2003-02-28 07:08:51 +00:00
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/* GDB Notifications to Observers.
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2004-07-28 17:26:27 +00:00
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Copyright 2003, 2004 Free Software Foundation, Inc.
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2003-02-28 07:08:51 +00:00
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* An observer is an entity who is interested in being notified when GDB
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reaches certain states, or certain events occur in GDB. The entity being
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observed is called the Subject. To receive notifications, the observer
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attaches a callback to the subject. One subject can have several
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observers.
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This file implements an internal generic low-level event notification
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mechanism based on the Observer paradigm described in the book "Design
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Patterns". This generic event notification mechansim is then re-used
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to implement the exported high-level notification management routines
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for all possible notifications.
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The current implementation of the generic observer provides support
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for contextual data. This contextual data is given to the subject
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when attaching the callback. In return, the subject will provide
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this contextual data back to the observer as a parameter of the
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callback.
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FIXME: The current support for the contextual data is only partial,
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as it lacks a mechanism that would deallocate this data when the
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callback is detached. This is not a problem so far, as this contextual
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data is only used internally to hold a function pointer. Later on,
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if a certain observer needs to provide support for user-level
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contextual data, then the generic notification mechanism will need
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need to be enhanced to allow the observer to provide a routine to
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deallocate the data when attaching the callback.
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This file is currently maintained by hand, but the long term plan
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if the number of different notifications starts growing is to create
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a new script (observer.sh) that would generate this file, and the
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associated documentation. */
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#include "defs.h"
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#include "observer.h"
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2004-05-07 22:51:55 +00:00
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#include "command.h"
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#include "gdbcmd.h"
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static int observer_debug;
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2003-02-28 07:08:51 +00:00
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/* The internal generic observer. */
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typedef void (generic_observer_notification_ftype) (const void *data,
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const void *args);
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struct observer
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{
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generic_observer_notification_ftype *notify;
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/* No memory management needed for the following field for now. */
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void *data;
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};
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/* A list of observers, maintained by the subject. A subject is
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actually represented by its list of observers. */
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struct observer_list
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{
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struct observer_list *next;
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struct observer *observer;
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};
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/* Allocate a struct observer_list, intended to be used as a node
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in the list of observers maintained by a subject. */
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static struct observer_list *
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xalloc_observer_list_node (void)
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{
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struct observer_list *node = XMALLOC (struct observer_list);
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node->observer = XMALLOC (struct observer);
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return node;
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}
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/* The opposite of xalloc_observer_list_node, frees the memory for
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the given node. */
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static void
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xfree_observer_list_node (struct observer_list *node)
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{
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xfree (node->observer);
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xfree (node);
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}
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2003-02-28 07:19:32 +00:00
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/* Attach the callback NOTIFY to a SUBJECT. The DATA is also stored,
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in order for the subject to provide it back to the observer during
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a notification. */
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2003-02-28 07:08:51 +00:00
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static struct observer *
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generic_observer_attach (struct observer_list **subject,
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generic_observer_notification_ftype * notify,
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void *data)
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{
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struct observer_list *observer_list = xalloc_observer_list_node ();
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observer_list->next = *subject;
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observer_list->observer->notify = notify;
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observer_list->observer->data = data;
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*subject = observer_list;
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return observer_list->observer;
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}
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2003-02-28 07:19:32 +00:00
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/* Remove the given OBSERVER from the SUBJECT. Once detached, OBSERVER
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should no longer be used, as it is no longer valid. */
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2003-02-28 07:08:51 +00:00
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static void
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generic_observer_detach (struct observer_list **subject,
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const struct observer *observer)
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{
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struct observer_list *previous_node = NULL;
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struct observer_list *current_node = *subject;
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while (current_node != NULL)
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{
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if (current_node->observer == observer)
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{
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if (previous_node != NULL)
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previous_node->next = current_node->next;
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else
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*subject = current_node->next;
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xfree_observer_list_node (current_node);
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return;
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}
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previous_node = current_node;
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current_node = current_node->next;
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}
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/* We should never reach this point. However, this should not be
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a very serious error, so simply report a warning to the user. */
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2005-02-10 Andrew Cagney <cagney@gnu.org>
Mark up all error and warning messages.
* ada-lang.c, amd64-tdep.c, arch-utils.c, breakpoint.c: Update.
* bsd-kvm.c, bsd-uthread.c, coff-solib.h, coffread.c: Update.
* core-aout.c, core-regset.c, corefile.c, corelow.c: Update.
* cp-abi.c, cp-support.c, cp-valprint.c, cris-tdep.c: Update.
* dbxread.c, demangle.c, doublest.c, dsrec.c: Update.
* dve3900-rom.c, dwarf2expr.c, dwarf2loc.c: Update.
* dwarf2read.c, dwarfread.c, elfread.c, eval.c: Update.
* event-top.c, exec.c, expprint.c, f-lang.c: Update.
* f-typeprint.c, f-valprint.c, fbsd-nat.c, findvar.c: Update.
* frame.c, frv-linux-tdep.c, gcore.c, gdbtypes.c: Update.
* gnu-nat.c, gnu-v2-abi.c, gnu-v3-abi.c, go32-nat.c: Update.
* hpacc-abi.c, hppa-hpux-nat.c, hppa-hpux-tdep.c: Update.
* hppa-linux-nat.c, hppa-linux-tdep.c, hppa-tdep.c: Update.
* hpread.c, hpux-thread.c, i386-linux-nat.c: Update.
* i386-linux-tdep.c, i386-tdep.c, i386bsd-nat.c: Update.
* i386gnu-nat.c, i387-tdep.c, ia64-linux-nat.c: Update.
* ia64-tdep.c, inf-child.c, inf-ptrace.c, inf-ttrace.c: Update.
* infcall.c, infcmd.c, inflow.c, infptrace.c, infrun.c: Update.
* inftarg.c, interps.c, irix5-nat.c, jv-lang.c: Update.
* kod-cisco.c, kod.c, language.c, libunwind-frame.c: Update.
* linespec.c, linux-nat.c, linux-thread-db.c, m2-lang.c: Update.
* m32r-rom.c, m68hc11-tdep.c, m68k-tdep.c: Update.
* m68klinux-nat.c, macrocmd.c, macroexp.c, main.c: Update.
* maint.c, mdebugread.c, mem-break.c, memattr.c: Update.
* mips-linux-tdep.c, mips-tdep.c, mipsread.c, monitor.c: Update.
* nlmread.c, nto-procfs.c, objc-lang.c, objfiles.c: Update.
* observer.c, ocd.c, p-lang.c, p-typeprint.c: Update.
* p-valprint.c, pa64solib.c, parse.c, ppc-linux-tdep.c: Update.
* ppcnbsd-tdep.c, printcmd.c, procfs.c, remote-e7000.c: Update.
* remote-fileio.c, remote-m32r-sdi.c, remote-rdi.c: Update.
* remote-rdp.c, remote-sim.c, remote-st.c: Update.
* remote-utils.c, remote-utils.h, remote.c: Update.
* rom68k-rom.c, rs6000-nat.c, s390-tdep.c, scm-lang.c: Update.
* ser-e7kpc.c, ser-tcp.c, ser-unix.c, sh-tdep.c: Update.
* sh3-rom.c, shnbsd-tdep.c, sol-thread.c, solib-aix5.c: Update.
* solib-frv.c, solib-irix.c, solib-osf.c, solib-pa64.c: Update.
* solib-som.c, solib-sunos.c, solib-svr4.c, solib.c: Update.
* somread.c, somsolib.c, source.c, stabsread.c: Update.
* stack.c, std-regs.c, symfile-mem.c, symfile.c: Update.
* symmisc.c, symtab.c, target.c, thread.c, top.c: Update.
* tracepoint.c, trad-frame.c, typeprint.c, utils.c: Update.
* uw-thread.c, valarith.c, valops.c, valprint.c: Update.
* value.c, varobj.c, version.in, win32-nat.c, wince.c: Update.
* xcoffread.c, xcoffsolib.c, cli/cli-cmds.c: Update.
* cli/cli-decode.c, cli/cli-dump.c, cli/cli-logging.c: Update.
* cli/cli-script.c, cli/cli-setshow.c, mi/mi-cmd-break.c: Update.
* mi/mi-cmd-disas.c, mi/mi-cmd-env.c, mi/mi-cmd-file.c: Update.
* mi/mi-cmd-stack.c, mi/mi-cmd-var.c, mi/mi-getopt.c: Update.
* mi/mi-symbol-cmds.c, tui/tui-layout.c, tui/tui-stack.c: Update.
* tui/tui-win.c: Update.
2005-02-11 04:06:14 +00:00
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warning (_("Failed to detach observer"));
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2003-02-28 07:08:51 +00:00
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}
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2003-02-28 07:19:32 +00:00
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/* Send a notification to all the observers of SUBJECT. ARGS is passed to
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all observers as an argument to the notification callback. */
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2003-02-28 07:08:51 +00:00
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static void
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generic_observer_notify (struct observer_list *subject, const void *args)
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{
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struct observer_list *current_node = subject;
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while (current_node != NULL)
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{
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(*current_node->observer->notify) (current_node->observer->data, args);
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current_node = current_node->next;
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}
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}
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2003-03-18 18:05:51 +00:00
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2003-12-12 16:14:26 +00:00
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/* The following code is only used to unit-test the observers from our
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testsuite. DO NOT USE IT within observer.c (or anywhere else for
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that matter)! */
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2003-03-18 18:05:51 +00:00
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2003-12-12 16:14:26 +00:00
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/* If we define these variables and functions as `static', the
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compiler will optimize them out. */
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2003-03-18 18:05:51 +00:00
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2003-12-12 16:14:26 +00:00
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int observer_test_first_observer = 0;
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int observer_test_second_observer = 0;
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int observer_test_third_observer = 0;
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2003-03-18 18:05:51 +00:00
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2003-12-12 16:14:26 +00:00
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void
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2004-04-16 17:26:40 +00:00
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observer_test_first_notification_function (struct bpstats *bs)
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2003-03-18 18:05:51 +00:00
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{
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observer_test_first_observer++;
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}
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2003-12-12 16:14:26 +00:00
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void
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2004-04-16 17:26:40 +00:00
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observer_test_second_notification_function (struct bpstats *bs)
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2003-03-18 18:05:51 +00:00
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{
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observer_test_second_observer++;
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}
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2003-12-12 16:14:26 +00:00
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void
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2004-04-16 17:26:40 +00:00
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observer_test_third_notification_function (struct bpstats *bs)
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2003-03-18 18:05:51 +00:00
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{
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observer_test_third_observer++;
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}
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2004-05-07 22:51:55 +00:00
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extern initialize_file_ftype _initialize_observer; /* -Wmissing-prototypes */
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void
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_initialize_observer (void)
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{
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add_setshow_zinteger_cmd ("observer", class_maintenance, &observer_debug, "\
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2004-07-28 17:26:27 +00:00
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Set observer debugging.", "\
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Show observer debugging.", "\
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2005-02-10 17:32:53 +00:00
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When non-zero, observer debugging is enabled.",
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NULL, /* PRINT: Observer debugging is %s. */
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2004-05-07 22:51:55 +00:00
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NULL, NULL,
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&setdebuglist, &showdebuglist);
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}
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2004-04-15 14:29:21 +00:00
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#include "observer.inc"
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