text: /*
   * Copyright (c) 1988-1989 Hans-J. Boehm, Alan J. Demers
   * Copyright (c) 1991-1995 by Xerox Corporation.  All rights reserved.
   * Copyright (c) 1996-1999 by Silicon Graphics.  All rights reserved.
   * Copyright (c) 1999 by Hewlett-Packard Company.  All rights reserved.
   * Copyright (c) 2007 Free Software Foundation, Inc.
   * Copyright (c) 2000-2011 by Hewlett-Packard Development Company.
   * Copyright (c) 2009-2020 Ivan Maidanski
   *
   * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
   *
   * Permission is hereby granted to use or copy this program
   * for any purpose,  provided the above notices are retained on all copies.
   * Permission to modify the code and to distribute modified code is granted,
   * provided the above notices are retained, and a notice that the code was
   * modified is included with the above copyright notice.
   */
  
  /*
   * Note that this defines a large number of tuning hooks, which can
   * safely be ignored in nearly all cases.  For normal use it suffices
   * to call only GC_MALLOC and perhaps GC_REALLOC.
   * For better performance, also look at GC_MALLOC_ATOMIC, and
   * GC_enable_incremental.  If you need an action to be performed
   * immediately before an object is collected, look at GC_register_finalizer.
   * Everything else is best ignored unless you encounter performance
   * problems.
   */
  
  #ifndef GC_H
  #define GC_H
  
  /* Help debug mixed up preprocessor symbols.    */
  #if (defined(WIN64) && !defined(_WIN64)) && defined(_MSC_VER)
  #pragma message("Warning: Expecting _WIN64 for x64 targets! Notice the leading underscore!")
  #endif
  
  #include "gc_version.h"
          /* Define version numbers here to allow test on build machine   */
          /* for cross-builds.  Note that this defines the header         */
          /* version number, which may or may not match that of the       */
          /* dynamic library.  GC_get_version() can be used to obtain     */
          /* the latter.                                                  */
  
  #include "gc_config_macros.h"
  
  #ifdef __cplusplus
    extern "C" {
  #endif
  
  typedef void * GC_PTR;  /* preserved only for backward compatibility    */
  
  /* Define word and signed_word to be unsigned and signed types of the   */
  /* size as char * or void *.  There seems to be no way to do this       */
  /* even semi-portably.  The following is probably no better/worse       */
  /* than almost anything else.                                           */
  /* The ANSI standard suggests that size_t and ptrdiff_t might be        */
  /* better choices.  But those had incorrect definitions on some older   */
  /* systems.  Notably "typedef int size_t" is WRONG.                     */
  #ifdef _WIN64
  # if defined(__int64) && !defined(CPPCHECK)
      typedef unsigned __int64 GC_word;
      typedef __int64 GC_signed_word;
  # else
      typedef unsigned long long GC_word;
      typedef long long GC_signed_word;
  # endif
  #else
    typedef unsigned long GC_word;
    typedef long GC_signed_word;
  #endif
  
  /* Get the GC library version. The returned value is a constant in the  */
  /* form: ((version_major<<16) | (version_minor<<8) | version_micro).    */
  GC_API unsigned GC_CALL GC_get_version(void);
  
  /* Public read-only variables */
  /* The supplied getter functions are preferred for new code.            */
  
  GC_API GC_ATTR_DEPRECATED GC_word GC_gc_no;
                          /* Counter incremented per collection.          */
                          /* Includes empty GCs at startup.               */
  GC_API GC_word GC_CALL GC_get_gc_no(void);
                          /* GC_get_gc_no() is unsynchronized, so         */
                          /* it requires GC_call_with_alloc_lock() to     */
                          /* avoid data races on multiprocessors.         */
  
  #ifdef GC_THREADS
    GC_API GC_ATTR_DEPRECATED int GC_parallel;
                          /* GC is parallelized for performance on        */
                          /* multiprocessors.  Set to a non-zero value    */
                          /* only implicitly if collector is built with   */
                          /* PARALLEL_MARK defined, and if either         */
                          /* GC_MARKERS (or GC_NPROCS) environment        */
                          /* variable is set to > 1, or multiple cores    */
                          /* (processors) are available, or the client    */
                          /* calls GC_set_markers_count() before the GC   */
                          /* initialization.  The getter does             */
                          /* not use or need synchronization (i.e.        */
                          /* acquiring the GC lock).  GC_parallel value   */
                          /* is equal to the number of marker threads     */
                          /* minus one (i.e. number of existing parallel  */
                          /* marker threads excluding the initiating one).*/
    GC_API int GC_CALL GC_get_parallel(void);
  
    /* Set the number of marker threads (including the initiating one)    */
    /* to the desired value at start-up.  Zero value means the collector  */
    /* is to decide.  Has no effect if called after GC initialization.    */
    /* If the correct non-zero value is passed, then GC_parallel should   */
    /* be set to the value minus one.  The function does not use any      */
    /* synchronization.                                                   */
    GC_API void GC_CALL GC_set_markers_count(unsigned);
  #endif
  
  
  /* Public R/W variables */
  /* The supplied setter and getter functions are preferred for new code. */
  
  typedef void * (GC_CALLBACK * GC_oom_func)(size_t /* bytes_requested */);
  GC_API GC_ATTR_DEPRECATED GC_oom_func GC_oom_fn;
                          /* When there is insufficient memory to satisfy */
                          /* an allocation request, we return             */
                          /* (*GC_oom_fn)(size).  By default this just    */
                          /* returns NULL.                                */
                          /* If it returns, it must return 0 or a valid   */
                          /* pointer to a previously allocated heap       */
                          /* object.  GC_oom_fn must not be 0.            */
                          /* Both the supplied setter and the getter      */
                          /* acquire the GC lock (to avoid data races).   */
  GC_API void GC_CALL GC_set_oom_fn(GC_oom_func) GC_ATTR_NONNULL(1);
  GC_API GC_oom_func GC_CALL GC_get_oom_fn(void);
  
  typedef void (GC_CALLBACK * GC_on_heap_resize_proc)(GC_word /* new_size */);
  GC_API GC_ATTR_DEPRECATED GC_on_heap_resize_proc GC_on_heap_resize;
                          /* Invoked when the heap grows or shrinks.      */
                          /* Called with the world stopped (and the       */
                          /* allocation lock held).  May be 0.            */
  GC_API void GC_CALL GC_set_on_heap_resize(GC_on_heap_resize_proc);
  GC_API GC_on_heap_resize_proc GC_CALL GC_get_on_heap_resize(void);
                          /* Both the supplied setter and the getter      */
                          /* acquire the GC lock (to avoid data races).   */
  
  typedef enum {
      GC_EVENT_START /* COLLECTION */,
      GC_EVENT_MARK_START,
      GC_EVENT_MARK_END,
      GC_EVENT_RECLAIM_START,
      GC_EVENT_RECLAIM_END,
      GC_EVENT_END /* COLLECTION */,
      GC_EVENT_PRE_STOP_WORLD /* STOPWORLD_BEGIN */,
      GC_EVENT_POST_STOP_WORLD /* STOPWORLD_END */,
      GC_EVENT_PRE_START_WORLD /* STARTWORLD_BEGIN */,
      GC_EVENT_POST_START_WORLD /* STARTWORLD_END */,
      GC_EVENT_THREAD_SUSPENDED,
      GC_EVENT_THREAD_UNSUSPENDED
  } GC_EventType;
  
  typedef void (GC_CALLBACK * GC_on_collection_event_proc)(GC_EventType);
                          /* Invoked to indicate progress through the     */
                          /* collection process.  Not used for thread     */
                          /* suspend/resume notifications.  Called with   */
                          /* the GC lock held (or, even, the world        */
                          /* stopped).  May be 0 (means no notifier).     */
  GC_API void GC_CALL GC_set_on_collection_event(GC_on_collection_event_proc);
  GC_API GC_on_collection_event_proc GC_CALL GC_get_on_collection_event(void);
                          /* Both the supplied setter and the getter      */
                          /* acquire the GC lock (to avoid data races).   */
  
  #if defined(GC_THREADS) || (defined(GC_BUILD) && defined(NN_PLATFORM_CTR))
    typedef void (GC_CALLBACK * GC_on_thread_event_proc)(GC_EventType,
                                                  void * /* thread_id */);
                          /* Invoked when a thread is suspended or        */
                          /* resumed during collection.  Called with the  */
                          /* GC lock held (and the world stopped          */
                          /* partially).  May be 0 (means no notifier).   */
    GC_API void GC_CALL GC_set_on_thread_event(GC_on_thread_event_proc);
    GC_API GC_on_thread_event_proc GC_CALL GC_get_on_thread_event(void);
                          /* Both the supplied setter and the getter      */
                          /* acquire the GC lock (to avoid data races).   */
  #endif
  
  GC_API GC_ATTR_DEPRECATED int GC_find_leak;
                          /* Set to true to turn on the leak-finding mode */
                          /* (do not actually garbage collect, but simply */
                          /* report inaccessible memory that was not      */
                          /* deallocated with GC_FREE).  Initial value    */
                          /* is determined by FIND_LEAK macro.            */
                          /* The value should not typically be modified   */
                          /* after GC initialization (and, thus, it does  */
                          /* not use or need synchronization).            */
  GC_API void GC_CALL GC_set_find_leak(int);
  GC_API int GC_CALL GC_get_find_leak(void);
  
  GC_API GC_ATTR_DEPRECATED int GC_all_interior_pointers;
                          /* Arrange for pointers to object interiors to  */
                          /* be recognized as valid.  Typically should    */
                          /* not be changed after GC initialization (in   */
                          /* case of calling it after the GC is           */
                          /* initialized, the setter acquires the GC lock */
                          /* (to avoid data races).  The initial value    */
                          /* depends on whether the GC is built with      */
                          /* ALL_INTERIOR_POINTERS macro defined or not.  */
                          /* Unless DONT_ADD_BYTE_AT_END is defined, this */
                          /* also affects whether sizes are increased by  */
                          /* at least a byte to allow "off the end"       */
                          /* pointer recognition.  Must be only 0 or 1.   */
  GC_API void GC_CALL GC_set_all_interior_pointers(int);
  GC_API int GC_CALL GC_get_all_interior_pointers(void);
  
  GC_API GC_ATTR_DEPRECATED int GC_finalize_on_demand;
                          /* If nonzero, finalizers will only be run in   */
                          /* response to an explicit GC_invoke_finalizers */
                          /* call.  The default is determined by whether  */
                          /* the FINALIZE_ON_DEMAND macro is defined      */
                          /* when the collector is built.                 */
                          /* The setter and getter are unsynchronized.    */
  GC_API void GC_CALL GC_set_finalize_on_demand(int);
  GC_API int GC_CALL GC_get_finalize_on_demand(void);
  
  GC_API GC_ATTR_DEPRECATED int GC_java_finalization;
                          /* Mark objects reachable from finalizable      */
                          /* objects in a separate post-pass.  This makes */
                          /* it a bit safer to use non-topologically-     */
                          /* ordered finalization.  Default value is      */
                          /* determined by JAVA_FINALIZATION macro.       */
                          /* Enables register_finalizer_unreachable to    */
                          /* work correctly.                              */
                          /* The setter and getter are unsynchronized.    */
  GC_API void GC_CALL GC_set_java_finalization(int);
  GC_API int GC_CALL GC_get_java_finalization(void);
  
  typedef void (GC_CALLBACK * GC_finalizer_notifier_proc)(void);
  GC_API GC_ATTR_DEPRECATED GC_finalizer_notifier_proc GC_finalizer_notifier;
                          /* Invoked by the collector when there are      */
                          /* objects to be finalized.  Invoked at most    */
                          /* once per GC cycle.  Never invoked unless     */
                          /* GC_finalize_on_demand is set.                */
                          /* Typically this will notify a finalization    */
                          /* thread, which will call GC_invoke_finalizers */
                          /* in response.  May be 0 (means no notifier).  */
                          /* Both the supplied setter and the getter      */
                          /* acquire the GC lock (to avoid data races).   */
  GC_API void GC_CALL GC_set_finalizer_notifier(GC_finalizer_notifier_proc);
  GC_API GC_finalizer_notifier_proc GC_CALL GC_get_finalizer_notifier(void);
  
  GC_API
  # ifndef GC_DONT_GC
      GC_ATTR_DEPRECATED
  # endif
    int GC_dont_gc;       /* != 0 ==> Do not collect.  This overrides     */
                          /* explicit GC_gcollect() calls as well.        */
                          /* Used as a counter, so that nested enabling   */
                          /* and disabling work correctly.  Should        */
                          /* normally be updated with GC_enable() and     */
                          /* GC_disable() calls.  Direct assignment to    */
                          /* GC_dont_gc is deprecated.  To check whether  */
                          /* GC is disabled, GC_is_disabled() is          */
                          /* preferred for new code.                      */
  
  GC_API GC_ATTR_DEPRECATED int GC_dont_expand;
                          /* Do not expand the heap unless explicitly     */
                          /* requested or forced to.  The setter and      */
                          /* getter are unsynchronized.                   */
  GC_API void GC_CALL GC_set_dont_expand(int);
  GC_API int GC_CALL GC_get_dont_expand(void);
  
  GC_API GC_ATTR_DEPRECATED int GC_use_entire_heap;
                  /* Causes the non-incremental collector to use the      */
                  /* entire heap before collecting.  This sometimes       */
                  /* results in more large block fragmentation, since     */
                  /* very large blocks will tend to get broken up         */
                  /* during each GC cycle.  It is likely to result in a   */
                  /* larger working set, but lower collection             */
                  /* frequencies, and hence fewer instructions executed   */
                  /* in the collector.                                    */
  
  GC_API GC_ATTR_DEPRECATED int GC_full_freq;
                              /* Number of partial collections between    */
                              /* full collections.  Matters only if       */
                              /* GC_is_incremental_mode().                */
                              /* Full collections are also triggered if   */
                              /* the collector detects a substantial      */
                              /* increase in the number of in-use heap    */
                              /* blocks.  Values in the tens are now      */
                              /* perfectly reasonable, unlike for         */
                              /* earlier GC versions.                     */
                          /* The setter and getter are unsynchronized, so */
                          /* GC_call_with_alloc_lock() is required to     */
                          /* avoid data races (if the value is modified   */
                          /* after the GC is put to multi-threaded mode). */
  GC_API void GC_CALL GC_set_full_freq(int);
  GC_API int GC_CALL GC_get_full_freq(void);
  
  GC_API GC_ATTR_DEPRECATED GC_word GC_non_gc_bytes;
                          /* Bytes not considered candidates for          */
                          /* collection.  Used only to control scheduling */
                          /* of collections.  Updated by                  */
                          /* GC_malloc_uncollectable and GC_free.         */
                          /* Wizards only.                                */
                          /* The setter and getter are unsynchronized, so */
                          /* GC_call_with_alloc_lock() is required to     */
                          /* avoid data races (if the value is modified   */
                          /* after the GC is put to multi-threaded mode). */
  GC_API void GC_CALL GC_set_non_gc_bytes(GC_word);
  GC_API GC_word GC_CALL GC_get_non_gc_bytes(void);
  
  GC_API GC_ATTR_DEPRECATED int GC_no_dls;
                          /* Don't register dynamic library data segments. */
                          /* Wizards only.  Should be used only if the     */
                          /* application explicitly registers all roots.   */
                          /* (In some environments like Microsoft Windows  */
                          /* and Apple's Darwin, this may also prevent     */
                          /* registration of the main data segment as part */
                          /* of the root set.)                             */
                          /* The setter and getter are unsynchronized.     */
  GC_API void GC_CALL GC_set_no_dls(int);
  GC_API int GC_CALL GC_get_no_dls(void);
  
  GC_API GC_ATTR_DEPRECATED GC_word GC_free_space_divisor;
                          /* We try to make sure that we allocate at      */
                          /* least N/GC_free_space_divisor bytes between  */
                          /* collections, where N is twice the number     */
                          /* of traced bytes, plus the number of untraced */
                          /* bytes (bytes in "atomic" objects), plus      */
                          /* a rough estimate of the root set size.       */
                          /* N approximates GC tracing work per GC.       */
                          /* The initial value is GC_FREE_SPACE_DIVISOR.  */
                          /* Increasing its value will use less space     */
                          /* but more collection time.  Decreasing it     */
                          /* will appreciably decrease collection time    */
                          /* at the expense of space.                     */
                          /* The setter and getter are unsynchronized, so */
                          /* GC_call_with_alloc_lock() is required to     */
                          /* avoid data races (if the value is modified   */
                          /* after the GC is put to multi-threaded mode). */
                          /* In GC v7.1 (and before), the setter returned */
                          /* the old value.                               */
  GC_API void GC_CALL GC_set_free_space_divisor(GC_word);
  GC_API GC_word GC_CALL GC_get_free_space_divisor(void);
  
  GC_API GC_ATTR_DEPRECATED GC_word GC_max_retries;
                          /* The maximum number of GCs attempted before   */
                          /* reporting out of memory after heap           */
                          /* expansion fails.  Initially 0.               */
                          /* The setter and getter are unsynchronized, so */
                          /* GC_call_with_alloc_lock() is required to     */
                          /* avoid data races (if the value is modified   */
                          /* after the GC is put to multi-threaded mode). */
  GC_API void GC_CALL GC_set_max_retries(GC_word);
  GC_API GC_word GC_CALL GC_get_max_retries(void);
  
  
  GC_API GC_ATTR_DEPRECATED char *GC_stackbottom;
                                  /* The cold end (bottom) of user stack. */
                                  /* May be set in the client prior to    */
                                  /* calling any GC_ routines.  This      */
                                  /* avoids some overhead, and            */
                                  /* potentially some signals that can    */
                                  /* confuse debuggers.  Otherwise the    */
                                  /* collector attempts to set it         */
                                  /* automatically.                       */
                                  /* For multi-threaded code, this is the */
                                  /* cold end of the stack for the        */
                                  /* primordial thread.  Portable clients */
                                  /* should use GC_get_stack_base(),      */
                                  /* GC_call_with_gc_active() and         */
                                  /* GC_register_my_thread() instead.     */
  
  GC_API GC_ATTR_DEPRECATED int GC_dont_precollect;
                                  /* Do not collect as part of GC         */
                                  /* initialization.  Should be set only  */
                                  /* if the client wants a chance to      */
                                  /* manually initialize the root set     */
                                  /* before the first collection.         */
                                  /* Interferes with blacklisting.        */
                                  /* Wizards only.  The setter and getter */
                                  /* are unsynchronized (and no external  */
                                  /* locking is needed since the value is */
                                  /* accessed at GC initialization only). */
  GC_API void GC_CALL GC_set_dont_precollect(int);
  GC_API int GC_CALL GC_get_dont_precollect(void);
  
  GC_API GC_ATTR_DEPRECATED unsigned long GC_time_limit;
                                 /* If incremental collection is enabled, */
                                 /* we try to terminate collections       */
                                 /* after this many milliseconds (plus    */
                                 /* the amount of nanoseconds as given in */
                                 /* the latest GC_set_time_limit_tv call, */
                                 /* if any).  Not a hard time bound.      */
                                 /* Setting this variable to              */
                                 /* GC_TIME_UNLIMITED will essentially    */
                                 /* disable incremental collection while  */
                                 /* leaving generational collection       */
                                 /* enabled.                              */
  #define GC_TIME_UNLIMITED 999999
                                 /* Setting GC_time_limit to this value   */
                                 /* will disable the "pause time exceeded"*/
                                 /* tests.                                */
                          /* The setter and getter are unsynchronized, so */
                          /* GC_call_with_alloc_lock() is required to     */
                          /* avoid data races (if the value is modified   */
                          /* after the GC is put to multi-threaded mode). */
                          /* The setter does not update the value of the  */
                          /* nanosecond part of the time limit (it is     */
                          /* zero unless ever set by GC_set_time_limit_tv */
                          /* call).                                       */
  GC_API void GC_CALL GC_set_time_limit(unsigned long);
  GC_API unsigned long GC_CALL GC_get_time_limit(void);
  
  /* A portable type definition of time with a nanosecond precision.      */
  struct GC_timeval_s {
    unsigned long tv_ms;  /* time in milliseconds */
    unsigned long tv_nsec;/* nanoseconds fraction (<1000000) */
  };
  
  /* Public procedures */
  
  /* Set/get the time limit of the incremental collections.  This is      */
  /* similar to GC_set_time_limit and GC_get_time_limit but the time is   */
  /* provided with the nanosecond precision.  The value of tv_nsec part   */
  /* should be less than a million.  If the value of tv_ms part is        */
  /* GC_TIME_UNLIMITED then tv_nsec is ignored.  Initially, the value of  */
  /* tv_nsec part of the time limit is zero.  The functions do not use    */
  /* any synchronization.  Defined only if the library has been compiled  */
  /* without NO_CLOCK.                                                    */
  GC_API void GC_CALL GC_set_time_limit_tv(struct GC_timeval_s);
  GC_API struct GC_timeval_s GC_CALL GC_get_time_limit_tv(void);
  
  /* Set/get the minimum value of the ratio of allocated bytes since GC   */
  /* to the amount of finalizers created since that GC (value >           */
  /* GC_bytes_allocd / (GC_fo_entries - last_fo_entries)) which triggers  */
  /* the collection instead heap expansion.  The value has no effect in   */
  /* the GC incremental mode.  The default value is 10000 unless          */
  /* GC_ALLOCD_BYTES_PER_FINALIZER macro with a custom value is defined   */
  /* to build libgc.  The default value might be not the right choice for */
  /* clients where e.g. most objects have a finalizer.  Zero value        */
  /* effectively disables taking amount of finalizers in the decision     */
  /* whether to collect or not.  The functions do not use any             */
  /* synchronization.                                                     */
  GC_API void GC_CALL GC_set_allocd_bytes_per_finalizer(GC_word);
  GC_API GC_word GC_CALL GC_get_allocd_bytes_per_finalizer(void);
  
  /* Tell the collector to start various performance measurements.        */
  /* Only the total time taken by full collections is calculated, as      */
  /* of now.  And, currently, there is no way to stop the measurements.   */
  /* The function does not use any synchronization.  Defined only if the  */
  /* library has been compiled without NO_CLOCK.                          */
  GC_API void GC_CALL GC_start_performance_measurement(void);
  
  /* Get the total time of all full collections since the start of the    */
  /* performance measurements.  The measurement unit is one millisecond.  */
  /* Note that the returned value wraps around on overflow.               */
  /* The function does not use any synchronization.  Defined only if the  */
  /* library has been compiled without NO_CLOCK.                          */
  GC_API unsigned long GC_CALL GC_get_full_gc_total_time(void);
  
  /* Set whether the GC will allocate executable memory pages or not.     */
  /* A non-zero argument instructs the collector to allocate memory with  */
  /* the executable flag on.  Must be called before the collector is      */
  /* initialized.  May have no effect on some platforms.  The default     */
  /* value is controlled by NO_EXECUTE_PERMISSION macro (if present then  */
  /* the flag is off).  Portable clients should have                      */
  /* GC_set_pages_executable(1) call (before GC_INIT) provided they are   */
  /* going to execute code on any of the GC-allocated memory objects.     */
  GC_API void GC_CALL GC_set_pages_executable(int);
  
  /* Returns non-zero value if the GC is set to the allocate-executable   */
  /* mode.  The mode could be changed by GC_set_pages_executable (before  */
  /* GC_INIT) unless the former has no effect on the platform.  Does not  */
  /* use or need synchronization (i.e. acquiring the allocator lock).     */
  GC_API int GC_CALL GC_get_pages_executable(void);
  
  /* The setter and getter of the minimum value returned by the internal  */
  /* min_bytes_allocd().  The value should not be zero; the default value */
  /* is one.  Not synchronized.                                           */
  GC_API void GC_CALL GC_set_min_bytes_allocd(size_t);
  GC_API size_t GC_CALL GC_get_min_bytes_allocd(void);
  
  /* Set/get the size in pages of units operated by GC_collect_a_little.  */
  /* The value should not be zero.  Not synchronized.                     */
  GC_API void GC_CALL GC_set_rate(int);
  GC_API int GC_CALL GC_get_rate(void);
  
  /* Set/get the maximum number of prior attempts at the world-stop       */
  /* marking.  Not synchronized.                                          */
  GC_API void GC_CALL GC_set_max_prior_attempts(int);
  GC_API int GC_CALL GC_get_max_prior_attempts(void);
  
  /* Control whether to disable algorithm deciding if a collection should */
  /* be started when we allocated enough to amortize GC.  Both the setter */
  /* and the getter acquire the GC lock (to avoid data races).            */
  GC_API void GC_CALL GC_set_disable_automatic_collection(int);
  GC_API int GC_CALL GC_get_disable_automatic_collection(void);
  
  /* Overrides the default handle-fork mode.  Non-zero value means GC     */
  /* should install proper pthread_atfork handlers.  Has effect only if   */
  /* called before GC_INIT.  Clients should invoke GC_set_handle_fork     */
  /* with non-zero argument if going to use fork with GC functions called */
  /* in the forked child.  (Note that such client and atfork handlers     */
  /* activities are not fully POSIX-compliant.)  GC_set_handle_fork       */
  /* instructs GC_init to setup GC fork handlers using pthread_atfork,    */
  /* the latter might fail (or, even, absent on some targets) causing     */
  /* abort at GC initialization.  Issues with missing (or failed)         */
  /* pthread_atfork() could be avoided by invocation                      */
  /* of GC_set_handle_fork(-1) at application start-up and surrounding    */
  /* each fork() with the relevant GC_atfork_prepare/parent/child calls.  */
  GC_API void GC_CALL GC_set_handle_fork(int);
  
  /* Routines to handle POSIX fork() manually (no-op if handled           */
  /* automatically).  GC_atfork_prepare should be called immediately      */
  /* before fork(); GC_atfork_parent should be invoked just after fork in */
  /* the branch that corresponds to parent process (i.e., fork result is  */
  /* non-zero); GC_atfork_child is to be called immediately in the child  */
  /* branch (i.e., fork result is 0). Note that GC_atfork_child() call    */
  /* should, of course, precede GC_start_mark_threads call (if any).      */
  GC_API void GC_CALL GC_atfork_prepare(void);
  GC_API void GC_CALL GC_atfork_parent(void);
  GC_API void GC_CALL GC_atfork_child(void);
  
  /* Initialize the collector.  Portable clients should call GC_INIT()    */
  /* from the main program instead.                                       */
  GC_API void GC_CALL GC_init(void);
  
  /* Returns non-zero (TRUE) if and only if the collector is initialized  */
  /* (or, at least, the initialization is in progress).                   */
  GC_API int GC_CALL GC_is_init_called(void);
  
  /* Perform the collector shutdown.  (E.g. dispose critical sections on  */
  /* Win32 target.)  A duplicate invocation is a no-op.  GC_INIT should   */
  /* not be called after the shutdown.  See also GC_win32_free_heap().    */
  GC_API void GC_CALL GC_deinit(void);
  
  /* General purpose allocation routines, with roughly malloc calling     */
  /* conv.  The atomic versions promise that no relevant pointers are     */
  /* contained in the object.  The non-atomic versions guarantee that the */
  /* new object is cleared.  GC_malloc_uncollectable allocates            */
  /* an object that is scanned for pointers to collectible                */
  /* objects, but is not itself collectible.  The object is scanned even  */
  /* if it does not appear to be reachable.  GC_malloc_uncollectable and  */
  /* GC_free called on the resulting object implicitly update             */
  /* GC_non_gc_bytes appropriately.                                       */
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_malloc(size_t /* size_in_bytes */);
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_malloc_atomic(size_t /* size_in_bytes */);
  GC_API GC_ATTR_MALLOC char * GC_CALL GC_strdup(const char *);
  GC_API GC_ATTR_MALLOC char * GC_CALL
          GC_strndup(const char *, size_t) GC_ATTR_NONNULL(1);
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_malloc_uncollectable(size_t /* size_in_bytes */);
  GC_API GC_ATTR_DEPRECATED void * GC_CALL GC_malloc_stubborn(size_t);
  
  /* GC_memalign() is not well tested.                                    */
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(2) void * GC_CALL
          GC_memalign(size_t /* align */, size_t /* lb */);
  GC_API int GC_CALL GC_posix_memalign(void ** /* memptr */, size_t /* align */,
                          size_t /* lb */) GC_ATTR_NONNULL(1);
  
  /* Explicitly deallocate an object.  Dangerous if used incorrectly.     */
  /* Requires a pointer to the base of an object.                         */
  /* An object should not be enabled for finalization (and it should not  */
  /* contain registered disappearing links of any kind) when it is        */
  /* explicitly deallocated.                                              */
  /* GC_free(0) is a no-op, as required by ANSI C for free.               */
  GC_API void GC_CALL GC_free(void *);
  
  /* The "stubborn" objects allocation is not supported anymore.  Exists  */
  /* only for the backward compatibility.                                 */
  #define GC_MALLOC_STUBBORN(sz)  GC_MALLOC(sz)
  #define GC_NEW_STUBBORN(t)      GC_NEW(t)
  #define GC_CHANGE_STUBBORN(p)   GC_change_stubborn(p)
  GC_API GC_ATTR_DEPRECATED void GC_CALL GC_change_stubborn(const void *);
  
  /* Inform the collector that the object has been changed.               */
  /* Only non-NULL pointer stores into the object are considered to be    */
  /* changes.  Matters only if the incremental collection is enabled in   */
  /* the manual VDB mode (otherwise the function does nothing).           */
  /* Should be followed typically by GC_reachable_here called for each    */
  /* of the stored pointers.                                              */
  GC_API void GC_CALL GC_end_stubborn_change(const void *) GC_ATTR_NONNULL(1);
  
  /* Return a pointer to the base (lowest address) of an object given     */
  /* a pointer to a location within the object.                           */
  /* I.e., map an interior pointer to the corresponding base pointer.     */
  /* Note that with debugging allocation, this returns a pointer to the   */
  /* actual base of the object, i.e. the debug information, not to        */
  /* the base of the user object.                                         */
  /* Return 0 if displaced_pointer doesn't point to within a valid        */
  /* object.                                                              */
  /* Note that a deallocated object in the garbage collected heap         */
  /* may be considered valid, even if it has been deallocated with        */
  /* GC_free.                                                             */
  GC_API void * GC_CALL GC_base(void * /* displaced_pointer */);
  
  /* Return non-zero (TRUE) if and only if the argument points to         */
  /* somewhere in GC heap.  Primary use is as a fast alternative to       */
  /* GC_base to check whether the pointed object is allocated by GC       */
  /* or not.  It is assumed that the collector is already initialized.    */
  GC_API int GC_CALL GC_is_heap_ptr(const void *);
  
  /* Given a pointer to the base of an object, return its size in bytes.  */
  /* The returned size may be slightly larger than what was originally    */
  /* requested.                                                           */
  GC_API size_t GC_CALL GC_size(const void * /* obj_addr */) GC_ATTR_NONNULL(1);
  
  /* For compatibility with C library.  This is occasionally faster than  */
  /* a malloc followed by a bcopy.  But if you rely on that, either here  */
  /* or with the standard C library, your code is broken.  In my          */
  /* opinion, it shouldn't have been invented, but now we're stuck. -HB   */
  /* The resulting object has the same kind as the original.              */
  /* It is an error to have changes enabled for the original object.      */
  /* It does not change the content of the object from its beginning to   */
  /* the minimum of old size and new_size_in_bytes; the content above in  */
  /* case of object size growth is initialized to zero (not guaranteed    */
  /* for atomic object type).  The function follows ANSI conventions for  */
  /* NULL old_object (i.e., equivalent to GC_malloc regardless of new     */
  /* size).  If new size is zero (and old_object is non-NULL) then the    */
  /* call is equivalent to GC_free (and NULL is returned).  If old_object */
  /* is non-NULL, it must have been returned by an earlier call to        */
  /* GC_malloc* or GC_realloc.  In case of the allocation failure, the    */
  /* memory pointed by old_object is untouched (and not freed).           */
  /* If the returned pointer is not the same as old_object and both of    */
  /* them are non-NULL then old_object is freed.  Returns either NULL (in */
  /* case of the allocation failure or zero new size) or pointer to the   */
  /* allocated memory.                                                    */
  GC_API void * GC_CALL GC_realloc(void * /* old_object */,
                                   size_t /* new_size_in_bytes */)
                          /* 'realloc' attr */ GC_ATTR_ALLOC_SIZE(2);
  
  /* Explicitly increase the heap size.   */
  /* Returns 0 on failure, 1 on success.  */
  GC_API int GC_CALL GC_expand_hp(size_t /* number_of_bytes */);
  
  /* Limit the heap size to n bytes.  Useful when you're debugging,       */
  /* especially on systems that don't handle running out of memory well.  */
  /* n == 0 ==> unbounded.  This is the default.  This setter function is */
  /* unsynchronized (so it might require GC_call_with_alloc_lock to avoid */
  /* data races).                                                         */
  GC_API void GC_CALL GC_set_max_heap_size(GC_word /* n */);
  
  /* Inform the collector that a certain section of statically allocated  */
  /* memory contains no pointers to garbage collected memory.  Thus it    */
  /* need not be scanned.  This is sometimes important if the application */
  /* maps large read/write files into the address space, which could be   */
  /* mistaken for dynamic library data segments on some systems.          */
  /* Both section start and end are not needed to be pointer-aligned.     */
  GC_API void GC_CALL GC_exclude_static_roots(void * /* low_address */,
                                              void * /* high_address_plus_1 */);
  
  /* Clear the number of entries in the exclusion table.  Wizards only.   */
  GC_API void GC_CALL GC_clear_exclusion_table(void);
  
  /* Clear the set of root segments.  Wizards only.                       */
  GC_API void GC_CALL GC_clear_roots(void);
  
  /* Add a root segment.  Wizards only.                                   */
  /* Both segment start and end are not needed to be pointer-aligned.     */
  /* low_address must not be greater than high_address_plus_1.            */
  GC_API void GC_CALL GC_add_roots(void * /* low_address */,
                                   void * /* high_address_plus_1 */);
  
  /* Remove a root segment.  Wizards only.                                */
  /* May be unimplemented on some platforms.                              */
  GC_API void GC_CALL GC_remove_roots(void * /* low_address */,
                                      void * /* high_address_plus_1 */);
  
  /* Add a displacement to the set of those considered valid by the       */
  /* collector.  GC_register_displacement(n) means that if p was returned */
  /* by GC_malloc, then (char *)p + n will be considered to be a valid    */
  /* pointer to p.  N must be small and less than the size of p.          */
  /* (All pointers to the interior of objects from the stack are          */
  /* considered valid in any case.  This applies to heap objects and      */
  /* static data.)                                                        */
  /* Preferably, this should be called before any other GC procedures.    */
  /* Calling it later adds to the probability of excess memory            */
  /* retention.                                                           */
  /* This is a no-op if the collector has recognition of                  */
  /* arbitrary interior pointers enabled, which is now the default.       */
  GC_API void GC_CALL GC_register_displacement(size_t /* n */);
  
  /* The following version should be used if any debugging allocation is  */
  /* being done.                                                          */
  GC_API void GC_CALL GC_debug_register_displacement(size_t /* n */);
  
  /* Explicitly trigger a full, world-stop collection.    */
  GC_API void GC_CALL GC_gcollect(void);
  
  /* Same as above but ignores the default stop_func setting and tries to */
  /* unmap as much memory as possible (regardless of the corresponding    */
  /* switch setting).  The recommended usage: on receiving a system       */
  /* low-memory event; before retrying a system call failed because of    */
  /* the system is running out of resources.                              */
  GC_API void GC_CALL GC_gcollect_and_unmap(void);
  
  /* Trigger a full world-stopped collection.  Abort the collection if    */
  /* and when stop_func returns a nonzero value.  Stop_func will be       */
  /* called frequently, and should be reasonably fast.  (stop_func is     */
  /* called with the allocation lock held and the world might be stopped; */
  /* it's not allowed for stop_func to manipulate pointers to the garbage */
  /* collected heap or call most of GC functions.)  This works even       */
  /* if virtual dirty bits, and hence incremental collection is not       */
  /* available for this architecture.  Collections can be aborted faster  */
  /* than normal pause times for incremental collection.  However,        */
  /* aborted collections do no useful work; the next collection needs     */
  /* to start from the beginning.  stop_func must not be 0.               */
  /* GC_try_to_collect() returns 0 if the collection was aborted (or the  */
  /* collections are disabled), 1 if it succeeded.                        */
  typedef int (GC_CALLBACK * GC_stop_func)(void);
  GC_API int GC_CALL GC_try_to_collect(GC_stop_func /* stop_func */)
                                                          GC_ATTR_NONNULL(1);
  
  /* Set and get the default stop_func.  The default stop_func is used by */
  /* GC_gcollect() and by implicitly triggered collections (except for    */
  /* the case when handling out of memory).  Must not be 0.               */
  /* Both the setter and getter acquire the GC lock to avoid data races.  */
  GC_API void GC_CALL GC_set_stop_func(GC_stop_func /* stop_func */)
                                                          GC_ATTR_NONNULL(1);
  GC_API GC_stop_func GC_CALL GC_get_stop_func(void);
  
  /* Return the number of bytes in the heap.  Excludes collector private  */
  /* data structures.  Excludes the unmapped memory (returned to the OS). */
  /* Includes empty blocks and fragmentation loss.  Includes some pages   */
  /* that were allocated but never written.                               */
  /* This is an unsynchronized getter, so it should be called typically   */
  /* with the GC lock held to avoid data races on multiprocessors (the    */
  /* alternative is to use GC_get_heap_usage_safe or GC_get_prof_stats    */
  /* API calls instead).                                                  */
  /* This getter remains lock-free (unsynchronized) for compatibility     */
  /* reason since some existing clients call it from a GC callback        */
  /* holding the allocator lock.  (This API function and the following    */
  /* four ones below were made thread-safe in GC v7.2alpha1 and           */
  /* reverted back in v7.2alpha7 for the reason described.)               */
  GC_API size_t GC_CALL GC_get_heap_size(void);
  
  /* Return a lower bound on the number of free bytes in the heap         */
  /* (excluding the unmapped memory space).  This is an unsynchronized    */
  /* getter (see GC_get_heap_size comment regarding thread-safety).       */
  GC_API size_t GC_CALL GC_get_free_bytes(void);
  
  /* Return the size (in bytes) of the unmapped memory (which is returned */
  /* to the OS but could be remapped back by the collector later unless   */
  /* the OS runs out of system/virtual memory). This is an unsynchronized */
  /* getter (see GC_get_heap_size comment regarding thread-safety).       */
  GC_API size_t GC_CALL GC_get_unmapped_bytes(void);
  
  /* Return the number of bytes allocated since the last collection.      */
  /* This is an unsynchronized getter (see GC_get_heap_size comment       */
  /* regarding thread-safety).                                            */
  GC_API size_t GC_CALL GC_get_bytes_since_gc(void);
  
  /* Return the number of explicitly deallocated bytes of memory since    */
  /* the recent collection.  This is an unsynchronized getter.            */
  GC_API size_t GC_CALL GC_get_expl_freed_bytes_since_gc(void);
  
  /* Return the total number of bytes allocated in this process.          */
  /* Never decreases, except due to wrapping.  This is an unsynchronized  */
  /* getter (see GC_get_heap_size comment regarding thread-safety).       */
  GC_API size_t GC_CALL GC_get_total_bytes(void);
  
  /* Return the total number of bytes obtained from OS.  Includes the     */
  /* unmapped memory.  Never decreases.  It is an unsynchronized getter.  */
  GC_API size_t GC_CALL GC_get_obtained_from_os_bytes(void);
  
  /* Return the heap usage information.  This is a thread-safe (atomic)   */
  /* alternative for the five above getters.   (This function acquires    */
  /* the allocator lock thus preventing data racing and returning the     */
  /* consistent result.)  Passing NULL pointer is allowed for any         */
  /* argument.  Returned (filled in) values are of word type.             */
  GC_API void GC_CALL GC_get_heap_usage_safe(GC_word * /* pheap_size */,
                                             GC_word * /* pfree_bytes */,
                                             GC_word * /* punmapped_bytes */,
                                             GC_word * /* pbytes_since_gc */,
                                             GC_word * /* ptotal_bytes */);
  
  /* Structure used to query GC statistics (profiling information).       */
  /* More fields could be added in the future.  To preserve compatibility */
  /* new fields should be added only to the end, and no deprecated fields */
  /* should be removed from.                                              */
  struct GC_prof_stats_s {
    GC_word heapsize_full;
              /* Heap size in bytes (including the area unmapped to OS).  */
              /* Same as GC_get_heap_size() + GC_get_unmapped_bytes().    */
    GC_word free_bytes_full;
              /* Total bytes contained in free and unmapped blocks.       */
              /* Same as GC_get_free_bytes() + GC_get_unmapped_bytes().   */
    GC_word unmapped_bytes;
              /* Amount of memory unmapped to OS.  Same as the value      */
              /* returned by GC_get_unmapped_bytes().                     */
    GC_word bytes_allocd_since_gc;
              /* Number of bytes allocated since the recent collection.   */
              /* Same as returned by GC_get_bytes_since_gc().             */
    GC_word allocd_bytes_before_gc;
              /* Number of bytes allocated before the recent garbage      */
              /* collection.  The value may wrap.  Same as the result of  */
              /* GC_get_total_bytes() - GC_get_bytes_since_gc().          */
    GC_word non_gc_bytes;
              /* Number of bytes not considered candidates for garbage    */
              /* collection.  Same as returned by GC_get_non_gc_bytes().  */
    GC_word gc_no;
              /* Garbage collection cycle number.  The value may wrap     */
              /* (and could be -1).  Same as returned by GC_get_gc_no().  */
    GC_word markers_m1;
              /* Number of marker threads (excluding the initiating one). */
              /* Same as returned by GC_get_parallel (or 0 if the         */
              /* collector is single-threaded).                           */
    GC_word bytes_reclaimed_since_gc;
              /* Approximate number of reclaimed bytes after recent GC.   */
    GC_word reclaimed_bytes_before_gc;
              /* Approximate number of bytes reclaimed before the recent  */
              /* garbage collection.  The value may wrap.                 */
    GC_word expl_freed_bytes_since_gc;
              /* Number of bytes freed explicitly since the recent GC.    */
              /* Same as returned by GC_get_expl_freed_bytes_since_gc().  */
    GC_word obtained_from_os_bytes;
              /* Total amount of memory obtained from OS, in bytes.       */
  };
  
  /* Atomically get GC statistics (various global counters).  Clients     */
  /* should pass the size of the buffer (of GC_prof_stats_s type) to fill */
  /* in the values - this is for interoperability between different GC    */
  /* versions, an old client could have fewer fields, and vice versa,     */
  /* client could use newer gc.h (with more entries declared in the       */
  /* structure) than that of the linked libgc binary; in the latter case, */
  /* unsupported (unknown) fields are filled in with -1.  Return the size */
  /* (in bytes) of the filled in part of the structure (excluding all     */
  /* unknown fields, if any).                                             */
  GC_API size_t GC_CALL GC_get_prof_stats(struct GC_prof_stats_s *,
                                          size_t /* stats_sz */);
  #ifdef GC_THREADS
    /* Same as above but unsynchronized (i.e., not holding the allocation */
    /* lock).  Clients should call it using GC_call_with_alloc_lock to    */
    /* avoid data races on multiprocessors.                               */
    GC_API size_t GC_CALL GC_get_prof_stats_unsafe(struct GC_prof_stats_s *,
                                                   size_t /* stats_sz */);
  #endif
  
  /* Get the element value (converted to bytes) at a given index of       */
  /* size_map table which provides requested-to-actual allocation size    */
  /* mapping.  Assumes the collector is initialized.  Returns -1 if the   */
  /* index is out of size_map table bounds. Does not use synchronization, */
  /* thus clients should call it using GC_call_with_alloc_lock typically  */
  /* to avoid data races on multiprocessors.                              */
  GC_API size_t GC_CALL GC_get_size_map_at(int i);
  
  /* Count total memory use in bytes by all allocated blocks.  Acquires   */
  /* the lock.                                                            */
  GC_API size_t GC_CALL GC_get_memory_use(void);
  
  /* Disable garbage collection.  Even GC_gcollect calls will be          */
  /* ineffective.                                                         */
  GC_API void GC_CALL GC_disable(void);
  
  /* Return non-zero (TRUE) if and only if garbage collection is disabled */
  /* (i.e., GC_dont_gc value is non-zero).  Does not acquire the lock.    */
  GC_API int GC_CALL GC_is_disabled(void);
  
  /* Try to re-enable garbage collection.  GC_disable() and GC_enable()   */
  /* calls nest.  Garbage collection is enabled if the number of calls to */
  /* both functions is equal.                                             */
  GC_API void GC_CALL GC_enable(void);
  
  /* Select whether to use the manual VDB mode for the incremental        */
  /* collection.  Has no effect if called after enabling the incremental  */
  /* collection.  The default value is off unless the collector is        */
  /* compiled with MANUAL_VDB defined.  The manual VDB mode should be     */
  /* used only if the client has the appropriate GC_END_STUBBORN_CHANGE   */
  /* and GC_reachable_here (or, alternatively, GC_PTR_STORE_AND_DIRTY)    */
  /* calls (to ensure proper write barriers).  Both the setter and getter */
  /* are not synchronized, and are defined only if the library has been   */
  /* compiled without SMALL_CONFIG.                                       */
  GC_API void GC_CALL GC_set_manual_vdb_allowed(int);
  GC_API int GC_CALL GC_get_manual_vdb_allowed(void);
  
  /* Enable incremental/generational collection.  Not advisable unless    */
  /* dirty bits are available or most heap objects are pointer-free       */
  /* (atomic) or immutable.  Don't use in leak finding mode.  Ignored if  */
  /* GC_dont_gc is non-zero.  Only the generational piece of this is      */
  /* functional if GC_time_limit is set to GC_TIME_UNLIMITED.  Causes     */
  /* thread-local variant of GC_gcj_malloc() to revert to locked          */
  /* allocation.  Must be called before any such GC_gcj_malloc() calls.   */
  /* For best performance, should be called as early as possible.         */
  /* On some platforms, calling it later may have adverse effects.        */
  /* Safe to call before GC_INIT().  Includes a  GC_init() call.          */
  GC_API void GC_CALL GC_enable_incremental(void);
  
  /* Return non-zero (TRUE) if and only if the incremental mode is on.    */
  /* Does not acquire the lock.                                           */
  GC_API int GC_CALL GC_is_incremental_mode(void);
  
  #define GC_PROTECTS_POINTER_HEAP  1 /* May protect non-atomic objects.  */
  #define GC_PROTECTS_PTRFREE_HEAP  2
  #define GC_PROTECTS_STATIC_DATA   4 /* Currently never.                 */
  #define GC_PROTECTS_STACK         8 /* Probably impractical.            */
  
  #define GC_PROTECTS_NONE 0
  
  /* Does incremental mode write-protect pages?  Returns zero or  */
  /* more of the above GC_PROTECTS_*, or'ed together.             */
  /* The collector is assumed to be initialized before this call. */
  /* The result is not affected by GC_set_manual_vdb_allowed().   */
  /* Call of GC_enable_incremental() may change the result to     */
  /* GC_PROTECTS_NONE if some implementation is chosen at runtime */
  /* not needing to write-protect the pages.                      */
  GC_API int GC_CALL GC_incremental_protection_needs(void);
  
  /* Force start of incremental collection.  Acquires the GC lock.        */
  /* No-op unless GC incremental mode is on.                              */
  GC_API void GC_CALL GC_start_incremental_collection(void);
  
  /* Perform some garbage collection work, if appropriate.        */
  /* Return 0 if there is no more work to be done (including the  */
  /* case when garbage collection is not appropriate).            */
  /* Typically performs an amount of work corresponding roughly   */
  /* to marking from one page.  May do more work if further       */
  /* progress requires it, e.g. if incremental collection is      */
  /* disabled.  It is reasonable to call this in a wait loop      */
  /* until it returns 0.                                          */
  GC_API int GC_CALL GC_collect_a_little(void);
  
  /* Allocate an object of size lb bytes.  The client guarantees that     */
  /* as long as the object is live, it will be referenced by a pointer    */
  /* that points to somewhere within the first 256 bytes of the object.   */
  /* (This should normally be declared volatile to prevent the compiler   */
  /* from invalidating this assertion.)  This routine is only useful      */
  /* if a large array is being allocated.  It reduces the chance of       */
  /* accidentally retaining such an array as a result of scanning an      */
  /* integer that happens to be an address inside the array.  (Actually,  */
  /* it reduces the chance of the allocator not finding space for such    */
  /* an array, since it will try hard to avoid introducing such a false   */
  /* reference.)  On a SunOS 4.X or MS Windows system this is recommended */
  /* for arrays likely to be larger than 100 KB or so.  For other systems,*/
  /* or if the collector is not configured to recognize all interior      */
  /* pointers, the threshold is normally much higher.                     */
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_malloc_ignore_off_page(size_t /* lb */);
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_malloc_atomic_ignore_off_page(size_t /* lb */);
  
  #ifdef GC_ADD_CALLER
  # define GC_EXTRAS GC_RETURN_ADDR, __FILE__, __LINE__
  # define GC_EXTRA_PARAMS GC_word ra, const char * s, int i
  #else
  # define GC_EXTRAS __FILE__, __LINE__
  # define GC_EXTRA_PARAMS const char * s, int i
  #endif
  
  /* The following is only defined if the library has been suitably       */
  /* compiled:                                                            */
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_malloc_atomic_uncollectable(size_t /* size_in_bytes */);
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_debug_malloc_atomic_uncollectable(size_t, GC_EXTRA_PARAMS);
  
  /* Debugging (annotated) allocation.  GC_gcollect will check            */
  /* objects allocated in this way for overwrites, etc.                   */
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_debug_malloc(size_t /* size_in_bytes */, GC_EXTRA_PARAMS);
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_debug_malloc_atomic(size_t /* size_in_bytes */, GC_EXTRA_PARAMS);
  GC_API GC_ATTR_MALLOC char * GC_CALL
          GC_debug_strdup(const char *, GC_EXTRA_PARAMS);
  GC_API GC_ATTR_MALLOC char * GC_CALL
          GC_debug_strndup(const char *, size_t, GC_EXTRA_PARAMS)
                                                          GC_ATTR_NONNULL(1);
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_debug_malloc_uncollectable(size_t /* size_in_bytes */,
                                        GC_EXTRA_PARAMS);
  GC_API GC_ATTR_DEPRECATED void * GC_CALL
          GC_debug_malloc_stubborn(size_t /* size_in_bytes */, GC_EXTRA_PARAMS);
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_debug_malloc_ignore_off_page(size_t /* size_in_bytes */,
                                          GC_EXTRA_PARAMS);
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_debug_malloc_atomic_ignore_off_page(size_t /* size_in_bytes */,
                                          GC_EXTRA_PARAMS);
  GC_API void GC_CALL GC_debug_free(void *);
  GC_API void * GC_CALL GC_debug_realloc(void * /* old_object */,
                          size_t /* new_size_in_bytes */, GC_EXTRA_PARAMS)
                          /* 'realloc' attr */ GC_ATTR_ALLOC_SIZE(2);
  GC_API GC_ATTR_DEPRECATED void GC_CALL GC_debug_change_stubborn(const void *);
  GC_API void GC_CALL GC_debug_end_stubborn_change(const void *)
                                                          GC_ATTR_NONNULL(1);
  
  /* Routines that allocate objects with debug information (like the      */
  /* above), but just fill in dummy file and line number information.     */
  /* Thus they can serve as drop-in malloc/realloc replacements.  This    */
  /* can be useful for two reasons:                                       */
  /* 1) It allows the collector to be built with DBG_HDRS_ALL defined     */
  /*    even if some allocation calls come from 3rd party libraries       */
  /*    that can't be recompiled.                                         */
  /* 2) On some platforms, the file and line information is redundant,    */
  /*    since it can be reconstructed from a stack trace.  On such        */
  /*    platforms it may be more convenient not to recompile, e.g. for    */
  /*    leak detection.  This can be accomplished by instructing the      */
  /*    linker to replace malloc/realloc with these.                      */
  GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
          GC_debug_malloc_replacement(size_t /* size_in_bytes */);
  GC_API /* 'realloc' attr */ GC_ATTR_ALLOC_SIZE(2) void * GC_CALL
          GC_debug_realloc_replacement(void * /* object_addr */,
                                       size_t /* size_in_bytes */);
  
  #ifdef GC_DEBUG_REPLACEMENT
  # define GC_MALLOC(sz) GC_debug_malloc_replacement(sz)
  # define GC_REALLOC(old, sz) GC_debug_realloc_replacement(old, sz)
  #elif defined(GC_DEBUG)
  # define GC_MALLOC(sz) GC_debug_malloc(sz, GC_EXTRAS)
  # define GC_REALLOC(old, sz) GC_debug_realloc(old, sz, GC_EXTRAS)
  #else
  # define GC_MALLOC(sz) GC_malloc(sz)
  # define GC_REALLOC(old, sz) GC_realloc(old, sz)
  #endif /* !GC_DEBUG_REPLACEMENT && !GC_DEBUG */
  
  #ifdef GC_DEBUG
  # define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, GC_EXTRAS)
  # define GC_STRDUP(s) GC_debug_strdup(s, GC_EXTRAS)
  # define GC_STRNDUP(s, sz) GC_debug_strndup(s, sz, GC_EXTRAS)
  # define GC_MALLOC_ATOMIC_UNCOLLECTABLE(sz) \
                          GC_debug_malloc_atomic_uncollectable(sz, GC_EXTRAS)
  # define GC_MALLOC_UNCOLLECTABLE(sz) \
                          GC_debug_malloc_uncollectable(sz, GC_EXTRAS)
  # define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
                          GC_debug_malloc_ignore_off_page(sz, GC_EXTRAS)
  # define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
                          GC_debug_malloc_atomic_ignore_off_page(sz, GC_EXTRAS)
  # define GC_FREE(p) GC_debug_free(p)
  # define GC_REGISTER_FINALIZER(p, f, d, of, od) \
        GC_debug_register_finalizer(p, f, d, of, od)
  # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
        GC_debug_register_finalizer_ignore_self(p, f, d, of, od)
  # define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
        GC_debug_register_finalizer_no_order(p, f, d, of, od)
  # define GC_REGISTER_FINALIZER_UNREACHABLE(p, f, d, of, od) \
        GC_debug_register_finalizer_unreachable(p, f, d, of, od)
  # define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p)
  # define GC_PTR_STORE_AND_DIRTY(p, q) GC_debug_ptr_store_and_dirty(p, q)
  # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
        GC_general_register_disappearing_link(link, \
                                          GC_base((/* no const */ void *)(obj)))
  # define GC_REGISTER_LONG_LINK(link, obj) \
        GC_register_long_link(link, GC_base((/* no const */ void *)(obj)))
  # define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n)
  #else
  # define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz)
  # define GC_STRDUP(s) GC_strdup(s)
  # define GC_STRNDUP(s, sz) GC_strndup(s, sz)
  # define GC_MALLOC_ATOMIC_UNCOLLECTABLE(sz) GC_malloc_atomic_uncollectable(sz)
  # define GC_MALLOC_UNCOLLECTABLE(sz) GC_malloc_uncollectable(sz)
  # define GC_MALLOC_IGNORE_OFF_PAGE(sz) \
                          GC_malloc_ignore_off_page(sz)
  # define GC_MALLOC_ATOMIC_IGNORE_OFF_PAGE(sz) \
                          GC_malloc_atomic_ignore_off_page(sz)
  # define GC_FREE(p) GC_free(p)
  # define GC_REGISTER_FINALIZER(p, f, d, of, od) \
        GC_register_finalizer(p, f, d, of, od)
  # define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
        GC_register_finalizer_ignore_self(p, f, d, of, od)
  # define GC_REGISTER_FINALIZER_NO_ORDER(p, f, d, of, od) \
        GC_register_finalizer_no_order(p, f, d, of, od)
  # define GC_REGISTER_FINALIZER_UNREACHABLE(p, f, d, of, od) \
        GC_register_finalizer_unreachable(p, f, d, of, od)
  # define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p)
  # define GC_PTR_STORE_AND_DIRTY(p, q) GC_ptr_store_and_dirty(p, q)
  # define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
        GC_general_register_disappearing_link(link, obj)
  # define GC_REGISTER_LONG_LINK(link, obj) \
        GC_register_long_link(link, obj)
  # define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n)
  #endif /* !GC_DEBUG */
  
  /* The following are included because they are often convenient, and    */
  /* reduce the chance for a misspecified size argument.  But calls may   */
  /* expand to something syntactically incorrect if t is a complicated    */
  /* type expression.  Note that, unlike C++ new operator, these ones     */
  /* may return NULL (if out of memory).                                  */
  #define GC_NEW(t)               ((t*)GC_MALLOC(sizeof(t)))
  #define GC_NEW_ATOMIC(t)        ((t*)GC_MALLOC_ATOMIC(sizeof(t)))
  #define GC_NEW_UNCOLLECTABLE(t) ((t*)GC_MALLOC_UNCOLLECTABLE(sizeof(t)))
  
  #ifdef GC_REQUIRE_WCSDUP
    /* This might be unavailable on some targets (or not needed). */
    /* wchar_t should be defined in stddef.h */
    GC_API GC_ATTR_MALLOC wchar_t * GC_CALL
          GC_wcsdup(const wchar_t *) GC_ATTR_NONNULL(1);
    GC_API GC_ATTR_MALLOC wchar_t * GC_CALL
          GC_debug_wcsdup(const wchar_t *, GC_EXTRA_PARAMS) GC_ATTR_NONNULL(1);
  # ifdef GC_DEBUG
  #   define GC_WCSDUP(s) GC_debug_wcsdup(s, GC_EXTRAS)
  # else
  #   define GC_WCSDUP(s) GC_wcsdup(s)
  # endif
  #endif /* GC_REQUIRE_WCSDUP */
  
  /* Finalization.  Some of these primitives are grossly unsafe.          */
  /* The idea is to make them both cheap, and sufficient to build         */
  /* a safer layer, closer to Modula-3, Java, or PCedar finalization.     */
  /* The interface represents my conclusions from a long discussion       */
  /* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes,              */
  /* Christian Jacobi, and Russ Atkinson.  It's not perfect, and          */
  /* probably nobody else agrees with it.     Hans-J. Boehm  3/13/92      */
  typedef void (GC_CALLBACK * GC_finalization_proc)(void * /* obj */,
                                                    void * /* client_data */);
  
  GC_API void GC_CALL GC_register_finalizer(void * /* obj */,
                          GC_finalization_proc /* fn */, void * /* cd */,
                          GC_finalization_proc * /* ofn */, void ** /* ocd */)
                                                  GC_ATTR_NONNULL(1);
  GC_API void GC_CALL GC_debug_register_finalizer(void * /* obj */,
                          GC_finalization_proc /* fn */, void * /* cd */,
                          GC_finalization_proc * /* ofn */, void ** /* ocd */)
                                                  GC_ATTR_NONNULL(1);
          /* When obj is no longer accessible, invoke             */
          /* (*fn)(obj, cd).  If a and b are inaccessible, and    */
          /* a points to b (after disappearing links have been    */
          /* made to disappear), then only a will be              */
          /* finalized.  (If this does not create any new         */
          /* pointers to b, then b will be finalized after the    */
          /* next collection.)  Any finalizable object that       */
          /* is reachable from itself by following one or more    */
          /* pointers will not be finalized (or collected).       */
          /* Thus cycles involving finalizable objects should     */
          /* be avoided, or broken by disappearing links.         */
          /* All but the last finalizer registered for an object  */
          /* is ignored.                                          */
          /* No-op in the leak-finding mode.                      */
          /* Finalization may be removed by passing 0 as fn.      */
          /* Finalizers are implicitly unregistered when they are */
          /* enqueued for finalization (i.e. become ready to be   */
          /* finalized).                                          */
          /* The old finalizer and client data are stored in      */
          /* *ofn and *ocd.  (ofn and/or ocd may be NULL.         */
          /* The allocation lock is held while *ofn and *ocd are  */
          /* updated.  In case of error (no memory to register    */
          /* new finalizer), *ofn and *ocd remain unchanged.)     */
          /* Fn is never invoked on an accessible object,         */
          /* provided hidden pointers are converted to real       */
          /* pointers only if the allocation lock is held, and    */
          /* such conversions are not performed by finalization   */
          /* routines.                                            */
          /* If GC_register_finalizer is aborted as a result of   */
          /* a signal, the object may be left with no             */
          /* finalization, even if neither the old nor new        */
          /* finalizer were NULL.                                 */
          /* Obj should be the starting address of an object      */
          /* allocated by GC_malloc or friends. Obj may also be   */
          /* NULL or point to something outside GC heap (in this  */
          /* case, fn is ignored, *ofn and *ocd are set to NULL). */
          /* Note that any garbage collectible object referenced  */
          /* by cd will be considered accessible until the        */
          /* finalizer is invoked.                                */
  
  /* Another versions of the above follow.  It ignores            */
  /* self-cycles, i.e. pointers from a finalizable object to      */
  /* itself.  There is a stylistic argument that this is wrong,   */
  /* but it's unavoidable for C++, since the compiler may         */
  /* silently introduce these.  It's also benign in that specific */
  /* case.  And it helps if finalizable objects are split to      */
  /* avoid cycles.                                                */
  /* Note that cd will still be viewed as accessible, even if it  */
  /* refers to the object itself.                                 */
  GC_API void GC_CALL GC_register_finalizer_ignore_self(void * /* obj */,
                          GC_finalization_proc /* fn */, void * /* cd */,
                          GC_finalization_proc * /* ofn */, void ** /* ocd */)
                                                  GC_ATTR_NONNULL(1);
  GC_API void GC_CALL GC_debug_register_finalizer_ignore_self(void * /* obj */,
                          GC_finalization_proc /* fn */, void * /* cd */,
                          GC_finalization_proc * /* ofn */, void ** /* ocd */)
                                                  GC_ATTR_NONNULL(1);
  
  /* Another version of the above.  It ignores all cycles.        */
  /* It should probably only be used by Java implementations.     */
  /* Note that cd will still be viewed as accessible, even if it  */
  /* refers to the object itself.                                 */
  GC_API void GC_CALL GC_register_finalizer_no_order(void * /* obj */,
                          GC_finalization_proc /* fn */, void * /* cd */,
                          GC_finalization_proc * /* ofn */, void ** /* ocd */)
                                                  GC_ATTR_NONNULL(1);
  GC_API void GC_CALL GC_debug_register_finalizer_no_order(void * /* obj */,
                          GC_finalization_proc /* fn */, void * /* cd */,
                          GC_finalization_proc * /* ofn */, void ** /* ocd */)
                                                  GC_ATTR_NONNULL(1);
  
  /* This is a special finalizer that is useful when an object's  */
  /* finalizer must be run when the object is known to be no      */
  /* longer reachable, not even from other finalizable objects.   */
  /* It behaves like "normal" finalization, except that the       */
  /* finalizer is not run while the object is reachable from      */
  /* other objects specifying unordered finalization.             */
  /* Effectively it allows an object referenced, possibly         */
  /* indirectly, from an unordered finalizable object to override */
  /* the unordered finalization request.                          */
  /* This can be used in combination with finalizer_no_order so   */
  /* as to release resources that must not be released while an   */
  /* object can still be brought back to life by other            */
  /* finalizers.                                                  */
  /* Only works if GC_java_finalization is set.  Probably only    */
  /* of interest when implementing a language that requires       */
  /* unordered finalization (e.g. Java, C#).                      */
  GC_API void GC_CALL GC_register_finalizer_unreachable(void * /* obj */,
                          GC_finalization_proc /* fn */, void * /* cd */,
                          GC_finalization_proc * /* ofn */, void ** /* ocd */)
                                                  GC_ATTR_NONNULL(1);
  GC_API void GC_CALL GC_debug_register_finalizer_unreachable(void * /* obj */,
                          GC_finalization_proc /* fn */, void * /* cd */,
                          GC_finalization_proc * /* ofn */, void ** /* ocd */)
                                                  GC_ATTR_NONNULL(1);
  
  #define GC_NO_MEMORY 2  /* Failure due to lack of memory.       */
  
  /* The following routine may be used to break cycles between    */
  /* finalizable objects, thus causing cyclic finalizable         */
  /* objects to be finalized in the correct order.  Standard      */
  /* use involves calling GC_register_disappearing_link(&p),      */
  /* where p is a pointer that is not followed by finalization    */
  /* code, and should not be considered in determining            */
  /* finalization order.                                          */
  GC_API int GC_CALL GC_register_disappearing_link(void ** /* link */)
                                                  GC_ATTR_NONNULL(1);
          /* Link should point to a field of a heap allocated     */
          /* object obj.  *link will be cleared when obj is       */
          /* found to be inaccessible.  This happens BEFORE any   */
          /* finalization code is invoked, and BEFORE any         */
          /* decisions about finalization order are made.         */
          /* This is useful in telling the finalizer that         */
          /* some pointers are not essential for proper           */
          /* finalization.  This may avoid finalization cycles.   */
          /* Note that obj may be resurrected by another          */
          /* finalizer, and thus the clearing of *link may        */
          /* be visible to non-finalization code.                 */
          /* There's an argument that an arbitrary action should  */
          /* be allowed here, instead of just clearing a pointer. */
          /* But this causes problems if that action alters, or   */
          /* examines connectivity.  Returns GC_DUPLICATE if link */
          /* was already registered, GC_SUCCESS if registration   */
          /* succeeded, GC_NO_MEMORY if it failed for lack of     */
          /* memory, and GC_oom_fn did not handle the problem.    */
          /* Only exists for backward compatibility.  See below:  */
  
  GC_API int GC_CALL GC_general_register_disappearing_link(void ** /* link */,
                                                      const void * /* obj */)
                          GC_ATTR_NONNULL(1) GC_ATTR_NONNULL(2);
          /* A slight generalization of the above. *link is       */
          /* cleared when obj first becomes inaccessible.  This   */
          /* can be used to implement weak pointers easily and    */
          /* safely. Typically link will point to a location      */
          /* holding a disguised pointer to obj.  (A pointer      */
          /* inside an "atomic" object is effectively disguised.) */
          /* In this way, weak pointers are broken before any     */
          /* object reachable from them gets finalized.           */
          /* Each link may be registered only with one obj value, */
          /* i.e. all objects but the last one (link registered   */
          /* with) are ignored.  This was added after a long      */
          /* email discussion with John Ellis.                    */
          /* link must be non-NULL (and be properly aligned).     */
          /* obj must be a pointer to the first word of an object */
          /* allocated by GC_malloc or friends.   A link          */
          /* disappears when it is unregistered manually, or when */
          /* (*link) is cleared, or when the object containing    */
          /* this link is garbage collected.  It is unsafe to     */
          /* explicitly deallocate the object containing link.    */
          /* Explicit deallocation of obj may or may not cause    */
          /* link to eventually be cleared.                       */
          /* No-op in the leak-finding mode.                      */
          /* This function can be used to implement certain types */
          /* of weak pointers.  Note, however, this generally     */
          /* requires that the allocation lock is held (see       */
          /* GC_call_with_alloc_lock() below) when the disguised  */
          /* pointer is accessed.  Otherwise a strong pointer     */
          /* could be recreated between the time the collector    */
          /* decides to reclaim the object and the link is        */
          /* cleared.  Returns GC_SUCCESS if registration         */
          /* succeeded (a new link is registered), GC_DUPLICATE   */
          /* if link was already registered (with some object),   */
          /* GC_NO_MEMORY if registration failed for lack of      */
          /* memory (and GC_oom_fn did not handle the problem),   */
          /* GC_UNIMPLEMENTED if GC_find_leak is true.            */
  
  GC_API int GC_CALL GC_move_disappearing_link(void ** /* link */,
                                               void ** /* new_link */)
                          GC_ATTR_NONNULL(2);
          /* Moves a link previously registered via               */
          /* GC_general_register_disappearing_link (or            */
          /* GC_register_disappearing_link).  Does not change the */
          /* target object of the weak reference.  Does not       */
          /* change (*new_link) content.  May be called with      */
          /* new_link equal to link (to check whether link has    */
          /* been registered).  Returns GC_SUCCESS on success,    */
          /* GC_DUPLICATE if there is already another             */
          /* disappearing link at the new location (never         */
          /* returned if new_link is equal to link), GC_NOT_FOUND */
          /* if no link is registered at the original location.   */
  
  GC_API int GC_CALL GC_unregister_disappearing_link(void ** /* link */);
          /* Undoes a registration by either of the above two     */
          /* routines.  Returns 0 if link was not actually        */
          /* registered (otherwise returns 1).                    */
  
  GC_API int GC_CALL GC_register_long_link(void ** /* link */,
                                      const void * /* obj */)
                          GC_ATTR_NONNULL(1) GC_ATTR_NONNULL(2);
          /* Similar to GC_general_register_disappearing_link but */
          /* *link only gets cleared when obj becomes truly       */
          /* inaccessible.  An object becomes truly inaccessible  */
          /* when it can no longer be resurrected from its        */
          /* finalizer (e.g. by assigning itself to a pointer     */
          /* traceable from root).  This can be used to implement */
          /* long weak pointers easily and safely.                */
  
  GC_API int GC_CALL GC_move_long_link(void ** /* link */,
                                       void ** /* new_link */)
                          GC_ATTR_NONNULL(2);
          /* Similar to GC_move_disappearing_link but for a link  */
          /* previously registered via GC_register_long_link.     */
  
  GC_API int GC_CALL GC_unregister_long_link(void ** /* link */);
          /* Similar to GC_unregister_disappearing_link but for a */
          /* registration by either of the above two routines.    */
  
  /* Support of toggle-ref style of external memory management    */
  /* without hooking up to the host retain/release machinery.     */
  /* The idea of toggle-ref is that an external reference to      */
  /* an object is kept and it can be either a strong or weak      */
  /* reference; a weak reference is used when the external peer   */
  /* has no interest in the object, and a strong otherwise.       */
  typedef enum {
     GC_TOGGLE_REF_DROP,
     GC_TOGGLE_REF_STRONG,
     GC_TOGGLE_REF_WEAK
  } GC_ToggleRefStatus;
  
  /* The callback is to decide (return) the new state of a given  */
  /* object.  Invoked by the collector for all objects registered */
  /* for toggle-ref processing.  Invoked with the allocation lock */
  /* held (but the "world" is running).                           */
  typedef GC_ToggleRefStatus (GC_CALLBACK *GC_toggleref_func)(void * /* obj */);
  
  /* Set (register) a callback that decides the state of a given  */
  /* object (by, probably, inspecting its native state).          */
  /* The argument may be 0 (means no callback).  Both the setter  */
  /* and the getter acquire the allocation lock (to avoid data    */
  /* races).                                                      */
  GC_API void GC_CALL GC_set_toggleref_func(GC_toggleref_func);
  GC_API GC_toggleref_func GC_CALL GC_get_toggleref_func(void);
  
  /* Register a given object for toggle-ref processing.  It will  */
  /* be stored internally and the toggle-ref callback will be     */
  /* invoked on the object until the callback returns             */
  /* GC_TOGGLE_REF_DROP or the object is collected.  If is_strong */
  /* is true then the object is registered with a strong ref,     */
  /* a weak one otherwise.  Returns GC_SUCCESS if registration    */
  /* succeeded (or no callback registered yet), GC_NO_MEMORY if   */
  /* it failed for lack of memory.                                */
  GC_API int GC_CALL GC_toggleref_add(void * /* obj */, int /* is_strong */)
                                                  GC_ATTR_NONNULL(1);
  
  /* Finalizer callback support.  Invoked by the collector (with  */
  /* the allocation lock held) for each unreachable object        */
  /* enqueued for finalization.                                   */
  typedef void (GC_CALLBACK * GC_await_finalize_proc)(void * /* obj */);
  GC_API void GC_CALL GC_set_await_finalize_proc(GC_await_finalize_proc);
  GC_API GC_await_finalize_proc GC_CALL GC_get_await_finalize_proc(void);
                          /* Zero means no callback.  The setter  */
                          /* and getter acquire the lock too.     */
  
  /* Returns !=0 if GC_invoke_finalizers has something to do.     */
  /* Does not use any synchronization.                            */
  GC_API int GC_CALL GC_should_invoke_finalizers(void);
  
  GC_API int GC_CALL GC_invoke_finalizers(void);
          /* Run finalizers for all objects that are ready to     */
          /* be finalized.  Return the number of finalizers       */
          /* that were run.  Normally this is also called         */
          /* implicitly during some allocations.  If              */
          /* GC_finalize_on_demand is nonzero, it must be called  */
          /* explicitly.                                          */
  
  /* Explicitly tell the collector that an object is reachable    */
  /* at a particular program point.  This prevents the argument   */
  /* pointer from being optimized away, even it is otherwise no   */
  /* longer needed.  It should have no visible effect in the      */
  /* absence of finalizers or disappearing links.  But it may be  */
  /* needed to prevent finalizers from running while the          */
  /* associated external resource is still in use.                */
  /* The function is sometimes called keep_alive in other         */
  /* settings.                                                    */
  #if defined(__GNUC__) && !defined(__INTEL_COMPILER)
  # if defined(__e2k__)
  #   define GC_reachable_here(ptr) \
                  __asm__ __volatile__ (" " : : "r"(ptr) : "memory")
  # else
  #   define GC_reachable_here(ptr) \
                  __asm__ __volatile__ (" " : : "X"(ptr) : "memory")
  # endif
  #else
    GC_API void GC_CALL GC_noop1(GC_word);
  # ifdef LINT2
  #   define GC_reachable_here(ptr) GC_noop1(~(GC_word)(ptr)^(~(GC_word)0))
                  /* The expression matches the one of COVERT_DATAFLOW(). */
  # else
  #   define GC_reachable_here(ptr) GC_noop1((GC_word)(ptr))
  # endif
  #endif
  
  /* GC_set_warn_proc can be used to redirect or filter warning messages. */
  /* p may not be a NULL pointer.  msg is printf format string (arg must  */
  /* match the format).  Both the setter and the getter acquire the GC    */
  /* lock (to avoid data races).  In GC v7.1 (and before), the setter     */
  /* returned the old warn_proc value.                                    */
  typedef void (GC_CALLBACK * GC_warn_proc)(char * /* msg */,
                                            GC_word /* arg */);
  GC_API void GC_CALL GC_set_warn_proc(GC_warn_proc /* p */) GC_ATTR_NONNULL(1);
  /* GC_get_warn_proc returns the current warn_proc.                      */
  GC_API GC_warn_proc GC_CALL GC_get_warn_proc(void);
  
  /* GC_ignore_warn_proc may be used as an argument for GC_set_warn_proc  */
  /* to suppress all warnings (unless statistics printing is turned on).  */
  GC_API void GC_CALLBACK GC_ignore_warn_proc(char *, GC_word);
  
  /* Change file descriptor of GC log.  Unavailable on some targets.      */
  GC_API void GC_CALL GC_set_log_fd(int);
  
  /* abort_func is invoked on GC fatal aborts (just before OS-dependent   */
  /* abort or exit(1) is called).  Must be non-NULL.  The default one     */
  /* outputs msg to stderr provided msg is non-NULL.  msg is NULL if      */
  /* invoked before exit(1) otherwise msg is non-NULL (i.e., if invoked   */
  /* before abort).  Both the setter and getter acquire the GC lock.      */
  /* Both the setter and getter are defined only if the library has been  */
  /* compiled without SMALL_CONFIG.                                       */
  typedef void (GC_CALLBACK * GC_abort_func)(const char * /* msg */);
  GC_API void GC_CALL GC_set_abort_func(GC_abort_func) GC_ATTR_NONNULL(1);
  GC_API GC_abort_func GC_CALL GC_get_abort_func(void);
  
  /* A portable way to abort the application because of not enough memory.*/
  GC_API void GC_CALL GC_abort_on_oom(void);
  
  /* The following is intended to be used by a higher level       */
  /* (e.g. Java-like) finalization facility.  It is expected      */
  /* that finalization code will arrange for hidden pointers to   */
  /* disappear.  Otherwise objects can be accessed after they     */
  /* have been collected.                                         */
  /* Should not be used in the leak-finding mode.                 */
  /* Note that putting pointers in atomic objects or in           */
  /* non-pointer slots of "typed" objects is equivalent to        */
  /* disguising them in this way, and may have other advantages.  */
  typedef GC_word GC_hidden_pointer;
  #define GC_HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
  /* Converting a hidden pointer to a real pointer requires verifying     */
  /* that the object still exists.  This involves acquiring the           */
  /* allocator lock to avoid a race with the collector.                   */
  #define GC_REVEAL_POINTER(p) ((void *)GC_HIDE_POINTER(p))
  
  #if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS)
    /* This exists only for compatibility (the GC-prefixed symbols are    */
    /* preferred for new code).                                           */
  # define HIDE_POINTER(p) GC_HIDE_POINTER(p)
  # define REVEAL_POINTER(p) GC_REVEAL_POINTER(p)
  #endif
  
  /* The routines to acquire/release the allocator lock.                  */
  /* The lock is not reentrant.  GC_alloc_unlock() should not be called   */
  /* unless the lock is acquired by the current thread.                   */
  #ifdef GC_THREADS
    GC_API void GC_CALL GC_alloc_lock(void);
    GC_API void GC_CALL GC_alloc_unlock(void);
  #else
    /* No need for real locking if the client is single-threaded.         */
  # define GC_alloc_lock() (void)0
  # define GC_alloc_unlock() (void)0
  #endif /* !GC_THREADS */
  
  typedef void * (GC_CALLBACK * GC_fn_type)(void * /* client_data */);
  GC_API void * GC_CALL GC_call_with_alloc_lock(GC_fn_type /* fn */,
                                  void * /* client_data */) GC_ATTR_NONNULL(1);
  
  /* These routines are intended to explicitly notify the collector       */
  /* of new threads.  Often this is unnecessary because thread creation   */
  /* is implicitly intercepted by the collector, using header-file        */
  /* defines, or linker-based interception.  In the long run the intent   */
  /* is to always make redundant registration safe.  In the short run,    */
  /* this is being implemented a platform at a time.                      */
  /* The interface is complicated by the fact that we probably will not   */
  /* ever be able to automatically determine the stack bottom for thread  */
  /* stacks on all platforms.                                             */
  
  /* Structure representing the bottom (cold end) of a thread stack.      */
  /* On most platforms this contains just a single address.               */
  struct GC_stack_base {
    void * mem_base;      /* the bottom of the general-purpose stack */
  # if defined(__e2k__) \
       || defined(__ia64) || defined(__ia64__) || defined(_M_IA64)
      void * reg_base;    /* the bottom of the register stack */
  # endif
  };
  
  typedef void * (GC_CALLBACK * GC_stack_base_func)(
                  struct GC_stack_base * /* sb */, void * /* arg */);
  
  /* Call a function with a stack base structure corresponding to         */
  /* somewhere in the GC_call_with_stack_base frame.  This often can      */
  /* be used to provide a sufficiently accurate stack bottom.  And we     */
  /* implement it everywhere.                                             */
  GC_API void * GC_CALL GC_call_with_stack_base(GC_stack_base_func /* fn */,
                                          void * /* arg */) GC_ATTR_NONNULL(1);
  
  #define GC_SUCCESS 0
  #define GC_DUPLICATE 1          /* Was already registered.              */
  #define GC_NO_THREADS 2         /* No thread support in GC.             */
          /* GC_NO_THREADS is not returned by any GC function anymore.    */
  #define GC_UNIMPLEMENTED 3 /* Not yet implemented on this platform.     */
  #define GC_NOT_FOUND 4          /* Requested link not found (returned   */
                                  /* by GC_move_disappearing_link).       */
  
  #if defined(GC_DARWIN_THREADS) || defined(GC_WIN32_THREADS)
    /* Use implicit thread registration and processing (via Win32 DllMain */
    /* or Darwin task_threads).  Deprecated.  Must be called before       */
    /* GC_INIT() and other GC routines.  Should be avoided if             */
    /* GC_pthread_create, GC_beginthreadex (or GC_CreateThread) could be  */
    /* called instead.  Disables parallelized GC on Win32.                */
    GC_API void GC_CALL GC_use_threads_discovery(void);
  #endif
  
  #ifdef GC_THREADS
    /* Suggest the GC to use the specific signal to suspend threads.      */
    /* Has no effect after GC_init and on non-POSIX systems.              */
    GC_API void GC_CALL GC_set_suspend_signal(int);
  
    /* Suggest the GC to use the specific signal to resume threads.       */
    /* Has no effect after GC_init and on non-POSIX systems.              */
    GC_API void GC_CALL GC_set_thr_restart_signal(int);
  
    /* Return the signal number (constant after initialization) used by   */
    /* the GC to suspend threads on POSIX systems.  Return -1 otherwise.  */
    GC_API int GC_CALL GC_get_suspend_signal(void);
  
    /* Return the signal number (constant after initialization) used by   */
    /* the garbage collector to restart (resume) threads on POSIX         */
    /* systems.  Return -1 otherwise.                                     */
    GC_API int GC_CALL GC_get_thr_restart_signal(void);
  
    /* Restart marker threads after POSIX fork in child.  Meaningless in  */
    /* other situations.  Should not be called if fork followed by exec.  */
    GC_API void GC_CALL GC_start_mark_threads(void);
  
    /* Explicitly enable GC_register_my_thread() invocation.              */
    /* Done implicitly if a GC thread-creation function is called (or     */
    /* implicit thread registration is activated, or the collector is     */
    /* compiled with GC_ALWAYS_MULTITHREADED defined).  Otherwise, it     */
    /* must be called from the main (or any previously registered) thread */
    /* between the collector initialization and the first explicit        */
    /* registering of a thread (it should be called as late as possible). */
    GC_API void GC_CALL GC_allow_register_threads(void);
  
    /* Register the current thread, with the indicated stack bottom, as   */
    /* a new thread whose stack(s) should be traced by the GC.  If it     */
    /* is not implicitly called by the GC, this must be called before a   */
    /* thread can allocate garbage collected memory, or assign pointers   */
    /* to the garbage collected heap.  Once registered, a thread will be  */
    /* stopped during garbage collections.                                */
    /* This call must be previously enabled (see above).                  */
    /* This should never be called from the main thread, where it is      */
    /* always done implicitly.  This is normally done implicitly if GC_   */
    /* functions are called to create the thread, e.g. by including gc.h  */
    /* (which redefines some system functions) before calling the system  */
    /* thread creation function.  Nonetheless, thread cleanup routines    */
    /* (e.g., pthread key destructor) typically require manual thread     */
    /* registering (and unregistering) if pointers to GC-allocated        */
    /* objects are manipulated inside.                                    */
    /* It is also always done implicitly on some platforms if             */
    /* GC_use_threads_discovery() is called at start-up.  Except for the  */
    /* latter case, the explicit call is normally required for threads    */
    /* created by third-party libraries.                                  */
    /* A manually registered thread requires manual unregistering.        */
    /* Returns GC_SUCCESS on success, GC_DUPLICATE if already registered. */
    GC_API int GC_CALL GC_register_my_thread(const struct GC_stack_base *)
                                                          GC_ATTR_NONNULL(1);
  
    /* Return non-zero (TRUE) if and only if the calling thread is        */
    /* registered with the garbage collector.                             */
    GC_API int GC_CALL GC_thread_is_registered(void);
  
    /* Notify the collector about the stack and the alt-stack of the      */
    /* current thread.  stack_start/size is used to determine the stack   */
    /* boundaries when a thread is suspended while it is on an alt-stack. */
    GC_API void GC_CALL GC_register_altstack(void * /* stack_start */,
                                             GC_word /* stack_size */,
                                             void * /* altstack_base */,
                                             GC_word /* altstack_size */);
  
    /* Unregister the current thread.  Only an explicitly registered      */
    /* thread (i.e. for which GC_register_my_thread() returns GC_SUCCESS) */
    /* is allowed (and required) to call this function.  (As a special    */
    /* exception, it is also allowed to once unregister the main thread.) */
    /* The thread may no longer allocate garbage collected memory or      */
    /* manipulate pointers to the garbage collected heap after making     */
    /* this call.  Specifically, if it wants to return or otherwise       */
    /* communicate a pointer to the garbage-collected heap to another     */
    /* thread, it must do this before calling GC_unregister_my_thread,    */
    /* most probably by saving it in a global data structure.  Must not   */
    /* be called inside a GC callback function (except for                */
    /* GC_call_with_stack_base() one).                                    */
    GC_API int GC_CALL GC_unregister_my_thread(void);
  
    /* Stop/start the world explicitly.  Not recommended for general use. */
    GC_API void GC_CALL GC_stop_world_external(void);
    GC_API void GC_CALL GC_start_world_external(void);
  #endif /* GC_THREADS */
  
  /* Wrapper for functions that are likely to block (or, at least, do not */
  /* allocate garbage collected memory and/or manipulate pointers to the  */
  /* garbage collected heap) for an appreciable length of time.  While fn */
  /* is running, the collector is said to be in the "inactive" state for  */
  /* the current thread (this means that the thread is not suspended and  */
  /* the thread's stack frames "belonging" to the functions in the        */
  /* "inactive" state are not scanned during garbage collections).  It is */
  /* assumed that the collector is already initialized and the current    */
  /* thread is registered.  It is allowed for fn to call                  */
  /* GC_call_with_gc_active() (even recursively), thus temporarily        */
  /* toggling the collector's state back to "active".  The latter         */
  /* technique might be used to make stack scanning more precise (i.e.    */
  /* scan only stack frames of functions that allocate garbage collected  */
  /* memory and/or manipulate pointers to the garbage collected heap).    */
  GC_API void * GC_CALL GC_do_blocking(GC_fn_type /* fn */,
                                  void * /* client_data */) GC_ATTR_NONNULL(1);
  
  /* Call a function switching to the "active" state of the collector for */
  /* the current thread (i.e. the user function is allowed to call any    */
  /* GC function and/or manipulate pointers to the garbage collected      */
  /* heap).  GC_call_with_gc_active() has the functionality opposite to   */
  /* GC_do_blocking() one.  It is assumed that the collector is already   */
  /* initialized and the current thread is registered.  fn may toggle     */
  /* the collector thread's state temporarily to "inactive" one by using  */
  /* GC_do_blocking.  GC_call_with_gc_active() often can be used to       */
  /* provide a sufficiently accurate stack bottom.                        */
  GC_API void * GC_CALL GC_call_with_gc_active(GC_fn_type /* fn */,
                                  void * /* client_data */) GC_ATTR_NONNULL(1);
  
  /* Attempt to fill in the GC_stack_base structure with the stack bottom */
  /* for this thread.  This appears to be required to implement anything  */
  /* like the JNI AttachCurrentThread in an environment in which new      */
  /* threads are not automatically registered with the collector.         */
  /* It is also unfortunately hard to implement well on many platforms.   */
  /* Returns GC_SUCCESS or GC_UNIMPLEMENTED.  This function acquires the  */
  /* GC lock on some platforms.                                           */
  GC_API int GC_CALL GC_get_stack_base(struct GC_stack_base *)
                                                          GC_ATTR_NONNULL(1);
  
  /* Fill in the GC_stack_base structure with the cold end (bottom) of    */
  /* the stack of the current thread (or coroutine).                      */
  /* Unlike GC_get_stack_base, it retrieves the value stored in the       */
  /* collector (which is initially set by the collector upon the thread   */
  /* is started or registered manually but it could be later updated by   */
  /* client using GC_set_stackbottom).  Returns the GC-internal non-NULL  */
  /* handle of the thread which could be passed to GC_set_stackbottom     */
  /* later.  It is assumed that the collector is already initialized and  */
  /* the thread is registered.  Acquires the GC lock to avoid data races. */
  GC_API void * GC_CALL GC_get_my_stackbottom(struct GC_stack_base *)
                                                          GC_ATTR_NONNULL(1);
  
  /* Set the cool end of the user (coroutine) stack of the specified      */
  /* thread.  The GC thread handle is either the one returned by          */
  /* GC_get_my_stackbottom or NULL (the latter designates the current     */
  /* thread).  The caller should hold the GC lock (e.g. using             */
  /* GC_call_with_alloc_lock).  Also, the function could be used for      */
  /* setting GC_stackbottom value (the bottom of the primordial thread)   */
  /* before the collector is initialized (the GC lock is not needed to be */
  /* acquired in this case).                                              */
  GC_API void GC_CALL GC_set_stackbottom(void * /* gc_thread_handle */,
                                         const struct GC_stack_base *)
                                                          GC_ATTR_NONNULL(2);
  
  /* The following routines are primarily intended for use with a         */
  /* preprocessor which inserts calls to check C pointer arithmetic.      */
  /* They indicate failure by invoking the corresponding _print_proc.     */
  
  /* Check that p and q point to the same object.                 */
  /* Fail conspicuously if they don't.                            */
  /* Returns the first argument.                                  */
  /* Succeeds if neither p nor q points to the heap.              */
  /* May succeed if both p and q point to between heap objects.   */
  GC_API void * GC_CALL GC_same_obj(void * /* p */, void * /* q */);
  
  /* Checked pointer pre- and post- increment operations.  Note that      */
  /* the second argument is in units of bytes, not multiples of the       */
  /* object size.  This should either be invoked from a macro, or the     */
  /* call should be automatically generated.                              */
  GC_API void * GC_CALL GC_pre_incr(void **, ptrdiff_t /* how_much */)
                                                          GC_ATTR_NONNULL(1);
  GC_API void * GC_CALL GC_post_incr(void **, ptrdiff_t /* how_much */)
                                                          GC_ATTR_NONNULL(1);
  
  /* Check that p is visible                                              */
  /* to the collector as a possibly pointer containing location.          */
  /* If it isn't fail conspicuously.                                      */
  /* Returns the argument in all cases.  May erroneously succeed          */
  /* in hard cases.  (This is intended for debugging use with             */
  /* untyped allocations.  The idea is that it should be possible, though */
  /* slow, to add such a call to all indirect pointer stores.)            */
  /* Currently useless for multi-threaded worlds.                         */
  GC_API void * GC_CALL GC_is_visible(void * /* p */);
  
  /* Check that if p is a pointer to a heap page, then it points to       */
  /* a valid displacement within a heap object.                           */
  /* Fail conspicuously if this property does not hold.                   */
  /* Uninteresting with GC_all_interior_pointers.                         */
  /* Always returns its argument.                                         */
  GC_API void * GC_CALL GC_is_valid_displacement(void * /* p */);
  
  /* Explicitly dump the GC state.  This is most often called from the    */
  /* debugger, or by setting the GC_DUMP_REGULARLY environment variable,  */
  /* but it may be useful to call it from client code during debugging.   */
  /* The current collection number is printed in the header of the dump.  */
  /* Acquires the GC lock to avoid data races.                            */
  /* Defined only if the library has been compiled without NO_DEBUGGING.  */
  GC_API void GC_CALL GC_dump(void);
  
  /* The same as GC_dump but allows to specify the name of dump and does  */
  /* not acquire the lock.  If name is non-NULL, it is printed to help    */
  /* identifying individual dumps.  Otherwise the current collection      */
  /* number is used as the name.                                          */
  /* Defined only if the library has been compiled without NO_DEBUGGING.  */
  GC_API void GC_CALL GC_dump_named(const char * /* name */);
  
  /* Dump information about each block of every GC memory section.        */
  /* Defined only if the library has been compiled without NO_DEBUGGING.  */
  GC_API void GC_CALL GC_dump_regions(void);
  
  /* Dump information about every registered disappearing link and        */
  /* finalizable object.                                                  */
  /* Defined only if the library has been compiled without NO_DEBUGGING.  */
  GC_API void GC_CALL GC_dump_finalization(void);
  
  /* Safer, but slow, pointer addition.  Probably useful mainly with      */
  /* a preprocessor.  Useful only for heap pointers.                      */
  /* Only the macros without trailing digits are meant to be used         */
  /* by clients.  These are designed to model the available C pointer     */
  /* arithmetic expressions.                                              */
  /* Even then, these are probably more useful as                         */
  /* documentation than as part of the API.                               */
  /* Note that GC_PTR_ADD evaluates the first argument more than once.    */
  #if defined(GC_DEBUG) && defined(__GNUC__)
  # define GC_PTR_ADD3(x, n, type_of_result) \
          ((type_of_result)GC_same_obj((x)+(n), (x)))
  # define GC_PRE_INCR3(x, n, type_of_result) \
          ((type_of_result)GC_pre_incr((void **)(&(x)), (n)*sizeof(*x)))
  # define GC_POST_INCR3(x, n, type_of_result) \
          ((type_of_result)GC_post_incr((void **)(&(x)), (n)*sizeof(*x)))
  # define GC_PTR_ADD(x, n) GC_PTR_ADD3(x, n, __typeof__(x))
  # define GC_PRE_INCR(x, n) GC_PRE_INCR3(x, n, __typeof__(x))
  # define GC_POST_INCR(x) GC_POST_INCR3(x, 1, __typeof__(x))
  # define GC_POST_DECR(x) GC_POST_INCR3(x, -1, __typeof__(x))
  #else /* !GC_DEBUG || !__GNUC__ */
    /* We can't do this right without typeof, which ANSI decided was not    */
    /* sufficiently useful.  Without it we resort to the non-debug version. */
    /* TODO: This should eventually support C++0x decltype. */
  # define GC_PTR_ADD(x, n) ((x)+(n))
  # define GC_PRE_INCR(x, n) ((x) += (n))
  # define GC_POST_INCR(x) ((x)++)
  # define GC_POST_DECR(x) ((x)--)
  #endif /* !GC_DEBUG || !__GNUC__ */
  
  /* Safer assignment of a pointer to a non-stack location.       */
  #ifdef GC_DEBUG
  # define GC_PTR_STORE(p, q) \
          (*(void **)GC_is_visible((void *)(p)) = \
                      GC_is_valid_displacement((void *)(q)))
  #else
  # define GC_PTR_STORE(p, q) (*(void **)(p) = (void *)(q))
  #endif
  
  /* GC_PTR_STORE_AND_DIRTY(p,q) is equivalent to GC_PTR_STORE(p,q)       */
  /* followed by GC_END_STUBBORN_CHANGE(p) and GC_reachable_here(q)       */
  /* (assuming p and q do not have side effects).                         */
  GC_API void GC_CALL GC_ptr_store_and_dirty(void * /* p */,
                                             const void * /* q */);
  GC_API void GC_CALL GC_debug_ptr_store_and_dirty(void * /* p */,
                                                   const void * /* q */);
  
  /* Functions called to report pointer checking errors */
  GC_API void (GC_CALLBACK * GC_same_obj_print_proc)(void * /* p */,
                                                     void * /* q */);
  GC_API void (GC_CALLBACK * GC_is_valid_displacement_print_proc)(void *);
  GC_API void (GC_CALLBACK * GC_is_visible_print_proc)(void *);
  
  #ifdef GC_PTHREADS
    /* For pthread support, we generally need to intercept a number of    */
    /* thread library calls.  We do that here by macro defining them.     */
  # ifdef __cplusplus
      } /* extern "C" */
  # endif
  # include "gc_pthread_redirects.h"
  # ifdef __cplusplus
      extern "C" {
  # endif
  #endif
  
  /* This returns a list of objects, linked through their first word.     */
  /* Its use can greatly reduce lock contention problems, since the       */
  /* allocation lock can be acquired and released many fewer times.       */
  GC_API GC_ATTR_MALLOC void * GC_CALL GC_malloc_many(size_t /* lb */);
  #define GC_NEXT(p) (*(void * *)(p))     /* Retrieve the next element    */
                                          /* in returned list.            */
  
  /* A filter function to control the scanning of dynamic libraries.      */
  /* If implemented, called by GC before registering a dynamic library    */
  /* (discovered by GC) section as a static data root (called only as     */
  /* a last reason not to register).  The filename of the library, the    */
  /* address and the length of the memory region (section) are passed.    */
  /* This routine should return nonzero if that region should be scanned. */
  /* Always called with the allocation lock held.  Depending on the       */
  /* platform, might be called with the "world" stopped.                  */
  typedef int (GC_CALLBACK * GC_has_static_roots_func)(
                                          const char * /* dlpi_name */,
                                          void * /* section_start */,
                                          size_t /* section_size */);
  
  /* Register a new callback (a user-supplied filter) to control the      */
  /* scanning of dynamic libraries.  Replaces any previously registered   */
  /* callback.  May be 0 (means no filtering).  May be unused on some     */
  /* platforms (if the filtering is unimplemented or inappropriate).      */
  GC_API void GC_CALL GC_register_has_static_roots_callback(
                                          GC_has_static_roots_func);
  
  #if !defined(CPPCHECK) && !defined(GC_WINDOWS_H_INCLUDED) && defined(WINAPI)
    /* windows.h is included before gc.h */
  # define GC_WINDOWS_H_INCLUDED
  #endif
  
  #if defined(GC_WIN32_THREADS) \
      && (!defined(GC_PTHREADS) || defined(GC_BUILD) \
          || defined(GC_WINDOWS_H_INCLUDED))
                  /* Note: for Cygwin and pthreads-win32, this is skipped */
                  /* unless windows.h is included before gc.h.            */
  
  # if (!defined(GC_NO_THREAD_DECLS) || defined(GC_BUILD)) \
       && !defined(GC_DONT_INCL_WINDOWS_H)
  
  #   ifdef __cplusplus
        } /* Including windows.h in an extern "C" context no longer works. */
  #   endif
  
  #   if !defined(_WIN32_WCE) && !defined(__CEGCC__)
  #     include <process.h> /* For _beginthreadex, _endthreadex */
  #   endif
  
  #   if defined(GC_BUILD) || !defined(GC_DONT_INCLUDE_WINDOWS_H)
  #     include <windows.h>
  #     define GC_WINDOWS_H_INCLUDED
  #   endif
  
  #   ifdef __cplusplus
        extern "C" {
  #   endif
  
  #   ifdef GC_UNDERSCORE_STDCALL
        /* Explicitly prefix exported/imported WINAPI (__stdcall) symbols */
        /* with '_' (underscore).  Might be useful if MinGW/x86 is used.  */
  #     define GC_CreateThread _GC_CreateThread
  #     define GC_ExitThread _GC_ExitThread
  #   endif
  
  #   ifndef DECLSPEC_NORETURN
        /* Typically defined in winnt.h. */
  #     ifdef GC_WINDOWS_H_INCLUDED
  #       define DECLSPEC_NORETURN /* empty */
  #     else
  #       define DECLSPEC_NORETURN __declspec(noreturn)
  #     endif
  #   endif
  
  #   if !defined(_UINTPTR_T) && !defined(_UINTPTR_T_DEFINED) \
         && !defined(UINTPTR_MAX)
        typedef GC_word GC_uintptr_t;
  #   else
        typedef uintptr_t GC_uintptr_t;
  #   endif
  
  #   ifdef _WIN64
  #     define GC_WIN32_SIZE_T GC_uintptr_t
  #   elif defined(GC_WINDOWS_H_INCLUDED)
  #     define GC_WIN32_SIZE_T DWORD
  #   else
  #     define GC_WIN32_SIZE_T unsigned long
  #   endif
  
  #   ifdef GC_INSIDE_DLL
        /* Export GC DllMain to be invoked from client DllMain.   */
  #     ifdef GC_UNDERSCORE_STDCALL
  #       define GC_DllMain _GC_DllMain
  #     endif
  #     ifdef GC_WINDOWS_H_INCLUDED
          GC_API BOOL WINAPI GC_DllMain(HINSTANCE /* inst */,
                                        ULONG /* reason */,
                                        LPVOID /* reserved */);
  #     else
          GC_API int __stdcall GC_DllMain(void *, unsigned long, void *);
  #     endif
  #   endif /* GC_INSIDE_DLL */
  
      /* All threads must be created using GC_CreateThread or             */
      /* GC_beginthreadex, or must explicitly call GC_register_my_thread  */
      /* (and call GC_unregister_my_thread before thread termination), so */
      /* that they will be recorded in the thread table.  For backward    */
      /* compatibility, it is possible to build the GC with GC_DLL        */
      /* defined, and to call GC_use_threads_discovery.  This implicitly  */
      /* registers all created threads, but appears to be less robust.    */
      /* Currently the collector expects all threads to fall through and  */
      /* terminate normally, or call GC_endthreadex() or GC_ExitThread,   */
      /* so that the thread is properly unregistered.                     */
  #   ifdef GC_WINDOWS_H_INCLUDED
        GC_API HANDLE WINAPI GC_CreateThread(
                  LPSECURITY_ATTRIBUTES /* lpThreadAttributes */,
                  GC_WIN32_SIZE_T /* dwStackSize */,
                  LPTHREAD_START_ROUTINE /* lpStartAddress */,
                  LPVOID /* lpParameter */, DWORD /* dwCreationFlags */,
                  LPDWORD /* lpThreadId */);
  
        GC_API DECLSPEC_NORETURN void WINAPI GC_ExitThread(
                                                  DWORD /* dwExitCode */);
  #   else
        struct _SECURITY_ATTRIBUTES;
        GC_API void *__stdcall GC_CreateThread(struct _SECURITY_ATTRIBUTES *,
                                  GC_WIN32_SIZE_T,
                                  unsigned long (__stdcall *)(void *),
                                  void *, unsigned long, unsigned long *);
        GC_API DECLSPEC_NORETURN void __stdcall GC_ExitThread(unsigned long);
  #   endif
  
  #   if !defined(_WIN32_WCE) && !defined(__CEGCC__)
        GC_API GC_uintptr_t GC_CALL GC_beginthreadex(
                          void * /* security */, unsigned /* stack_size */,
                          unsigned (__stdcall *)(void *),
                          void * /* arglist */, unsigned /* initflag */,
                          unsigned * /* thrdaddr */);
  
        /* Note: _endthreadex() is not currently marked as no-return in   */
        /* VC++ and MinGW headers, so we don't mark it neither.           */
        GC_API void GC_CALL GC_endthreadex(unsigned /* retval */);
  #   endif /* !_WIN32_WCE */
  
  # endif /* !GC_NO_THREAD_DECLS */
  
  # ifdef GC_WINMAIN_REDIRECT
      /* win32_threads.c implements the real WinMain(), which will start  */
      /* a new thread to call GC_WinMain() after initializing the garbage */
      /* collector.                                                       */
  #   define WinMain GC_WinMain
  # endif
  
    /* For compatibility only. */
  # define GC_use_DllMain GC_use_threads_discovery
  
  # ifndef GC_NO_THREAD_REDIRECTS
  #   define CreateThread GC_CreateThread
  #   define ExitThread GC_ExitThread
  #   undef _beginthreadex
  #   define _beginthreadex GC_beginthreadex
  #   undef _endthreadex
  #   define _endthreadex GC_endthreadex
  /* #define _beginthread { > "Please use _beginthreadex instead of _beginthread" < } */
  # endif /* !GC_NO_THREAD_REDIRECTS */
  
  #endif /* GC_WIN32_THREADS */
  
  /* Public setter and getter for switching "unmap as much as possible"   */
  /* mode on(1) and off(0).  Has no effect unless unmapping is turned on. */
  /* Has no effect on implicitly-initiated garbage collections.  Initial  */
  /* value is controlled by GC_FORCE_UNMAP_ON_GCOLLECT.  The setter and   */
  /* getter are unsynchronized.                                           */
  GC_API void GC_CALL GC_set_force_unmap_on_gcollect(int);
  GC_API int GC_CALL GC_get_force_unmap_on_gcollect(void);
  
  /* Fully portable code should call GC_INIT() from the main program      */
  /* before making any other GC_ calls.  On most platforms this is a      */
  /* no-op and the collector self-initializes.  But a number of           */
  /* platforms make that too hard.                                        */
  /* A GC_INIT call is required if the collector is built with            */
  /* THREAD_LOCAL_ALLOC defined and the initial allocation call is not    */
  /* to GC_malloc() or GC_malloc_atomic().                                */
  
  #if defined(__CYGWIN32__) || defined(__CYGWIN__)
    /* Similarly gnu-win32 DLLs need explicit initialization from the     */
    /* main program, as does AIX.                                         */
  # ifdef __x86_64__
      /* Cygwin/x64 does not add leading underscore to symbols anymore.   */
      extern int __data_start__[], __data_end__[];
      extern int __bss_start__[], __bss_end__[];
  #   define GC_DATASTART ((GC_word)__data_start__ < (GC_word)__bss_start__ \
                           ? (void *)__data_start__ : (void *)__bss_start__)
  #   define GC_DATAEND ((GC_word)__data_end__ > (GC_word)__bss_end__ \
                         ? (void *)__data_end__ : (void *)__bss_end__)
  # else
      extern int _data_start__[], _data_end__[], _bss_start__[], _bss_end__[];
  #   define GC_DATASTART ((GC_word)_data_start__ < (GC_word)_bss_start__ \
                           ? (void *)_data_start__ : (void *)_bss_start__)
  #   define GC_DATAEND ((GC_word)_data_end__ > (GC_word)_bss_end__ \
                        ? (void *)_data_end__ : (void *)_bss_end__)
  # endif /* !__x86_64__ */
  # define GC_INIT_CONF_ROOTS GC_add_roots(GC_DATASTART, GC_DATAEND); \
                                   GC_gcollect() /* For blacklisting. */
          /* Required at least if GC is in a DLL.  And doesn't hurt. */
  #elif defined(_AIX)
    extern int _data[], _end[];
  # define GC_DATASTART ((void *)_data)
  # define GC_DATAEND ((void *)_end)
  # define GC_INIT_CONF_ROOTS GC_add_roots(GC_DATASTART, GC_DATAEND)
  #elif (defined(HOST_ANDROID) || defined(__ANDROID__)) \
        && defined(IGNORE_DYNAMIC_LOADING)
    /* This is ugly but seems the only way to register data roots of the  */
    /* client shared library if the GC dynamic loading support is off.    */
  # pragma weak __dso_handle
    extern int __dso_handle[];
    GC_API void * GC_CALL GC_find_limit(void * /* start */, int /* up */);
  # define GC_INIT_CONF_ROOTS (void)(__dso_handle != 0 \
                                     ? (GC_add_roots(__dso_handle, \
                                              GC_find_limit(__dso_handle, \
                                                            1 /*up*/)), 0) : 0)
  #else
  # define GC_INIT_CONF_ROOTS /* empty */
  #endif
  
  #ifdef GC_DONT_EXPAND
    /* Set GC_dont_expand to TRUE at start-up */
  # define GC_INIT_CONF_DONT_EXPAND GC_set_dont_expand(1)
  #else
  # define GC_INIT_CONF_DONT_EXPAND /* empty */
  #endif
  
  #ifdef GC_FORCE_UNMAP_ON_GCOLLECT
    /* Turn on "unmap as much as possible on explicit GC" mode at start-up */
  # define GC_INIT_CONF_FORCE_UNMAP_ON_GCOLLECT \
                  GC_set_force_unmap_on_gcollect(1)
  #else
  # define GC_INIT_CONF_FORCE_UNMAP_ON_GCOLLECT /* empty */
  #endif
  
  #ifdef GC_DONT_GC
    /* This is for debugging only (useful if environment variables are    */
    /* unsupported); cannot call GC_disable as goes before GC_init.       */
  # define GC_INIT_CONF_MAX_RETRIES (void)(GC_dont_gc = 1)
  #elif defined(GC_MAX_RETRIES) && !defined(CPPCHECK)
    /* Set GC_max_retries to the desired value at start-up */
  # define GC_INIT_CONF_MAX_RETRIES GC_set_max_retries(GC_MAX_RETRIES)
  #else
  # define GC_INIT_CONF_MAX_RETRIES /* empty */
  #endif
  
  #if defined(GC_ALLOCD_BYTES_PER_FINALIZER) && !defined(CPPCHECK)
    /* Set GC_allocd_bytes_per_finalizer to the desired value at start-up. */
  # define GC_INIT_CONF_ALLOCD_BYTES_PER_FINALIZER \
          GC_set_allocd_bytes_per_finalizer(GC_ALLOCD_BYTES_PER_FINALIZER)
  #else
  # define GC_INIT_CONF_ALLOCD_BYTES_PER_FINALIZER /* empty */
  #endif
  
  #if defined(GC_FREE_SPACE_DIVISOR) && !defined(CPPCHECK)
    /* Set GC_free_space_divisor to the desired value at start-up */
  # define GC_INIT_CONF_FREE_SPACE_DIVISOR \
                  GC_set_free_space_divisor(GC_FREE_SPACE_DIVISOR)
  #else
  # define GC_INIT_CONF_FREE_SPACE_DIVISOR /* empty */
  #endif
  
  #if defined(GC_FULL_FREQ) && !defined(CPPCHECK)
    /* Set GC_full_freq to the desired value at start-up */
  # define GC_INIT_CONF_FULL_FREQ GC_set_full_freq(GC_FULL_FREQ)
  #else
  # define GC_INIT_CONF_FULL_FREQ /* empty */
  #endif
  
  #if defined(GC_TIME_LIMIT) && !defined(CPPCHECK)
    /* Set GC_time_limit (in ms) to the desired value at start-up. */
  # define GC_INIT_CONF_TIME_LIMIT GC_set_time_limit(GC_TIME_LIMIT)
  #else
  # define GC_INIT_CONF_TIME_LIMIT /* empty */
  #endif
  
  #if defined(GC_MARKERS) && defined(GC_THREADS) && !defined(CPPCHECK)
    /* Set the number of marker threads (including the initiating */
    /* one) to the desired value at start-up.                     */
  # define GC_INIT_CONF_MARKERS GC_set_markers_count(GC_MARKERS)
  #else
  # define GC_INIT_CONF_MARKERS /* empty */
  #endif
  
  #if defined(GC_SIG_SUSPEND) && defined(GC_THREADS) && !defined(CPPCHECK)
  # define GC_INIT_CONF_SUSPEND_SIGNAL GC_set_suspend_signal(GC_SIG_SUSPEND)
  #else
  # define GC_INIT_CONF_SUSPEND_SIGNAL /* empty */
  #endif
  
  #if defined(GC_SIG_THR_RESTART) && defined(GC_THREADS) && !defined(CPPCHECK)
  # define GC_INIT_CONF_THR_RESTART_SIGNAL \
                  GC_set_thr_restart_signal(GC_SIG_THR_RESTART)
  #else
  # define GC_INIT_CONF_THR_RESTART_SIGNAL /* empty */
  #endif
  
  #if defined(GC_MAXIMUM_HEAP_SIZE) && !defined(CPPCHECK)
    /* Limit the heap size to the desired value (useful for debugging).   */
    /* The limit could be overridden either at the program start-up by    */
    /* the similar environment variable or anytime later by the           */
    /* corresponding API function call.                                   */
  # define GC_INIT_CONF_MAXIMUM_HEAP_SIZE \
                  GC_set_max_heap_size(GC_MAXIMUM_HEAP_SIZE)
  #else
  # define GC_INIT_CONF_MAXIMUM_HEAP_SIZE /* empty */
  #endif
  
  #ifdef GC_IGNORE_WARN
    /* Turn off all warnings at start-up (after GC initialization) */
  # define GC_INIT_CONF_IGNORE_WARN GC_set_warn_proc(GC_ignore_warn_proc)
  #else
  # define GC_INIT_CONF_IGNORE_WARN /* empty */
  #endif
  
  #if defined(GC_INITIAL_HEAP_SIZE) && !defined(CPPCHECK)
    /* Set heap size to the desired value at start-up */
  # define GC_INIT_CONF_INITIAL_HEAP_SIZE \
                  { size_t heap_size = GC_get_heap_size(); \
                    if (heap_size < (GC_INITIAL_HEAP_SIZE)) \
                      (void)GC_expand_hp((GC_INITIAL_HEAP_SIZE) - heap_size); }
  #else
  # define GC_INIT_CONF_INITIAL_HEAP_SIZE /* empty */
  #endif
  
  /* Portable clients should call this at the program start-up.  More     */
  /* over, some platforms require this call to be done strictly from the  */
  /* primordial thread.  Multiple invocations are harmless.               */
  #define GC_INIT() { GC_INIT_CONF_DONT_EXPAND; /* pre-init */ \
                      GC_INIT_CONF_FORCE_UNMAP_ON_GCOLLECT; \
                      GC_INIT_CONF_MAX_RETRIES; \
                      GC_INIT_CONF_ALLOCD_BYTES_PER_FINALIZER; \
                      GC_INIT_CONF_FREE_SPACE_DIVISOR; \
                      GC_INIT_CONF_FULL_FREQ; \
                      GC_INIT_CONF_TIME_LIMIT; \
                      GC_INIT_CONF_MARKERS; \
                      GC_INIT_CONF_SUSPEND_SIGNAL; \
                      GC_INIT_CONF_THR_RESTART_SIGNAL; \
                      GC_INIT_CONF_MAXIMUM_HEAP_SIZE; \
                      GC_init(); /* real GC initialization */ \
                      GC_INIT_CONF_ROOTS; /* post-init */ \
                      GC_INIT_CONF_IGNORE_WARN; \
                      GC_INIT_CONF_INITIAL_HEAP_SIZE; }
  
  /* win32S may not free all resources on process exit.                   */
  /* This explicitly deallocates the heap.  Defined only for Windows.     */
  GC_API void GC_CALL GC_win32_free_heap(void);
  
  #if defined(__SYMBIAN32__)
    void GC_init_global_static_roots(void);
  #endif
  
  #if defined(_AMIGA) && !defined(GC_AMIGA_MAKINGLIB)
    /* Allocation really goes through GC_amiga_allocwrapper_do.   */
    void *GC_amiga_realloc(void *, size_t);
  # define GC_realloc(a,b) GC_amiga_realloc(a,b)
    void GC_amiga_set_toany(void (*)(void));
    extern int GC_amiga_free_space_divisor_inc;
    extern void *(*GC_amiga_allocwrapper_do)(size_t, void *(GC_CALL *)(size_t));
  # define GC_malloc(a) \
          (*GC_amiga_allocwrapper_do)(a,GC_malloc)
  # define GC_malloc_atomic(a) \
          (*GC_amiga_allocwrapper_do)(a,GC_malloc_atomic)
  # define GC_malloc_uncollectable(a) \
          (*GC_amiga_allocwrapper_do)(a,GC_malloc_uncollectable)
  # define GC_malloc_atomic_uncollectable(a) \
          (*GC_amiga_allocwrapper_do)(a,GC_malloc_atomic_uncollectable)
  # define GC_malloc_ignore_off_page(a) \
          (*GC_amiga_allocwrapper_do)(a,GC_malloc_ignore_off_page)
  # define GC_malloc_atomic_ignore_off_page(a) \
          (*GC_amiga_allocwrapper_do)(a,GC_malloc_atomic_ignore_off_page)
  #endif /* _AMIGA && !GC_AMIGA_MAKINGLIB */
  
  #ifdef __cplusplus
    } /* extern "C" */
  #endif
  
  #endif /* GC_H */
  