only stack frames of functions that allocate garbage collected  */
1543 /* memory and/or manipulate pointers to the garbage collected heap).    */
1544 GC_API void * GC_CALL GC_do_blocking(GC_fn_type /* fn */,
1545                                 void * /* client_data */) GC_ATTR_NONNULL(1);
1546 
1547 /* Call a function switching to the "active" state of the collector for */
1548 /* the current thread (i.e. the user function is allowed to call any    */
1549 /* GC function and/or manipulate pointers to the garbage collected      */
1550 /* heap).  GC_call_with_gc_active() has the functionality opposite to   */
1551 /* GC_do_blocking() one.  It is assumed that the collector is already   */
1552 /* initialized and the current thread is registered.  fn may toggle     */
1553 /* the collector thread's state temporarily to "inactive" one by using  */
1554 /* GC_do_blocking.  GC_call_with_gc_active() often can be used to       */
1555 /* provide a sufficiently accurate stack base.                          */
1556 GC_API void * GC_CALL GC_call_with_gc_active(GC_fn_type /* fn */,
1557                                 void * /* client_data */) GC_ATTR_NONNULL(1);
1558 
1559 /* Attempt to fill in the GC_stack_base structure with the stack base   */
1560 /* for this thread.  This appears to be required to implement anything  */
1561 /* like the JNI AttachCurrentThread in an environment in which new      */
1562 /* threads are not automatically registered with the collector.         */
1563 /* It is also unfortunately hard to implement well on many platforms.   */
1564 /* Returns GC_SUCCESS or GC_UNIMPLEMENTED.  This function acquires the  */
1565 /* GC lock on some platforms.                                           */
1566 GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *)
1567                                                         GC_ATTR_NONNULL(1);
1568 
1569 /* The following routines are primarily intended for use with a         */
1570 /* preprocessor which inserts calls to check C pointer arithmetic.      */
1571 /* They indicate failure by invoking the corresponding _print_proc.     */
1572 
1573 /* Check that p and q point to the same object.                 */
1574 /* Fail conspicuously if they don't.                            */
1575 /* Returns the first argument.                                  */
1576 /* Succeeds if neither p nor q points to the heap.              */
1577 /* May succeed if both p and q point to between heap objects.   */
1578 GC_API void * GC_CALL GC_same_obj(void * /* p */, void * /* q */);
1579 
1580 /* Checked pointer pre- and post- increment operations.  Note that      */
1581 /* the second argument is in units of bytes, not multiples of the       */
1582 /* object size.  This should either be invoked from a macro, or the     */
1583 /* call should be automatically generated.                              */
1584 GC_API void * GC_CALL GC_pre_incr(void **, ptrdiff_t /* how_much */)
1585                                                         GC_ATTR_NONNULL(1);
1586 GC_API void * GC_CALL GC_post_incr(void **, ptrdiff_t /* how_much */)
1587                                                         GC_ATTR_NONNULL(1);
1588 
1589 /* Check that p is visible                                              */
1590 /* to the collector as a possibly pointer containing location.          */
1591 /* If it isn't fail conspicuously.                                      */
1592 /* Returns the argument in all cases.  May erroneously succeed          */
1593 /* in hard cases.  (This is intended for debugging use with             */
1594 /* untyped allocations.  The idea is that it should be possible, though */
1595 /* slow, to add such a call to all indirect pointer stores.)            */
1596 /* Currently useless for multi-threaded worlds.                         */
1597 GC_API void * GC_CALL GC_is_visible(void * /* p */);
1598 
1599 /* Check that if p is a pointer to a heap page, then it points to       */
1600 /* a valid displacement within a heap object.                           */
1601 /* Fail conspicuously if this property does not hold.                   */
1602 /* Uninteresting with GC_all_interior_pointers.                         */
1603 /* Always returns its argument.                                         */
1604 GC_API void * GC_CALL GC_is_valid_displacement(void * /* p */);
1605 
1606 /* Explicitly dump the GC state.  This is most often called from the    */
1607 /* debugger, or by setting the GC_DUMP_REGULARLY environment variable,  */
1608 /* but it may be useful to call it from client code during debugging.   */
1609 /* The current collection number is printed in the header of the dump.  */
1610 /* Acquires the GC lock to avoid data races.                            */
1611 /* Defined only if the library has been compiled without NO_DEBUGGING.  */
1612 GC_API void GC_CALL GC_dump(void);
1613 
1614 /* The same as GC_dump but allows to specify the name of dump and does  */
1615 /* not acquire the lock.  If name is non-NULL, it is printed to help    */
1616 /* identifying individual dumps.  Otherwise the current collection      */
1617 /* number is used as the name.                                          */
1618 /* Defined only if the library has been compiled without NO_DEBUGGING.  */
1619 GC_API void GC_CALL GC_dump_named(const char * /* name */);
1620 
1621 /* Dump information about each block of every GC memory section.        */
1622 /* Defined only if the library has been compiled without NO_DEBUGGING.  */
1623 GC_API void GC_CALL GC_dump_regions(void);
1624 
1625 /* Dump information about every registered disappearing link and        */
1626 /* finalizable object.                                                  */
1627 /* Defined only if the library has been compiled without NO_DEBUGGING.  */
1628 GC_API void GC_CALL GC_dump_finalization(void);
1629 
1630 /* Safer, but slow, pointer addition.  Probably useful mainly with      */
1631 /* a preprocessor.  Useful only for heap pointers.                      */
1632 /* Only the macros without trailing digits are meant to be used         */
1633 /* by clients.  These are designed to model the available C pointer     */
1634 /* arithmetic expressions.                                              */
1635 /* Even then, these are probably more useful as                         */
1636 /* documentation than as part of the API.                               */
1637 /* Note that GC_PTR_ADD evaluates the first argument more than once.    */
1638 #if defined(GC_DEBUG) && defined(__GNUC__)
1639 # define GC_PTR_ADD3(x, n, type_of_result) \
1640         ((type_of_result)GC_same_obj((x)+(n), (x)))
1641 # define GC_PRE_INCR3(x, n, type_of_result) \
1642         ((type_of_result)GC_pre_incr((void **)(&(x)), (n)*sizeof(*x)))
1643 # define GC_POST_INCR3(x, n, type_of_result) \
1644         ((type_of_result)GC_post_incr((void **)(&(x)), (n)*sizeof(*x)))
1645 # define GC_PTR_ADD(x, n) GC_PTR_ADD3(x, n, __typeof__(x))
1646 # define GC_PRE_INCR(x, n) GC_PRE_INCR3(x, n, __typeof__(x))
1647 # define GC_POST_INCR(x) GC_POST_INCR3(x, 1, __typeof__(x))
1648 # define GC_POST_DECR(x) GC_POST_INCR3(x, -1, __typeof__(x))
1649 #else /* !GC_DEBUG || !__GNUC__ */
1650   /* We can't do this right without typeof, which ANSI decided was not    */
1651   /* sufficiently useful.  Without it we resort to the non-debug version. */
1652   /* TODO: This should eventually support C++0x decltype. */
1653 # define GC_PTR_ADD(x, n) ((x)+(n))
1654 # define GC_PRE_INCR(x, n) ((x) += (n))
1655 # define GC_POST_INCR(x) ((x)++)
1656 # define GC_POST_DECR(x) ((x)--)
1657 #endif /* !GC_DEBUG || !__GNUC__ */
1658 
1659 /* Safer assignment of a pointer to a non-stack location.       */
1660 #ifdef GC_DEBUG
1661 # define GC_PTR_STORE(p, q) \
1662         (*(void **)GC_is_visible((void *)(p)) = \
1663                     GC_is_valid_displacement((void *)(q)))
1664 #else
1665 # define GC_PTR_STORE(p, q) (*(void **)(p) = (void *)(q))
1666 #endif
1667 
1668 /* GC_PTR_STORE_AND_DIRTY(p,q) is equivalent to GC_PTR_STORE(p,q)       */
1669 /* followed by GC_END_STUBBORN_CHANGE(p) and GC_reachable_here(q)       */
1670 /* (assuming p and q do not have side effects).                         */
1671 GC_API void GC_CALL GC_ptr_store_and_dirty(void * /* p */,
1672                                            const void * /* q */);
1673 GC_API void GC_CALL GC_debug_ptr_store_and_dirty(void * /* p */,
1674                                                  const void * /* q */);
1675 
1676 /* Functions called to report pointer checking errors */
1677 GC_API void (GC_CALLBACK * GC_same_obj_print_proc)(void * /* p */,
1678                                                    void * /* q */);
1679 GC_API void (GC_CALLBACK * GC_is_valid_displacement_print_proc)(void *);
1680 GC_API void (GC_CALLBACK * GC_is_visible_print_proc)(void *);
1681 
1682 #ifdef GC_PTHREADS
1683   /* For pthread support, we generally need to intercept a number of    */
1684   /* thread library calls.  We do that here by macro defining them.     */
1685 # ifdef __cplusplus
1686     } /* extern "C" */
1687 # endif
1688 # include "gc_pthread_redirects.h"
1689 # ifdef __cplusplus
1690     extern "C" {
1691 # endif
1692 #endif
1693 
1694 /* This returns a list of objects, linked through their first word.     */
1695 /* Its use can greatly reduce lock contention problems, since the       */
1696 /* allocation lock can be acquired and released many fewer times.       */
1697 GC_API GC_ATTR_MALLOC void * GC_CALL GC_malloc_many(size_t /* lb */);
1698 #define GC_NEXT(p) (*(void * *)(p))     /* Retrieve the next element    */
1699                                         /* in returned list.            */
1700 
1701 /* A filter function to control the scanning of dynamic libraries.      */
1702 /* If implemented, called by GC before registering a dynamic library    */
1703 /* (discovered by GC) section as a static data root (called only as     */
1704 /* a last reason not to register).  The filename of the library, the    */
1705 /* address and the length of the memory region (section) are passed.    */
1706 /* This routine should return nonzero if that region should be scanned. */
1707 /* Always called with the allocation lock held.  Depending on the       */
1708 /* platform, might be called with the "world" stopped.                  */
1709 typedef int (GC_CALLBACK * GC_has_static_roots_func)(
1710                                         const char * /* dlpi_name */,
1711                                         void * /* section_start */,
1712                                         size_t /* section_size */);
1713 
1714 /* Register a new callback (a user-supplied filter) to control the      */
1715 /* scanning of dynamic libraries.  Replaces any previously registered   */
1716 /* callback.  May be 0 (means no filtering).  May be unused on some     */
1717 /* platforms (if the filtering is unimplemented or inappropriate).      */
1718 GC_API void GC_CALL GC_register_has_static_roots_callback(
1719                                         GC_has_static_roots_func);
1720 
1721 #if !defined(CPPCHECK) && !defined(GC_WINDOWS_H_INCLUDED) && defined(WINAPI)
1722   /* windows.h is included before gc.h */
1723 # define GC_WINDOWS_H_INCLUDED
1724 #endif
1725 
1726 #if defined(GC_WIN32_THREADS) \
1727     && (!defined(GC_PTHREADS) || defined(GC_BUILD) \
1728         || defined(GC_WINDOWS_H_INCLUDED))
1729                 /* Note: for Cygwin and pthreads-win32, this is skipped */
1730                 /* unless windows.h is included before gc.h.            */
1731 
1732 # if (!defined(GC_NO_THREAD_DECLS) || defined(GC_BUILD)) \
1733      && !defined(GC_DONT_INCL_WINDOWS_H)
1734 
1735 #   ifdef __cplusplus
1736       } /* Including windows.h in an extern "C" context no longer works. */
1737 #   endif
1738 
1739 #   if !defined(_WIN32_WCE) && !defined(__CEGCC__)
1740 #     include <process.h> /* For _beginthreadex, _endthreadex */
1741 #   endif
1742 
1743 #   if defined(GC_BUILD) || !defined(GC_DONT_INCLUDE_WINDOWS_H)
1744 #     include <windows.h>
1745 #     define GC_WINDOWS_H_INCLUDED
1746 #   endif
1747 
1748 #   ifdef __cplusplus
1749       extern "C" {
1750 #   endif
1751 
1752 #   ifdef GC_UNDERSCORE_STDCALL
1753       /* Explicitly prefix exported/imported WINAPI (__stdcall) symbols */
1754       /* with '_' (underscore).  Might be useful if MinGW/x86 is used.  */
1755 #     define GC_CreateThread _GC_CreateThread
1756 #     define GC_ExitThread _GC_ExitThread
1757 #   endif
1758 
1759 #   ifndef DECLSPEC_NORETURN
1760       /* Typically defined in winnt.h. */
1761 #     ifdef GC_WINDOWS_H_INCLUDED
1762 #       define DECLSPEC_NORETURN /* empty */
1763 #     else
1764 #       define DECLSPEC_NORETURN __declspec(noreturn)
1765 #     endif
1766 #   endif
1767 
1768 #   if !defined(_UINTPTR_T) && !defined(_UINTPTR_T_DEFINED) \
1769        && !defined(UINTPTR_MAX)
1770       typedef GC_word GC_uintptr_t;
1771 #   else
1772       typedef uintptr_t GC_uintptr_t;
1773 #   endif
1774 
1775 #   ifdef _WIN64
1776 #     define GC_WIN32_SIZE_T GC_uintptr_t
1777 #   elif defined(GC_WINDOWS_H_INCLUDED)
1778 #     define GC_WIN32_SIZE_T DWORD
1779 #   else
1780 #     define GC_WIN32_SIZE_T unsigned long
1781 #   endif
1782 
1783 #   ifdef GC_INSIDE_DLL
1784       /* Export GC DllMain to be invoked from client DllMain.   */
1785 #     ifdef GC_UNDERSCORE_STDCALL
1786 #       define GC_DllMain _GC_DllMain
1787 #     endif
1788 #     ifdef GC_WINDOWS_H_INCLUDED
1789         GC_API BOOL WINAPI GC_DllMain(HINSTANCE /* inst */,
1790                                       ULONG /* reason */,
1791                                       LPVOID /* reserved */);
1792 #     else
1793         GC_API int __stdcall GC_DllMain(void *, unsigned long, void *);
1794 #     endif
1795 #   endif /* GC_INSIDE_DLL */
1796 
1797     /* All threads must be created using GC_CreateThread or             */
1798     /* GC_beginthreadex, or must explicitly call GC_register_my_thread  */
1799     /* (and call GC_unregister_my_thread before thread termination), so */
1800     /* that they will be recorded in the thread table.  For backward    */
1801     /* compatibility, it is possible to build the GC with GC_DLL        */
1802     /* defined, and to call GC_use_threads_discovery.  This implicitly  */
1803     /* registers all created threads, but appears to be less robust.    */
1804     /* Currently the collector expects all threads to fall through and  */
1805     /* terminate normally, or call GC_endthreadex() or GC_ExitThread,   */
1806     /* so that the thread is properly unregistered.                     */
1807 #   ifdef GC_WINDOWS_H_INCLUDED
1808       GC_API HANDLE WINAPI GC_CreateThread(
1809                 LPSECURITY_ATTRIBUTES /* lpThreadAttributes */,
1810                 GC_WIN32_SIZE_T /* dwStackSize */,
1811                 LPTHREAD_START_ROUTINE /* lpStartAddress */,
1812                 LPVOID /* lpParameter */, DWORD /* dwCreationFlags */,
1813                 LPDWORD /* lpThreadId */);
1814 
1815       GC_API DECLSPEC_NORETURN void WINAPI GC_ExitThread(
1816                                                 DWORD /* dwExitCode */);
1817 #   else
1818       struct _SECURITY_ATTRIBUTES;
1819       GC_API void *__stdcall GC_CreateThread(struct _SECURITY_ATTRIBUTES *,
1820                                 GC_WIN32_SIZE_T,
1821                                 unsigned long (__stdcall *)(void *),
1822                                 void *, unsigned long, unsigned long *);
1823       GC_API DECLSPEC_NORETURN void __stdcall GC_ExitThread(unsigned long);
1824 #   endif
1825 
1826 #   if !defined(_WIN32_WCE) && !defined(__CEGCC__)
1827       GC_API GC_uintptr_t GC_CALL GC_beginthreadex(
1828                         void * /* security */, unsigned /* stack_size */,
1829                         unsigned (__stdcall *)(void *),
1830                         void * /* arglist */, unsigned /* initflag */,
1831                         unsigned * /* thrdaddr */);
1832 
1833       /* Note: _endthreadex() is not currently marked as no-return in   */
1834       /* VC++ and MinGW headers, so we don't mark it neither.           */
1835       GC_API void GC_CALL GC_endthreadex(unsigned /* retval */);
1836 #   endif /* !_WIN32_WCE */
1837 
1838 # endif /* !GC_NO_THREAD_DECLS */
1839 
1840 # ifdef GC_WINMAIN_REDIRECT
1841     /* win32_threads.c implements the real WinMain(), which will start  */
1842     /* a new thread to call GC_WinMain() after initializing the garbage */
1843     /* collector.                                                       */
1844 #   define WinMain GC_WinMain
1845 # endif
1846 
1847   /* For compatibility only. */
1848 # define GC_use_DllMain GC_use_threads_discovery
1849 
1850 # ifndef GC_NO_THREAD_REDIRECTS
1851 #   define CreateThread GC_CreateThread
1852 #   define ExitThread GC_ExitThread
1853 #   undef _beginthreadex
1854 #   define _beginthreadex GC_beginthreadex
1855 #   undef _endthreadex
1856 #   define _endthreadex GC_endthreadex
1857 /* #define _beginthread { > "Please use _beginthreadex instead of _beginthread" < } */
1858 # endif /* !GC_NO_THREAD_REDIRECTS */
1859 
1860 #endif /* GC_WIN32_THREADS */
1861 
1862 /* Public setter and getter for switching "unmap as much as possible"   */
1863 /* mode on(1) and off(0).  Has no effect unless unmapping is turned on. */
1864 /* Has no effect on implicitly-initiated garbage collections.  Initial  */
1865 /* value is controlled by GC_FORCE_UNMAP_ON_GCOLLECT.  The setter and   */
1866 /* getter are unsynchronized.                                           */
1867 GC_API void GC_CALL GC_set_force_unmap_on_gcollect(int);
1868 GC_API int GC_CALL GC_get_force_unmap_on_gcollect(void);
1869 
1870 /* Fully portable code should call GC_INIT() from the main program      */
1871 /* before making any other GC_ calls.  On most platforms this is a      */
1872 /* no-op and the collector self-initializes.  But a number of           */
1873 /* platforms make that too hard.                                        */
1874 /* A GC_INIT call is required if the collector is built with            */
1875 /* THREAD_LOCAL_ALLOC defined and the initial allocation call is not    */
1876 /* to GC_malloc() or GC_malloc_atomic().                                */
1877 
1878 #if defined(__CYGWIN32__) || defined(__CYGWIN__)
1879   /* Similarly gnu-win32 DLLs need explicit initialization from the     */
1880   /* main program, as does AIX.                                         */
1881 # ifdef __x86_64__
1882     /* Cygwin/x64 does not add leading underscore to symbols anymore.   */
1883     extern int __data_start__[], __data_end__[];
1884     extern int __bss_start__[], __bss_end__[];
1885 #   define GC_DATASTART ((GC_word)__data_start__ < (GC_word)__bss_start__ \
1886                          ? (void *)__data_start__ : (void *)__bss_start__)
1887 #   define GC_DATAEND ((GC_word)__data_end__ > (GC_word)__bss_end__ \
1888                        ? (void *)__data_end__ : (void *)__bss_end__)
1889 # else
1890     extern int _data_start__[], _data_end__[], _bss_start__[], _bss_end__[];
1891 #   define GC_DATASTART ((GC_word)_data_start__ < (GC_word)_bss_start__ \
1892                          ? (void *)_data_start__ : (void *)_bss_start__)
1893 #   define GC_DATAEND ((GC_word)_data_end__ > (GC_word)_bss_end__ \
1894                       ? (void *)_data_end__ : (void *)_bss_end__)
1895 # endif /* !__x86_64__ */
1896 # define GC_INIT_CONF_ROOTS GC_add_roots(GC_DATASTART, GC_DATAEND); \
1897                                  GC_gcollect() /* For blacklisting. */
1898         /* Required at least if GC is in a DLL.  And doesn't hurt. */
1899 #elif defined(_AIX)
1900   extern int _data[], _end[];
1901 # define GC_DATASTART ((void *)_data)
1902 # define GC_DATAEND ((void *)_end)
1903 # define GC_INIT_CONF_ROOTS GC_add_roots(GC_DATASTART, GC_DATAEND)
1904 #elif (defined(HOST_ANDROID) || defined(__ANDROID__)) \
1905       && defined(IGNORE_DYNAMIC_LOADING)
1906   /* This is ugly but seems the only way to register data roots of the  */
1907   /* client shared library if the GC dynamic loading support is off.    */
1908 # pragma weak __dso_handle
1909   extern int __dso_handle[];
1910   GC_API void * GC_CALL GC_find_limit(void * /* start */, int /* up */);
1911 # define GC_INIT_CONF_ROOTS (void)(__dso_handle != 0 \
1912                                    ? (GC_add_roots(__dso_handle, \
1913                                             GC_find_limit(__dso_handle, \
1914                                                           1 /*up*/)), 0) : 0)
1915 #else
1916 # define GC_INIT_CONF_ROOTS /* empty */
1917 #endif
1918 
1919 #ifdef GC_DONT_EXPAND
1920   /* Set GC_dont_expand to TRUE at start-up */
1921 # define GC_INIT_CONF_DONT_EXPAND GC_set_dont_expand(1)
1922 #else
1923 # define GC_INIT_CONF_DONT_EXPAND /* empty */
1924 #endif
1925 
1926 #ifdef GC_FORCE_UNMAP_ON_GCOLLECT
1927   /* Turn on "unmap as much as possible on explicit GC" mode at start-up */
1928 # define GC_INIT_CONF_FORCE_UNMAP_ON_GCOLLECT \
1929                 GC_set_force_unmap_on_gcollect(1)
1930 #else
1931 # define GC_INIT_CONF_FORCE_UNMAP_ON_GCOLLECT /* empty */
1932 #endif
1933 
1934 #ifdef GC_DONT_GC
1935   /* This is for debugging only (useful if environment variables are    */
1936   /* unsupported); cannot call GC_disable as goes before GC_init.       */
1937 # define GC_INIT_CONF_MAX_RETRIES (void)(GC_dont_gc = 1)
1938 #elif defined(GC_MAX_RETRIES) && !defined(CPPCHECK)
1939   /* Set GC_max_retries to the desired value at start-up */
1940 # define GC_INIT_CONF_MAX_RETRIES GC_set_max_retries(GC_MAX_RETRIES)
1941 #else
1942 # define GC_INIT_CONF_MAX_RETRIES /* empty */
1943 #endif
1944 
1945 #if defined(GC_FREE_SPACE_DIVISOR) && !defined(CPPCHECK)
1946   /* Set GC_free_space_divisor to the desired value at start-up */
1947 # define GC_INIT_CONF_FREE_SPACE_DIVISOR \
1948                 GC_set_free_space_divisor(GC_FREE_SPACE_DIVISOR)
1949 #else
1950 # define GC_INIT_CONF_FREE_SPACE_DIVISOR /* empty */
1951 #endif
1952 
1953 #if defined(GC_FULL_FREQ) && !defined(CPPCHECK)
1954   /* Set GC_full_freq to the desired value at start-up */
1955 # define GC_INIT_CONF_FULL_FREQ GC_set_full_freq(GC_FULL_FREQ)
1956 #else
1957 # define GC_INIT_CONF_FULL_FREQ /* empty */
1958 #endif
1959 
1960 #if defined(GC_TIME_LIMIT) && !defined(CPPCHECK)
1961   /* Set GC_time_limit to the desired value at start-up */
1962 # define GC_INIT_CONF_TIME_LIMIT GC_set_time_limit(GC_TIME_LIMIT)
1963 #else
1964 # define GC_INIT_CONF_TIME_LIMIT /* empty */
1965 #endif
1966 
1967 #if defined(GC_SIG_SUSPEND) && defined(GC_THREADS) && !defined(CPPCHECK)
1968 # define GC_INIT_CONF_SUSPEND_SIGNAL GC_set_suspend_signal(GC_SIG_SUSPEND)
1969 #else
1970 # define GC_INIT_CONF_SUSPEND_SIGNAL /* empty */
1971 #endif
1972 
1973 #if defined(GC_SIG_THR_RESTART) && defined(GC_THREADS) && !defined(CPPCHECK)
1974 # define GC_INIT_CONF_THR_RESTART_SIGNAL \
1975                 GC_set_thr_restart_signal(GC_SIG_THR_RESTART)
1976 #else
1977 # define GC_INIT_CONF_THR_RESTART_SIGNAL /* empty */
1978 #endif
1979 
1980 #if defined(GC_MAXIMUM_HEAP_SIZE) && !defined(CPPCHECK)
1981   /* Limit the heap size to the desired value (useful for debugging).   */
1982   /* The limit could be overridden either at the program start-up by    */
1983   /* the similar environment variable or anytime later by the           */
1984   /* corresponding API function call.                                   */
1985 # define GC_INIT_CONF_MAXIMUM_HEAP_SIZE \
1986                 GC_set_max_heap_size(GC_MAXIMUM_HEAP_SIZE)
1987 #else
1988 # define GC_INIT_CONF_MAXIMUM_HEAP_SIZE /* empty */
1989 #endif
1990 
1991 #ifdef GC_IGNORE_WARN
1992   /* Turn off all warnings at start-up (after GC initialization) */
1993 # define GC_INIT_CONF_IGNORE_WARN GC_set_warn_proc(GC_ignore_warn_proc)
1994 #else
1995 # define GC_INIT_CONF_IGNORE_WARN /* empty */
1996 #endif
1997 
1998 #if defined(GC_INITIAL_HEAP_SIZE) && !defined(CPPCHECK)
1999   /* Set heap size to the desired value at start-up */
2000 # define GC_INIT_CONF_INITIAL_HEAP_SIZE \
2001                 { size_t heap_size = GC_get_heap_size(); \
2002                   if (heap_size < (GC_INITIAL_HEAP_SIZE)) \
2003                     (void)GC_expand_hp((GC_INITIAL_HEAP_SIZE) - heap_size); }
2004 #else
2005 # define GC_INIT_CONF_INITIAL_HEAP_SIZE /* empty */
2006 #endif
2007 
2008 /* Portable clients should call this at the program start-up.  More     */
2009 /* over, some platforms require this call to be done strictly from the  */
2010 /* primordial thread.  Multiple invocations are harmless.               */
2011 #define GC_INIT() { GC_INIT_CONF_DONT_EXPAND; /* pre-init */ \
2012                     GC_INIT_CONF_FORCE_UNMAP_ON_GCOLLECT; \
2013                     GC_INIT_CONF_MAX_RETRIES; \
2014                     GC_INIT_CONF_FREE_SPACE_DIVISOR; \
2015                     GC_INIT_CONF_FULL_FREQ; \
2016                     GC_INIT_CONF_TIME_LIMIT; \
2017                     GC_INIT_CONF_SUSPEND_SIGNAL; \
2018                     GC_INIT_CONF_THR_RESTART_SIGNAL; \
2019                     GC_INIT_CONF_MAXIMUM_HEAP_SIZE; \
2020                     GC_init(); /* real GC initialization */ \
2021                     GC_INIT_CONF_ROOTS; /* post-init */ \
2022                     GC_INIT_CONF_IGNORE_WARN; \
2023                     GC_INIT_CONF_INITIAL_HEAP_SIZE; }
2024 
2025 /* win32S may not free all resources on process exit.   */
2026 /* This explicitly deallocates the heap.                */
2027 GC_API void GC_CALL GC_win32_free_heap(void);
2028 
2029 #if defined(__SYMBIAN32__)
2030   void GC_init_global_static_roots(void);
2031 #endif
2032 
2033 #if defined(_AMIGA) && !defined(GC_AMIGA_MAKINGLIB)
2034   /* Allocation really goes through GC_amiga_allocwrapper_do.   */
2035   void *GC_amiga_realloc(void *, size_t);
2036 # define GC_realloc(a,b) GC_amiga_realloc(a,b)
2037   void GC_amiga_set_toany(void (*)(void));
2038   extern int GC_amiga_free_space_divisor_inc;
2039   extern void *(*GC_amiga_allocwrapper_do)(size_t, void *(GC_CALL *)(size_t));
2040 # define GC_malloc(a) \
2041         (*GC_amiga_allocwrapper_do)(a,GC_malloc)
2042 # define GC_malloc_atomic(a) \
2043         (*GC_amiga_allocwrapper_do)(a,GC_malloc_atomic)
2044 # define GC_malloc_uncollectable(a) \
2045         (*GC_amiga_allocwrapper_do)(a,GC_malloc_uncollectable)
2046 # define GC_malloc_atomic_uncollectable(a) \
2047         (*GC_amiga_allocwrapper_do)(a,GC_malloc_atomic_uncollectable)
2048 # define GC_malloc_ignore_off_page(a) \
2049         (*GC_amiga_allocwrapper_do)(a,GC_malloc_ignore_off_page)
2050 # define GC_malloc_atomic_ignore_off_page(a) \
2051         (*GC_amiga_allocwrapper_do)(a,GC_malloc_atomic_ignore_off_page)
2052 #endif /* _AMIGA && !GC_AMIGA_MAKINGLIB */
2053 
2054 #ifdef __cplusplus
2055   } /* extern "C" */
2056 #endif
2057 
2058 #endif /* GC_H */
2059