*** empty log message ***

NEWS

@@ -147,6 +147,24 @@ an exception with a key of 'unbound-variable instead of 'misc-error.
 ** The initial default output port is now unbuffered if it's using a
 tty device.  Previously in this situation it was line-buffered.
 
+** gc-thunk is deprecated
+
+gc-thunk will be removed in next release of Guile.  It has been
+replaced by after-gc-hook.
+
+** New hook: after-gc-hook
+
+after-gc-hook takes over the role of gc-thunk.  This hook is run at
+the first SCM_TICK after a GC.  (Thus, the code is run at the same
+point during evaluation as signal handlers.)
+
+Note that this hook should be used only for diagnostic and debugging
+purposes.  It is not certain that it will continue to be well-defined
+when this hook is run in the future.
+
+C programmers: Note the new C level hooks scm_before_gc_c_hook,
+scm_before_sweep_c_hook, scm_after_gc_c_hook.
+
 * Changes to Scheme functions and syntax
 
 ** close-input-port and close-output-port are now R5RS
@@ -345,6 +363,56 @@ Use scm_mutex_init and scm_cond_init instead.
      currently executing threads, nor call the destructor function
      associated with the key.
 
+** New function: scm_c_hook_init (scm_c_hook_t *HOOK, void *HOOK_DATA, scm_c_hook_type_t TYPE)
+
+Initialize a C level hook HOOK with associated HOOK_DATA and type
+TYPE.  (See scm_c_hook_run ().)
+
+** New function: scm_c_hook_add (scm_c_hook_t *HOOK, scm_c_hook_function_t FUNC, void *FUNC_DATA, int APPENDP)
+
+Add hook function FUNC with associated FUNC_DATA to HOOK.  If APPENDP
+is true, add it last, otherwise first.  The same FUNC can be added
+multiple times if FUNC_DATA differ and vice versa.
+
+** New function: scm_c_hook_remove (scm_c_hook_t *HOOK, scm_c_hook_function_t FUNC, void *FUNC_DATA)
+
+Remove hook function FUNC with associated FUNC_DATA from HOOK.  A
+function is only removed if both FUNC and FUNC_DATA matches.
+
+** New function: void *scm_c_hook_run (scm_c_hook_t *HOOK, void *DATA)
+
+Run hook HOOK passing DATA to the hook functions.
+
+If TYPE is SCM_C_HOOK_NORMAL, all hook functions are run.  The value
+returned is undefined.
+
+If TYPE is SCM_C_HOOK_OR, hook functions are run until a function
+returns a non-NULL value.  This value is returned as the result of
+scm_c_hook_run.  If all functions return NULL, NULL is returned.
+
+If TYPE is SCM_C_HOOK_AND, hook functions are run until a function
+returns a NULL value, and NULL is returned.  If all functions returns
+a non-NULL value, the last value is returned.
+
+** New C level GC hooks
+
+Five new C level hooks has been added to the garbage collector.
+
+  scm_before_gc_c_hook
+  scm_after_gc_c_hook
+
+are run before locking and after unlocking the heap.  The system is
+thus in a mode where evaluation can take place.  (Except that
+scm_before_gc_c_hook must not allocate new cells.)
+
+  scm_before_mark_c_hook
+  scm_before_sweep_c_hook
+  scm_after_sweep_c_hook
+
+are run when the heap is locked.  These are intended for extension of
+the GC in a modular fashion.  Examples are the weaks and guardians
+modules.
+
 * Changes to system call interfaces:
 
 ** The "select" procedure now tests port buffers for the ability to

RELEASE

@@ -14,10 +14,10 @@ In release 1.4:
 - remove kw.h, scm_tc16_kw
 - remove genio.h
 - remove deprecated function scm_newsmob.
-- remove deprecated function scm_make_named_hook.
 
 In release 1.5:
 - remove deprecated macros: SCM_INPORTP, SCM_OUTPORTP
+- remove gc-thunk (It has been replaced by after-gc-hook.)
 
 Modules sort.c and random.c should be factored out into separate
 modules (but still be distributed with guile-core) when we get a new

libguile/ChangeLog

@@ -1,4 +1,54 @@
-2000-04-21  Mikael Djurfeldt  <mdj@thalamus.nada.kth.se>
+2000-04-22  Mikael Djurfeldt  <mdj@thalamus.nada.kth.se>
+
+	Better modularization of GC extensions through new C level GC
+	hooks:
+	
+	* weaks.c (scm_weaks_prehistory): New function: Add
+	scm_weak_vector_gc_init to scm_before_mark_c_hook; Add
+	scm_mark_weak_vector_spines to scm_before_sweep_c_hook.
+	(scm_scan_weak_vectors): New function; added to
+	scm_after_sweep_c_hook.
+
+	* weaks.h (scm_weak_vectors, scm_weaks_prehistory): Added
+	declarations.
+
+	* guardians.h (scm_guardian_gc_init, scm_guardian_zombify): Are
+	now static.
+
+	* guardians.c (scm_guardian_gc_init): Turned into a hook function
+	and added to scm_before_mark_c_hook.
+	(scm_guardian_zombify): Turned into a hook function and added to
+	scm_before_sweep_c_hook.
+
+	* async.c (scm_sys_gc_async_thunk): Run after-gc-hook.
+	Added #include "libguile/gc.h".
+
+	* gc.h: Added #include "libguile/hooks.h".
+
+	* gc.c: Removed #include "libguile/guardians.h".
+	(scm_before_gc_c_hook, scm_before_mark_c_hook,
+	scm_before_sweep_c_hook, scm_after_sweep_c_hook,
+	scm_after_gc_c_hook): New C level hooks.
+	(scm_after_gc_hook): New Scheme level hook.
+	(scm_gc_sweep): Moved scanning of weak vectors to weaks.c.
+	(scm_igc): Moved initialization of scm_weak_vectors and the call
+	to scm_guardian_gc_init to respective module.
+	(scm_mark_weak_vector_spines): Moved to weaks.c;
+	Call to scm_guardian_zombify moved to guardians.c;
+	Run scm_before_gc_c_hook, scm_before_sweep_c_hook,
+	scm_after_gc_c_hook at appropriate places.
+	(scm_init_gc): Initialize scm_after_gc_hook.
+
+	* hooks.c, hooks.h (scm_make_hook_with_name): Removed deprecated
+	function.
+
+	* init.c (scm_boot_guile_1): Added `scm_init_hooks'.
+
+	* Makefile.am: Added hooks.c, hooks.h, hooks.x.
+
+	* feature.c, feature.h: Broke out hook code into separate files.
+
+	* hooks.c, hooks.h: New files.
 
 	* *.*: Change includes so that they always use the "prefixes"
 	libguile/, qt/, guile-readline/, or libltdl/.