1mX Session Management Library0m

			1mVersion 1.00m

		   1mX Consortium Standard0m

		 1mX Version 11, Release 6.40m


			 4mRalph24m 4mMor0m
			X Consortium



	    Copyright © 1993, 1994 X Consortium







Permission  is hereby granted, free of charge, to any person
obtaining a copy of this software and associated  documenta-
tion files (the ``Software''), to deal in the Software with-
out restriction, including without limitation the rights  to
use,  copy,  modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to
whom the Software is furnished to do so, subject to the fol-
lowing conditions:

The above copyright notice and this permission notice  shall
be  included  in  all  copies or substantial portions of the
Software.

THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF	 ANY
KIND,  EXPRESS	OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PUR-
POSE  AND  NONINFRINGEMENT.  IN NO EVENT SHALL THE X CONSOR-
TIUM BE LIABLE FOR ANY CLAIM, DAMAGES  OR  OTHER  LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR  THE	 USE
OR OTHER DEALINGS IN THE SOFTWARE.

Except	as  contained in this notice, the name of the X Con-
sortium shall not be used in  advertising  or  otherwise  to
promote	 the  sale,  use  or other dealings in this Software
without prior written authorization from the X Consortium.















X Window System is a trademark of X Consortium, Inc.



































































































































1m1.  Overview of Session Management0m

The purpose of the X Session Management Protocol  (XSMP)  is
to provide a uniform mechanism for users to save and restore
their sessions.	 A 4msession24m is a group of  clients,	 each  of
which  has a particular state.	The session is controlled by
a network service called the 4msession24m 4mmanager24m.	  The  session
manager	 issues	 commands  to  its  clients on behalf of the
user.  These commands may cause clients to save their  state
or  to	terminate.  It is expected that the client will save
its state in such a way that the client can be restarted  at
a  later  time	and  resume its operation as if it had never
been terminated.  A client's state might include information
about  the file currently being edited, the current position
of the insertion point within the file, or the start  of  an
uncommitted  transaction.   The	 means	by which clients are
restarted is unspecified by this protocol.

For purposes of this protocol, a 4mclient24m of the session  man-
ager  is  defined as a connection to the session manager.  A
client is typically, though not necessarily, a process	run-
ning an application program connected to an X display.	How-
ever, a client may be connected to more than one  X  display
or not be connected to any X displays at all.

1m2.  The Session Management Library0m

The  Session  Management  Library (SMlib) is a low-level "C"
language interface to XSMP.   It  is  expected	that  higher
level toolkits, such as Xt, will hide many of the details of
session management  from  clients.   Higher  level  toolkits
might  also be developed for session managers to use, but no
such effort is currently under way.

SMlib has two parts to it:

·    One set of functions for clients that want to  be	part
     of a session

·    One set of functions for session managers to call

Some applications will use both sets of functions and act as
4mnested24m 4msession24m 4mmanagers24m.	 That is, they will be both a  ses-
sion manager and a client of another session.  An example is
a mail program that could start a text	editor	for  editing
the  text  of a mail message.  The mail program is part of a
regular session and, at the same time, is also acting  as  a
session manager to the editor.

Clients	 initialize by connecting to the session manager and
obtaining a 4mclient-ID24m that uniquely identifies them  in  the
session.  The session manager maintains a list of properties
for each client in the session.	 These	properties  describe
the client's environment and, most importantly, describe how



			    - 1 -





1mX Session Management Library		      X11, Release 6.40m


the client  can	 be  restarted	(via  an  4mSmRestartCommand24m).
Clients are expected to save their state in such a way as to
allow multiple instantiations of themselves  to	 be  managed
independently.	For example, clients may use their client-ID
as part of a filename in which to store the state for a par-
ticular	 instantiation.	  The  client-ID  should be saved as
part of the 4mSmRestartCommand24m so that the client will  retain
the same ID after it is restarted.

Once the client initializes itself with the session manager,
it must be ready to respond to	messages  from	the  session
manager.   For	example, it might be asked to save its state
or to terminate.  In the case of  a  shutdown,	the  session
manager might give each client a chance to interact with the
user and cancel the shutdown.

1m3.  Understanding SMlib's Dependence on ICE0m

The X Session Management Protocol is layered on top  of	 the
Inter-Client  Exchange	(ICE) Protocol.	 The ICE protocol is
designed to multiplex several protocols over a	single	con-
nection.   As a result, working with SMlib requires a little
knowledge of how the ICE library works.

The ICE library	 utilizes  callbacks  to  process  messages.
When  a	 client detects that there is data to read on an ICE
connection, it should call the 4mIceProcessMessages24m	function.
4mIceProcessMessages24m	 will read the message header and look at
the major opcode in order to determine	which  protocol	 the
message	 was intended for.  The appropriate protocol library
will then be triggered to unpack the message and hand it off
to the client via a callback.

The  main  point to be aware of is that an application using
SMlib must have some code that detects when there is data to
read  on  an  ICE connection.  This can be done via a 4mselect0m
call on the file descriptor for the ICE connection, but more
typically, 4mXtAppAddInput24m will be used to register a callback
that will invoke 4mIceProcessMessages24m each time there is  data
to read on the ICE connection.

To further complicate things, knowing which file descriptors
to call 4mselect24m on requires an understanding of how ICE  con-
nections  are  created.	  On the client side, a call must be
made to 4mSmcOpenConnection24m in order to open a connection with
a session manager.  4mSmcOpenConnection24m will internally make a
call into 4mIceOpenConnection24m, which will, in turn,	determine
if  an	ICE connection already exists between the client and
session manager.  Most likely, a connection will not already
exist  and  a  new ICE connection will be created.  The main
point to be aware of is that, on the client side, it is	 not
obvious	 when  ICE  connections	 get  created  or destroyed,
because connections are shared when possible.  To deal	with
this,  the  ICE	 library lets the application register watch



			    - 2 -





1mX Session Management Library		      X11, Release 6.40m


procedures that will be invoked each time an ICE  connection
is  opened  or closed.	These watch procedures could be used
to add or remove ICE  file  descriptors	 from  the  list  of
descriptors to call 4mselect24m on.

On  the session manager side, things work a bit differently.
The session manager has complete control over  the  creation
of  ICE	 connections.  The session manager has to first call
4mIceListenForConnections24m in order to start listening for con-
nections   from	 clients.   Once  a  connection	 attempt  is
detected, 4mIceAcceptConnection24m must be called, and	the  ses-
sion  manager  can simply add the new ICE file descriptor to
the list of descriptors to call 4mselect24m on.

For further information on the library functions related  to
ICE connections, see the 4mInter-Client24m 4mExchange24m 4mLibrary24m stan-
dard.

1m4.  Header Files and Library Name0m

Applications (both  session  managers  and  clients)  should
include	 the header file <4mX11/SM/SMlib.h24m>.	 This header file
defines all of the SMlib data structures and function proto-
types.	 4mSMlib.h24m  includes	 the  header  file <4mX11/SM/SM.h24m>,
which defines all of the SMlib constants.

Because SMlib is dependent on ICE, applications should	link
against SMlib and ICElib by using 4m-lSM24m 4m-lICE24m.

1m5.  Session Management Client (Smc) Functions0m

This section discusses how Session Management clients:

·    Connect to the Session Manager

·    Close the connection

·    Modify callbacks

·    Set, delete, and retrieve Session Manager properties

·    Interact with the user

·    Request a ``Save Yourself''

·    Request a ``Save Yourself Phase 2''

·    Complete a ``Save Yourself''

·    Use Smc informational functions

·    Handle Errors





			    - 3 -





1mX Session Management Library		      X11, Release 6.40m


1m5.1.	Connecting to the Session Manager0m

To open a connection with a session manager, use 4mSmcOpenCon-0m
4mnection24m.
__
|
SmcConn SmcOpenConnection(4mnetwork_ids_list24m, 4mcontext24m, 4mxsmp_major_rev24m, 4mxsmp_minor_rev24m,
		    4mmask24m, 4mcallbacks24m, 4mprevious_id24m, 4mclient_id_ret24m, 4merror_length24m, 4merror_string_ret24m)
    char *4mnetwork_ids_list24m;
    SmPointer 4mcontext24m;
    int 4mxsmp_major_rev24m;
    int 4mxsmp_minor_rev24m;
    unsigned long 4mmask24m;
    SmcCallbacks *4mcallbacks24m;
    char *4mprevious_id24m;
    char **4mclient_id_ret24m;
    int 4merror_length24m;
    char *4merror_string_ret24m;


4mnetwork_ids_list0m
	  Specifies the network ID(s) of  the  session	man-
	  ager.

4mcontext24m   A  pointer  to  an opaque object or NULL.  Used to
	  determine if an ICE connection can be shared	(see
	  below).

4mxsmp_major_rev0m
	  The highest major version of the XSMP the applica-
	  tion supports.

4mxsmp_minor_rev0m
	  The highest minor version of the XSMP the applica-
	  tion	supports (for the specified xsmp_major_rev).

4mmask24m      A mask indicating which callbacks to register.

4mcallbacks24m The callbacks to register.   These  callbacks  are
	  used	to respond to messages from the session man-
	  ager.

4mprevious_id0m
	  The client ID from the previous session.

4mclient_id_ret0m
	  The client ID for the current session is returned.

4merror_length0m
	  Length of the error_string_ret argument passed in.

4merror_string_ret0m
	  Returns a null-terminated error message,  if	any.
	  The	error_string_ret  argument  points  to	user



			    - 4 -





1mX Session Management Library		      X11, Release 6.40m


	  supplied memory.  No more than error_length  bytes
	  are used.
|__

The  network_ids_list  argument	 is a null-terminated string
containing a list of network IDs for  the  session  manager,
separated by commas.  If network_ids_list is NULL, the value
of the 4mSESSION_MANAGER24m environment variable  will	be  used.
Each network ID has the following format:

     tcp/<hostname>:<portnumber>    or
     decnet/<hostname>::<objname>   or
     local/<hostname>:<path>


An  attempt  will  be  made to use the first network ID.  If
that fails, an attempt will be made using the second network
ID, and so on.

After  the connection is established, 4mSmcOpenConnection24m reg-
isters the client with the session manager.  If	 the  client
is  being  restarted  from  a  previous session, previous_id
should contain a null  terminated  string  representing	 the
client ID from the previous session.  If the client is first
joining the session, previous_id should be set to NULL.	  If
previous_id  is specified but is determined to be invalid by
the session manager, SMlib will re-register the client	with
previous_id set to NULL.

If  4mSmcOpenConnection24m succeeds, it returns an opaque connec-
tion pointer of type 4mSmcConn24m and the client_id_ret	 argument
contains  the  client  ID  to be used for this session.	 The
client_id_ret should be freed with a call to  4mfree24m	 when  no
longer	needed.	 On failure, 4mSmcOpenConnection24m returns NULL,
and the reason for failure is returned in  error_string_ret.

Note that SMlib uses the ICE protocol to establish a connec-
tion with the session manager.	If an ICE connection already
exists	between	 the client and session manager, it might be
possible for the same ICE connection to be used for  session
management.

The  context argument indicates how willing the client is to
share the ICE connection with other protocols.	 If  context
is NULL, then the caller is always willing to share the con-
nection.  If context is not NULL, then	the  caller  is	 not
willing to use a previously opened ICE connection that has a
different non-NULL context associated with it.

As previously discussed (section 3, ``Understanding  SMlib's
Dependence  on ICE''), the client will have to keep track of
when ICE connections are created or destroyed (using 4mIceAdd-0m
4mConnectionWatch24m and 4mIceRemoveConnectionWatch24m), and will have
to call 4mIceProcessMessages24m each time  a  4mselect24m  shows  that



			    - 5 -





1mX Session Management Library		      X11, Release 6.40m


there  is  data	 to  read on an ICE connection.	 For further
information, see the 4mInter-Client24m 4mExchange24m 4mLibrary24m standard.

The  callbacks	argument contains a set of callbacks used to
respond to session manager events.  The mask argument speci-
fies  which  callbacks are set.	 All of the callbacks speci-
fied in this version of SMlib are mandatory.  The mask argu-
ment is necessary in order to maintain backwards compatibil-
ity in future versions of the library.

The following values may be ORed together to obtain  a	mask
value:


4mSmcSaveYourselfProcMask0m
4mSmcDieProcMask0m
4mSmcSaveCompleteProcMask0m
4mSmcShutdownCancelledProcMask0m


For  each  callback,  the  client  can register a pointer to
client data.  When SMlib invokes the callback, it will	pass
the client data pointer.

__
|
typedef struct {

     struct {
	  SmcSaveYourselfProc callback;
	  SmPointer client_data;
     } save_yourself;

     struct {
	  SmcDieProc callback;
	  SmPointer client_data;
     } die;

     struct {
	  SmcSaveCompleteProc callback;
	  SmPointer client_data;
     } save_complete;

     struct {
	  SmcShutdownCancelledProc callback;
	  SmPointer client_data;
     } shutdown_cancelled;

} SmcCallbacks;

|__






			    - 6 -





1mX Session Management Library		      X11, Release 6.40m


1m5.1.1.  The Save Yourself Callback0m

The Save Yourself callback is of type 4mSmcSaveYourselfProc24m.
__
|
typedef void (*SmcSaveYourselfProc)();

void SaveYourselfProc(4msmc_conn24m, 4mclient_data24m, 4msave_type24m, 4mshutdown24m, 4minteract_style24m, 4mfast24m)
    SmcConn 4msmc_conn24m;
    SmPointer 4mclient_data24m;
    int 4msave_type24m;
    Bool 4mshutdown24m;
    int 4minteract_style24m;
    Bool 4mfast24m;


4msmc_conn24m  The session management connection object.

4mclient_data0m
	  Client data specified when the callback was regis-
	  tered.

4msave_type24m Specifies the type of information that  should  be
	  saved.

4mshutdown24m  Specifies if a shutdown is taking place.

4minteract_style0m
	  The type of interaction allowed with the user.

4mfast24m      If  4mTrue24m,  the  client  should  save  its state as
	  quickly as possible.
|__

The session manager sends a ``Save Yourself'' message  to  a
client either to checkpoint it or just before termination so
that it can save its state.  The client responds  with	zero
or  more  calls to 4mSmcSetProperties24m to update the properties
indicating how to restart the client.  When all the  proper-
ties have been set, the client calls 4mSmcSaveYourselfDone24m.

If  interact_style  is	4mSmInteractStyleNone24m, the client must
not interact with the user while saving	 state.	  If  inter-
act_style  is 4mSmInteractStyleErrors24m, the client may interact
with the user only if an error condition arises.  If  inter-
act_style  is 4mSmInteractStyleAny24m, then the client may inter-
act with the user for any purpose.  Because only one  client
can  interact  with the user at a time, the client must call
4mSmcInteractRequest24m and wait for an ``Interact'' message from
the  session  manager.	 When the client is done interacting
with the user, it calls	 4mSmcInteractDone24m.	 The  client  may
only  call  4mSmcInteractRequest24m  after  it	receives a ``Save
Yourself'' message and before it calls	4mSmcSaveYourselfDone24m.




			    - 7 -





1mX Session Management Library		      X11, Release 6.40m


If  save_type  is  4mSmSaveLocal24m,  the  client must update the
properties to reflect its current state.   Specifically,  it
should	save enough information to restore the state as seen
by the user of this client.  It should not affect the  state
as  seen  by other users.  If save_type is 4mSmSaveGlobal24m, the
user wants the client to commit all of its  data  to  perma-
nent,  globally accessible storage.  If save_type is 4mSmSave-0m
4mBoth24m, the client should do both of these  (it  should  first
commit	the  data  to  permanent storage before updating its
properties).

Some examples are as follows:


·    If a word processor were sent a ``Save Yourself''	with
     a type of 4mSmSaveLocal24m, it could create a temporary file
     that included the current contents	 of  the  file,	 the
     location  of  the cursor, and other aspects of the cur-
     rent  editing  session.   It  would  then	update	 its
     SmRestartCommand  property	 with  enough information to
     find this temporary file.

·    If a word processor were sent a ``Save Yourself''	with
     a	type  of 4mSmSaveGlobal24m, it would simply save the cur-
     rently edited file.

·    If a word processor were sent a ``Save Yourself''	with
     a type of 4mSmSaveBoth24m, it would first save the currently
     edited file.  It would then  create  a  temporary	file
     with  information	such  as the current position of the
     cursor and what file  is  being  edited.	Finally,  it
     would  update its SmRestartCommand property with enough
     information to find the temporary file.

The shutdown argument specifies whether the system is  being
shut  down.   The  interaction	is  different  depending  on
whether or not shutdown is set.	 If not shutting  down,	 the
client	should	save  its  state  and wait for a ``Save Com-
plete'' message.  If shutting down,  the  client  must	save
state  and then prevent interaction until it receives either
a ``Die'' or a ``Shutdown Cancelled.''

The fast argument specifies that the client should save	 its
state  as  quickly as possible.	 For example, if the session
manager knows that power is about to fail, it would set fast
to 4mTrue24m.

1m5.1.2.  The Die Callback0m

The Die callback is of type 4mSmcDieProc24m.
__
|





			    - 8 -





1mX Session Management Library		      X11, Release 6.40m


typedef void (*SmcDieProc)();

void DieProc(4msmc_conn24m, 4mclient_data24m)
    SmcConn 4msmc_conn24m;
    SmPointer 4mclient_data24m;


4msmc_conn24m  The session management connection object.

4mclient_data0m
	  Client data specified when the callback was regis-
	  tered.
|__

The session manager sends a ``Die'' message to a client when
it  wants  it  to die.	The client should respond by calling
4mSmcCloseConnection24m.  A session manager that behaves properly
will  send  a  ``Save  Yourself'' message before the ``Die''
message.

1m5.1.3.  The Save Complete Callback0m

The Save Complete callback is of type 4mSmcSaveCompleteProc24m.
__
|
typedef void (*SmcSaveCompleteProc)();

void SaveCompleteProc(4msmc_conn24m, 4mclient_data24m)
    SmcConn 4msmc_conn24m;
    SmPointer 4mclient_data24m;


4msmc_conn24m  The session management connection object.

4mclient_data0m
	  Client data specified when the callback was regis-
	  tered.
|__

When  the session manager is done with a checkpoint, it will
send each of the clients a ``Save Complete''  message.	 The
client is then free to change its state.

1m5.1.4.  The Shutdown Cancelled Callback0m

The  Shutdown  Cancelled callback is of type 4mSmcShutdownCan-0m
4mcelledProc24m.
__
|








			    - 9 -





1mX Session Management Library		      X11, Release 6.40m


typedef void (*SmcShutdownCancelledProc)();

void ShutdownCancelledProc(4msmc_conn24m, 4mclient_data24m)
    SmcConn 4msmc_conn24m;
    SmPointer 4mclient_data24m;


4msmc_conn24m  The session management connection object.

4mclient_data0m
	  Client data specified when the callback was regis-
	  tered.
|__

The  session  manager sends a ``Shutdown Cancelled'' message
when the user cancelled the shutdown during  an	 interaction
(see  section  5.5,  ``Interacting  With  the  User'').	 The
client can now continue as if the shutdown  had	 never	hap-
pened.	 If  the  client  has not called 4mSmcSaveYourselfDone0m
yet, it can either abort the save and then call 4mSmcSaveYour-0m
4mselfDone24m  with  the success argument set to 4mFalse24m, or it can
continue with the save	and  then  call	 4mSmcSaveYourselfDone0m
with  the success argument set to reflect the outcome of the
save.

1m5.2.	Closing the Connection0m

To close a connection with a session manager, use 4mSmcCloseC-0m
4monnection24m.

__
|
SmcCloseStatus SmcCloseConnection(4msmc_conn24m, 4mcount24m, 4mreason_msgs24m)
    SmcConn 4msmc_conn24m;
    int 4mcount24m;
    char **4mreason_msgs24m;


4msmc_conn24m  The session management connection object.

4mcount24m     The number of reason messages.

4mreason_msgs0m
	  The reasons for closing the connection.
|__

The  reason_msgs argument will most likely be NULL if resig-
nation is expected by the client.  Otherwise, it contains  a
list  of  null-terminated Compound Text strings representing
the reason for termination.  The session manager should dis-
play these reason messages to the user.

Note that SMlib used the ICE protocol to establish a connec-
tion with the session manager, and various  protocols  other



			   - 10 -





1mX Session Management Library		      X11, Release 6.40m


than session management may be active on the ICE connection.
When 4mSmcCloseConnection24m is called, the ICE	 connection  will
be  closed  only  if all protocols have been shutdown on the
connection.  Check the ICElib standard for 4mIceAddConnection-0m
4mWatch24m  and 4mIceRemoveConnectionWatch24m to learn how to set up a
callback to be invoked each time an ICE connection is opened
or  closed.   Typically	 this  callback adds/removes the ICE
file descriptor from the list of active descriptors to	call
4mselect24m on (or calls 4mXtAppAddInput24m or 4mXtRemoveInput24m).

4mSmcCloseConnection24m returns one of the following values:

·    4mSmcClosedNow24m	-  the	ICE connection was closed at this
     time, the watch procedures were invoked, and  the	con-
     nection was freed.

·    4mSmcClosedASAP24m - an IO error had occurred on the connec-
     tion, but 4mSmcCloseConnection24m is being called	within	a
     nested  4mIceProcessMessages24m.	The watch procedures have
     been invoked at this time, but the connection  will  be
     freed  as	soon  as  possible  (when  the nesting level
     reaches zero and 4mIceProcessMessages24m returns a status of
     4mIceProcessMessagesConnectionClosed24m).

·    4mSmcConnectionInUse24m  -	 the connection was not closed at
     this time, because it is being  used  by  other  active
     protocols.

1m5.3.	Modifying Callbacks0m

To modify callbacks set up in 4mSmcOpenConnection24m, use 4mSmcMod-0m
4mifyCallbacks24m.
__
|
void SmcModifyCallbacks(4msmc_conn24m, 4mmask24m, 4mcallbacks24m)
    SmcConn 4msmc_conn24m;
    unsigned long 4mmask24m;
    SmcCallbacks *4mcallbacks24m;


4msmc_conn24m  The session management connection object.

4mmask24m      A mask indicating which callbacks to modify.

4mcallbacks24m The new callbacks.
|__

When specifying a value for the mask argument, the following
values may be ORed together:


4mSmcSaveYourselfProcMask0m
4mSmcDieProcMask0m
4mSmcSaveCompleteProcMask0m



			   - 11 -





1mX Session Management Library		      X11, Release 6.40m


4mSmcShutdownCancelledProcMask0m


1m5.4.	 Setting,  Deleting, and Retrieving Session Management0m
1mProperties0m

To  set	 session  management properties for this client, use
4mSmcSetProperties24m.
__
|
void SmcSetProperties(4msmc_conn24m, 4mnum_props24m, 4mprops24m)
    SmcConn 4msmc_conn24m;
    int 4mnum_props24m;
    SmProp **4mprops24m;


4msmc_conn24m  The session management connection object.

4mnum_props24m The number of properties.

4mprops24m     The list of properties to set.
|__

The properties are specified as an array of property  point-
ers.   Previously  set	property  values may be over-written
using the 4mSmcSetProperties24m function.  Note that the  session
manager	 is not expected to restore property values when the
session is restarted.  Because of this, clients	 should	 not
try  to	 use  the  session manager as a database for storing
application specific state.

For a description of session management properties  and	 the
4mSmProp24m  structure, see section 7, ``Session Management Prop-
erties.''


To delete properties  previously  set  by  the	client,	 use
4mSmcDeleteProperties24m.
__
|
void SmcDeleteProperties(4msmc_conn24m, 4mnum_props24m, 4mprop_names24m)
    SmcConn 4msmc_conn24m;
    int 4mnum_props24m;
    char **4mprop_names24m;


4msmc_conn24m  The session management connection object.

4mnum_props24m The number of properties.

4mprop_names0m
	  The list of properties to delete.





			   - 12 -





1mX Session Management Library		      X11, Release 6.40m


|__


To  get	 properties  previously	 stored	 by  the client, use
4mSmcGetProperties24m.
__
|
Status SmcGetProperties(4msmc_conn24m, 4mprop_reply_proc24m, 4mclient_data24m)
    SmcConn 4msmc_conn24m;
    SmcPropReplyProc 4mprop_reply_proc24m;
    SmPointer 4mclient_data24m;


4msmc_conn24m  The session management connection object.

4mprop_reply_proc0m
	  The callback to be  invoked  when  the  properties
	  reply comes back.

4mclient_data0m
	  This	pointer to client data will be passed to the
	  4mSmcPropReplyProc24m callback.
|__

The return value of 4mSmcGetProperties24m is zero for failure and
a positive value for success.

Note  that  the	 library does not block until the properties
reply comes back.  Rather, a  callback	of  type  4mSmcPropRe-0m
4mplyProc24m is invoked when the data is ready.
__
|
typedef void (*SmcPropReplyProc)();

void PropReplyProc(4msmc_conn24m, 4mclient_data24m, 4mnum_props24m, 4mprops24m)
    SmcConn 4msmc_conn24m;
    SmPointer 4mclient_data24m;
    int 4mnum_props24m;
    SmProp **4mprops24m;


4msmc_conn24m  The session management connection object.

4mclient_data0m
	  Client data specified when the callback was regis-
	  tered.

4mnum_props24m The number of properties returned.

4mprops24m     The list of properties returned.
|__

To free each property, use 4mSmFreeProperty24m	(see  section  8,
``Freeing  Data'').   To  free the actual array of pointers,



			   - 13 -





1mX Session Management Library		      X11, Release 6.40m


use 4mfree24m.

1m5.5.	Interacting With the User0m

After receiving a ``Save Yourself'' message with  an  inter-
act_style  of  4mSmInteractStyleErrors24m  or 4mSmInteractStyleAny24m,
the client may choose to interact with	the  user.   Because
only  one  client  can interact with the user at a time, the
client must call 4mSmcInteractRequest24m and wait for an ``Inter-
act'' message from the session manager.
__
|
Status SmcInteractRequest(4msmc_conn24m, 4mdialog_type24m, 4minteract_proc24m, 4mclient_data24m)
    SmcConn 4msmc_conn24m;
    int 4mdialog_type24m;
    SmcInteractProc 4minteract_proc24m;
    SmPointer 4mclient_data24m;


4msmc_conn24m  The session management connection object.

4mdialog_type0m
	  The type of dialog the client wishes to present to
	  the user.

4minteract_proc0m
	  The callback to be invoked when  the	``Interact''
	  message arrives from the session manager.

4mclient_data0m
	  This	pointer to client data will be passed to the
	  4mSmcInteractProc24m	callback  when	the  ``Interact''
	  message arrives.
|__

The  return  value of 4mSmcInteractRequest24m is zero for failure
and a positive value for success.

The dialog_type	 argument  specifies  either  4mSmDialogError24m,
indicating  that  the client wants to start an error dialog,
or 4mSmDialogNormal24m, meaning that the client wishes to start a
nonerror dialog.

Note  that  if	a shutdown is in progress, the user may have
the option of cancelling the shutdown.	If the	shutdown  is
cancelled, the clients that have not interacted yet with the
user will receive a ``Shutdown Cancelled''  message  instead
of the ``Interact'' message.

The  4mSmcInteractProc24m  callback  will  be  invoked	when  the
``Interact'' message arrives from the session manager.
__
|




			   - 14 -





1mX Session Management Library		      X11, Release 6.40m


typedef void (*SmcInteractProc)();

void InteractProc(4msmc_conn24m, 4mclient_data24m)
    SmcConn 4msmc_conn24m;
    SmPointer 4mclient_data24m;


4msmc_conn24m  The session management connection object.

4mclient_data0m
	  Client data specified when the callback was regis-
	  tered.
|__


After  interacting with the user (in response to an ``Inter-
act'' message), you should call 4mSmcInteractDone24m.
__
|
void SmcInteractDone(4msmc_conn24m, 4mcancel_shutdown24m)
    SmcConn 4msmc_conn24m;
    Bool 4mcancel_shutdown24m;


4msmc_conn24m  The session management connection object.

4mcancel_shutdown0m
	  If 4mTrue24m, indicates that the user requests that the
	  entire shutdown be cancelled.
|__

The  cancel_shutdown argument may only be 4mTrue24m if the corre-
sponding ``Save Yourself'' specified 4mTrue24m for  shutdown  and
4mSmInteractStyleErrors24m  or	4mSmInteractStyleAny24m for the inter-
act_style.

1m5.6.	Requesting a Save Yourself0m

To request a checkpoint from the session manager, use 4mSmcRe-0m
4mquestSaveYourself24m.
__
|
void SmcRequestSaveYourself(4msmc_conn24m, 4msave_type24m, 4mshutdown24m, 4minteract_style24m, 4mfast24m, 4mglobal24m)
    SmcConn 4msmc_conn24m;
    int 4msave_type24m;
    Bool 4mshutdown24m;
    int 4minteract_style24m;
    Bool 4mfast24m;
    Bool 4mglobal24m;


4msmc_conn24m  The session management connection object.





			   - 15 -





1mX Session Management Library		      X11, Release 6.40m


4msave_type24m Specifies  the  type of information that should be
	  saved.

4mshutdown24m  Specifies if a shutdown is taking place.

4minteract_style0m
	  The type of interaction allowed with the user.

4mfast24m      If 4mTrue24m, the  client  should  save	its  state  as
	  quickly as possible.

4mglobal24m    Controls who gets the ``Save Yourself.''
|__

The  save_type, shutdown, interact_style, and fast arguments
are discussed in more detail in section	 5.1.1,	 ``The	Save
Yourself Callback.''

If  global  is	set to 4mTrue24m, then the resulting ``Save Your-
self'' should be sent to all clients in	 the  session.	 For
example,  a  vendor  of a Uninterruptible Power Supply (UPS)
might include a Session Management client that would monitor
the  status  of	 the UPS and generate a fast shutdown if the
power is about to be lost.

If global is set to 4mFalse24m, then the ``Save Yourself'' should
only be sent to the client that requested it.

1m5.7.	Requesting a Save Yourself Phase 20m

In  response to a ``Save Yourself, the client may request to
be informed when all the other clients are quiescent so that
it  can save their state.  To do so, use 4mSmcRequestSaveYour-0m
4mselfPhase224m.
__
|
Status SmcRequestSaveYourselfPhase2(4msmc_conn24m, 4msave_yourself_phase2_proc24m, 4mclient_data24m)
    SmcConn 4msmc_conn24m;
    SmcSaveYourselfPhase2Proc 4msave_yourself_phase2_proc24m;
    SmPointer 4mclient_data24m;


4msmc_conn24m  The session management connection object.

4msave_yourself_phase2_proc0m
	  The callback to be invoked when the  ``Save  Your-
	  self	Phase  2''  message arrives from the session
	  manager.

4mclient_data0m
	  This pointer to client data will be passed to	 the
	  4mSmcSaveYourselfPhase2Proc24m callback when the ``Save
	  Yourself Phase 2'' message arrives.




			   - 16 -





1mX Session Management Library		      X11, Release 6.40m


|__

The return value of 4mSmcRequestSaveYourselfPhase224m is zero for
failure and a positive value for success.

This  request is needed by clients that manage other clients
(for example, window managers, workspace  managers,  and  so
on).   The  manager  must  make sure that all of the clients
that are being managed are in an idle state  so	 that  their
state can be saved.

1m5.8.	Completing a Save Yourself0m

After  saving  state in response to a ``Save Yourself'' mes-
sage, you should call 4mSmcSaveYourselfDone24m.
__
|
void SmcSaveYourselfDone(4msmc_conn24m, 4msuccess24m)
    SmcConn 4msmc_conn24m;
    Bool 4msuccess24m;


4msmc_conn24m  The session management connection object.

4msuccess24m   If 4mTrue24m, the ``Save Yourself'' operation was  com-
	  pleted successfully.
|__

Before calling 4mSmcSaveYourselfDone24m, the client must have set
each required property at least once since the client regis-
tered with the session manager.

1m5.9.	Using Smc Informational Functions0m

__
|
int SmcProtocolVersion(4msmc_conn24m)
    SmcConn 4msmc_conn24m;
|__

4mSmcProtocolVersion24m	 returns the major version of the session
management protocol associated with this session.


__
|
int SmcProtocolRevision(4msmc_conn24m)
    SmcConn 4msmc_conn24m;
|__

4mSmcProtocolRevision24m returns the minor version of the session
management protocol associated with this session.





			   - 17 -





1mX Session Management Library		      X11, Release 6.40m

__
|
char *SmcVendor(4msmc_conn24m)
    SmcConn 4msmc_conn24m;
|__

4mSmcVendor24m returns a string that provides some identification
of the owner of the session manager.  The string  should  be
freed with a call to 4mfree24m.


__
|
char *SmcRelease(4msmc_conn24m)
    SmcConn 4msmc_conn24m;
|__

4mSmcRelease24m returns a string that provides the release number
of the session manager.	 The string should be freed  with  a
call to 4mfree24m.


__
|
char *SmcClientID(4msmc_conn24m)
    SmcConn 4msmc_conn24m;
|__

4mSmcClientID24m  returns a null-terminated string for the client
ID associated with this connection.   This  information	 was
also  returned in 4mSmcOpenConnection24m (it is provided here for
convenience).  Call 4mfree24m on this pointer when the client  ID
is no longer needed.


__
|
IceConn SmcGetIceConnection(4msmc_conn24m)
    SmcConn 4msmc_conn24m;
|__

4mSmcGetIceConnection24m  returns the ICE connection object asso-
ciated with this session management connection object.	 The
ICE  connection	 object	 can  be used to get some additional
information about the connection.  Some of the	more  useful
functions  which  can  be used on the IceConn are 4mIceConnec-0m
4mtionNumber24m, 4mIceConnectionString24m,  4mIceLastSentSequenceNumber24m,
4mIceLastReceivedSequenceNumber24m,  and  4mIcePing24m.	  For  further
information, see the 4mInter-Client24m 4mExchange24m 4mLibrary24m standard.

1m5.10.	 Error Handling0m

If the client receives an unexpected protocol error from the
session manager, an error handler is invoked  by  SMlib.   A
default	 error	handler	 exists that simply prints the error



			   - 18 -





1mX Session Management Library		      X11, Release 6.40m


message to 4mstderr24m and exits if the severity of the error  is
fatal.	 The client can change this error handler by calling
the 4mSmcSetErrorHandler24m function.
__
|
SmcErrorHandler SmcSetErrorHandler(4mhandler24m)
    SmcErrorHandler 4mhandler24m;


4mhandler24m   The  error  handler.   You  should  pass	 NULL  to
	  restore the default handler.
|__

4mSmcSetErrorHandler24m returns the previous error handler.

The 4mSmcErrorHandler24m has the following type:
__
|
typedef void (*SmcErrorHandler)();

void ErrorHandler(4msmc_conn24m, 4mswap24m, 4moffending_minor_opcode24m, 4moffending_sequence_num24m, 4merror_class24m, 4mseverity24m, 4mvalues24m)
    SmcConn 4msmc_conn24m;
    Bool 4mswap24m;
    int 4moffending_minor_opcode24m;
    unsigned long 4moffending_sequence_num24m;
    int 4merror_class24m;
    int 4mseverity24m;
    IcePointer 4mvalues24m;


4msmc_conn24m  The session management connection object.

4mswap24m      A flag that indicates if the specified values need
	  byte swapping.

4moffending_minor_opcode0m
	  The minor opcode of the offending message.

4moffending_sequence_num0m
	  The sequence number of the offending message.

4merror_class0m
	  The error class of the offending message.

4mseverity24m  4mIceCanContinue24m, 4mIceFatalToProtocol24m, or 4mIceFatalTo-0m
	  4mConnection24m.

4mvalues24m    Any  additional error values specific to the minor
	  opcode and class.
|__

Note that this error handler is invoked for protocol related
errors.	  To  install an error handler to be invoked when an
IO error  occurs,  use	4mIceSetIOErrorHandler24m.   For  further



			   - 19 -





1mX Session Management Library		      X11, Release 6.40m


information, see the 4mInter-Client24m 4mExchange24m 4mLibrary24m standard.

1m6.  Session Management Server (Sms) Functions0m

This section discusses how Session Management servers:

·    Initialize the library

·    Register the client

·    Send a ``Save Yourself'' message

·    Send a ``Save Yourself Phase 2'' message

·    Send an ``Interact'' message

·    Send a ``Save Complete'' message

·    Send a ``Die'' message

·    Cancel a shutdown

·    Return properties

·    Ping a client

·    Clean up after a client disconnects

·    Use Sms informational functions

·    Handle errors

1m6.1.	Initializing the Library0m

4mSmsInitialize24m is the first SMlib  function	 that  should  be
called	by a session manager.  It provides information about
the session manager and registers a callback  that  will  be
invoked	 each time a new client connects to the session man-
ager.
__
|
Status SmsInitialize(4mvendor24m, 4mrelease24m, 4mnew_client_proc24m, 4mmanager_data24m, 4mhost_based_auth_proc24m,
		    4merror_length24m, 4merror_string_ret24m)
    char *4mvendor24m;
    char *4mrelease24m;
    SmsNewClientProc 4mnew_client_proc24m;
    SmPointer 4mmanager_data24m;
    IceHostBasedAuthProc 4mhost_based_auth_proc24m;
    int 4merror_length24m;
    char *4merror_string_ret24m;


4mvendor24m    A string specifying the session manager vendor.




			   - 20 -





1mX Session Management Library		      X11, Release 6.40m


4mrelease24m   A string specifying the	session	 manager  release
	  number.

4mnew_client_proc0m
	  Callback to be invoked each time a new client con-
	  nects to the session manager.

4mmanager_data0m
	  When the  4mSmsNewClientProc24m  callback  is	 invoked,
	  this pointer to manager data will be passed.

4mhost_based_auth_proc0m
	  Host based authentication callback.

4merror_length0m
	  Length of the error_string_ret argument passed in.

4merror_string_ret0m
	  Returns a null-terminated error message,  if	any.
	  The  error_string_ret points to user supplied mem-
	  ory.	No more than error_length bytes are used.
|__

After the 4mSmsInitialize24m function is called, the session man-
ager  should  call  the	 4mIceListenForConnections24m function to
listen for new connections.  Afterwards, each time a  client
connects,  the	session manager should call 4mIceAcceptConnec-0m
4mtion24m.

See section  9,	 ``Authentication  of  Clients,''  for	more
details	 on authentication (including host based authentica-
tion).	Also see the 4mInter-Client24m 4mExchange24m 4mLibrary24m  standard
for  further details on listening for and accepting ICE con-
nections.

Each time a new client connects to the session manager,	 the
4mSmsNewClientProc24m  callback	 is invoked.  The session manager
obtains a new opaque connection object that  it	 should	 use
for  all  future interaction with the client.  At this time,
the session manager must also register a set of callbacks to
respond	 to  the  different  messages  that the client might
send.
__
|
typedef Status (*SmsNewClientProc)();

Status NewClientProc(4msms_conn24m, 4mmanager_data24m, 4mmask_ret24m, 4mcallbacks_ret24m, 4mfailure_reason_ret24m)
    SmsConn 4msms_conn24m;
    SmPointer 4mmanager_data24m;
    unsigned long *4mmask_ret24m;
    SmsCallbacks *4mcallbacks_ret24m;
    char **4mfailure_reason_ret24m;





			   - 21 -





1mX Session Management Library		      X11, Release 6.40m


4msms_conn24m  A new opaque connection object.

4mmanager_data0m
	  Manager data specified when the callback was	reg-
	  istered.

4mmask_ret24m  On  return,  indicates which callbacks were set by
	  the session manager.

4mcallbacks_ret0m
	  On return, contains the  callbacks  registered  by
	  the session manager.

4mfailure_reason_ret0m
	  Failure reason returned.
|__

If  a  failure	occurs, the 4mSmsNewClientProc24m should return a
zero status as well as allocate and return a failure  reason
string in failure_reason_ret.  SMlib will be responsible for
freeing this memory.

The session manager must register  a  set  of  callbacks  to
respond	 to  client events.  The mask_ret argument specifies
which callbacks are set.  All of the callbacks specified  in
this  version of SMlib are mandatory.  The mask_ret argument
is necessary in order to maintain backwards compatibility in
future versions of the library.

The  following	values may be ORed together to obtain a mask
value:


4mSmsRegisterClientProcMask0m
4mSmsInteractRequestProcMask0m
4mSmsInteractDoneProcMask0m
4mSmsSaveYourselfRequestProcMask0m
4mSmsSaveYourselfP2RequestProcMask0m
4mSmsSaveYourselfDoneProcMask0m
4mSmsCloseConnectionProcMask0m
4mSmsSetPropertiesProcMask0m
4mSmsDeletePropertiesProcMask0m
4mSmsGetPropertiesProcMask0m


For each  callback,  the  session  manager  can	 register  a
pointer	 to  manager  data  specific to that callback.	This
pointer will be passed to the callback when it is invoked by
SMlib.
__
|

typedef struct {
     struct {



			   - 22 -





1mX Session Management Library		      X11, Release 6.40m


	  SmsRegisterClientProc callback;
	  SmPointer manager_data;
     } register_client;

     struct {
	  SmsInteractRequestProc callback;
	  SmPointer manager_data;
     } interact_request;

     struct {
	  SmsInteractDoneProc callback;
	  SmPointer manager_data;
     } interact_done;

     struct {
	  SmsSaveYourselfRequestProc callback;
	  SmPointer manager_data;
     } save_yourself_request;

     struct {
	  SmsSaveYourselfPhase2RequestProc callback;
	  SmPointer manager_data;
     } save_yourself_phase2_request;

     struct {
	  SmsSaveYourselfDoneProc callback;
	  SmPointer manager_data;
     } save_yourself_done;

     struct {
	  SmsCloseConnectionProc callback;
	  SmPointer manager_data;
     } close_connection;

     struct {
	  SmsSetPropertiesProc callback;
	  SmPointer manager_data;
     } set_properties;

     struct {
	  SmsDeletePropertiesProc callback;
	  SmPointer manager_data;
     } delete_properties;

     struct {
	  SmsGetPropertiesProc callback;
	  SmPointer manager_data;
     } get_properties;

} SmsCallbacks;

|__





			   - 23 -





1mX Session Management Library		      X11, Release 6.40m


1m6.1.1.  The Register Client Callback0m

The Register Client callback is the first callback that will
be invoked after the client connects to the session manager.
Its type is 4mSmsRegisterClientProc24m.
__
|
typedef Status (*SmsRegisterClientProc();

Status RegisterClientProc(4msms_conn24m, 4mmanager_data24m, 4mprevious_id24m)
    SmsConn 4msms_conn24m;
    SmPointer 4mmanager_data24m;
    char *4mprevious_id24m;


4msms_conn24m  The session management connection object.

4mmanager_data0m
	  Manager  data specified when the callback was reg-
	  istered.

4mprevious_id0m
	  The client ID from the previous session.
|__

Before any further interaction takes place with the  client,
the client must be registered with the session manager.

If  the	 client	 is being restarted from a previous session,
previous_id will contain a null-terminated string represent-
ing  the  client ID from the previous session.	Call 4mfree24m on
the previous_id pointer when it is no longer needed.  If the
client	is  first  joining  the session, previous_id will be
NULL.

If previous_id is invalid, the session	manager	 should	 not
register  the  client  at  this	 time.	This callback should
return a status of zero, which will cause an  error  message
to  be	sent  to  the client.  The client should re-register
with previous_id set to NULL.

Otherwise, the session manager should  register	 the  client
with  a unique client ID by calling the 4mSmsRegisterClientRe-0m
4mply24m function (to be discussed shortly), and the 4mSmsRegister-0m
4mClientProc24m callback should return a status of one.

1m6.1.2.  The Interact Request Callback0m

The Interact Request callback is of type 4mSmsInteractRequest-0m
4mProc24m.
__
|





			   - 24 -





1mX Session Management Library		      X11, Release 6.40m


typedef void (*SmsInteractRequestProc)();

void InteractRequestProc(4msms_conn24m, 4mmanager_data24m, 4mdialog_type24m)
    SmsConn 4msms_conn24m;
    SmPointer 4mmanager_data24m;
    int 4mdialog_type24m;


4msms_conn24m  The session management connection object.

4mmanager_data0m
	  Manager data specified when the callback was	reg-
	  istered.

4mdialog_type0m
	  The type of dialog the client wishes to present to
	  the user.
|__

When a client receives a ``Save Yourself'' message  with  an
interact_style	 of   4mSmInteractStyleErrors24m  or  4mSmInteract-0m
4mStyleAny24m, the client may choose to interact with  the  user.
Because	 only  one  client  can	 interact with the user at a
time, the client must request to  interact  with  the  user.
The session manager should keep a queue of all clients wish-
ing to interact.  It should send an ``Interact'' message  to
one  client at a time and wait for an ``Interact Done'' mes-
sage before continuing with the next client.

The dialog_type	 argument  specifies  either  4mSmDialogError24m,
indicating  that  the client wants to start an error dialog,
or 4mSmDialogNormal24m, meaning that the client wishes to start a
nonerror dialog.

If  a  shutdown is in progress, the user may have the option
of cancelling the shutdown.  If the  shutdown  is  cancelled
(specified  in	the  ``Interact Done'' message), the session
manager should send a ``Shutdown Cancelled'' message to each
client that requested to interact.

1m6.1.3.  The Interact Done Callback0m

When  the  client  is  done  interacting  with the user, the
4mSmsInteractDoneProc24m callback will be invoked.
__
|
typedef void (*SmsInteractDoneProc)();

void InteractDoneProc(4msms_conn24m, 4mmanager_data24m, 4mcancel_shutdown24m)
    SmsConn 4msms_conn24m;
    SmPointer 4mmanager_data24m;
    Bool 4mcancel_shutdown24m;





			   - 25 -





1mX Session Management Library		      X11, Release 6.40m


4msms_conn24m  The session management connection object.

4mmanager_data0m
	  Manager data specified when the callback was	reg-
	  istered.

4mcancel_shutdown0m
	  Specifies  if	 the  user  requests that the entire
	  shutdown be cancelled.
|__

Note that the shutdown can be cancelled only if	 the  corre-
sponding  ``Save  Yourself'' specified 4mTrue24m for shutdown and
4mSmInteractStyleErrors24m or 4mSmInteractStyleAny24m for  the	inter-
act_style.

1m6.1.4.  The Save Yourself Request Callback0m

The  Save  Yourself Request callback is of type 4mSmsSaveYour-0m
4mselfRequestProc24m.
__
|
typedef void (*SmsSaveYourselfRequestProc)();

void SaveYourselfRequestProc(4msms_conn24m, 4mmanager_data24m, 4msave_type24m, 4mshutdown24m, 4minteract_style24m, 4mfast24m, 4mglobal24m)
    SmsConn 4msms_conn24m;
    SmPointer 4mmanager_data24m;
    int 4msave_type24m;
    Bool 4mshutdown24m;
    int 4minteract_style24m;
    Bool 4mfast24m;
    Bool 4mglobal24m;


4msms_conn24m  The session management connection object.

4mmanager_data0m
	  Manager data specified when the callback was	reg-
	  istered.

4msave_type24m Specifies  the  type of information that should be
	  saved.

4mshutdown24m  Specifies if a shutdown is taking place.

4minteract_style0m
	  The type of interaction allowed with the user.

4mfast24m      If 4mTrue24m, the  client  should  save	its  state  as
	  quickly as possible.

4mglobal24m    Controls who gets the ``Save Yourself.''





			   - 26 -





1mX Session Management Library		      X11, Release 6.40m


|__

The  Save  Yourself  Request  prompts the session manager to
initiate a checkpoint or shutdown.  For information  on	 the
save_type, shutdown, interact_style, and fast arguments, see
section 6.3, ``Sending a Save Yourself Message.''

If global is set to 4mTrue24m, then the	 resulting  ``Save  Your-
self'' should be sent to all applications.  If global is set
to 4mFalse24m, then the ``Save Yourself'' should only be sent  to
the client that requested it.

1m6.1.5.  The Save Yourself Phase 2 Request Callback0m

The Save Yourself  Phase  2  Request  callback	is  of	type
4mSmsSaveYourselfPhase2RequestProc24m.
__
|
typedef void (*SmsSaveYourselfPhase2RequestProc)();

void SmsSaveYourselfPhase2RequestProc(4msms_conn24m, 4mmanager_data24m)
    SmsConn 4msms_conn24m;
    SmPointer 4mmanager_data24m;


4msms_conn24m  The session management connection object.

4mmanager_data0m
	  Manager  data specified when the callback was reg-
	  istered.
|__

This request is sent by clients that  manage  other  clients
(for  example,	window	managers, workspace managers, and so
on).  Such managers must make sure that all of	the  clients
that  are  being  managed are in an idle state so that their
state can be saved.

1m6.1.6.  The Save Yourself Done Callback0m

When the client is done saving its state in  response  to  a
``Save	Yourself'' message, the 4mSmsSaveYourselfDoneProc24m will
be invoked.
__
|
typedef void (*SmsSaveYourselfDoneProc)();

void SaveYourselfDoneProc(4msms_conn24m, 4mmanager_data24m, 4msuccess24m)
    SmsConn 4msms_conn24m;
    SmPointer 4mmanager_data24m;
    Bool 4msuccess24m;






			   - 27 -





1mX Session Management Library		      X11, Release 6.40m


4msms_conn24m  The session management connection object.

4mmanager_data0m
	  Manager data specified when the callback was	reg-
	  istered.

4msuccess24m   If 4mTrue24m, the Save Yourself operation was completed
	  successfully.
|__

Before the ``Save Yourself Done'' was sent, the client	must
have  set each required property at least once since it reg-
istered with the session manager.

1m6.1.7.  The Connection Closed Callback0m

If the client properly terminates (that is,  it	 calls	4mSmc-0m
4mCloseConnection24m),	the  4mSmsCloseConnectionProc24m  callback  is
invoked.
__
|
typedef void (*SmsCloseConnectionProc)();

void CloseConnectionProc(4msms_conn24m, 4mmanager_data24m, 4mcount24m, 4mreason_msgs24m)
    SmsConn 4msms_conn24m;
    SmPointer 4mmanager_data24m;
    int 4mcount24m;
    char **4mreason_msgs24m;


4msms_conn24m  The session management connection object.

4mmanager_data0m
	  Manager data specified when the callback was	reg-
	  istered.

4mcount24m     The number of reason messages.

4mreason_msgs0m
	  The reasons for closing the connection.
|__

The  reason_msgs  argument  will most likely be NULL and the
count argument zero (0) if resignation is  expected  by	 the
user.  Otherwise, it contains a list of null-terminated Com-
pound Text strings representing the reason for	termination.
The  session manager should display these reason messages to
the user.

Call 4mSmFreeReasons24m to free the reason messages.  For further
information, see section 8, ``Freeing Data.''






			   - 28 -





1mX Session Management Library		      X11, Release 6.40m


1m6.1.8.  The Set Properties Callback0m

When the client sets session management properties, the 4mSms-0m
4mSetPropertiesProc24m callback will be invoked.
__
|
typedef void (*SmsSetPropertiesProc)();

void SetPropertiesProc(4msms_conn24m, 4mmanager_data24m, 4mnum_props24m, 4mprops24m)
    SmsConn 4msms_conn24m;
    SmPointer 4mmanager_data24m;
    int 4mnum_props24m;
    SmProp **4mprops24m;


4msmc_conn24m  The session management connection object.

4mmanager_data0m
	  Manager data specified when the callback was	reg-
	  istered.

4mnum_props24m The number of properties.

4mprops24m     The list of properties to set.
|__

The  properties are specified as an array of property point-
ers.  For a description of session management properties and
the  4mSmProp24m  structure,  see section 7, ``Session Management
Properties.''

Previously set property values may  be	over-written.	Some
properties  have  predefined semantics.	 The session manager
is required to store nonpredefined properties.

To free each  property,	 use  4mSmFreeProperty24m.   For  further
information,  see  section  8, ``Freeing Data.''  You should
free the actual array of pointers with a call to 4mfree24m.

1m6.1.9.  The Delete Properties Callback0m

When the client deletes session management  properties,	 the
4mSmsDeletePropertiesProc24m callback will be invoked.
__
|
typedef void (*SmsDeletePropertiesProc)();

void DeletePropertiesProc(4msms_conn24m, 4mmanager_data24m, 4mnum_props24m, 4mprop_names24m)
    SmsConn 4msms_conn24m;
    SmPointer 4mmanager_data24m;
    int 4mnum_props24m;
    char **4mprop_names24m;





			   - 29 -





1mX Session Management Library		      X11, Release 6.40m


4msmc_conn24m  The session management connection object.

4mmanager_data0m
	  Manager  data specified when the callback was reg-
	  istered.

4mnum_props24m The number of properties.

4mprop_names0m
	  The list of properties to delete.
|__

The properties are specified as an array of strings.  For  a
description  of session management properties and the 4mSmProp0m
structure, see section 7, ``Session Management Properties.''

1m6.1.10.  The Get Properties Callback0m

The 4mSmsGetPropertiesProc24m callback is invoked when the client
wants to retrieve properties it set.
__
|
typedef void (*SmsGetPropertiesProc)();

void GetPropertiesProc(4msms_conn24m, 4mmanager_data24m)
    SmsConn 4msms_conn24m;
    SmPointer 4mmanager_data24m;


4msmc_conn24m  The session management connection object.

4mmanager_data0m
	  Manager data specified when the callback was	reg-
	  istered.
|__

The session manager should respond by calling 4mSmsReturnProp-0m
4merties24m.  All of the properties set for this client should be
returned.

1m6.2.	Registering the Client0m

To register a client (in response to a 4mSmsRegisterClientProc0m
callback), use 4mSmsRegisterClientReply24m.
__
|
Status SmsRegisterClientReply(4msms_conn24m, 4mclient_id24m)
    SmsConn 4msms_conn24m;
    char *4mclient_id24m;


4msms_conn24m  The session management connection object.





			   - 30 -





1mX Session Management Library		      X11, Release 6.40m


4mclient_id24m A null-terminated  string  representing	a  unique
	  client ID.
|__

The return value of 4mSmsRegisterClientReply24m is zero for fail-
ure and a positive value for success.  Failure will occur if
SMlib  can  not allocate memory to hold a copy of the client
ID for it's own internal needs.

If a non-NULL previous_id was specified when the client reg-
istered	 itself,  client_id  should  be	 identical to previ-
ous_id.

Otherwise, client_id should be a unique ID freshly generated
by  the	 session  manager.  In addition, the session manager
should send a ``Save Yourself'' message with type  =  Local,
shutdown  =  False,  interact-style = None, and fast = False
immediately after registering the client.

Note that once a client ID has been assigned to the  client,
the  client  keeps  this  ID indefinitely.  If the client is
terminated and restarted, it will be reassigned the same ID.
It  is	desirable  to be able to pass client IDs around from
machine to machine, from user to user, and from session man-
ager to session manager, while retaining the identity of the
client.	 This, combined with the indefinite  persistence  of
client	IDs,  means  that  client  IDs	need  to be globally
unique.

You should call the 4mSmsGenerateClientID24m function to generate
a globally unique client ID.
__
|
char *SmsGenerateClientID(4msms_conn24m)
    SmsConn 4msms_conn24m;


4msms_conn24m  The session management connection object.
|__

NULL  will  be	returned  if  the ID could not be generated.
Otherwise, the return value of the function  is	 the  client
ID.   It  should be freed with a call to 4mfree24m when no longer
needed.

1m6.3.	Sending a Save Yourself Message0m

To send a ``Save Yourself'' to a  client,  use	4mSmsSaveYour-0m
4mself24m.
__
|






			   - 31 -





1mX Session Management Library		      X11, Release 6.40m


void SmsSaveYourself(4msms_conn24m, 4msave_type24m, 4mshutdown24m, 4minteract_style24m, 4mfast24m)
    SmsConn 4msms_conn24m;
    int 4msave_type24m;
    Bool 4mshutdown24m;
    int 4minteract_style24m;
    Bool 4mfast24m;


4msms_conn24m  The session management connection object.

4msave_type24m Specifies  the  type of information that should be
	  saved.

4mshutdown24m  Specifies if a shutdown is taking place.

4minteract_style0m
	  The type of interaction allowed with the user.

4mfast24m      If 4mTrue24m, the  client  should  save	its  state  as
	  quickly as possible.
|__

The  session  manager sends a ``Save Yourself'' message to a
client either to checkpoint it or just before termination so
that  it  can save its state.  The client responds with zero
or more ``Set Properties'' messages to update the properties
indicating  how to restart the client.	When all the proper-
ties have been set,  the  client  sends	 a  ``Save  Yourself
Done'' message.

If  interact_style  is	4mSmInteractStyleNone24m, the client must
not interact with the user while saving	 state.	  If  inter-
act_style  is 4mSmInteractStyleErrors24m, the client may interact
with the user only if an error condition arises.  If  inter-
act_style  is 4mSmInteractStyleAny24m, then the client may inter-
act with the user for any purpose.  The client must send  an
``Interact  Request''  message	and wait for an ``Interact''
message from the session manager before it can interact with
the  user.   When  the	client	is done interacting with the
user, it should send  an  ``Interact  Done''  message.	 The
``Interact  Request''  message	can be sent any time after a
``Save Yourself'' and before a ``Save Yourself Done.''

If save_type is 4mSmSaveLocal24m,  the	client	must  update  the
properties  to	reflect its current state.  Specifically, it
should save enough information to restore the state as	seen
by  the user of this client.  It should not affect the state
as seen by other users.	 If save_type  is  4mSmSaveGlobal24m  the
user  wants  the  client to commit all of its data to perma-
nent, globally accessible storage.  If save_type is  4mSmSave-0m
4mBoth24m,  the	 client	 should do both of these (it should first
commit the data to permanent  storage  before  updating	 its
properties).




			   - 32 -





1mX Session Management Library		      X11, Release 6.40m


The shutdown argument specifies whether the session is being
shut  down.   The  interaction	is  different  depending  on
whether	 or not shutdown is set.  If not shutting down, then
the client can save and resume normal operation.   If  shut-
ting down, the client must save and then must prevent inter-
action until it receives either a ``Die''  or  a  ``Shutdown
Cancelled,''  because  anything the user does after the save
will be lost.

The fast argument specifies that the client should save	 its
state  as  quickly as possible.	 For example, if the session
manager knows that power is about to  fail,  it	 should	 set
fast to 4mTrue24m.

1m6.4.	Sending a Save Yourself Phase 2 Message0m

In  order  to  send a ``Save Yourself Phase 2'' message to a
client, use 4mSmsSaveYourselfPhase224m.
__
|
void SmsSaveYourselfPhase2(4msms_conn24m)
    SmsConn 4msms_conn24m;


4msms_conn24m  The session management connection object.
|__

The session manager sends this message to a client that	 has
previously sent a ``Save Yourself Phase 2 Request'' message.
This message informs the client that all other	clients	 are
in  a  fixed  state  and  this client can save state that is
associated with other clients.

1m6.5.	Sending an Interact Message0m

To send an ``Interact'' message to a client,  use  4mSmsInter-0m
4mact24m.
__
|
void SmsInteract(4msms_conn24m)
    SmsConn 4msms_conn24m;


4msms_conn24m  The session management connection object.
|__

The  ``Interact'' message grants the client the privilege of
interacting with the user.  When the client is	done  inter-
acting with the user, it must send an ``Interact Done'' mes-
sage to the session manager.







			   - 33 -





1mX Session Management Library		      X11, Release 6.40m


1m6.6.	Sending a Save Complete Message0m

To send	 a  ``Save  Complete''	message	 to  a	client,	 use
4mSmsSaveComplete24m.
__
|
void SmsSaveComplete(4msms_conn24m)
    SmsConn 4msms_conn24m;


4msms_conn24m  The session management connection object.
|__

The  session manager sends this message when it is done with
a checkpoint.  The client is then free to change its  state.

1m6.7.	Sending a Die Message0m

To send a ``Die'' message to a client, use 4mSmsDie24m.
__
|
void SmsDie(4msms_conn24m)
    SmsConn 4msms_conn24m;


4msms_conn24m  The session management connection object.
|__

Before	the session manager terminates, it should wait for a
``Connection Closed'' message from each client that it	sent
a ``Die'' message to, timing out appropriately.

1m6.8.	Cancelling a Shutdown0m

To cancel a shutdown, use 4mSmsShutdownCancelled24m.
__
|
void SmsShutdownCancelled(4msms_conn24m)
    SmsConn 4msms_conn24m;


4msms_conn24m  The session management connection object.
|__

The  client  can  now  continue as if the shutdown had never
happened.  If the client has  not  sent	 a  ``Save  Yourself
Done''	message yet, it can either abort the save and send a
``Save Yourself Done'' with  the  success  argument  set  to
4mFalse24m,  or	 it  can continue with the save and send a ``Save
Yourself Done'' with the success argument set to reflect the
outcome of the save.






			   - 34 -





1mX Session Management Library		      X11, Release 6.40m


1m6.9.	Returning Properties0m

In  response  to  a  ``Get Properties'' message, the session
manager should call 4mSmsReturnProperties24m.
__
|
void SmsReturnProperties(4msms_conn24m, 4mnum_props24m, 4mprops24m)
    SmsConn 4msms_conn24m;
    int 4mnum_props24m;
    SmProp **4mprops24m;


4msms_conn24m  The session management connection object.

4mnum_props24m The number of properties.

4mprops24m     The list of properties to return to the client.
|__

The properties are returned as an array of  property  point-
ers.  For a description of session management properties and
the 4mSmProp24m structure, see section	7,  ``Session  Management
Properties.''

1m6.10.	 Pinging a Client0m

To  check  that	 a client is still alive, you should use the
4mIcePing24m function provided by the ICE library.  To do so, the
ICE  connection	 must be obtained using the 4mSmsGetIceConnec-0m
4mtion24m (see section	6.12,  ``Using	Sms  Informational  Func-
tions'').

__
|
void IcePing(4mice_conn24m, 4mping_reply_proc24m, 4mclient_data24m)
    IceConn 4mice_conn24m;
    IcePingReplyProc 4mping_reply_proc24m;
    IcePointer 4mclient_data24m;


4mice_conn24m  A valid ICE connection object.

4mping_reply_proc0m
	  The	callback  to  invoke  when  the	 Ping  reply
	  arrives.

4mclient_data0m
	  This pointer will  be	 passed	 to  the  4mIcePingRe-0m
	  4mplyProc24m callback.
|__

When the Ping reply is ready (if ever), the 4mIcePingReplyProc0m
callback will be invoked.  A  session  manager	should	have
some  sort  of	timeout	 period,  after which it assumes the



			   - 35 -





1mX Session Management Library		      X11, Release 6.40m


client has unexpectedly died.

__
|
typedef void (*IcePingReplyProc)();

void PingReplyProc(4mice_conn24m, 4mclient_data24m)
    IceConn 4mice_conn24m;
    IcePointer 4mclient_data24m;


4mice_conn24m  The ICE connection object.

4mclient_data0m
	  The client data specified in the call to  4mIcePing24m.
|__


1m6.11.	 Cleaning Up After a Client Disconnects0m

When  the  session  manager receives a ``Connection Closed''
message or otherwise detects that  the	client	aborted	 the
connection,  it should call the 4mSmsCleanUp24m function in order
to free up the connection object.
__
|
void SmsCleanUp(4msms_conn24m)
    SmsConn 4msms_conn24m;


4msms_conn24m  The session management connection object.
|__


1m6.12.	 Using Sms Informational Functions0m

__
|
int SmsProtocolVersion(4msms_conn24m)
    SmsConn 4msms_conn24m;

|__

4mSmsProtocolVersion24m returns the major version of the  session
management protocol associated with this session.


__
|
int SmsProtocolRevision(4msms_conn24m)
    SmsConn 4msms_conn24m;






			   - 36 -





1mX Session Management Library		      X11, Release 6.40m


|__

4mSmsProtocolRevision24m returns the minor version of the session
management protocol associated with this session.


__
|
char *SmsClientID(4msms_conn24m)
    SmsConn 4msms_conn24m;

|__

4mSmsClientID24m returns a null-terminated string for the  client
ID associated with this connection.  You should call 4mfree24m on
this pointer when the client ID is no longer needed.


To obtain the host name of a client, use  4mSmsClientHostName24m.
This host name will be needed to restart the client.
__
|
char *SmsClientHostName(4msms_conn24m)
    SmsConn 4msms_conn24m;
|__

The  string returned is of the form 4mprotocol24m/4mhostname24m, where
4mprotocol24m is one of {tcp, decnet, local}.	You  should  call
4mfree24m on the string returned when it is no longer needed.


__
|
IceConn SmsGetIceConnection(4msms_conn24m)
    SmsConn 4msms_conn24m;
|__

4mSmsGetIceConnection24m  returns the ICE connection object asso-
ciated with this session management connection object.	 The
ICE  connection	 object	 can  be used to get some additional
information about the connection.  Some of the	more  useful
functions  which  can  be used on the IceConn are 4mIceConnec-0m
4mtionNumber24m, and 4mIceLastSequenceNumber24m.  For further informa-
tion, see the 4mInter-Client24m 4mExchange24m 4mLibrary24m standard.

1m6.13.	 Error Handling0m

If the session manager receives an unexpected protocol error
from a client, an error handler	 is  invoked  by  SMlib.   A
default	 error	handler exists which simply prints the error
message (it does not exit).  The session manager can  change






			   - 37 -





1mX Session Management Library		      X11, Release 6.40m


this error handler by calling 4mSmsSetErrorHandler24m.
__
|
SmsErrorHandler SmsSetErrorHandler(4mhandler24m)
    SmsErrorHandler 4mhandler24m;


4mhandler24m   The  error  handler.   You  should  pass	 NULL  to
	  restore the default handler.
|__

4mSmsSetErrorHandler24m returns the previous error handler.   The
4mSmsErrorHandler24m has the following type:
__
|
typedef void (*SmsErrorHandler)();

void ErrorHandler(4msms_conn24m, 4mswap24m, 4moffending_minor_opcode24m, 4moffending_sequence_num24m, 4merror_class24m, 4mseverity24m, 4mvalues24m)
    SmsConn 4msms_conn24m;
    Bool 4mswap24m;
    int 4moffending_minor_opcode24m;
    unsigned long 4moffending_sequence_num24m;
    int 4merror_class24m;
    int 4mseverity24m;
    IcePointer 4mvalues24m;


4msms_conn24m  The session management connection object.

4mswap24m      A  flag	which  indicates  if the specified values
	  need byte swapping.

4moffending_minor_opcode0m
	  The minor opcode of the offending message.

4moffending_sequence_num0m
	  The sequence number of the offending message.

4merror_class0m
	  The error class of the offending message.

4mseverity24m  4mIceCanContinue24m, 4mIceFatalToProtocol24m, or 4mIceFatalTo-0m
	  4mConnection24m.

4mvalues24m    Any  additional error values specific to the minor
	  opcode and class.
|__

Note that this error handler is invoked for protocol related
errors.	  To  install an error handler to be invoked when an
IO error  occurs,  use	4mIceSetIOErrorHandler24m.   For  further
information, see the 4mInter-Client24m 4mExchange24m 4mLibrary24m standard.





			   - 38 -





1mX Session Management Library		      X11, Release 6.40m


1m7.  Session Management Properties0m

Each property is defined by the 4mSmProc24m structure:


typedef struct {
     char *name;	 /* name of property */
     char *type;	 /* type of property */
     int num_vals;	 /* number of values */
     SmPropValue *vals;	 /* the list of values */
} SmProp;

typedef struct {
     int length;	 /* the length of the value */
     SmPointer value;	 /* the value */
} SmPropValue;


The X Session Management Protocol defines a list  of  prede-
fined properties, several of which are required to be set by
the client.  The following table  specifies  the  predefined
properties  and	 indicates  which  ones	 are required.	Each
property has a type associated with it.

A type of SmCARD8 indicates that there is  a  single  1-byte
value.	 A type of SmARRAY8 indicates that there is a single
array of bytes.	 A type	 of  SmLISTofARRAY8  indicates	that
there is a list of array of bytes.


-------------------------------------------------------------
1mName		       Type	     POSIX Type	      Required0m
-------------------------------------------------------------
SmCloneCommand	     OS-specific   SmLISTofARRAY8     Yes
SmCurrentDirectory   OS-specific   SmARRAY8	       No
SmDiscardCommand     OS-specific   SmLISTofARRAY8     No*
SmEnvironment	     OS-specific   SmLISTofARRAY8      No
SmProcessID	     OS-specific   SmARRAY8	       No
SmProgram	     OS-specific   SmARRAY8	      Yes
SmRestartCommand     OS-specific   SmLISTofARRAY8     Yes
SmResignCommand	     OS-specific   SmLISTofARRAY8      No
SmRestartStyleHint   SmCARD8	   SmCARD8	       No
SmShutdownCommand    OS-specific   SmLISTofARRAY8      No
SmUserID	     SmARRAY8	   SmARRAY8	      Yes
-------------------------------------------------------------


*  Required if any state is stored in an external repository
(for example, state file).

·    SmCloneCommand

     This is like the SmRestartCommand, except it restarts a
     copy  of  the application.	 The only difference is that



			   - 39 -





1mX Session Management Library		      X11, Release 6.40m


     the application does not supply its client ID at regis-
     ter  time.	  On  POSIX  systems, this should be of type
     SmLISTofARRAY8.

·    SmCurrentDirectory

     On POSIX-based systems, this specifies the value of the
     current  directory	 that  needs  to  be set up prior to
     starting the SmProgram and should of type SmARRAY8.

·    SmDiscardCommand

     The discard command contains a command that when deliv-
     ered  to the host that the client is running on (deter-
     mined from the connection), will cause  it	 to  discard
     any  information about the current state.	If this com-
     mand is not specified, the Session Manager will  assume
     that  all	of  the	 client's  state  is  encoded in the
     SmRestartCommand.	On POSIX systems, the type should be
     SmLISTofARRAY8.

·    SmEnvironment

     On	 POSIX	based systems, this will be of type SmLISTo-
     fARRAY8, where the ARRAY8s alternate  between  environ-
     ment variable name and environment variable value.

·    SmProcessID

     This   specifies  an  OS-specific	identifier  for	 the
     process.  On POSIX systems,  this	should	contain	 the
     return  value of 4mgetpid24m turned into a Latin-1 (decimal)
     string.

·    SmProgram

     This is the name of the program that  is  running.	  On
     POSIX systems, this should be first parameter passed to
     4mexecve24m and should be of type SmARRAY8.

·    SmRestartCommand

     The restart  command  contains  a	command	 that,	when
     delivered	to  the	 host  that the client is running on
     (determined from the connection), will cause the client
     to	 restart  in its current state.	 On POSIX-based sys-
     tems, this is of type SmLISTofARRAY8, and each  of	 the
     elements in the array represents an element in the 4margv0m
     array.  This restart command  should  ensure  that	 the
     client restarts with the specified client-ID.

·    SmResignCommand





			   - 40 -





1mX Session Management Library		      X11, Release 6.40m


     A	client that sets the SmRestartStyleHint to SmRestar-
     tAnway uses this property to  specify  a  command	that
     undoes  the  effect of the client and removes any saved
     state.  As	 an  example,  consider	 a  user  that	runs
     4mxmodmap24m, which registers with the Session Manager, sets
     SmRestartStyleHint to SmRestartAnyway, and then  termi-
     nates.   To  allow	 the  Session Manager (at the user's
     request) to undo this, 4mxmodmap24m would register	 a  SmRe-
     signCommand that undoes the effects of the 4mxmodmap24m.

·    SmRestartStyleHint

     If	 the  RestartStyleHint	property is present, it will
     contain the style of restarting the client prefers.  If
     this  style  is  not  specified,  SmRestartIfRunning is
     assumed.  The possible values are as follows:

     -----------------------------
     1mName		      Value0m
     -----------------------------
     SmRestartIfRunning	      0
     SmRestartAnyway	      1
     SmRestartImmediately     2
     SmRestartNever	      3
     -----------------------------


     The SmRestartIfRunning style is used in the usual case.
     The  client  should be restarted in the next session if
     it was running at the end of the current session.

     The SmRestartAnyway style is used to tell	the  Session
     Manager that the application should be restarted in the
     next session even if it exits before the  current	ses-
     sion  is  terminated.   It should be noted that this is
     only a hint and the Session  Manager  will	 follow	 the
     policies  specified  by  its  users in determining what
     applications to restart.

     A client that uses SmRestartAnyway should also set	 the
     SmResignCommand  and  SmShutdownCommand  properties  to
     commands that undo the state of  the  client  after  it
     exits.

     The SmRestartImmediately style is like SmRestartAnyway,
     but, in addition, the client is meant to  run  continu-
     ously.  If the client exits, the Session Manager should
     try to restart it in the current session.

     SmRestartNever style specifies that the client does not
     wish to be restarted in the next session.

·    SmShutdownCommand




			   - 41 -





1mX Session Management Library		      X11, Release 6.40m


     This  command  is executed at shutdown time to clean up
     after a client that is no longer running  but  retained
     its  state	 by  setting SmRestartStyleHint to SmRestar-
     tAnyway.  The client must not remove any saved state as
     the  client  is still part of the session.	 As an exam-
     ple, consider a client that turns on a camera at  start
     up time.  This client then exits.	At session shutdown,
     the user wants the	 camera	 turned	 off.	This  client
     would set the SmRestartStyleHint to SmRestartAnyway and
     would register a SmShutdownCommand that would turn	 off
     the camera.

·    SmUserID

     Specifies	the  user  ID.	On POSIX-based systems, this
     will contain the user's name  (the	 pw_name  member  of
     struct 4mpasswd24m).

1m8.  Freeing Data0m

To free an individual property, use 4mSmFreeProperty24m.
__
|
void SmFreeProperty(4mprop24m)
    SmProp *4mprop24m;


4mprop24m      The property to free.
|__


To  free  the reason strings from the 4mSmsCloseConnectionProc0m
callback, use 4mSmFreeReasons24m.
__
|
void SmFreeReasons(4mcount24m, 4mreasons24m)
    int 4mcount24m;
    char **4mreasons24m;


4mcount24m     The number of reason strings.

4mreasons24m   The list of reason strings to free.
|__


1m9.  Authentication of Clients0m

As stated earlier, the session management protocol  is	lay-
ered  on top of ICE.  Authentication occurs at two levels in
the ICE protocol:

·    The first is when an ICE connection is opened.




			   - 42 -





1mX Session Management Library		      X11, Release 6.40m


·    The second is when a Protocol Setup occurs	 on  an	 ICE
     connection.

The  authentication methods that are available are implemen-
tation-dependent (that is.,  dependent	on  the	 ICElib	 and
SMlib implementations in use).	For further information, see
the 4mInter-Client24m 4mExchange24m 4mLibrary24m standard.

1m10.  Working in a Multi-Threaded Environment0m

To declare that multiple threads in an application  will  be
using SMlib (or any other library layered on top of ICElib),
you should call 4mIceInitThreads24m.   For  further  information,
see the 4mInter-Client24m 4mExchange24m 4mLibrary24m standard.

1m11.  Acknowledgements0m

Thanks	to  the	 following people for their participation in
the X Session Management design: Jordan Brown, Ellis  Cohen,
Donna  Converse,  Stephen  Gildea,  Vania  Joloboff,  Stuart
Marks, Bob Scheifler, Ralph Swick, and Mike Wexler.




































			   - 43 -

































































			   - 44 -









		     1mTable of Contents0m


1. Overview of Session Management  . . . . . . . . . . .   1
2. The Session Management Library  . . . . . . . . . . .   1
3. Understanding SMlib's Dependence on ICE . . . . . . .   2
4. Header Files and Library Name . . . . . . . . . . . .   3
5. Session Management Client (Smc) Functions . . . . . .   3
5.1. Connecting to the Session Manager . . . . . . . . .   4
5.1.1. The Save Yourself Callback  . . . . . . . . . . .   7
5.1.2. The Die Callback	 . . . . . . . . . . . . . . . .   8
5.1.3. The Save Complete Callback  . . . . . . . . . . .   9
5.1.4. The Shutdown Cancelled Callback . . . . . . . . .   9
5.2. Closing the Connection  . . . . . . . . . . . . . .  10
5.3. Modifying Callbacks . . . . . . . . . . . . . . . .  11
5.4. Setting, Deleting, and Retrieving Session Man-
agement Properties . . . . . . . . . . . . . . . . . . .  12
5.5. Interacting With the User . . . . . . . . . . . . .  14
5.6. Requesting a Save Yourself	 . . . . . . . . . . . .  15
5.7. Requesting a Save Yourself Phase 2	 . . . . . . . .  16
5.8. Completing a Save Yourself	 . . . . . . . . . . . .  17
5.9. Using Smc Informational Functions . . . . . . . . .  17
5.10. Error Handling . . . . . . . . . . . . . . . . . .  18
6. Session Management Server (Sms) Functions . . . . . .  20
6.1. Initializing the Library  . . . . . . . . . . . . .  20
6.1.1. The Register Client Callback  . . . . . . . . . .  24
6.1.2. The Interact Request Callback . . . . . . . . . .  24
6.1.3. The Interact Done Callback  . . . . . . . . . . .  25
6.1.4. The Save Yourself Request Callback  . . . . . . .  26
6.1.5. The Save Yourself Phase 2 Request Callback  . . .  27
6.1.6. The Save Yourself Done Callback . . . . . . . . .  27
6.1.7. The Connection Closed Callback  . . . . . . . . .  28
6.1.8. The Set Properties Callback . . . . . . . . . . .  29
6.1.9. The Delete Properties Callback  . . . . . . . . .  29
6.1.10. The Get Properties Callback  . . . . . . . . . .  30
6.2. Registering the Client  . . . . . . . . . . . . . .  30
6.3. Sending a Save Yourself Message . . . . . . . . . .  31
6.4. Sending a Save Yourself Phase 2 Message . . . . . .  33
6.5. Sending an Interact Message . . . . . . . . . . . .  33
6.6. Sending a Save Complete  Message  . . . . . . . . .  34
6.7. Sending a Die Message . . . . . . . . . . . . . . .  34
6.8. Cancelling a Shutdown . . . . . . . . . . . . . . .  34
6.9. Returning Properties  . . . . . . . . . . . . . . .  35
6.10. Pinging a Client . . . . . . . . . . . . . . . . .  35
6.11. Cleaning Up After a Client Disconnects . . . . . .  36
6.12. Using Sms Informational Functions	 . . . . . . . .  36
6.13. Error Handling . . . . . . . . . . . . . . . . . .  37
7. Session Management Properties . . . . . . . . . . . .  39
8. Freeing Data	 . . . . . . . . . . . . . . . . . . . .  42
9. Authentication of Clients . . . . . . . . . . . . . .  42
10. Working in a Multi-Threaded Environment  . . . . . .  43
11. Acknowledgements . . . . . . . . . . . . . . . . . .  43




			     iii