/* 
 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
 * Copyright (c) 1991-1995 by Xerox Corporation.  All rights reserved.
 * Copyright 1996-1999 by Silicon Graphics.  All rights reserved.
 * Copyright 1999 by Hewlett-Packard Company.  All rights reserved.
 * Copyright (C) 2007 Free Software Foundation, Inc
 *
 * 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.
 * If you are using Solaris threads, look at the end of this file.
 * Everything else is best ignored unless you encounter performance
 * problems.
 */
 
#ifndef _GC_H

# define _GC_H

# 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.  The GC_version variable can be used	*/
	/* to obtain the latter.					*/

# include "gc_config_macros.h"

# ifdef __cplusplus
    extern "C" {
# endif


/* 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 ptr_diff_t might be 	*/
/* better choices.  But those had incorrect definitions on some older	*/
/* systems.  Notably "typedef int size_t" is WRONG.			*/
#ifndef _WIN64
  typedef unsigned long GC_word;
  typedef long GC_signed_word;
#else
  /* Win64 isn't really supported yet, but this is the first step. And	*/
  /* it might cause error messages to show up in more plausible places.	*/
  /* This needs basetsd.h, which is included by windows.h.	 	*/
  typedef unsigned long long GC_word;
  typedef long long GC_signed_word;
#endif

/* Public read-only variables */

GC_API GC_word GC_gc_no;/* Counter incremented per collection.  	*/
			/* Includes empty GCs at startup.		*/

GC_API int GC_parallel;	/* GC is parallelized for performance on	*/
			/* multiprocessors.  Currently set only		*/
			/* implicitly if collector is built with	*/
			/* -DPARALLEL_MARK and if either:		*/
			/*  Env variable GC_NPROC is set to > 1, or	*/
			/*  GC_NPROC is not set and this is an MP.	*/
			/* If GC_parallel is set, incremental		*/
			/* collection is only partially functional,	*/
			/* and may not be desirable.			*/
			

/* Public R/W variables */

GC_API void * (*GC_oom_fn) (size_t bytes_requested);
			/* When there is insufficient memory to satisfy */
			/* an allocation request, we return		*/
			/* (*GC_oom_fn)().  By default this just	*/
			/* returns 0.					*/
			/* If it returns, it must return 0 or a valid	*/
			/* pointer to a previously allocated heap 	*/
			/* object.					*/

GC_API int GC_find_leak;
			/* 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.		*/

GC_API int GC_all_interior_pointers;
			/* Arrange for pointers to object interiors to	*/
			/* be recognized as valid.  May not be changed	*/
			/* after GC initialization.			*/
			/* Initial value is determined by 		*/
			/* -DALL_INTERIOR_POINTERS.			*/
			/* 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 0 or 1.				*/

GC_API 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.			*/

GC_API int GC_java_finalization;
			/* Mark objects reachable from finalizable 	*/
			/* objects in a separate postpass.  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.				*/

GC_API void (* GC_finalizer_notifier)(void);
			/* 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.					*/

GC_API int GC_dont_gc;	/* != 0 ==> Dont collect.  In versions 6.2a1+,	*/
			/* this overrides explicit GC_gcollect() calls.	*/
			/* 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.					*/

GC_API int GC_dont_expand;
			/* Dont expand heap unless explicitly requested */
			/* or forced to.				*/

GC_API int GC_use_entire_heap;
		/* Causes the nonincremental collector to use the	*/
		/* entire heap before collecting.  This was the only 	*/
		/* option for GC versions < 5.0.  This sometimes	*/
		/* results in more large block fragmentation, since	*/
		/* very larg 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 int GC_full_freq;    /* Number of partial collections between	*/
			    /* full collections.  Matters only if	*/
			    /* GC_incremental is set.			*/
			    /* 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.			*/
			
GC_API 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.				   */

GC_API 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 Microsoft Windows environments, this will	 */
			/* usually also prevent registration of the	 */
			/* main data segment as part of the root set.	 */

GC_API 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.	*/
			/* Initially, GC_free_space_divisor = 3.	*/
			/* Increasing its value will use less space	*/
			/* but more collection time.  Decreasing it	*/
			/* will appreciably decrease collection time	*/
			/* at the expense of space.			*/

GC_API GC_word GC_max_retries;
			/* The maximum number of GCs attempted before	*/
			/* reporting out of memory after heap		*/
			/* expansion fails.  Initially 0.		*/
			

GC_API char *GC_stackbottom;    /* Cool end 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 multithreaded code, this is the	*/
				/* cold end of the stack for the	*/
				/* primordial thread.			*/	
				
GC_API int GC_dont_precollect;  /* Don't collect as part of 		*/
				/* 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.			*/

GC_API unsigned long GC_time_limit;
				/* If incremental collection is enabled, */
				/* We try to terminate collections	 */
				/* after this many milliseconds.  Not a	 */
				/* hard time bound.  Setting this 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.				 */

/* Public procedures */

/* Initialize the collector.  Portable clients should call GC_INIT() from
 * the main program instead.
 */
GC_API void GC_init(void);

/*
 * general purpose allocation routines, with roughly malloc calling conv.
 * The atomic versions promise that no relevant pointers are contained
 * in the object.  The nonatomic versions guarantee that the new object
 * is cleared.  GC_malloc_stubborn promises that no changes to the object
 * will occur after GC_end_stubborn_change has been called on the
 * result of GC_malloc_stubborn. GC_malloc_uncollectable allocates an object
 * that is scanned for pointers to collectable objects, but is not itself
 * collectable.  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.
 *
 * Note that the GC_malloc_stubborn support is stubbed out by default
 * starting in 6.0.  GC_malloc_stubborn is an alias for GC_malloc unless
 * the collector is built with STUBBORN_ALLOC defined.
 */
GC_API void * GC_malloc(size_t size_in_bytes);
GC_API void * GC_malloc_atomic(size_t size_in_bytes);
GC_API char * GC_strdup (const char *str);
GC_API void * GC_malloc_uncollectable(size_t size_in_bytes);
GC_API void * GC_malloc_stubborn(size_t size_in_bytes);

/* The following is only defined if the library has been suitably	*/
/* compiled:								*/
GC_API void * GC_malloc_atomic_uncollectable(size_t size_in_bytes);

/* Explicitly deallocate an object.  Dangerous if used incorrectly.     */
/* Requires a pointer to the base of an object.				*/
/* If the argument is stubborn, it should not be changeable when freed. */
/* An object should not be enable for finalization when it is 		*/
/* explicitly deallocated.						*/
/* GC_free(0) is a no-op, as required by ANSI C for free.		*/
GC_API void GC_free(void * object_addr);

/*
 * Stubborn objects may be changed only if the collector is explicitly informed.
 * The collector is implicitly informed of coming change when such
 * an object is first allocated.  The following routines inform the
 * collector that an object will no longer be changed, or that it will
 * once again be changed.  Only nonNIL pointer stores into the object
 * are considered to be changes.  The argument to GC_end_stubborn_change
 * must be exacly the value returned by GC_malloc_stubborn or passed to
 * GC_change_stubborn.  (In the second case it may be an interior pointer
 * within 512 bytes of the beginning of the objects.)
 * There is a performance penalty for allowing more than
 * one stubborn object to be changed at once, but it is acceptable to
 * do so.  The same applies to dropping stubborn objects that are still
 * changeable.
 */
GC_API void GC_change_stubborn(void *);
GC_API void GC_end_stubborn_change(void *);

/* 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 bas 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_base(void * displaced_pointer);

/* 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_size(void * object_addr);

/* 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.		*/
/* If the argument is stubborn, the result will have changes enabled.	*/
/* It is an error to have changes enabled for the original object.	*/
/* Follows ANSI comventions for NULL old_object.			*/
GC_API void * GC_realloc(void * old_object, size_t new_size_in_bytes);
				   
/* Explicitly increase the heap size.	*/
/* Returns 0 on failure, 1 on success.  */
GC_API int 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.				*/
GC_API void 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.		*/
GC_API void GC_exclude_static_roots(void * low_address,
				    void * high_address_plus_1);

/* Clear the set of root segments.  Wizards only. */
GC_API void GC_clear_roots(void);

/* Add a root segment.  Wizards only. */
GC_API void GC_add_roots(void * low_address, void * high_address_plus_1);

/* Remove a root segment.  Wizards only. */
GC_API void 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_register_displacement(size_t n);

/* The following version should be used if any debugging allocation is	*/
/* being done.								*/
GC_API void GC_debug_register_displacement(size_t n);

/* Explicitly trigger a full, world-stop collection. 	*/
GC_API void GC_gcollect(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.  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.						*/
/* Return 0 if the collection was aborted, 1 if it succeeded.		*/
typedef int (* GC_stop_func)(void);
GC_API int GC_try_to_collect(GC_stop_func stop_func);

/* Return the number of bytes in the heap.  Excludes collector private	*/
/* data structures.  Includes empty blocks and fragmentation loss.	*/
/* Includes some pages that were allocated but never written.		*/
GC_API size_t GC_get_heap_size(void);

/* Return a lower bound on the number of free bytes in the heap.	*/
GC_API size_t GC_get_free_bytes(void);

/* Return the number of bytes allocated since the last collection.	*/
GC_API size_t GC_get_bytes_since_gc(void);

/* Return the total number of bytes allocated in this process.		*/
/* Never decreases, except due to wrapping.				*/
GC_API size_t GC_get_total_bytes(void);

/* Disable garbage collection.  Even GC_gcollect calls will be 		*/
/* ineffective.								*/
GC_API void GC_disable(void);

/* Reenable garbage collection.  GC_disable() and GC_enable() calls 	*/
/* nest.  Garbage collection is enabled if the number of calls to both	*/
/* both functions is equal.						*/
GC_API void GC_enable(void);

/* Enable incremental/generational collection.	*/
/* Not advisable unless dirty bits are 		*/
/* available or most heap objects are		*/
/* pointerfree(atomic) or immutable.		*/
/* Don't use in leak finding mode.		*/
/* Ignored if GC_dont_gc is true.		*/
/* Only the generational piece of this is	*/
/* functional if GC_parallel is TRUE		*/
/* or if GC_time_limit is GC_TIME_UNLIMITED.	*/
/* Causes GC_local_gcj_malloc() to revert to	*/
/* locked allocation.  Must be called 		*/
/* before any GC_local_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_enable_incremental(void);

/* Does incremental mode write-protect pages?  Returns zero or	*/
/* more of the following, or'ed together:			*/
#define GC_PROTECTS_POINTER_HEAP  1 /* May protect non-atomic objs.	*/
#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
GC_API int GC_incremental_protection_needs(void);

/* Perform some garbage collection work, if appropriate.	*/
/* Return 0 if there is no more work to be done.		*/
/* 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_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 100K 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 void * GC_malloc_ignore_off_page(size_t lb);
GC_API void * GC_malloc_atomic_ignore_off_page(size_t lb);

#if defined(__sgi) && !defined(__GNUC__) && _COMPILER_VERSION >= 720
#   define GC_ADD_CALLER
#   define GC_RETURN_ADDR (GC_word)__return_address
#endif

#if defined(__linux__) || defined(__GLIBC__)
# include <features.h>
# if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1 || __GLIBC__ > 2) \
     && !defined(__ia64__) && !defined(__UCLIBC__)
#   ifndef GC_HAVE_BUILTIN_BACKTRACE
#     define GC_HAVE_BUILTIN_BACKTRACE
#   endif
# endif
# if defined(__i386__) || defined(__x86_64__)
#   define GC_CAN_SAVE_CALL_STACKS
# endif
#endif

#if defined(_MSC_VER) && _MSC_VER >= 1200 /* version 12.0+ (MSVC 6.0+)  */ \
    && !defined(_AMD64_)
# ifndef GC_HAVE_NO_BUILTIN_BACKTRACE
#   define GC_HAVE_BUILTIN_BACKTRACE
# endif
#endif

#if defined(GC_HAVE_BUILTIN_BACKTRACE) && !defined(GC_CAN_SAVE_CALL_STACKS)
# define GC_CAN_SAVE_CALL_STACKS
#endif

#if defined(__sparc__)
#   define GC_CAN_SAVE_CALL_STACKS
#endif

/* If we're on an a platform on which we can't save call stacks, but	*/
/* gcc is normally used, we go ahead and define GC_ADD_CALLER.  	*/
/* We make this decision independent of whether gcc is actually being	*/
/* used, in order to keep the interface consistent, and allow mixing	*/
/* of compilers.							*/
/* This may also be desirable if it is possible but expensive to	*/
/* retrieve the call chain.						*/
#if (defined(__linux__) || defined(__NetBSD__) || defined(__OpenBSD__) \
     || defined(__FreeBSD__) || defined(__DragonFly__)) & !defined(GC_CAN_SAVE_CALL_STACKS)
# define GC_ADD_CALLER
# if __GNUC__ >= 3 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95) 
    /* gcc knows how to retrieve return address, but we don't know */
    /* how to generate call stacks.				   */
#   define GC_RETURN_ADDR (GC_word)__builtin_return_address(0)
# else
    /* Just pass 0 for gcc compatibility. */
#   define GC_RETURN_ADDR 0
# endif
#endif

#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

/* Debugging (annotated) allocation.  GC_gcollect will check 		*/
/* objects allocated in this way for overwrites, etc.			*/
GC_API void * GC_debug_malloc(size_t size_in_bytes, GC_EXTRA_PARAMS);
GC_API void * GC_debug_malloc_atomic(size_t size_in_bytes, GC_EXTRA_PARAMS);
GC_API char * GC_debug_strdup(const char *str, GC_EXTRA_PARAMS);
GC_API void * GC_debug_malloc_uncollectable
	(size_t size_in_bytes, GC_EXTRA_PARAMS);
GC_API void * GC_debug_malloc_stubborn
	(size_t size_in_bytes, GC_EXTRA_PARAMS);
GC_API void * GC_debug_malloc_ignore_off_page
	(size_t size_in_bytes, GC_EXTRA_PARAMS);
GC_API void * GC_debug_malloc_atomic_ignore_off_page
	(size_t size_in_bytes, GC_EXTRA_PARAMS);
GC_API void GC_debug_free (void * object_addr);
GC_API void * GC_debug_realloc
	(void * old_object, size_t new_size_in_bytes, GC_EXTRA_PARAMS);
GC_API void GC_debug_change_stubborn(void *);
GC_API void GC_debug_end_stubborn_change(void *);

/* 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 void * GC_debug_malloc_replacement (size_t size_in_bytes);
GC_API void * GC_debug_realloc_replacement
	      (void * object_addr, size_t size_in_bytes);
  			 	 
# ifdef GC_DEBUG
#   define GC_MALLOC(sz) GC_debug_malloc(sz, GC_EXTRAS)
#   define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, GC_EXTRAS)
#   define GC_STRDUP(s) GC_debug_strdup((s), 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_REALLOC(old, sz) GC_debug_realloc(old, 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_MALLOC_STUBBORN(sz) GC_debug_malloc_stubborn(sz, GC_EXTRAS);
#   define GC_CHANGE_STUBBORN(p) GC_debug_change_stubborn(p)
#   define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p)
#   define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
	GC_general_register_disappearing_link(link, GC_base(obj))
#   define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n)
# else
#   define GC_MALLOC(sz) GC_malloc(sz)
#   define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz)
#   define GC_STRDUP(s) GC_strdup(s)
#   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_REALLOC(old, sz) GC_realloc(old, 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_MALLOC_STUBBORN(sz) GC_malloc_stubborn(sz)
#   define GC_CHANGE_STUBBORN(p) GC_change_stubborn(p)
#   define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p)
#   define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
	GC_general_register_disappearing_link(link, obj)
#   define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n)
# endif
/* The following are included because they are often convenient, and	*/
/* reduce the chance for a misspecifed size argument.  But calls may	*/
/* expand to something syntactically incorrect if t is a complicated	*/
/* type expression.  							*/
# define GC_NEW(t) (t *)GC_MALLOC(sizeof (t))
# define GC_NEW_ATOMIC(t) (t *)GC_MALLOC_ATOMIC(sizeof (t))
# define GC_NEW_STUBBORN(t) (t *)GC_MALLOC_STUBBORN(sizeof (t))
# define GC_NEW_UNCOLLECTABLE(t) (t *)GC_MALLOC_UNCOLLECTABLE(sizeof (t))

/* 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_finalization_proc) (void * obj, void * client_data);

GC_API void GC_register_finalizer(void * obj, GC_finalization_proc fn,
				  void * cd, GC_finalization_proc *ofn,
				  void * *ocd);
GC_API void GC_debug_register_finalizer
    	         (void * obj, GC_finalization_proc fn, void * cd,
		  GC_finalization_proc *ofn, void * *ocd);
	/* 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.						*/
	/* Finalization may be removed by passing 0 as fn.	*/
	/* Finalizers are implicitly unregistered just before   */
	/* they are invoked.					*/
	/* The old finalizer and client data are stored in	*/
	/* *ofn and *ocd.					*/ 
	/* 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 nonNULL starting address of an 	*/
	/* object allocated by GC_malloc or friends.		*/
	/* Note that any garbage collectable object referenced	*/
	/* by cd will be considered accessible until the	*/
	/* finalizer is invoked.				*/

/* PLTSCHEME: eager finalizers do not care about cycles at all.
   The intent is for guardian-like and will-like uses where
   the object will always be made immediately live again, but
   some action needed to be triggered by the object's (possibly
   temporary) unreachableness. */
GC_API void GC_register_eager_finalizer
                 (void * obj, int eager_level,
                  GC_finalization_proc fn, void * cd,
		  GC_finalization_proc *ofn, void * *ocd);

/* 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_register_finalizer_ignore_self
		(void * obj, GC_finalization_proc fn, void * cd,
		 GC_finalization_proc *ofn, void * *ocd);
GC_API void GC_debug_register_finalizer_ignore_self
		(void * obj, GC_finalization_proc fn, void * cd,
		 GC_finalization_proc *ofn, void * *ocd);

/* 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_register_finalizer_no_order
	  	(void * obj, GC_finalization_proc fn, void * cd,
	 	 GC_finalization_proc *ofn, void * *ocd);
GC_API void GC_debug_register_finalizer_no_order
		(void * obj, GC_finalization_proc fn, void * cd,
		 GC_finalization_proc *ofn, void * *ocd);

/* 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_register_finalizer_unreachable
	         (void * obj, GC_finalization_proc fn, void * cd,
		  GC_finalization_proc *ofn, void * *ocd);
GC_API void GC_debug_register_finalizer_unreachable
		 (void * obj, GC_finalization_proc fn, void * cd,
		  GC_finalization_proc *ofn, void * *ocd);

/* 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_register_disappearing_link(void * * link );
	/* 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 1 if link was already registered, 0 if	*/
	/* registration succeeded, 2 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_general_register_disappearing_link (void * * link, void * obj);
	/* 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 soft			*/
	/* pointers are broken before any object		*/
	/* reachable from them are finalized.  Each link	*/
	/* May be registered only once, i.e. with one obj	*/
	/* value.  This was added after a long email discussion */
	/* with John Ellis.					*/
	/* Obj must be a pointer to the first word of an object */
	/* we allocated.  It is unsafe to explicitly deallocate */
	/* the object containing link.  Explicitly deallocating */
	/* obj may or may not cause link to eventually be	*/
	/* cleared.						*/
	/* This can be used to implement certain types of	*/
	/* weak pointers.  Note however that this generally	*/
	/* requires that thje allocation lock is held (see	*/
	/* GC_call_with_allock_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.						*/

GC_API int GC_unregister_disappearing_link (void * * link);
	/* Returns 0 if link was not actually registered.	*/
	/* Undoes a registration by either of the above two	*/
	/* routines.						*/

/* Returns !=0  if GC_invoke_finalizers has something to do. 		*/
GC_API int GC_should_invoke_finalizers(void);

GC_API int 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)
#   define GC_reachable_here(ptr) \
    __asm__ volatile(" " : : "X"(ptr) : "memory");
# else
    GC_API void GC_noop1(GC_word x);
#   define GC_reachable_here(ptr) GC_noop1((GC_word)(ptr));
#endif

/* GC_set_warn_proc can be used to redirect or filter warning messages.	*/
/* p may not be a NULL pointer.						*/
typedef void (*GC_warn_proc) (char *msg, GC_word arg);
GC_API GC_warn_proc GC_set_warn_proc(GC_warn_proc p);
    /* Returns old warning procedure.	*/

GC_API GC_word GC_set_free_space_divisor(GC_word value);
    /* Set free_space_divisor.  See above for definition.	*/
    /* Returns old value.					*/
	
/* 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.						*/
/* Note that putting pointers in atomic objects or in 		*/
/* nonpointer slots of "typed" objects is equivalent to 	*/
/* disguising them in this way, and may have other advantages.	*/
# if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS)
    typedef GC_word GC_hidden_pointer;
#   define HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
#   define REVEAL_POINTER(p) ((void *)(HIDE_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.		*/
# endif /* I_HIDE_POINTERS */

typedef void * (*GC_fn_type) (void * client_data);
GC_API void * GC_call_with_alloc_lock (GC_fn_type fn, void * client_data);

/* 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 base for thread	*/
/* stacks on all platforms.						*/

/* Structure representing the base of a thread stack.  On most		*/
/* platforms this contains just a single address.			*/
struct GC_stack_base {
	void * mem_base;	/* Base of memory stack.	*/
#	if defined(__ia64) || defined(__ia64__)
	  void * reg_base;	/* Base of separate register stack.	*/
#	endif
};

typedef void * (*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 base.  And we 	*/
/* implement it everywhere.						*/
GC_API void * GC_call_with_stack_base(GC_stack_base_func fn, void *arg);

/* Register the current thread, with the indicated stack base, as	*/
/* a new thread whose stack(s) should be traced by the GC.  If a 	*/
/* platform does not implicitly do so, 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.					*/
/* Return codes:	*/
#define GC_SUCCESS 0
#define GC_DUPLICATE 1	/* Was already registered.	*/
#define GC_NO_THREADS 2	/* No thread support in GC.  	*/
#define GC_UNIMPLEMENTED 3	/* Not yet implemented on this platform. */
GC_API int GC_register_my_thread(struct GC_stack_base *);

/* Unregister the current 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.				*/
GC_API int GC_unregister_my_thread(void);

/* Attempt to fill in the GC_stack_base structure with the stack base	*/
/* 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.				*/
GC_API int GC_get_stack_base(struct GC_stack_base *);

/* 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_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_pre_incr (void * *p, size_t how_much);
GC_API void * GC_post_incr (void * *p, size_t how_much);

/* 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 multithreaded worlds.				*/
GC_API void * 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_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.	*/
/* PLTSCHEME: use GC_API */
GC_API void GC_dump(void);

/* Safer, but slow, pointer addition.  Probably useful mainly with 	*/
/* a preprocessor.  Useful only for heap pointers.			*/
#ifdef GC_DEBUG
#   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(&(x), (n)*sizeof(*x))
#   define GC_POST_INCR2(x, type_of_result) \
	((type_of_result)GC_post_incr(&(x), sizeof(*x))
#   ifdef __GNUC__
#       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, n) \
	    GC_POST_INCR3(x, typeof(x))
#   else
	/* We can't do this right without typeof, which ANSI	*/
	/* decided was not sufficiently useful.  Repeatedly	*/
	/* mentioning the arguments seems too dangerous to be	*/
	/* useful.  So does not casting the result.		*/
#   	define GC_PTR_ADD(x, n) ((x)+(n))
#   endif
#else	/* !GC_DEBUG */
#   define GC_PTR_ADD3(x, n, type_of_result) ((x)+(n))
#   define GC_PTR_ADD(x, n) ((x)+(n))
#   define GC_PRE_INCR3(x, n, type_of_result) ((x) += (n))
#   define GC_PRE_INCR(x, n) ((x) += (n))
#   define GC_POST_INCR2(x, n, type_of_result) ((x)++)
#   define GC_POST_INCR(x, n) ((x)++)
#endif

/* Safer assignment of a pointer to a nonstack location.	*/
#ifdef GC_DEBUG
#   define GC_PTR_STORE(p, q) \
	(*(void **)GC_is_visible(p) = GC_is_valid_displacement(q))
#else /* !GC_DEBUG */
#   define GC_PTR_STORE(p, q) (*(p) = (q))
#endif

/* Functions called to report pointer checking errors */
GC_API void (*GC_same_obj_print_proc) (void * p, void * q);

GC_API void (*GC_is_valid_displacement_print_proc) (void * p);

GC_API void (*GC_is_visible_print_proc) (void * p);


/* For pthread support, we generally need to intercept a number of 	*/
/* thread library calls.  We do that here by macro defining them.	*/

#if !defined(GC_USE_LD_WRAP) && !defined(GC_NO_THREAD_REDIRECTS) \
    && defined(GC_PTHREADS)
# include "gc_pthread_redirects.h"
#endif

# if defined(PCR) || defined(GC_SOLARIS_THREADS) || \
     defined(GC_PTHREADS) || defined(GC_WIN32_THREADS)
   	/* Any flavor of threads.	*/
/* 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.	*/
/* It is used internally by gc_local_alloc.h, which provides a simpler	*/
/* programming interface on Linux.					*/
void * GC_malloc_many(size_t lb);
#define GC_NEXT(p) (*(void * *)(p)) 	/* Retrieve the next element	*/
					/* in returned list.		*/

#endif /* THREADS */

/* Register a callback to control the scanning of dynamic libraries.
   When the GC scans the static data of a dynamic library, it will
   first call a user-supplied routine with filename of the library and
   the address and length of the memory region.  This routine should
   return nonzero if that region should be scanned.  */
GC_API void 
GC_register_has_static_roots_callback
  (int (*callback)(const char *, void *, size_t));


#if defined(GC_WIN32_THREADS) && !defined(__CYGWIN32__) \
	&& !defined(__CYGWIN__) \
	&& !defined(GC_PTHREADS)

#ifdef __cplusplus
    }  /* Including windows.h in an extern "C" context no longer works. */
#endif

#ifndef GC_NO_THREAD_DECLS
# include <windows.h>

#ifdef __cplusplus
    extern "C" {
#endif
  /*
   * All threads must be created using GC_CreateThread or GC_beginthreadex,
   * or must explicitly call GC_register_my_thread,
   * so that they will be recorded in the thread table.
   * For backwards compatibility, it is possible to build the GC
   * with GC_DLL defined, and to call GC_use_DllMain().
   * 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.  (An explicit call
   * to GC_unregister_my_thread() should also work, but risks unregistering
   * the thread twice.)
   */
   GC_API HANDLE WINAPI GC_CreateThread(
      LPSECURITY_ATTRIBUTES lpThreadAttributes,
      DWORD dwStackSize, LPTHREAD_START_ROUTINE lpStartAddress,
      LPVOID lpParameter, DWORD dwCreationFlags, LPDWORD lpThreadId );

#  if defined(_MSC_VER) && _MSC_VER >= 1200 && !defined(_UINTPTR_T_DEFINED)
     typedef unsigned long uintptr_t;
#  endif

   GC_API uintptr_t GC_beginthreadex(
     void *security, unsigned stack_size,
     unsigned ( __stdcall *start_address )( void * ),
     void *arglist, unsigned initflag, unsigned *thrdaddr);

   GC_API void GC_endthreadex(unsigned retval);

   GC_API void WINAPI GC_ExitThread(DWORD dwExitCode);

# if defined(_WIN32_WCE)
  /*
   * win32_threads.c implements the real WinMain, which will start a new thread
   * to call GC_WinMain after initializing the garbage collector.
   */
  GC_API int WINAPI GC_WinMain(
      HINSTANCE hInstance,
      HINSTANCE hPrevInstance,
      LPWSTR lpCmdLine,
      int nCmdShow );
#  ifndef GC_BUILD
#    define WinMain GC_WinMain
#  endif
# endif /* defined(_WIN32_WCE) */
#endif /* !GC_NO_THREAD_DECLS */

  /*
   * Use implicit thread registration via DllMain.
   * Must be called before GC_INIT and other GC routines.
   * Should be avoided if GC_beginthreadex and friends can be called
   * instead.
   */
GC_API void GC_use_DllMain(void);

# ifndef GC_NO_THREAD_REDIRECTS
#   define CreateThread GC_CreateThread
#   define ExitThread GC_ExitThread
#   define _beginthreadex GC_beginthreadex
#   define _endthreadex GC_endthreadex
#   define _beginthread { > "Please use _beginthreadex instead of _beginthread" < }
# endif /* !GC_NO_THREAD_REDIRECTS */

#endif /* defined(GC_WIN32_THREADS)  && !cygwin */

 /*
  * 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 (_AIX)
    /*
     * Similarly gnu-win32 DLLs need explicit initialization from
     * the main program, as does AIX.
     */
#   ifdef __CYGWIN32__
      extern int _data_start__[];
      extern int _data_end__[];
      extern int _bss_start__[];
      extern int _bss_end__[];
#     define GC_MAX(x,y) ((x) > (y) ? (x) : (y))
#     define GC_MIN(x,y) ((x) < (y) ? (x) : (y))
#     define GC_DATASTART ((void *) GC_MIN(_data_start__, _bss_start__))
#     define GC_DATAEND	 ((void *) GC_MAX(_data_end__, _bss_end__))
#     define GC_INIT() { GC_add_roots(GC_DATASTART, GC_DATAEND); \
			   GC_gcollect(); /* For blacklisting. */}
	/* Required at least if GC is in dll.  And doesn't hurt. */
#   endif
#   if defined(_AIX)
      extern int _data[], _end[];
#     define GC_DATASTART ((void *)((ulong)_data))
#     define GC_DATAEND ((void *)((ulong)_end))
#     define GC_INIT() { GC_add_roots(GC_DATASTART, GC_DATAEND); }
#   endif
#else
#   define GC_INIT() { GC_init(); }
#endif

#if !defined(_WIN32_WCE) \
    && ((defined(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \
        || defined(_WIN32) && !defined(__CYGWIN32__) && !defined(__CYGWIN__))
  /* win32S may not free all resources on process exit.  */
  /* This explicitly deallocates the heap.		 */
    GC_API void GC_win32_free_heap ();
#endif

#if ( defined(_AMIGA) && !defined(GC_AMIGA_MAKINGLIB) )
  /* Allocation really goes through GC_amiga_allocwrapper_do */
# include "gc_amiga_redirects.h"
#endif

#if defined(GC_REDIRECT_TO_LOCAL)
  /* Now redundant; that's the default with THREAD_LOCAL_ALLOC */
#endif

/* PLTSCHEME: */
typedef void (*GC_collect_start_callback_Proc)(void);
typedef void (*GC_collect_end_callback_Proc)(void);
GC_API void (*GC_custom_finalize)(void);
GC_API void (*GC_push_last_roots)(void);
GC_API void (*GC_push_last_roots_again)(void);
GC_API GC_collect_start_callback_Proc GC_set_collect_start_callback(GC_collect_start_callback_Proc);
GC_API GC_collect_end_callback_Proc GC_set_collect_end_callback(GC_collect_end_callback_Proc);
GC_API void (*GC_out_of_memory)(void);
GC_API int GC_did_mark_stack_overflow(void);
GC_API void GC_mark_from_mark_stack(void);
GC_API void GC_mark_overflow_recover(void *p);
GC_API void GC_flush_mark_stack(void);
GC_API long GC_get_memory_use(void);
GC_API void GC_pre_init(void);

#ifdef __cplusplus
    }  /* end of extern "C" */
#endif

#endif /* _GC_H */
