/* * 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 * Copyright (c) 2000-2011 by Hewlett-Packard Development Company. * Copyright (c) 2009-2020 Ivan Maidanski * * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED * OR IMPLIED. ANY USE IS AT YOUR OWN RISK. * * Permission is hereby granted to use or copy this program * for any purpose, provided the above notices are retained on all copies. * Permission to modify the code and to distribute modified code is granted, * provided the above notices are retained, and a notice that the code was * modified is included with the above copyright notice.
*/
/* * Note that this defines a large number of tuning hooks, which can * safely be ignored in nearly all cases. For normal use it suffices * to call only GC_MALLOC and perhaps GC_REALLOC. * For better performance, also look at GC_MALLOC_ATOMIC, and * GC_enable_incremental. If you need an action to be performed * immediately before an object is collected, look at GC_register_finalizer. * Everything else is best ignored unless you encounter performance * problems.
*/
#ifndef GC_H #define GC_H
/* Help debug mixed up preprocessor symbols. */ #if (defined(WIN64) && !defined(_WIN64)) && defined(_MSC_VER) #pragma message("Warning: Expecting _WIN64 for x64 targets! Notice the leading underscore!") #endif
#include"gc_version.h" /* Define version numbers here to allow test on build machine */ /* for cross-builds. Note that this defines the header */ /* version number, which may or may not match that of the */ /* dynamic library. GC_get_version() can be used to obtain */ /* the latter. */
#include"gc_config_macros.h"
#ifdef __cplusplus extern"C" { #endif
typedefvoid * GC_PTR; /* preserved only for backward compatibility */
/* Define word and signed_word to be unsigned and signed types of the */ /* size as char * or void *. There seems to be no way to do this */ /* even semi-portably. The following is probably no better/worse */ /* than almost anything else. */ /* The ANSI standard suggests that size_t and ptrdiff_t might be */ /* better choices. But those had incorrect definitions on some older */ /* systems. Notably "typedef int size_t" is WRONG. */ #ifdef _WIN64 # ifdefined(__int64) && !defined(CPPCHECK) typedefunsigned __int64 GC_word; typedef __int64 GC_signed_word; # else typedefunsignedlonglong GC_word; typedeflonglong GC_signed_word; # endif #else typedefunsignedlong GC_word; typedeflong GC_signed_word; #endif
/* Get the GC library version. The returned value is a constant in the */ /* form: ((version_major<<16) | (version_minor<<8) | version_micro). */
GC_API unsigned GC_CALL GC_get_version(void);
/* Public read-only variables */ /* The supplied getter functions are preferred for new code. */
GC_API GC_ATTR_DEPRECATED GC_word GC_gc_no; /* Counter incremented per collection. */ /* Includes empty GCs at startup. */
GC_API GC_word GC_CALL GC_get_gc_no(void); /* GC_get_gc_no() is unsynchronized, so */ /* it requires GC_call_with_alloc_lock() to */ /* avoid data races on multiprocessors. */
#ifdef GC_THREADS /* GC is parallelized for performance on multiprocessors. Set to */ /* a non-zero value when client calls GC_start_mark_threads() */ /* directly or starts the first non-main thread, provided the */ /* collector is built with PARALLEL_MARK defined, and either */ /* GC_MARKERS (or GC_NPROCS) environment variable is set to a value */ /* bigger than 1, or multiple cores (processors) are available, or */ /* the client calls GC_set_markers_count() before GC initialization. */ /* After setting, GC_parallel value is equal to the number of marker */ /* threads minus one (i.e. the number of existing parallel marker */ /* threads excluding the initiating one). */
GC_API GC_ATTR_DEPRECATED int GC_parallel;
/* Return value of GC_parallel. Does not acquire the GC lock. */
GC_API int GC_CALL GC_get_parallel(void);
/* Set the number of marker threads (including the initiating one) */ /* to the desired value at start-up. Zero value means the collector */ /* is to decide. If the correct non-zero value is passed, then later */ /* GC_parallel will be set to the value minus one. Has no effect if */ /* called after GC initialization. Does not itself cause creation of */ /* the marker threads. Does not use any synchronization. */
GC_API void GC_CALL GC_set_markers_count(unsigned); #endif
/* Public R/W variables */ /* The supplied setter and getter functions are preferred for new code. */
typedefvoid * (GC_CALLBACK * GC_oom_func)(size_t /* bytes_requested */);
GC_API GC_ATTR_DEPRECATED GC_oom_func GC_oom_fn; /* When there is insufficient memory to satisfy */ /* an allocation request, we return */ /* (*GC_oom_fn)(size). By default this just */ /* returns NULL. */ /* If it returns, it must return 0 or a valid */ /* pointer to a previously allocated heap */ /* object. GC_oom_fn must not be 0. */ /* Both the supplied setter and the getter */ /* acquire the GC lock (to avoid data races). */
GC_API void GC_CALL GC_set_oom_fn(GC_oom_func) GC_ATTR_NONNULL(1);
GC_API GC_oom_func GC_CALL GC_get_oom_fn(void);
typedefvoid (GC_CALLBACK * GC_on_heap_resize_proc)(GC_word /* new_size */);
GC_API GC_ATTR_DEPRECATED GC_on_heap_resize_proc GC_on_heap_resize; /* Invoked when the heap grows or shrinks. */ /* Called with the world stopped (and the */ /* allocation lock held). May be 0. */
GC_API void GC_CALL GC_set_on_heap_resize(GC_on_heap_resize_proc);
GC_API GC_on_heap_resize_proc GC_CALL GC_get_on_heap_resize(void); /* Both the supplied setter and the getter */ /* acquire the GC lock (to avoid data races). */
typedefvoid (GC_CALLBACK * GC_on_collection_event_proc)(GC_EventType); /* Invoked to indicate progress through the */ /* collection process. Not used for thread */ /* suspend/resume notifications. Called with */ /* the GC lock held (or, even, the world */ /* stopped). May be 0 (means no notifier). */
GC_API void GC_CALL GC_set_on_collection_event(GC_on_collection_event_proc);
GC_API GC_on_collection_event_proc GC_CALL GC_get_on_collection_event(void); /* Both the supplied setter and the getter */ /* acquire the GC lock (to avoid data races). */
#ifdefined(GC_THREADS) || (defined(GC_BUILD) && defined(NN_PLATFORM_CTR)) typedefvoid (GC_CALLBACK * GC_on_thread_event_proc)(GC_EventType, void * /* thread_id */); /* Invoked when a thread is suspended or */ /* resumed during collection. Called with the */ /* GC lock held (and the world stopped */ /* partially). May be 0 (means no notifier). */
GC_API void GC_CALL GC_set_on_thread_event(GC_on_thread_event_proc);
GC_API GC_on_thread_event_proc GC_CALL GC_get_on_thread_event(void); /* Both the supplied setter and the getter */ /* acquire the GC lock (to avoid data races). */ #endif
GC_API GC_ATTR_DEPRECATED int GC_find_leak; /* Set to true to turn on the leak-finding mode */ /* (do not actually garbage collect, but simply */ /* report inaccessible memory that was not */ /* deallocated with GC_FREE). Initial value */ /* is determined by FIND_LEAK macro. */ /* The value should not typically be modified */ /* after GC initialization (and, thus, it does */ /* not use or need synchronization). */
GC_API void GC_CALL GC_set_find_leak(int);
GC_API int GC_CALL GC_get_find_leak(void);
GC_API GC_ATTR_DEPRECATED int GC_all_interior_pointers; /* Arrange for pointers to object interiors to */ /* be recognized as valid. Typically should */ /* not be changed after GC initialization (in */ /* case of calling it after the GC is */ /* initialized, the setter acquires the GC lock */ /* (to avoid data races). The initial value */ /* depends on whether the GC is built with */ /* ALL_INTERIOR_POINTERS macro defined or not. */ /* Unless DONT_ADD_BYTE_AT_END is defined, this */ /* also affects whether sizes are increased by */ /* at least a byte to allow "off the end" */ /* pointer recognition. Must be only 0 or 1. */
GC_API void GC_CALL GC_set_all_interior_pointers(int);
GC_API int GC_CALL GC_get_all_interior_pointers(void);
GC_API GC_ATTR_DEPRECATED int GC_finalize_on_demand; /* If nonzero, finalizers will only be run in */ /* response to an explicit GC_invoke_finalizers */ /* call. The default is determined by whether */ /* the FINALIZE_ON_DEMAND macro is defined */ /* when the collector is built. */ /* The setter and getter are unsynchronized. */
GC_API void GC_CALL GC_set_finalize_on_demand(int);
GC_API int GC_CALL GC_get_finalize_on_demand(void);
GC_API GC_ATTR_DEPRECATED int GC_java_finalization; /* Mark objects reachable from finalizable */ /* objects in a separate post-pass. This makes */ /* it a bit safer to use non-topologically- */ /* ordered finalization. Default value is */ /* determined by JAVA_FINALIZATION macro. */ /* Enables register_finalizer_unreachable to */ /* work correctly. */ /* The setter and getter are unsynchronized. */
GC_API void GC_CALL GC_set_java_finalization(int);
GC_API int GC_CALL GC_get_java_finalization(void);
typedefvoid (GC_CALLBACK * GC_finalizer_notifier_proc)(void);
GC_API GC_ATTR_DEPRECATED GC_finalizer_notifier_proc GC_finalizer_notifier; /* Invoked by the collector when there are */ /* objects to be finalized. Invoked at most */ /* once per GC cycle. Never invoked unless */ /* GC_finalize_on_demand is set. */ /* Typically this will notify a finalization */ /* thread, which will call GC_invoke_finalizers */ /* in response. May be 0 (means no notifier). */ /* Both the supplied setter and the getter */ /* acquire the GC lock (to avoid data races). */
GC_API void GC_CALL GC_set_finalizer_notifier(GC_finalizer_notifier_proc);
GC_API GC_finalizer_notifier_proc GC_CALL GC_get_finalizer_notifier(void);
GC_API # ifndef GC_DONT_GC
GC_ATTR_DEPRECATED # endif int GC_dont_gc; /* != 0 ==> Do not collect. This overrides */ /* explicit GC_gcollect() calls as well. */ /* Used as a counter, so that nested enabling */ /* and disabling work correctly. Should */ /* normally be updated with GC_enable() and */ /* GC_disable() calls. Direct assignment to */ /* GC_dont_gc is deprecated. To check whether */ /* GC is disabled, GC_is_disabled() is */ /* preferred for new code. */
GC_API GC_ATTR_DEPRECATED int GC_dont_expand; /* Do not expand the heap unless explicitly */ /* requested or forced to. The setter and */ /* getter are unsynchronized. */
GC_API void GC_CALL GC_set_dont_expand(int);
GC_API int GC_CALL GC_get_dont_expand(void);
GC_API GC_ATTR_DEPRECATED int GC_use_entire_heap; /* Causes the non-incremental collector to use the */ /* entire heap before collecting. This sometimes */ /* results in more large block fragmentation, since */ /* very large blocks will tend to get broken up */ /* during each GC cycle. It is likely to result in a */ /* larger working set, but lower collection */ /* frequencies, and hence fewer instructions executed */ /* in the collector. */
GC_API GC_ATTR_DEPRECATED int GC_full_freq; /* Number of partial collections between */ /* full collections. Matters only if */ /* GC_is_incremental_mode(). */ /* Full collections are also triggered if */ /* the collector detects a substantial */ /* increase in the number of in-use heap */ /* blocks. Values in the tens are now */ /* perfectly reasonable, unlike for */ /* earlier GC versions. */ /* The setter and getter are unsynchronized, so */ /* GC_call_with_alloc_lock() is required to */ /* avoid data races (if the value is modified */ /* after the GC is put to multi-threaded mode). */
GC_API void GC_CALL GC_set_full_freq(int);
GC_API int GC_CALL GC_get_full_freq(void);
GC_API GC_ATTR_DEPRECATED GC_word GC_non_gc_bytes; /* Bytes not considered candidates for */ /* collection. Used only to control scheduling */ /* of collections. Updated by */ /* GC_malloc_uncollectable and GC_free. */ /* Wizards only. */ /* The setter and getter are unsynchronized, so */ /* GC_call_with_alloc_lock() is required to */ /* avoid data races (if the value is modified */ /* after the GC is put to multi-threaded mode). */
GC_API void GC_CALL GC_set_non_gc_bytes(GC_word);
GC_API GC_word GC_CALL GC_get_non_gc_bytes(void);
GC_API GC_ATTR_DEPRECATED int GC_no_dls; /* Don't register dynamic library data segments. */ /* Wizards only. Should be used only if the */ /* application explicitly registers all roots. */ /* (In some environments like Microsoft Windows */ /* and Apple's Darwin, this may also prevent */ /* registration of the main data segment as part */ /* of the root set.) */ /* The setter and getter are unsynchronized. */
GC_API void GC_CALL GC_set_no_dls(int);
GC_API int GC_CALL GC_get_no_dls(void);
GC_API GC_ATTR_DEPRECATED GC_word GC_free_space_divisor; /* We try to make sure that we allocate at */ /* least N/GC_free_space_divisor bytes between */ /* collections, where N is twice the number */ /* of traced bytes, plus the number of untraced */ /* bytes (bytes in "atomic" objects), plus */ /* a rough estimate of the root set size. */ /* N approximates GC tracing work per GC. */ /* The initial value is GC_FREE_SPACE_DIVISOR. */ /* Increasing its value will use less space */ /* but more collection time. Decreasing it */ /* will appreciably decrease collection time */ /* at the expense of space. */ /* The setter and getter are unsynchronized, so */ /* GC_call_with_alloc_lock() is required to */ /* avoid data races (if the value is modified */ /* after the GC is put to multi-threaded mode). */ /* In GC v7.1 (and before), the setter returned */ /* the old value. */
GC_API void GC_CALL GC_set_free_space_divisor(GC_word);
GC_API GC_word GC_CALL GC_get_free_space_divisor(void);
GC_API GC_ATTR_DEPRECATED GC_word GC_max_retries; /* The maximum number of GCs attempted before */ /* reporting out of memory after heap */ /* expansion fails. Initially 0. */ /* The setter and getter are unsynchronized, so */ /* GC_call_with_alloc_lock() is required to */ /* avoid data races (if the value is modified */ /* after the GC is put to multi-threaded mode). */
GC_API void GC_CALL GC_set_max_retries(GC_word);
GC_API GC_word GC_CALL GC_get_max_retries(void);
GC_API GC_ATTR_DEPRECATED char *GC_stackbottom; /* The cold end (bottom) of user stack. */ /* May be set in the client prior to */ /* calling any GC_ routines. This */ /* avoids some overhead, and */ /* potentially some signals that can */ /* confuse debuggers. Otherwise the */ /* collector attempts to set it */ /* automatically. */ /* For multi-threaded code, this is the */ /* cold end of the stack for the */ /* primordial thread. Portable clients */ /* should use GC_get_stack_base(), */ /* GC_call_with_gc_active() and */ /* GC_register_my_thread() instead. */
GC_API GC_ATTR_DEPRECATED int GC_dont_precollect; /* Do not collect as part of GC */ /* initialization. Should be set only */ /* if the client wants a chance to */ /* manually initialize the root set */ /* before the first collection. */ /* Interferes with blacklisting. */ /* Wizards only. The setter and getter */ /* are unsynchronized (and no external */ /* locking is needed since the value is */ /* accessed at GC initialization only). */
GC_API void GC_CALL GC_set_dont_precollect(int);
GC_API int GC_CALL GC_get_dont_precollect(void);
GC_API GC_ATTR_DEPRECATED unsignedlong GC_time_limit; /* If incremental collection is enabled, */ /* we try to terminate collections */ /* after this many milliseconds (plus */ /* the amount of nanoseconds as given in */ /* the latest GC_set_time_limit_tv call, */ /* if any). Not a hard time bound. */ /* Setting this variable to */ /* GC_TIME_UNLIMITED will essentially */ /* disable incremental collection while */ /* leaving generational collection */ /* enabled. */ #define GC_TIME_UNLIMITED 999999 /* Setting GC_time_limit to this value */ /* will disable the "pause time exceeded"*/ /* tests. */ /* The setter and getter are unsynchronized, so */ /* GC_call_with_alloc_lock() is required to */ /* avoid data races (if the value is modified */ /* after the GC is put to multi-threaded mode). */ /* The setter does not update the value of the */ /* nanosecond part of the time limit (it is */ /* zero unless ever set by GC_set_time_limit_tv */ /* call). */
GC_API void GC_CALL GC_set_time_limit(unsignedlong);
GC_API unsignedlong GC_CALL GC_get_time_limit(void);
/* A portable type definition of time with a nanosecond precision. */ struct GC_timeval_s { unsignedlong tv_ms; /* time in milliseconds */ unsignedlong tv_nsec;/* nanoseconds fraction (<1000000) */
};
/* Public procedures */
/* Set/get the time limit of the incremental collections. This is */ /* similar to GC_set_time_limit and GC_get_time_limit but the time is */ /* provided with the nanosecond precision. The value of tv_nsec part */ /* should be less than a million. If the value of tv_ms part is */ /* GC_TIME_UNLIMITED then tv_nsec is ignored. Initially, the value of */ /* tv_nsec part of the time limit is zero. The functions do not use */ /* any synchronization. Defined only if the library has been compiled */ /* without NO_CLOCK. */
GC_API void GC_CALL GC_set_time_limit_tv(struct GC_timeval_s);
GC_API struct GC_timeval_s GC_CALL GC_get_time_limit_tv(void);
/* Set/get the minimum value of the ratio of allocated bytes since GC */ /* to the amount of finalizers created since that GC (value > */ /* GC_bytes_allocd / (GC_fo_entries - last_fo_entries)) which triggers */ /* the collection instead heap expansion. The value has no effect in */ /* the GC incremental mode. The default value is 10000 unless */ /* GC_ALLOCD_BYTES_PER_FINALIZER macro with a custom value is defined */ /* to build libgc. The default value might be not the right choice for */ /* clients where e.g. most objects have a finalizer. Zero value */ /* effectively disables taking amount of finalizers in the decision */ /* whether to collect or not. The functions do not use any */ /* synchronization. */
GC_API void GC_CALL GC_set_allocd_bytes_per_finalizer(GC_word);
GC_API GC_word GC_CALL GC_get_allocd_bytes_per_finalizer(void);
/* Tell the collector to start various performance measurements. */ /* Only the total time taken by full collections is calculated, as */ /* of now. And, currently, there is no way to stop the measurements. */ /* The function does not use any synchronization. Defined only if the */ /* library has been compiled without NO_CLOCK. */
GC_API void GC_CALL GC_start_performance_measurement(void);
/* Get the total time of all full collections since the start of the */ /* performance measurements. The measurement unit is one millisecond. */ /* Note that the returned value wraps around on overflow. */ /* The function does not use any synchronization. Defined only if the */ /* library has been compiled without NO_CLOCK. */
GC_API unsignedlong GC_CALL GC_get_full_gc_total_time(void);
/* Set whether the GC will allocate executable memory pages or not. */ /* A non-zero argument instructs the collector to allocate memory with */ /* the executable flag on. Must be called before the collector is */ /* initialized. May have no effect on some platforms. The default */ /* value is controlled by NO_EXECUTE_PERMISSION macro (if present then */ /* the flag is off). Portable clients should have */ /* GC_set_pages_executable(1) call (before GC_INIT) provided they are */ /* going to execute code on any of the GC-allocated memory objects. */
GC_API void GC_CALL GC_set_pages_executable(int);
/* Returns non-zero value if the GC is set to the allocate-executable */ /* mode. The mode could be changed by GC_set_pages_executable (before */ /* GC_INIT) unless the former has no effect on the platform. Does not */ /* use or need synchronization (i.e. acquiring the allocator lock). */
GC_API int GC_CALL GC_get_pages_executable(void);
/* The setter and getter of the minimum value returned by the internal */ /* min_bytes_allocd(). The value should not be zero; the default value */ /* is one. Not synchronized. */
GC_API void GC_CALL GC_set_min_bytes_allocd(size_t);
GC_API size_t GC_CALL GC_get_min_bytes_allocd(void);
/* Set/get the size in pages of units operated by GC_collect_a_little. */ /* The value should not be zero. Not synchronized. */
GC_API void GC_CALL GC_set_rate(int);
GC_API int GC_CALL GC_get_rate(void);
/* Set/get the maximum number of prior attempts at the world-stop */ /* marking. Not synchronized. */
GC_API void GC_CALL GC_set_max_prior_attempts(int);
GC_API int GC_CALL GC_get_max_prior_attempts(void);
/* Control whether to disable algorithm deciding if a collection should */ /* be started when we allocated enough to amortize GC. Both the setter */ /* and the getter acquire the GC lock (to avoid data races). */
GC_API void GC_CALL GC_set_disable_automatic_collection(int);
GC_API int GC_CALL GC_get_disable_automatic_collection(void);
/* Overrides the default handle-fork mode. Non-zero value means GC */ /* should install proper pthread_atfork handlers. Has effect only if */ /* called before GC_INIT. Clients should invoke GC_set_handle_fork */ /* with non-zero argument if going to use fork with GC functions called */ /* in the forked child. (Note that such client and atfork handlers */ /* activities are not fully POSIX-compliant.) GC_set_handle_fork */ /* instructs GC_init to setup GC fork handlers using pthread_atfork, */ /* the latter might fail (or, even, absent on some targets) causing */ /* abort at GC initialization. Issues with missing (or failed) */ /* pthread_atfork() could be avoided by invocation */ /* of GC_set_handle_fork(-1) at application start-up and surrounding */ /* each fork() with the relevant GC_atfork_prepare/parent/child calls. */
GC_API void GC_CALL GC_set_handle_fork(int);
/* Routines to handle POSIX fork() manually (no-op if handled */ /* automatically). GC_atfork_prepare should be called immediately */ /* before fork(); GC_atfork_parent should be invoked just after fork in */ /* the branch that corresponds to parent process (i.e., fork result is */ /* non-zero); GC_atfork_child is to be called immediately in the child */ /* branch (i.e., fork result is 0). Note that GC_atfork_child() call */ /* should, of course, precede GC_start_mark_threads call (if any). */
GC_API void GC_CALL GC_atfork_prepare(void);
GC_API void GC_CALL GC_atfork_parent(void);
GC_API void GC_CALL GC_atfork_child(void);
/* Initialize the collector. Portable clients should call GC_INIT() */ /* from the main program instead. */
GC_API void GC_CALL GC_init(void);
/* Returns non-zero (TRUE) if and only if the collector is initialized */ /* (or, at least, the initialization is in progress). */
GC_API int GC_CALL GC_is_init_called(void);
/* Perform the collector shutdown. (E.g. dispose critical sections on */ /* Win32 target.) A duplicate invocation is a no-op. GC_INIT should */ /* not be called after the shutdown. See also GC_win32_free_heap(). */
GC_API void GC_CALL GC_deinit(void);
/* General purpose allocation routines, with roughly malloc calling */ /* conv. The atomic versions promise that no relevant pointers are */ /* contained in the object. The non-atomic versions guarantee that the */ /* new object is cleared. GC_malloc_uncollectable allocates */ /* an object that is scanned for pointers to collectible */ /* objects, but is not itself collectible. The object is scanned even */ /* if it does not appear to be reachable. GC_malloc_uncollectable and */ /* GC_free called on the resulting object implicitly update */ /* GC_non_gc_bytes appropriately. */
GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
GC_malloc(size_t /* size_in_bytes */);
GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
GC_malloc_atomic(size_t /* size_in_bytes */);
GC_API GC_ATTR_MALLOC char * GC_CALL GC_strdup(constchar *);
GC_API GC_ATTR_MALLOC char * GC_CALL
GC_strndup(constchar *, size_t) GC_ATTR_NONNULL(1);
GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
GC_malloc_uncollectable(size_t /* size_in_bytes */);
GC_API GC_ATTR_DEPRECATED void * GC_CALL GC_malloc_stubborn(size_t);
/* GC_memalign() is not well tested. */
GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(2) void * GC_CALL
GC_memalign(size_t /* align */, size_t /* lb */);
GC_API int GC_CALL GC_posix_memalign(void ** /* memptr */, size_t /* align */,
size_t /* lb */) GC_ATTR_NONNULL(1);
/* Explicitly deallocate an object. Dangerous if used incorrectly. */ /* Requires a pointer to the base of an object. */ /* An object should not be enabled for finalization (and it should not */ /* contain registered disappearing links of any kind) when it is */ /* explicitly deallocated. */ /* GC_free(0) is a no-op, as required by ANSI C for free. */
GC_API void GC_CALL GC_free(void *);
/* The "stubborn" objects allocation is not supported anymore. Exists */ /* only for the backward compatibility. */ #define GC_MALLOC_STUBBORN(sz) GC_MALLOC(sz) #define GC_NEW_STUBBORN(t) GC_NEW(t) #define GC_CHANGE_STUBBORN(p) GC_change_stubborn(p)
GC_API GC_ATTR_DEPRECATED void GC_CALL GC_change_stubborn(constvoid *);
/* Inform the collector that the object has been changed. */ /* Only non-NULL pointer stores into the object are considered to be */ /* changes. Matters only if the incremental collection is enabled in */ /* the manual VDB mode (otherwise the function does nothing). */ /* Should be followed typically by GC_reachable_here called for each */ /* of the stored pointers. */
GC_API void GC_CALL GC_end_stubborn_change(constvoid *) GC_ATTR_NONNULL(1);
/* Return a pointer to the base (lowest address) of an object given */ /* a pointer to a location within the object. */ /* I.e., map an interior pointer to the corresponding base pointer. */ /* Note that with debugging allocation, this returns a pointer to the */ /* actual base of the object, i.e. the debug information, not to */ /* the base of the user object. */ /* Return 0 if displaced_pointer doesn't point to within a valid */ /* object. */ /* Note that a deallocated object in the garbage collected heap */ /* may be considered valid, even if it has been deallocated with */ /* GC_free. */
GC_API void * GC_CALL GC_base(void * /* displaced_pointer */);
/* Return non-zero (TRUE) if and only if the argument points to */ /* somewhere in GC heap. Primary use is as a fast alternative to */ /* GC_base to check whether the pointed object is allocated by GC */ /* or not. It is assumed that the collector is already initialized. */
GC_API int GC_CALL GC_is_heap_ptr(constvoid *);
/* Given a pointer to the base of an object, return its size in bytes. */ /* The returned size may be slightly larger than what was originally */ /* requested. */
GC_API size_t GC_CALL GC_size(constvoid * /* obj_addr */) GC_ATTR_NONNULL(1);
/* For compatibility with C library. This is occasionally faster than */ /* a malloc followed by a bcopy. But if you rely on that, either here */ /* or with the standard C library, your code is broken. In my */ /* opinion, it shouldn't have been invented, but now we're stuck. -HB */ /* The resulting object has the same kind as the original. */ /* It is an error to have changes enabled for the original object. */ /* It does not change the content of the object from its beginning to */ /* the minimum of old size and new_size_in_bytes; the content above in */ /* case of object size growth is initialized to zero (not guaranteed */ /* for atomic object type). The function follows ANSI conventions for */ /* NULL old_object (i.e., equivalent to GC_malloc regardless of new */ /* size). If new size is zero (and old_object is non-NULL) then the */ /* call is equivalent to GC_free (and NULL is returned). If old_object */ /* is non-NULL, it must have been returned by an earlier call to */ /* GC_malloc* or GC_realloc. In case of the allocation failure, the */ /* memory pointed by old_object is untouched (and not freed). */ /* If the returned pointer is not the same as old_object and both of */ /* them are non-NULL then old_object is freed. Returns either NULL (in */ /* case of the allocation failure or zero new size) or pointer to the */ /* allocated memory. */
GC_API void * GC_CALL GC_realloc(void * /* old_object */,
size_t /* new_size_in_bytes */) /* 'realloc' attr */ GC_ATTR_ALLOC_SIZE(2);
/* Explicitly increase the heap size. */ /* Returns 0 on failure, 1 on success. */
GC_API int GC_CALL GC_expand_hp(size_t /* number_of_bytes */);
/* Limit the heap size to n bytes. Useful when you're debugging, */ /* especially on systems that don't handle running out of memory well. */ /* n == 0 ==> unbounded. This is the default. This setter function is */ /* unsynchronized (so it might require GC_call_with_alloc_lock to avoid */ /* data races). */
GC_API void GC_CALL GC_set_max_heap_size(GC_word /* n */);
/* Inform the collector that a certain section of statically allocated */ /* memory contains no pointers to garbage collected memory. Thus it */ /* need not be scanned. This is sometimes important if the application */ /* maps large read/write files into the address space, which could be */ /* mistaken for dynamic library data segments on some systems. */ /* Both section start and end are not needed to be pointer-aligned. */
GC_API void GC_CALL GC_exclude_static_roots(void * /* low_address */, void * /* high_address_plus_1 */);
/* Clear the number of entries in the exclusion table. Wizards only. */
GC_API void GC_CALL GC_clear_exclusion_table(void);
/* Clear the set of root segments. Wizards only. */
GC_API void GC_CALL GC_clear_roots(void);
/* Add a root segment. Wizards only. */ /* May merge adjacent or overlapping segments if appropriate. */ /* Both segment start and end are not needed to be pointer-aligned. */ /* low_address must not be greater than high_address_plus_1. */
GC_API void GC_CALL GC_add_roots(void * /* low_address */, void * /* high_address_plus_1 */);
/* Remove root segments located fully in the region. Wizards only. */
GC_API void GC_CALL GC_remove_roots(void * /* low_address */, void * /* high_address_plus_1 */);
/* Add a displacement to the set of those considered valid by the */ /* collector. GC_register_displacement(n) means that if p was returned */ /* by GC_malloc, then (char *)p + n will be considered to be a valid */ /* pointer to p. N must be small and less than the size of p. */ /* (All pointers to the interior of objects from the stack are */ /* considered valid in any case. This applies to heap objects and */ /* static data.) */ /* Preferably, this should be called before any other GC procedures. */ /* Calling it later adds to the probability of excess memory */ /* retention. */ /* This is a no-op if the collector has recognition of */ /* arbitrary interior pointers enabled, which is now the default. */
GC_API void GC_CALL GC_register_displacement(size_t /* n */);
/* The following version should be used if any debugging allocation is */ /* being done. */
GC_API void GC_CALL GC_debug_register_displacement(size_t /* n */);
/* Same as above but ignores the default stop_func setting and tries to */ /* unmap as much memory as possible (regardless of the corresponding */ /* switch setting). The recommended usage: on receiving a system */ /* low-memory event; before retrying a system call failed because of */ /* the system is running out of resources. */
GC_API void GC_CALL GC_gcollect_and_unmap(void);
/* Trigger a full world-stopped collection. Abort the collection if */ /* and when stop_func returns a nonzero value. Stop_func will be */ /* called frequently, and should be reasonably fast. (stop_func is */ /* called with the allocation lock held and the world might be stopped; */ /* it's not allowed for stop_func to manipulate pointers to the garbage */ /* collected heap or call most of GC functions.) This works even */ /* if virtual dirty bits, and hence incremental collection is not */ /* available for this architecture. Collections can be aborted faster */ /* than normal pause times for incremental collection. However, */ /* aborted collections do no useful work; the next collection needs */ /* to start from the beginning. stop_func must not be 0. */ /* GC_try_to_collect() returns 0 if the collection was aborted (or the */ /* collections are disabled), 1 if it succeeded. */ typedefint (GC_CALLBACK * GC_stop_func)(void);
GC_API int GC_CALL GC_try_to_collect(GC_stop_func /* stop_func */)
GC_ATTR_NONNULL(1);
/* Set and get the default stop_func. The default stop_func is used by */ /* GC_gcollect() and by implicitly triggered collections (except for */ /* the case when handling out of memory). Must not be 0. */ /* Both the setter and getter acquire the GC lock to avoid data races. */
GC_API void GC_CALL GC_set_stop_func(GC_stop_func /* stop_func */)
GC_ATTR_NONNULL(1);
GC_API GC_stop_func GC_CALL GC_get_stop_func(void);
/* Return the number of bytes in the heap. Excludes collector private */ /* data structures. Excludes the unmapped memory (returned to the OS). */ /* Includes empty blocks and fragmentation loss. Includes some pages */ /* that were allocated but never written. */ /* This is an unsynchronized getter, so it should be called typically */ /* with the GC lock held to avoid data races on multiprocessors (the */ /* alternative is to use GC_get_heap_usage_safe or GC_get_prof_stats */ /* API calls instead). */ /* This getter remains lock-free (unsynchronized) for compatibility */ /* reason since some existing clients call it from a GC callback */ /* holding the allocator lock. (This API function and the following */ /* four ones below were made thread-safe in GC v7.2alpha1 and */ /* reverted back in v7.2alpha7 for the reason described.) */
GC_API size_t GC_CALL GC_get_heap_size(void);
/* Return a lower bound on the number of free bytes in the heap */ /* (excluding the unmapped memory space). This is an unsynchronized */ /* getter (see GC_get_heap_size comment regarding thread-safety). */
GC_API size_t GC_CALL GC_get_free_bytes(void);
/* Return the size (in bytes) of the unmapped memory (which is returned */ /* to the OS but could be remapped back by the collector later unless */ /* the OS runs out of system/virtual memory). This is an unsynchronized */ /* getter (see GC_get_heap_size comment regarding thread-safety). */
GC_API size_t GC_CALL GC_get_unmapped_bytes(void);
/* Return the number of bytes allocated since the last collection. */ /* This is an unsynchronized getter (see GC_get_heap_size comment */ /* regarding thread-safety). */
GC_API size_t GC_CALL GC_get_bytes_since_gc(void);
/* Return the number of explicitly deallocated bytes of memory since */ /* the recent collection. This is an unsynchronized getter. */
GC_API size_t GC_CALL GC_get_expl_freed_bytes_since_gc(void);
/* Return the total number of bytes allocated in this process. */ /* Never decreases, except due to wrapping. This is an unsynchronized */ /* getter (see GC_get_heap_size comment regarding thread-safety). */
GC_API size_t GC_CALL GC_get_total_bytes(void);
/* Return the total number of bytes obtained from OS. Includes the */ /* unmapped memory. Never decreases. It is an unsynchronized getter. */
GC_API size_t GC_CALL GC_get_obtained_from_os_bytes(void);
/* Return the heap usage information. This is a thread-safe (atomic) */ /* alternative for the five above getters. (This function acquires */ /* the allocator lock thus preventing data racing and returning the */ /* consistent result.) Passing NULL pointer is allowed for any */ /* argument. Returned (filled in) values are of word type. */
GC_API void GC_CALL GC_get_heap_usage_safe(GC_word * /* pheap_size */,
GC_word * /* pfree_bytes */,
GC_word * /* punmapped_bytes */,
GC_word * /* pbytes_since_gc */,
GC_word * /* ptotal_bytes */);
/* Structure used to query GC statistics (profiling information). */ /* More fields could be added in the future. To preserve compatibility */ /* new fields should be added only to the end, and no deprecated fields */ /* should be removed from. */ struct GC_prof_stats_s {
GC_word heapsize_full; /* Heap size in bytes (including the area unmapped to OS). */ /* Same as GC_get_heap_size() + GC_get_unmapped_bytes(). */
GC_word free_bytes_full; /* Total bytes contained in free and unmapped blocks. */ /* Same as GC_get_free_bytes() + GC_get_unmapped_bytes(). */
GC_word unmapped_bytes; /* Amount of memory unmapped to OS. Same as the value */ /* returned by GC_get_unmapped_bytes(). */
GC_word bytes_allocd_since_gc; /* Number of bytes allocated since the recent collection. */ /* Same as returned by GC_get_bytes_since_gc(). */
GC_word allocd_bytes_before_gc; /* Number of bytes allocated before the recent garbage */ /* collection. The value may wrap. Same as the result of */ /* GC_get_total_bytes() - GC_get_bytes_since_gc(). */
GC_word non_gc_bytes; /* Number of bytes not considered candidates for garbage */ /* collection. Same as returned by GC_get_non_gc_bytes(). */
GC_word gc_no; /* Garbage collection cycle number. The value may wrap */ /* (and could be -1). Same as returned by GC_get_gc_no(). */
GC_word markers_m1; /* Number of marker threads (excluding the initiating one). */ /* Same as returned by GC_get_parallel (or 0 if the */ /* collector is single-threaded). */
GC_word bytes_reclaimed_since_gc; /* Approximate number of reclaimed bytes after recent GC. */
GC_word reclaimed_bytes_before_gc; /* Approximate number of bytes reclaimed before the recent */ /* garbage collection. The value may wrap. */
GC_word expl_freed_bytes_since_gc; /* Number of bytes freed explicitly since the recent GC. */ /* Same as returned by GC_get_expl_freed_bytes_since_gc(). */
GC_word obtained_from_os_bytes; /* Total amount of memory obtained from OS, in bytes. */
};
/* Atomically get GC statistics (various global counters). Clients */ /* should pass the size of the buffer (of GC_prof_stats_s type) to fill */ /* in the values - this is for interoperability between different GC */ /* versions, an old client could have fewer fields, and vice versa, */ /* client could use newer gc.h (with more entries declared in the */ /* structure) than that of the linked libgc binary; in the latter case, */ /* unsupported (unknown) fields are filled in with -1. Return the size */ /* (in bytes) of the filled in part of the structure (excluding all */ /* unknown fields, if any). */
GC_API size_t GC_CALL GC_get_prof_stats(struct GC_prof_stats_s *,
size_t /* stats_sz */); #ifdef GC_THREADS /* Same as above but unsynchronized (i.e., not holding the allocation */ /* lock). Clients should call it using GC_call_with_alloc_lock to */ /* avoid data races on multiprocessors. */
GC_API size_t GC_CALL GC_get_prof_stats_unsafe(struct GC_prof_stats_s *,
size_t /* stats_sz */); #endif
/* Get the element value (converted to bytes) at a given index of */ /* size_map table which provides requested-to-actual allocation size */ /* mapping. Assumes the collector is initialized. Returns -1 if the */ /* index is out of size_map table bounds. Does not use synchronization, */ /* thus clients should call it using GC_call_with_alloc_lock typically */ /* to avoid data races on multiprocessors. */
GC_API size_t GC_CALL GC_get_size_map_at(int i);
/* Count total memory use in bytes by all allocated blocks. Acquires */ /* the lock. */
GC_API size_t GC_CALL GC_get_memory_use(void);
/* Disable garbage collection. Even GC_gcollect calls will be */ /* ineffective. */
GC_API void GC_CALL GC_disable(void);
/* Return non-zero (TRUE) if and only if garbage collection is disabled */ /* (i.e., GC_dont_gc value is non-zero). Does not acquire the lock. */
GC_API int GC_CALL GC_is_disabled(void);
/* Try to re-enable garbage collection. GC_disable() and GC_enable() */ /* calls nest. Garbage collection is enabled if the number of calls to */ /* both functions is equal. */
GC_API void GC_CALL GC_enable(void);
/* Select whether to use the manual VDB mode for the incremental */ /* collection. Has no effect if called after enabling the incremental */ /* collection. The default value is off unless the collector is */ /* compiled with MANUAL_VDB defined. The manual VDB mode should be */ /* used only if the client has the appropriate GC_END_STUBBORN_CHANGE */ /* and GC_reachable_here (or, alternatively, GC_PTR_STORE_AND_DIRTY) */ /* calls (to ensure proper write barriers). Both the setter and getter */ /* are not synchronized, and are defined only if the library has been */ /* compiled without SMALL_CONFIG. */
GC_API void GC_CALL GC_set_manual_vdb_allowed(int);
GC_API int GC_CALL GC_get_manual_vdb_allowed(void);
/* Enable incremental/generational collection. Not advisable unless */ /* dirty bits are available or most heap objects are pointer-free */ /* (atomic) or immutable. Don't use in leak finding mode. Ignored if */ /* GC_dont_gc is non-zero. Only the generational piece of this is */ /* functional if GC_time_limit is set to GC_TIME_UNLIMITED. Causes */ /* thread-local variant of GC_gcj_malloc() to revert to locked */ /* allocation. Must be called before any such GC_gcj_malloc() calls. */ /* For best performance, should be called as early as possible. */ /* On some platforms, calling it later may have adverse effects. */ /* Safe to call before GC_INIT(). Includes a GC_init() call. */
GC_API void GC_CALL GC_enable_incremental(void);
/* Return non-zero (TRUE) if and only if the incremental mode is on. */ /* Does not acquire the lock. */
GC_API int GC_CALL GC_is_incremental_mode(void);
/* Does incremental mode write-protect pages? Returns zero or */ /* more of the above GC_PROTECTS_*, or'ed together. */ /* The collector is assumed to be initialized before this call. */ /* The result is not affected by GC_set_manual_vdb_allowed(). */ /* Call of GC_enable_incremental() may change the result to */ /* GC_PROTECTS_NONE if some implementation is chosen at runtime */ /* not needing to write-protect the pages. */
GC_API int GC_CALL GC_incremental_protection_needs(void);
/* Force start of incremental collection. Acquires the GC lock. */ /* No-op unless GC incremental mode is on. */
GC_API void GC_CALL GC_start_incremental_collection(void);
/* Perform some garbage collection work, if appropriate. */ /* Return 0 if there is no more work to be done (including the */ /* case when garbage collection is not appropriate). */ /* Typically performs an amount of work corresponding roughly */ /* to marking from one page. May do more work if further */ /* progress requires it, e.g. if incremental collection is */ /* disabled. It is reasonable to call this in a wait loop */ /* until it returns 0. */
GC_API int GC_CALL GC_collect_a_little(void);
/* Allocate an object of size lb bytes. The client guarantees that */ /* as long as the object is live, it will be referenced by a pointer */ /* that points to somewhere within the first 256 bytes of the object. */ /* (This should normally be declared volatile to prevent the compiler */ /* from invalidating this assertion.) This routine is only useful */ /* if a large array is being allocated. It reduces the chance of */ /* accidentally retaining such an array as a result of scanning an */ /* integer that happens to be an address inside the array. (Actually, */ /* it reduces the chance of the allocator not finding space for such */ /* an array, since it will try hard to avoid introducing such a false */ /* reference.) On a SunOS 4.X or MS Windows system this is recommended */ /* for arrays likely to be larger than 100 KB or so. For other systems,*/ /* or if the collector is not configured to recognize all interior */ /* pointers, the threshold is normally much higher. */
GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
GC_malloc_ignore_off_page(size_t /* lb */);
GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
GC_malloc_atomic_ignore_off_page(size_t /* lb */);
#ifdef GC_ADD_CALLER # define GC_EXTRAS GC_RETURN_ADDR, __FILE__, __LINE__ # define GC_EXTRA_PARAMS GC_word ra, constchar * s, int i #else # define GC_EXTRAS __FILE__, __LINE__ # define GC_EXTRA_PARAMS constchar * s, int i #endif
/* The following is only defined if the library has been suitably */ /* compiled: */
GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
GC_malloc_atomic_uncollectable(size_t /* size_in_bytes */);
GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
GC_debug_malloc_atomic_uncollectable(size_t, GC_EXTRA_PARAMS);
/* Routines that allocate objects with debug information (like the */ /* above), but just fill in dummy file and line number information. */ /* Thus they can serve as drop-in malloc/realloc replacements. This */ /* can be useful for two reasons: */ /* 1) It allows the collector to be built with DBG_HDRS_ALL defined */ /* even if some allocation calls come from 3rd party libraries */ /* that can't be recompiled. */ /* 2) On some platforms, the file and line information is redundant, */ /* since it can be reconstructed from a stack trace. On such */ /* platforms it may be more convenient not to recompile, e.g. for */ /* leak detection. This can be accomplished by instructing the */ /* linker to replace malloc/realloc with these. */
GC_API GC_ATTR_MALLOC GC_ATTR_ALLOC_SIZE(1) void * GC_CALL
GC_debug_malloc_replacement(size_t /* size_in_bytes */);
GC_API /* 'realloc' attr */ GC_ATTR_ALLOC_SIZE(2) void * GC_CALL
GC_debug_realloc_replacement(void * /* object_addr */,
size_t /* size_in_bytes */);
/* The following are included because they are often convenient, and */ /* reduce the chance for a misspecified size argument. But calls may */ /* expand to something syntactically incorrect if t is a complicated */ /* type expression. Note that, unlike C++ new operator, these ones */ /* may return NULL (if out of memory). */ #define GC_NEW(t) ((t*)GC_MALLOC(sizeof(t))) #define GC_NEW_ATOMIC(t) ((t*)GC_MALLOC_ATOMIC(sizeof(t))) #define GC_NEW_UNCOLLECTABLE(t) ((t*)GC_MALLOC_UNCOLLECTABLE(sizeof(t)))
#ifdef GC_REQUIRE_WCSDUP /* This might be unavailable on some targets (or not needed). */ /* wchar_t should be defined in stddef.h */
GC_API GC_ATTR_MALLOC wchar_t * GC_CALL
GC_wcsdup(constwchar_t *) GC_ATTR_NONNULL(1);
GC_API GC_ATTR_MALLOC wchar_t * GC_CALL
GC_debug_wcsdup(constwchar_t *, GC_EXTRA_PARAMS) GC_ATTR_NONNULL(1); # ifdef GC_DEBUG # define GC_WCSDUP(s) GC_debug_wcsdup(s, GC_EXTRAS) # else # define GC_WCSDUP(s) GC_wcsdup(s) # endif #endif/* GC_REQUIRE_WCSDUP */
/* Finalization. Some of these primitives are grossly unsafe. */ /* The idea is to make them both cheap, and sufficient to build */ /* a safer layer, closer to Modula-3, Java, or PCedar finalization. */ /* The interface represents my conclusions from a long discussion */ /* with Alan Demers, Dan Greene, Carl Hauser, Barry Hayes, */ /* Christian Jacobi, and Russ Atkinson. It's not perfect, and */ /* probably nobody else agrees with it. Hans-J. Boehm 3/13/92 */ typedefvoid (GC_CALLBACK * GC_finalization_proc)(void * /* obj */, void * /* client_data */);
GC_API void GC_CALL GC_register_finalizer(void * /* obj */,
GC_finalization_proc /* fn */, void * /* cd */,
GC_finalization_proc * /* ofn */, void ** /* ocd */)
GC_ATTR_NONNULL(1);
GC_API void GC_CALL GC_debug_register_finalizer(void * /* obj */,
GC_finalization_proc /* fn */, void * /* cd */,
GC_finalization_proc * /* ofn */, void ** /* ocd */)
GC_ATTR_NONNULL(1); /* When obj is no longer accessible, invoke */ /* (*fn)(obj, cd). If a and b are inaccessible, and */ /* a points to b (after disappearing links have been */ /* made to disappear), then only a will be */ /* finalized. (If this does not create any new */ /* pointers to b, then b will be finalized after the */ /* next collection.) Any finalizable object that */ /* is reachable from itself by following one or more */ /* pointers will not be finalized (or collected). */
--> --------------------
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