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Annotation of OpenXM_contrib2/asir2000/gc/include/gc.h, Revision 1.1

1.1     ! noro        1: /*
        !             2:  * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
        !             3:  * Copyright (c) 1991-1995 by Xerox Corporation.  All rights reserved.
        !             4:  * Copyright 1996 by Silicon Graphics.  All rights reserved.
        !             5:  *
        !             6:  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
        !             7:  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
        !             8:  *
        !             9:  * Permission is hereby granted to use or copy this program
        !            10:  * for any purpose,  provided the above notices are retained on all copies.
        !            11:  * Permission to modify the code and to distribute modified code is granted,
        !            12:  * provided the above notices are retained, and a notice that the code was
        !            13:  * modified is included with the above copyright notice.
        !            14:  */
        !            15:
        !            16: /*
        !            17:  * Note that this defines a large number of tuning hooks, which can
        !            18:  * safely be ignored in nearly all cases.  For normal use it suffices
        !            19:  * to call only GC_MALLOC and perhaps GC_REALLOC.
        !            20:  * For better performance, also look at GC_MALLOC_ATOMIC, and
        !            21:  * GC_enable_incremental.  If you need an action to be performed
        !            22:  * immediately before an object is collected, look at GC_register_finalizer.
        !            23:  * If you are using Solaris threads, look at the end of this file.
        !            24:  * Everything else is best ignored unless you encounter performance
        !            25:  * problems.
        !            26:  */
        !            27:
        !            28: #ifndef _GC_H
        !            29:
        !            30: # define _GC_H
        !            31: # define __GC
        !            32: # include <stddef.h>
        !            33:
        !            34: #if defined(__CYGWIN32__) && defined(GC_USE_DLL)
        !            35: #include "libgc_globals.h"
        !            36: #endif
        !            37:
        !            38: #if defined(_MSC_VER) && defined(_DLL)
        !            39: # ifdef GC_BUILD
        !            40: #   define GC_API __declspec(dllexport)
        !            41: # else
        !            42: #   define GC_API __declspec(dllimport)
        !            43: # endif
        !            44: #endif
        !            45:
        !            46: #if defined(__WATCOMC__) && defined(GC_DLL)
        !            47: # ifdef GC_BUILD
        !            48: #   define GC_API extern __declspec(dllexport)
        !            49: # else
        !            50: #   define GC_API extern __declspec(dllimport)
        !            51: # endif
        !            52: #endif
        !            53:
        !            54: #ifndef GC_API
        !            55: #define GC_API extern
        !            56: #endif
        !            57:
        !            58: # if defined(__STDC__) || defined(__cplusplus)
        !            59: #   define GC_PROTO(args) args
        !            60:     typedef void * GC_PTR;
        !            61: # else
        !            62: #   define GC_PROTO(args) ()
        !            63:     typedef char * GC_PTR;
        !            64: #  endif
        !            65:
        !            66: # ifdef __cplusplus
        !            67:     extern "C" {
        !            68: # endif
        !            69:
        !            70:
        !            71: /* Define word and signed_word to be unsigned and signed types of the  */
        !            72: /* size as char * or void *.  There seems to be no way to do this      */
        !            73: /* even semi-portably.  The following is probably no better/worse      */
        !            74: /* than almost anything else.                                          */
        !            75: /* The ANSI standard suggests that size_t and ptr_diff_t might be      */
        !            76: /* better choices.  But those appear to have incorrect definitions     */
        !            77: /* on may systems.  Notably "typedef int size_t" seems to be both      */
        !            78: /* frequent and WRONG.                                                 */
        !            79: typedef unsigned long GC_word;
        !            80: typedef long GC_signed_word;
        !            81:
        !            82: /* Public read-only variables */
        !            83:
        !            84: GC_API GC_word GC_gc_no;/* Counter incremented per collection.         */
        !            85:                        /* Includes empty GCs at startup.               */
        !            86:
        !            87:
        !            88: /* Public R/W variables */
        !            89:
        !            90: GC_API GC_PTR (*GC_oom_fn) GC_PROTO((size_t bytes_requested));
        !            91:                        /* When there is insufficient memory to satisfy */
        !            92:                        /* an allocation request, we return             */
        !            93:                        /* (*GC_oom_fn)().  By default this just        */
        !            94:                        /* returns 0.                                   */
        !            95:                        /* If it returns, it must return 0 or a valid   */
        !            96:                        /* pointer to a previously allocated heap       */
        !            97:                        /* object.                                      */
        !            98:
        !            99: GC_API int GC_quiet;   /* Disable statistics output.  Only matters if  */
        !           100:                        /* collector has been compiled with statistics  */
        !           101:                        /* enabled.  This involves a performance cost,  */
        !           102:                        /* and is thus not the default.                 */
        !           103:
        !           104: GC_API int GC_dont_gc; /* Dont collect unless explicitly requested, e.g. */
        !           105:                        /* because it's not safe.                         */
        !           106:
        !           107: GC_API int GC_dont_expand;
        !           108:                        /* Dont expand heap unless explicitly requested */
        !           109:                        /* or forced to.                                */
        !           110:
        !           111: GC_API int GC_full_freq;    /* Number of partial collections between   */
        !           112:                            /* full collections.  Matters only if       */
        !           113:                            /* GC_incremental is set.                   */
        !           114:
        !           115: GC_API GC_word GC_non_gc_bytes;
        !           116:                        /* Bytes not considered candidates for collection. */
        !           117:                        /* Used only to control scheduling of collections. */
        !           118:
        !           119: GC_API GC_word GC_free_space_divisor;
        !           120:                        /* We try to make sure that we allocate at      */
        !           121:                        /* least N/GC_free_space_divisor bytes between  */
        !           122:                        /* collections, where N is the heap size plus   */
        !           123:                        /* a rough estimate of the root set size.       */
        !           124:                        /* Initially, GC_free_space_divisor = 4.        */
        !           125:                        /* Increasing its value will use less space     */
        !           126:                        /* but more collection time.  Decreasing it     */
        !           127:                        /* will appreciably decrease collection time    */
        !           128:                        /* at the expense of space.                     */
        !           129:                        /* GC_free_space_divisor = 1 will effectively   */
        !           130:                        /* disable collections.                         */
        !           131:
        !           132: GC_API GC_word GC_max_retries;
        !           133:                        /* The maximum number of GCs attempted before   */
        !           134:                        /* reporting out of memory after heap           */
        !           135:                        /* expansion fails.  Initially 0.               */
        !           136:
        !           137:
        !           138: GC_API char *GC_stackbottom;   /* Cool end of user stack.              */
        !           139:                                /* May be set in the client prior to    */
        !           140:                                /* calling any GC_ routines.  This      */
        !           141:                                /* avoids some overhead, and            */
        !           142:                                /* potentially some signals that can    */
        !           143:                                /* confuse debuggers.  Otherwise the    */
        !           144:                                /* collector attempts to set it         */
        !           145:                                /* automatically.                       */
        !           146:                                /* For multithreaded code, this is the  */
        !           147:                                /* cold end of the stack for the        */
        !           148:                                /* primordial thread.                   */
        !           149:
        !           150: /* Public procedures */
        !           151: /*
        !           152:  * general purpose allocation routines, with roughly malloc calling conv.
        !           153:  * The atomic versions promise that no relevant pointers are contained
        !           154:  * in the object.  The nonatomic versions guarantee that the new object
        !           155:  * is cleared.  GC_malloc_stubborn promises that no changes to the object
        !           156:  * will occur after GC_end_stubborn_change has been called on the
        !           157:  * result of GC_malloc_stubborn. GC_malloc_uncollectable allocates an object
        !           158:  * that is scanned for pointers to collectable objects, but is not itself
        !           159:  * collectable.  GC_malloc_uncollectable and GC_free called on the resulting
        !           160:  * object implicitly update GC_non_gc_bytes appropriately.
        !           161:  */
        !           162: GC_API GC_PTR GC_malloc GC_PROTO((size_t size_in_bytes));
        !           163: GC_API GC_PTR GC_malloc_atomic GC_PROTO((size_t size_in_bytes));
        !           164: GC_API GC_PTR GC_malloc_uncollectable GC_PROTO((size_t size_in_bytes));
        !           165: GC_API GC_PTR GC_malloc_stubborn GC_PROTO((size_t size_in_bytes));
        !           166:
        !           167: /* The following is only defined if the library has been suitably      */
        !           168: /* compiled:                                                           */
        !           169: GC_API GC_PTR GC_malloc_atomic_uncollectable GC_PROTO((size_t size_in_bytes));
        !           170:
        !           171: /* Explicitly deallocate an object.  Dangerous if used incorrectly.     */
        !           172: /* Requires a pointer to the base of an object.                                */
        !           173: /* If the argument is stubborn, it should not be changeable when freed. */
        !           174: /* An object should not be enable for finalization when it is          */
        !           175: /* explicitly deallocated.                                             */
        !           176: /* GC_free(0) is a no-op, as required by ANSI C for free.              */
        !           177: GC_API void GC_free GC_PROTO((GC_PTR object_addr));
        !           178:
        !           179: /*
        !           180:  * Stubborn objects may be changed only if the collector is explicitly informed.
        !           181:  * The collector is implicitly informed of coming change when such
        !           182:  * an object is first allocated.  The following routines inform the
        !           183:  * collector that an object will no longer be changed, or that it will
        !           184:  * once again be changed.  Only nonNIL pointer stores into the object
        !           185:  * are considered to be changes.  The argument to GC_end_stubborn_change
        !           186:  * must be exacly the value returned by GC_malloc_stubborn or passed to
        !           187:  * GC_change_stubborn.  (In the second case it may be an interior pointer
        !           188:  * within 512 bytes of the beginning of the objects.)
        !           189:  * There is a performance penalty for allowing more than
        !           190:  * one stubborn object to be changed at once, but it is acceptable to
        !           191:  * do so.  The same applies to dropping stubborn objects that are still
        !           192:  * changeable.
        !           193:  */
        !           194: GC_API void GC_change_stubborn GC_PROTO((GC_PTR));
        !           195: GC_API void GC_end_stubborn_change GC_PROTO((GC_PTR));
        !           196:
        !           197: /* Return a pointer to the base (lowest address) of an object given    */
        !           198: /* a pointer to a location within the object.                          */
        !           199: /* Return 0 if displaced_pointer doesn't point to within a valid       */
        !           200: /* object.                                                             */
        !           201: GC_API GC_PTR GC_base GC_PROTO((GC_PTR displaced_pointer));
        !           202:
        !           203: /* Given a pointer to the base of an object, return its size in bytes. */
        !           204: /* The returned size may be slightly larger than what was originally   */
        !           205: /* requested.                                                          */
        !           206: GC_API size_t GC_size GC_PROTO((GC_PTR object_addr));
        !           207:
        !           208: /* For compatibility with C library.  This is occasionally faster than */
        !           209: /* a malloc followed by a bcopy.  But if you rely on that, either here */
        !           210: /* or with the standard C library, your code is broken.  In my         */
        !           211: /* opinion, it shouldn't have been invented, but now we're stuck. -HB  */
        !           212: /* The resulting object has the same kind as the original.             */
        !           213: /* If the argument is stubborn, the result will have changes enabled.  */
        !           214: /* It is an error to have changes enabled for the original object.     */
        !           215: /* Follows ANSI comventions for NULL old_object.                       */
        !           216: GC_API GC_PTR GC_realloc
        !           217:        GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes));
        !           218:
        !           219: /* Explicitly increase the heap size.  */
        !           220: /* Returns 0 on failure, 1 on success.  */
        !           221: GC_API int GC_expand_hp GC_PROTO((size_t number_of_bytes));
        !           222:
        !           223: /* Limit the heap size to n bytes.  Useful when you're debugging,      */
        !           224: /* especially on systems that don't handle running out of memory well. */
        !           225: /* n == 0 ==> unbounded.  This is the default.                         */
        !           226: GC_API void GC_set_max_heap_size GC_PROTO((GC_word n));
        !           227:
        !           228: /* Inform the collector that a certain section of statically allocated */
        !           229: /* memory contains no pointers to garbage collected memory.  Thus it   */
        !           230: /* need not be scanned.  This is sometimes important if the application */
        !           231: /* maps large read/write files into the address space, which could be  */
        !           232: /* mistaken for dynamic library data segments on some systems.         */
        !           233: GC_API void GC_exclude_static_roots GC_PROTO((GC_PTR start, GC_PTR finish));
        !           234:
        !           235: /* Clear the set of root segments.  Wizards only. */
        !           236: GC_API void GC_clear_roots GC_PROTO((void));
        !           237:
        !           238: /* Add a root segment.  Wizards only. */
        !           239: GC_API void GC_add_roots GC_PROTO((char * low_address,
        !           240:                                   char * high_address_plus_1));
        !           241:
        !           242: /* Add a displacement to the set of those considered valid by the      */
        !           243: /* collector.  GC_register_displacement(n) means that if p was returned */
        !           244: /* by GC_malloc, then (char *)p + n will be considered to be a valid   */
        !           245: /* pointer to n.  N must be small and less than the size of p.         */
        !           246: /* (All pointers to the interior of objects from the stack are         */
        !           247: /* considered valid in any case.  This applies to heap objects and     */
        !           248: /* static data.)                                                       */
        !           249: /* Preferably, this should be called before any other GC procedures.   */
        !           250: /* Calling it later adds to the probability of excess memory           */
        !           251: /* retention.                                                          */
        !           252: /* This is a no-op if the collector was compiled with recognition of   */
        !           253: /* arbitrary interior pointers enabled, which is now the default.      */
        !           254: GC_API void GC_register_displacement GC_PROTO((GC_word n));
        !           255:
        !           256: /* The following version should be used if any debugging allocation is */
        !           257: /* being done.                                                         */
        !           258: GC_API void GC_debug_register_displacement GC_PROTO((GC_word n));
        !           259:
        !           260: /* Explicitly trigger a full, world-stop collection.   */
        !           261: GC_API void GC_gcollect GC_PROTO((void));
        !           262:
        !           263: /* Trigger a full world-stopped collection.  Abort the collection if   */
        !           264: /* and when stop_func returns a nonzero value.  Stop_func will be      */
        !           265: /* called frequently, and should be reasonably fast.  This works even  */
        !           266: /* if virtual dirty bits, and hence incremental collection is not      */
        !           267: /* available for this architecture.  Collections can be aborted faster */
        !           268: /* than normal pause times for incremental collection.  However,       */
        !           269: /* aborted collections do no useful work; the next collection needs    */
        !           270: /* to start from the beginning.                                                */
        !           271: /* Return 0 if the collection was aborted, 1 if it succeeded.          */
        !           272: typedef int (* GC_stop_func) GC_PROTO((void));
        !           273: GC_API int GC_try_to_collect GC_PROTO((GC_stop_func stop_func));
        !           274:
        !           275: /* Return the number of bytes in the heap.  Excludes collector private */
        !           276: /* data structures.  Includes empty blocks and fragmentation loss.     */
        !           277: /* Includes some pages that were allocated but never written.          */
        !           278: GC_API size_t GC_get_heap_size GC_PROTO((void));
        !           279:
        !           280: /* Return the number of bytes allocated since the last collection.     */
        !           281: GC_API size_t GC_get_bytes_since_gc GC_PROTO((void));
        !           282:
        !           283: /* Enable incremental/generational collection. */
        !           284: /* Not advisable unless dirty bits are                 */
        !           285: /* available or most heap objects are          */
        !           286: /* pointerfree(atomic) or immutable.           */
        !           287: /* Don't use in leak finding mode.             */
        !           288: /* Ignored if GC_dont_gc is true.              */
        !           289: GC_API void GC_enable_incremental GC_PROTO((void));
        !           290:
        !           291: /* Perform some garbage collection work, if appropriate.       */
        !           292: /* Return 0 if there is no more work to be done.               */
        !           293: /* Typically performs an amount of work corresponding roughly  */
        !           294: /* to marking from one page.  May do more work if further      */
        !           295: /* progress requires it, e.g. if incremental collection is     */
        !           296: /* disabled.  It is reasonable to call this in a wait loop     */
        !           297: /* until it returns 0.                                         */
        !           298: GC_API int GC_collect_a_little GC_PROTO((void));
        !           299:
        !           300: /* Allocate an object of size lb bytes.  The client guarantees that    */
        !           301: /* as long as the object is live, it will be referenced by a pointer   */
        !           302: /* that points to somewhere within the first 256 bytes of the object.  */
        !           303: /* (This should normally be declared volatile to prevent the compiler  */
        !           304: /* from invalidating this assertion.)  This routine is only useful     */
        !           305: /* if a large array is being allocated.  It reduces the chance of      */
        !           306: /* accidentally retaining such an array as a result of scanning an     */
        !           307: /* integer that happens to be an address inside the array.  (Actually, */
        !           308: /* it reduces the chance of the allocator not finding space for such   */
        !           309: /* an array, since it will try hard to avoid introducing such a false  */
        !           310: /* reference.)  On a SunOS 4.X or MS Windows system this is recommended */
        !           311: /* for arrays likely to be larger than 100K or so.  For other systems, */
        !           312: /* or if the collector is not configured to recognize all interior     */
        !           313: /* pointers, the threshold is normally much higher.                    */
        !           314: GC_API GC_PTR GC_malloc_ignore_off_page GC_PROTO((size_t lb));
        !           315: GC_API GC_PTR GC_malloc_atomic_ignore_off_page GC_PROTO((size_t lb));
        !           316:
        !           317: #if defined(__sgi) && !defined(__GNUC__) && _COMPILER_VERSION >= 720
        !           318: #   define GC_ADD_CALLER
        !           319: #   define GC_RETURN_ADDR (GC_word)__return_address
        !           320: #endif
        !           321:
        !           322: #ifdef GC_ADD_CALLER
        !           323: #  define GC_EXTRAS GC_RETURN_ADDR, __FILE__, __LINE__
        !           324: #  define GC_EXTRA_PARAMS GC_word ra, char * descr_string, int descr_int
        !           325: #else
        !           326: #  define GC_EXTRAS __FILE__, __LINE__
        !           327: #  define GC_EXTRA_PARAMS char * descr_string, int descr_int
        !           328: #endif
        !           329:
        !           330: /* Debugging (annotated) allocation.  GC_gcollect will check           */
        !           331: /* objects allocated in this way for overwrites, etc.                  */
        !           332: GC_API GC_PTR GC_debug_malloc
        !           333:        GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
        !           334: GC_API GC_PTR GC_debug_malloc_atomic
        !           335:        GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
        !           336: GC_API GC_PTR GC_debug_malloc_uncollectable
        !           337:        GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
        !           338: GC_API GC_PTR GC_debug_malloc_stubborn
        !           339:        GC_PROTO((size_t size_in_bytes, GC_EXTRA_PARAMS));
        !           340: GC_API void GC_debug_free GC_PROTO((GC_PTR object_addr));
        !           341: GC_API GC_PTR GC_debug_realloc
        !           342:        GC_PROTO((GC_PTR old_object, size_t new_size_in_bytes,
        !           343:                  GC_EXTRA_PARAMS));
        !           344:
        !           345: GC_API void GC_debug_change_stubborn GC_PROTO((GC_PTR));
        !           346: GC_API void GC_debug_end_stubborn_change GC_PROTO((GC_PTR));
        !           347: # ifdef GC_DEBUG
        !           348: #   define GC_MALLOC(sz) GC_debug_malloc(sz, GC_EXTRAS)
        !           349: #   define GC_MALLOC_ATOMIC(sz) GC_debug_malloc_atomic(sz, GC_EXTRAS)
        !           350: #   define GC_MALLOC_UNCOLLECTABLE(sz) GC_debug_malloc_uncollectable(sz, \
        !           351:                                                        GC_EXTRAS)
        !           352: #   define GC_REALLOC(old, sz) GC_debug_realloc(old, sz, GC_EXTRAS)
        !           353: #   define GC_FREE(p) GC_debug_free(p)
        !           354: #   define GC_REGISTER_FINALIZER(p, f, d, of, od) \
        !           355:        GC_debug_register_finalizer(p, f, d, of, od)
        !           356: #   define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
        !           357:        GC_debug_register_finalizer_ignore_self(p, f, d, of, od)
        !           358: #   define GC_MALLOC_STUBBORN(sz) GC_debug_malloc_stubborn(sz, GC_EXTRAS);
        !           359: #   define GC_CHANGE_STUBBORN(p) GC_debug_change_stubborn(p)
        !           360: #   define GC_END_STUBBORN_CHANGE(p) GC_debug_end_stubborn_change(p)
        !           361: #   define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
        !           362:        GC_general_register_disappearing_link(link, GC_base(obj))
        !           363: #   define GC_REGISTER_DISPLACEMENT(n) GC_debug_register_displacement(n)
        !           364: # else
        !           365: #   define GC_MALLOC(sz) GC_malloc(sz)
        !           366: #   define GC_MALLOC_ATOMIC(sz) GC_malloc_atomic(sz)
        !           367: #   define GC_MALLOC_UNCOLLECTABLE(sz) GC_malloc_uncollectable(sz)
        !           368: #   define GC_REALLOC(old, sz) GC_realloc(old, sz)
        !           369: #   define GC_FREE(p) GC_free(p)
        !           370: #   define GC_REGISTER_FINALIZER(p, f, d, of, od) \
        !           371:        GC_register_finalizer(p, f, d, of, od)
        !           372: #   define GC_REGISTER_FINALIZER_IGNORE_SELF(p, f, d, of, od) \
        !           373:        GC_register_finalizer_ignore_self(p, f, d, of, od)
        !           374: #   define GC_MALLOC_STUBBORN(sz) GC_malloc_stubborn(sz)
        !           375: #   define GC_CHANGE_STUBBORN(p) GC_change_stubborn(p)
        !           376: #   define GC_END_STUBBORN_CHANGE(p) GC_end_stubborn_change(p)
        !           377: #   define GC_GENERAL_REGISTER_DISAPPEARING_LINK(link, obj) \
        !           378:        GC_general_register_disappearing_link(link, obj)
        !           379: #   define GC_REGISTER_DISPLACEMENT(n) GC_register_displacement(n)
        !           380: # endif
        !           381: /* The following are included because they are often convenient, and   */
        !           382: /* reduce the chance for a misspecifed size argument.  But calls may   */
        !           383: /* expand to something syntactically incorrect if t is a complicated   */
        !           384: /* type expression.                                                    */
        !           385: # define GC_NEW(t) (t *)GC_MALLOC(sizeof (t))
        !           386: # define GC_NEW_ATOMIC(t) (t *)GC_MALLOC_ATOMIC(sizeof (t))
        !           387: # define GC_NEW_STUBBORN(t) (t *)GC_MALLOC_STUBBORN(sizeof (t))
        !           388: # define GC_NEW_UNCOLLECTABLE(t) (t *)GC_MALLOC_UNCOLLECTABLE(sizeof (t))
        !           389:
        !           390: /* Finalization.  Some of these primitives are grossly unsafe.         */
        !           391: /* The idea is to make them both cheap, and sufficient to build                */
        !           392: /* a safer layer, closer to PCedar finalization.                       */
        !           393: /* The interface represents my conclusions from a long discussion      */
        !           394: /* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes,             */
        !           395: /* Christian Jacobi, and Russ Atkinson.  It's not perfect, and         */
        !           396: /* probably nobody else agrees with it.            Hans-J. Boehm  3/13/92      */
        !           397: typedef void (*GC_finalization_proc)
        !           398:        GC_PROTO((GC_PTR obj, GC_PTR client_data));
        !           399:
        !           400: GC_API void GC_register_finalizer
        !           401:        GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
        !           402:                  GC_finalization_proc *ofn, GC_PTR *ocd));
        !           403: GC_API void GC_debug_register_finalizer
        !           404:        GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
        !           405:                  GC_finalization_proc *ofn, GC_PTR *ocd));
        !           406:        /* When obj is no longer accessible, invoke             */
        !           407:        /* (*fn)(obj, cd).  If a and b are inaccessible, and    */
        !           408:        /* a points to b (after disappearing links have been    */
        !           409:        /* made to disappear), then only a will be              */
        !           410:        /* finalized.  (If this does not create any new         */
        !           411:        /* pointers to b, then b will be finalized after the    */
        !           412:        /* next collection.)  Any finalizable object that       */
        !           413:        /* is reachable from itself by following one or more    */
        !           414:        /* pointers will not be finalized (or collected).       */
        !           415:        /* Thus cycles involving finalizable objects should     */
        !           416:        /* be avoided, or broken by disappearing links.         */
        !           417:        /* All but the last finalizer registered for an object  */
        !           418:        /* is ignored.                                          */
        !           419:        /* Finalization may be removed by passing 0 as fn.      */
        !           420:        /* Finalizers are implicitly unregistered just before   */
        !           421:        /* they are invoked.                                    */
        !           422:        /* The old finalizer and client data are stored in      */
        !           423:        /* *ofn and *ocd.                                       */
        !           424:        /* Fn is never invoked on an accessible object,         */
        !           425:        /* provided hidden pointers are converted to real       */
        !           426:        /* pointers only if the allocation lock is held, and    */
        !           427:        /* such conversions are not performed by finalization   */
        !           428:        /* routines.                                            */
        !           429:        /* If GC_register_finalizer is aborted as a result of   */
        !           430:        /* a signal, the object may be left with no             */
        !           431:        /* finalization, even if neither the old nor new        */
        !           432:        /* finalizer were NULL.                                 */
        !           433:        /* Obj should be the nonNULL starting address of an     */
        !           434:        /* object allocated by GC_malloc or friends.            */
        !           435:        /* Note that any garbage collectable object referenced  */
        !           436:        /* by cd will be considered accessible until the        */
        !           437:        /* finalizer is invoked.                                */
        !           438:
        !           439: /* Another versions of the above follow.  It ignores           */
        !           440: /* self-cycles, i.e. pointers from a finalizable object to     */
        !           441: /* itself.  There is a stylistic argument that this is wrong,  */
        !           442: /* but it's unavoidable for C++, since the compiler may                */
        !           443: /* silently introduce these.  It's also benign in that specific        */
        !           444: /* case.                                                       */
        !           445: GC_API void GC_register_finalizer_ignore_self
        !           446:        GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
        !           447:                  GC_finalization_proc *ofn, GC_PTR *ocd));
        !           448: GC_API void GC_debug_register_finalizer_ignore_self
        !           449:        GC_PROTO((GC_PTR obj, GC_finalization_proc fn, GC_PTR cd,
        !           450:                  GC_finalization_proc *ofn, GC_PTR *ocd));
        !           451:
        !           452: /* The following routine may be used to break cycles between   */
        !           453: /* finalizable objects, thus causing cyclic finalizable                */
        !           454: /* objects to be finalized in the correct order.  Standard     */
        !           455: /* use involves calling GC_register_disappearing_link(&p),     */
        !           456: /* where p is a pointer that is not followed by finalization   */
        !           457: /* code, and should not be considered in determining           */
        !           458: /* finalization order.                                         */
        !           459: GC_API int GC_register_disappearing_link GC_PROTO((GC_PTR * /* link */));
        !           460:        /* Link should point to a field of a heap allocated     */
        !           461:        /* object obj.  *link will be cleared when obj is       */
        !           462:        /* found to be inaccessible.  This happens BEFORE any   */
        !           463:        /* finalization code is invoked, and BEFORE any         */
        !           464:        /* decisions about finalization order are made.         */
        !           465:        /* This is useful in telling the finalizer that         */
        !           466:        /* some pointers are not essential for proper           */
        !           467:        /* finalization.  This may avoid finalization cycles.   */
        !           468:        /* Note that obj may be resurrected by another          */
        !           469:        /* finalizer, and thus the clearing of *link may        */
        !           470:        /* be visible to non-finalization code.                 */
        !           471:        /* There's an argument that an arbitrary action should  */
        !           472:        /* be allowed here, instead of just clearing a pointer. */
        !           473:        /* But this causes problems if that action alters, or   */
        !           474:        /* examines connectivity.                               */
        !           475:        /* Returns 1 if link was already registered, 0          */
        !           476:        /* otherwise.                                           */
        !           477:        /* Only exists for backward compatibility.  See below:  */
        !           478:
        !           479: GC_API int GC_general_register_disappearing_link
        !           480:        GC_PROTO((GC_PTR * /* link */, GC_PTR obj));
        !           481:        /* A slight generalization of the above. *link is       */
        !           482:        /* cleared when obj first becomes inaccessible.  This   */
        !           483:        /* can be used to implement weak pointers easily and    */
        !           484:        /* safely. Typically link will point to a location      */
        !           485:        /* holding a disguised pointer to obj.  (A pointer      */
        !           486:        /* inside an "atomic" object is effectively             */
        !           487:        /* disguised.)   In this way soft                       */
        !           488:        /* pointers are broken before any object                */
        !           489:        /* reachable from them are finalized.  Each link        */
        !           490:        /* May be registered only once, i.e. with one obj       */
        !           491:        /* value.  This was added after a long email discussion */
        !           492:        /* with John Ellis.                                     */
        !           493:        /* Obj must be a pointer to the first word of an object */
        !           494:        /* we allocated.  It is unsafe to explicitly deallocate */
        !           495:        /* the object containing link.  Explicitly deallocating */
        !           496:        /* obj may or may not cause link to eventually be       */
        !           497:        /* cleared.                                             */
        !           498: GC_API int GC_unregister_disappearing_link GC_PROTO((GC_PTR * /* link */));
        !           499:        /* Returns 0 if link was not actually registered.       */
        !           500:        /* Undoes a registration by either of the above two     */
        !           501:        /* routines.                                            */
        !           502:
        !           503: /* Auxiliary fns to make finalization work correctly with displaced    */
        !           504: /* pointers introduced by the debugging allocators.                    */
        !           505: GC_API GC_PTR GC_make_closure GC_PROTO((GC_finalization_proc fn, GC_PTR data));
        !           506: GC_API void GC_debug_invoke_finalizer GC_PROTO((GC_PTR obj, GC_PTR data));
        !           507:
        !           508: GC_API int GC_invoke_finalizers GC_PROTO((void));
        !           509:        /* Run finalizers for all objects that are ready to     */
        !           510:        /* be finalized.  Return the number of finalizers       */
        !           511:        /* that were run.  Normally this is also called         */
        !           512:        /* implicitly during some allocations.  If              */
        !           513:        /* FINALIZE_ON_DEMAND is defined, it must be called     */
        !           514:        /* explicitly.                                          */
        !           515:
        !           516: /* GC_set_warn_proc can be used to redirect or filter warning messages.        */
        !           517: /* p may not be a NULL pointer.                                                */
        !           518: typedef void (*GC_warn_proc) GC_PROTO((char *msg, GC_word arg));
        !           519: GC_API GC_warn_proc GC_set_warn_proc GC_PROTO((GC_warn_proc p));
        !           520:     /* Returns old warning procedure.  */
        !           521:
        !           522: /* The following is intended to be used by a higher level      */
        !           523: /* (e.g. cedar-like) finalization facility.  It is expected    */
        !           524: /* that finalization code will arrange for hidden pointers to  */
        !           525: /* disappear.  Otherwise objects can be accessed after they    */
        !           526: /* have been collected.                                                */
        !           527: /* Note that putting pointers in atomic objects or in          */
        !           528: /* nonpointer slots of "typed" objects is equivalent to        */
        !           529: /* disguising them in this way, and may have other advantages. */
        !           530: # if defined(I_HIDE_POINTERS) || defined(GC_I_HIDE_POINTERS)
        !           531:     typedef GC_word GC_hidden_pointer;
        !           532: #   define HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
        !           533: #   define REVEAL_POINTER(p) ((GC_PTR)(HIDE_POINTER(p)))
        !           534:     /* Converting a hidden pointer to a real pointer requires verifying        */
        !           535:     /* that the object still exists.  This involves acquiring the      */
        !           536:     /* allocator lock to avoid a race with the collector.              */
        !           537: # endif /* I_HIDE_POINTERS */
        !           538:
        !           539: typedef GC_PTR (*GC_fn_type) GC_PROTO((GC_PTR client_data));
        !           540: GC_API GC_PTR GC_call_with_alloc_lock
        !           541:                GC_PROTO((GC_fn_type fn, GC_PTR client_data));
        !           542:
        !           543: /* Check that p and q point to the same object.                */
        !           544: /* Fail conspicuously if they don't.                           */
        !           545: /* Returns the first argument.                                 */
        !           546: /* Succeeds if neither p nor q points to the heap.             */
        !           547: /* May succeed if both p and q point to between heap objects.  */
        !           548: GC_API GC_PTR GC_same_obj GC_PROTO((GC_PTR p, GC_PTR q));
        !           549:
        !           550: /* Checked pointer pre- and post- increment operations.  Note that     */
        !           551: /* the second argument is in units of bytes, not multiples of the      */
        !           552: /* object size.  This should either be invoked from a macro, or the    */
        !           553: /* call should be automatically generated.                             */
        !           554: GC_API GC_PTR GC_pre_incr GC_PROTO((GC_PTR *p, size_t how_much));
        !           555: GC_API GC_PTR GC_post_incr GC_PROTO((GC_PTR *p, size_t how_much));
        !           556:
        !           557: /* Check that p is visible                                             */
        !           558: /* to the collector as a possibly pointer containing location.         */
        !           559: /* If it isn't fail conspicuously.                                     */
        !           560: /* Returns the argument in all cases.  May erroneously succeed         */
        !           561: /* in hard cases.  (This is intended for debugging use with            */
        !           562: /* untyped allocations.  The idea is that it should be possible, though        */
        !           563: /* slow, to add such a call to all indirect pointer stores.)           */
        !           564: /* Currently useless for multithreaded worlds.                         */
        !           565: GC_API GC_PTR GC_is_visible GC_PROTO((GC_PTR p));
        !           566:
        !           567: /* Check that if p is a pointer to a heap page, then it points to      */
        !           568: /* a valid displacement within a heap object.                          */
        !           569: /* Fail conspicuously if this property does not hold.                  */
        !           570: /* Uninteresting with ALL_INTERIOR_POINTERS.                           */
        !           571: /* Always returns its argument.                                                */
        !           572: GC_API GC_PTR GC_is_valid_displacement GC_PROTO((GC_PTR        p));
        !           573:
        !           574: /* Safer, but slow, pointer addition.  Probably useful mainly with     */
        !           575: /* a preprocessor.  Useful only for heap pointers.                     */
        !           576: #ifdef GC_DEBUG
        !           577: #   define GC_PTR_ADD3(x, n, type_of_result) \
        !           578:        ((type_of_result)GC_same_obj((x)+(n), (x)))
        !           579: #   define GC_PRE_INCR3(x, n, type_of_result) \
        !           580:        ((type_of_result)GC_pre_incr(&(x), (n)*sizeof(*x))
        !           581: #   define GC_POST_INCR2(x, type_of_result) \
        !           582:        ((type_of_result)GC_post_incr(&(x), sizeof(*x))
        !           583: #   ifdef __GNUC__
        !           584: #       define GC_PTR_ADD(x, n) \
        !           585:            GC_PTR_ADD3(x, n, typeof(x))
        !           586: #   define GC_PRE_INCR(x, n) \
        !           587:            GC_PRE_INCR3(x, n, typeof(x))
        !           588: #   define GC_POST_INCR(x, n) \
        !           589:            GC_POST_INCR3(x, typeof(x))
        !           590: #   else
        !           591:        /* We can't do this right without typeof, which ANSI    */
        !           592:        /* decided was not sufficiently useful.  Repeatedly     */
        !           593:        /* mentioning the arguments seems too dangerous to be   */
        !           594:        /* useful.  So does not casting the result.             */
        !           595: #      define GC_PTR_ADD(x, n) ((x)+(n))
        !           596: #   endif
        !           597: #else  /* !GC_DEBUG */
        !           598: #   define GC_PTR_ADD3(x, n, type_of_result) ((x)+(n))
        !           599: #   define GC_PTR_ADD(x, n) ((x)+(n))
        !           600: #   define GC_PRE_INCR3(x, n, type_of_result) ((x) += (n))
        !           601: #   define GC_PRE_INCR(x, n) ((x) += (n))
        !           602: #   define GC_POST_INCR2(x, n, type_of_result) ((x)++)
        !           603: #   define GC_POST_INCR(x, n) ((x)++)
        !           604: #endif
        !           605:
        !           606: /* Safer assignment of a pointer to a nonstack location.       */
        !           607: #ifdef GC_DEBUG
        !           608: # ifdef __STDC__
        !           609: #   define GC_PTR_STORE(p, q) \
        !           610:        (*(void **)GC_is_visible(p) = GC_is_valid_displacement(q))
        !           611: # else
        !           612: #   define GC_PTR_STORE(p, q) \
        !           613:        (*(char **)GC_is_visible(p) = GC_is_valid_displacement(q))
        !           614: # endif
        !           615: #else /* !GC_DEBUG */
        !           616: #   define GC_PTR_STORE(p, q) *((p) = (q))
        !           617: #endif
        !           618:
        !           619: /* Fynctions called to report pointer checking errors */
        !           620: GC_API void (*GC_same_obj_print_proc) GC_PROTO((GC_PTR p, GC_PTR q));
        !           621:
        !           622: GC_API void (*GC_is_valid_displacement_print_proc)
        !           623:        GC_PROTO((GC_PTR p));
        !           624:
        !           625: GC_API void (*GC_is_visible_print_proc)
        !           626:        GC_PROTO((GC_PTR p));
        !           627:
        !           628: #if defined(_SOLARIS_PTHREADS) && !defined(SOLARIS_THREADS)
        !           629: #   define SOLARIS_THREADS
        !           630: #endif
        !           631:
        !           632: #ifdef SOLARIS_THREADS
        !           633: /* We need to intercept calls to many of the threads primitives, so    */
        !           634: /* that we can locate thread stacks and stop the world.                        */
        !           635: /* Note also that the collector cannot see thread specific data.       */
        !           636: /* Thread specific data should generally consist of pointers to                */
        !           637: /* uncollectable objects, which are deallocated using the destructor   */
        !           638: /* facility in thr_keycreate.                                          */
        !           639: # include <thread.h>
        !           640: # include <signal.h>
        !           641:   int GC_thr_create(void *stack_base, size_t stack_size,
        !           642:                     void *(*start_routine)(void *), void *arg, long flags,
        !           643:                     thread_t *new_thread);
        !           644:   int GC_thr_join(thread_t wait_for, thread_t *departed, void **status);
        !           645:   int GC_thr_suspend(thread_t target_thread);
        !           646:   int GC_thr_continue(thread_t target_thread);
        !           647:   void * GC_dlopen(const char *path, int mode);
        !           648:
        !           649: # ifdef _SOLARIS_PTHREADS
        !           650: #   include <pthread.h>
        !           651:     extern int GC_pthread_create(pthread_t *new_thread,
        !           652:                                 const pthread_attr_t *attr,
        !           653:                                 void * (*thread_execp)(void *), void *arg);
        !           654:     extern int GC_pthread_join(pthread_t wait_for, void **status);
        !           655:
        !           656: #   undef thread_t
        !           657:
        !           658: #   define pthread_join GC_pthread_join
        !           659: #   define pthread_create GC_pthread_create
        !           660: #endif
        !           661:
        !           662: # define thr_create GC_thr_create
        !           663: # define thr_join GC_thr_join
        !           664: # define thr_suspend GC_thr_suspend
        !           665: # define thr_continue GC_thr_continue
        !           666: # define dlopen GC_dlopen
        !           667:
        !           668: # endif /* SOLARIS_THREADS */
        !           669:
        !           670:
        !           671: #if defined(IRIX_THREADS) || defined(LINUX_THREADS)
        !           672: /* We treat these similarly. */
        !           673: # include <pthread.h>
        !           674: # include <signal.h>
        !           675:
        !           676:   int GC_pthread_create(pthread_t *new_thread,
        !           677:                         const pthread_attr_t *attr,
        !           678:                        void *(*start_routine)(void *), void *arg);
        !           679:   int GC_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset);
        !           680:   int GC_pthread_join(pthread_t thread, void **retval);
        !           681:
        !           682: # define pthread_create GC_pthread_create
        !           683: # define pthread_sigmask GC_pthread_sigmask
        !           684: # define pthread_join GC_pthread_join
        !           685:
        !           686: #endif /* IRIX_THREADS || LINUX_THREADS */
        !           687:
        !           688: # if defined(PCR) || defined(SOLARIS_THREADS) || defined(WIN32_THREADS) || \
        !           689:        defined(IRIX_THREADS) || defined(LINUX_THREADS) || \
        !           690:        defined(IRIX_JDK_THREADS)
        !           691:        /* Any flavor of threads except SRC_M3. */
        !           692: /* This returns a list of objects, linked through their first          */
        !           693: /* word.  Its use can greatly reduce lock contention problems, since   */
        !           694: /* the allocation lock can be acquired and released many fewer times.  */
        !           695: /* lb must be large enough to hold the pointer field.                  */
        !           696: GC_PTR GC_malloc_many(size_t lb);
        !           697: #define GC_NEXT(p) (*(GC_PTR *)(p))    /* Retrieve the next element    */
        !           698:                                        /* in returned list.            */
        !           699: extern void GC_thr_init();     /* Needed for Solaris/X86       */
        !           700:
        !           701: #endif /* THREADS && !SRC_M3 */
        !           702:
        !           703: /*
        !           704:  * If you are planning on putting
        !           705:  * the collector in a SunOS 5 dynamic library, you need to call GC_INIT()
        !           706:  * from the statically loaded program section.
        !           707:  * This circumvents a Solaris 2.X (X<=4) linker bug.
        !           708:  */
        !           709: #if defined(sparc) || defined(__sparc)
        !           710: #   define GC_INIT() { extern end, etext; \
        !           711:                       GC_noop(&end, &etext); }
        !           712: #else
        !           713: # if defined(__CYGWIN32__) && defined(GC_USE_DLL)
        !           714:     /*
        !           715:      * Similarly gnu-win32 DLLs need explicit initialization
        !           716:      */
        !           717: #   define GC_INIT() { GC_add_roots(DATASTART, DATAEND); }
        !           718: # else
        !           719: #   define GC_INIT()
        !           720: # endif
        !           721: #endif
        !           722:
        !           723: #if (defined(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \
        !           724:      || defined(_WIN32)
        !           725:   /* win32S may not free all resources on process exit.  */
        !           726:   /* This explicitly deallocates the heap.              */
        !           727:     GC_API void GC_win32_free_heap ();
        !           728: #endif
        !           729:
        !           730: #ifdef __cplusplus
        !           731:     }  /* end of extern "C" */
        !           732: #endif
        !           733:
        !           734: #endif /* _GC_H */

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