path: root/specs/recordlib.ms

.\" Record Extension Library, v1.13
.\" Use -ms and macros.t
.\" edited for DP edits and code consistency w/ core protocol/xlib 4/1/96
.\" $Xorg: recordlib.ms,v 1.3 2000/08/17 19:42:36 cpqbld Exp $
.\" $XdotOrg: xc/doc/specs/Xext/recordlib.ms,v 1.2 2004/04/23 18:42:18 eich Exp $
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.\"
.hw XRecord-Register-Clients XRecord-Unregister-Clients
.hw XRecord-Intercept-Data XRecord-Query-Version XRecord-Process-Replies
.hw XRecord-EndOfData
.hw XButton-Released-Event XMotion-Event
.hw XRecord-Context
.EH ''''
.OH ''''
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.ps 11
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\s+3\fBX Record Extension Library\fP\s0
.sp
\fBVersion 1.13\fP
.sp
\fBX Consortium Standard\fP
.sp
\fBX Version 11, Release 6.8\fP
.sp 6
Martha Zimet
Network Computing Devices, Inc.
.sp 6
edited by
Stephen Gildea
X Consortium
.ce 0
.bp
.br
\&
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.LP
Copyright \(co 1994 Network Computing Devices, Inc.
.LP
Permission to use, copy, modify, distribute, and sell this
documentation for any purpose is hereby granted without fee,
provided that the above copyright notice and this permission
notice appear in all copies.  Network Computing Devices, Inc.
makes no representations about the suitability for any purpose
of the information in this document.  This documentation is
provided \*Qas is\*U without express or implied warranty.
.LP
Copyright \(co 1995  X Consortium
.LP
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
\*QSoftware\*U), to deal in the Software without 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 following conditions:
.LP
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
.LP
THE SOFTWARE IS PROVIDED \*QAS IS\*U, WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE X CONSORTIUM 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.
.LP
Except as contained in this notice, the name of the X Consortium and
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.
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.OH '\fBX11, Release 6.8\fP''\fBX Record Extension Library, Version 1.13\fP'
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.hy 14

.NH 1
Record Extension Overview
.XS
\*(SN Record Extension Overview
.XE
.LP
The purpose
of this extension is to support the recording and reporting of all
core X protocol and arbitrary X extension protocol.  This first section
gives an overview of the Record extension.  The following sections
describe how to use the Record extension library.
.NH 2
Synchronous Playback
.XS
\*(SN Synchronous Playback
.XE
.LP
Environment information is generally provided to an X-based playback
mechanism, which might use the XTest extension to synthesize input events.
This synchronization information defines the X state prior to
event synthesis (for example, location of the cursor, window locations and
sizes, installed colormap, window manager running, and so on) and the
consequences that occur after the playback mechanism synthesizes
the event.  If the user moves the mouse into the icon window and
presses and releases a mouse button, the device events
.PN MotionNotify ,
.PN ButtonPress ,
and
.PN ButtonRelease
are generated by the X server.
Because
X follows an event-driven model, there are consequences that
follow from
the user actions, or device events, that are in the form of X protocol.
As a result of the previous user actions, the client could
generate requests such as
.PN ImageText8
and
.PN PolyLine
to the X server,
or the X server could send non-device events such as
.PN Expose
and
.PN MapNotify
to the client window.  Both the requests and non-device events that
result from user actions are known as \fIconsequences\fP, which
can be used as a synchronization, or control point, during playback.
That is, the playback mechanism does not generate a specific synthesized
event until its matching synchronization condition occurs (for example,
the window is mapped or unmapped, the cursor changes, a text string
displays, and so on)
.LP
Because
it cannot be predicted what synchronization information is
required during playback, the Record extension makes no assumptions
about the intended use of the recorded data.  Facilities exist to
record any core X protocol or X extension protocol.
Therefore, Record does not enforce a specific synchronization
methodology.
.NH 2
Design Approach
.XS
\*(SN Design Approach
.XE
.LP
The design approach of the extension is to record core X protocol
and arbitrary X extension protocol entirely within the X server
itself.  When the extension has been requested to record specific
protocol by one or more recording clients, the protocol data is formatted
and returned to the recording clients.  The extension provides a mechanism
for capturing all events, including input device events that do not go to any
clients.
.NH 2
Record Clients
.XS
\*(SN Record Clients
.XE
.LP
The recommended
communication model for a Record application is to open two
connections to the server\*-one connection for recording control
and one connection for reading recorded protocol data.
.LP
Information about recording (for example, what clients to record,
what protocol to record for each client, and so on) is stored in
resources called \fIrecord contexts\fP\^
(type
.PN XRecordContext ).
Most Record extension functions take a record context as an argument.
Although in theory it is possible
to share record contexts between applications,
it is expected that
applications will use their own context when performing recording
operations.
.LP
A client that wishes to record X protocol does so through the library
functions defined in
section 3 \*QLibrary Extension Requests\*U.  A typical sequence
of requests that a client would make is as follows:
.Ip
.PN XRecordQueryVersion
\- query the extension protocol version.
.Ip
.PN XRecordCreateContext
\- request that the server create a record context
for access by this client, and express interest in clients and protocol
to be recorded.  This request returns an
.PN XRecordContext ,
which is an XID that is used
by most other extension requests to identify the specified context.
.Ip
.PN XRecordEnableContext
\- begin the recording and reporting of protocol
data.
.Ip
.PN XRecordDisableContext
\- end the recording and reporting of protocol data.
.Ip
.PN XRecordFreeContext
\- free the record context.
.LP
The header for this library is
.Pn < X11/extensions/record.h >.
All identifiers defined in the interface are supplied by this header
and are prefixed with \*QXRecord\*U.  The
.PN Xtst
library contains the
.PN XRecord
functions.
.NH 1
Common Arguments
.XS
\*(SN What Is Recorded
.XE
.LP
The Record extension functions
.PN XRecordCreateContext
and
.PN XRecordRegisterClients
allow applications to specify the following:
.Ip
Individual clients or sets of clients to record
.Ip
Ranges of core X protocol and X extension protocol to record for
each client
.LP
Protocol in the ranges specified by the recording client
will be recorded by the server.  The device_events
protocol type can be specified by a recording
client although it may not be sent to a recorded client.
The device_events type differs from delivered_events,
which also can be specified by a recording client;
delivered_events are actually delivered to one or more clients.
These event types are discussed in section 2.3 \*QProtocol Ranges\*U.
.LP
The Record extension functions
.PN XRecordCreateContext
and
.PN XRecordRegisterClients
have the common arguments
datum_flags,
clients, and ranges, which specify
whether server time and/or client
sequence number should precede protocol elements,
the clients or client set to
record, and the protocol ranges to record, respectively.
These are discussed in the following sections.
.NH 2
Datum Flags
.LP
The datum_flags argument is a set of flags OR'ed together to
specify options for the record context.  Specify zero to disable all
the options.
.LP
The
.PN XRecordFromServerTime
flag specifies that
.PN XRecordInterceptData
structures with a category of
.PN XRecordFromServer
will have a server_time field specific to each
protocol element.
.LP
The
.PN XRecordFromClientTime
flag specifies that
.PN XRecordInterceptData
structures with a category of
.PN XRecordFromClient
will have a server_time field specific to each protocol element.
.LP
The
.PN XRecordFromClientSequence
flag specifies that
.PN XRecordInterceptData
structures with a category of
.PN XRecordFromClient
or
.PN XRecordClientDied
will have a valid client_seq field.
.NH 2
Selecting Clients
.LP
The clients argument is a pointer to an array of
.PN XRecordClientSpec .
.PN XRecordClientSpec
is an integral type that holds a resource ID,
a client resource ID base, or one
of the \fIclient set\fP constants defined below.
.LP
Duplicate
elements in the array are ignored by the functions, and if any element
in the array is not valid, a
.PN "BadMatch"
error results.
A resource ID references the client that created that resource.
The client set may be one of the following constants:
.PN XRecordCurrentClients ,
.PN XRecordFutureClients ,
or
.PN XRecordAllClients .
.LP
If the element in the array identifies a particular client, protocol
specified by the ranges argument will be recorded by the server.
The recorded protocol data will not be returned to the recording client
until the record context has been enabled.  This is described in section
3.4 \*QData Transfer\*U.
.LP
If the element is
.PN XRecordCurrentClients ,
the protocol ranges specified by the
ranges argument, except for device_events, are associated with
each current client connection.  If the element is
.PN XRecordFutureClients ,
the protocol ranges specified by the ranges argument are associated
with each new client connection.  If the element is
.PN XRecordAllClients ,
the protocol ranges specified by the ranges argument are associated
with each current client connection and with each new client connection.
.LP
When the context is enabled, the data connection is unregistered if it
was registered.
If the context is enabled,
.PN XRecordCurrentClients
and
.PN XRecordAllClients
silently exclude the recording data connection.
It is an error to explicitly register the data connection.
.NH 2
Protocol Ranges
.LP
The functions
.PN XRecordCreateContext
and
.PN XRecordRegisterClients
have another common argument, ranges,
which is an array of pointers to
.PN XRecordRange
structures.  Each structure contains ranges of numeric values for each
of the protocol types that can be specified and recorded individually
by the Record extension.
An
.PN XRecordRange
structure must be allocated
by the Record library using the
.PN XRecordAllocRange
function.
.LP
The
.PN XRecordRange
typedef is a structure with the following members:
.LP
.sM
.Ds 0
.TA .5i 3.0i
.ta .5i 3.0i
XRecordRange:
	XRecordRange8 core_requests	/* core X requests */
	XRecordRange8 core_replies	/* core X replies */
	XRecordExtRange ext_requests	/* extension requests */
	XRecordExtRange ext_replies	/* extension replies */
	XRecordRange8 delivered_events	/* delivered core and ext events */
	XRecordRange8 device_events	/* all core and ext device events */
	XRecordRange8 errors	/* core X and X ext errors */
	Bool client_started	/* connection setup reply from server */
	Bool client_died	/* notification of client disconnect */
.De
.LP
.eM
The types used in
.PN XRecordRange
members are defined as follows.
The
.PN XRecordRange8
typedef is a structure with the following members:
.LP
.sM
.Ds 0
.TA .5i
.ta .5i
XRecordRange8:
	unsigned char first
	unsigned char last
.De
.LP
.eM
The
.PN XRecordRange16
typedef is a structure with the following members:
.LP
.sM
.Ds 0
.TA .5i
.ta .5i
XRecordRange16:
	unsigned short first
	unsigned short last
.De
.LP
.eM
The
.PN XRecordExtRange
typedef is a structure with the following members:
.LP
.sM
.Ds 0
.TA .5i 
.ta .5i 
XRecordExtRange:
	XRecordRange8 ext_major
	XRecordRange16 ext_minor
.De
.LP
.eM
If any of the values specified in
.PN XRecordRange
is invalid, a
.PN "BadValue"
error results.
.LP
The core_requests member specifies the range of core X protocol
requests to record.  Core X protocol requests with a major opcode
that is between first and last, inclusive, will be
recorded.  A
.PN "BadValue"
error results
if the value of first is greater than the value of last.
If the values of both first and last are zero, no core
X protocol requests will be recorded.
.LP
The core_replies member specifies the range of replies resulting
from core X protocol requests to record.  Replies that result from
core X protocol requests with a major opcode between first
and last, inclusive, will be recorded.  A
.PN "BadValue"
error results
if the value of first is greater than the value of last.
If the values of both first and last are zero,
no core X protocol replies will be recorded.
.LP
The ext_requests member specifies the range of X extension
requests to record.  X extension requests with a major opcode
between ext_major.first and ext_major.last, and with a
minor opcode
between ext_minor.first and ext_minor.last, inclusive, will be
recorded.  A
.PN "BadValue"
error results
if the value of ext_major.first is greater than the value of
ext_major.last or if the value of ext_minor.first is
greater than the value of ext_minor.last.  If the values of both
ext_major.first
and ext_major.last are zero,
no X extension requests will be recorded.
.LP
The ext_replies member specifies the range of replies resulting
from X extension requests to record.  Replies that result from an X
extension request with a major opcode between
ext_major.first and
ext_major.last, and a minor opcode that is between
ext_minor.first and ext_minor.last will be recorded.  A
.PN "BadValue"
error results
if the value of ext_major.first is greater than the value of
ext_major.last or if the value of ext_minor.first is greater than
the value of ext_minor.last.  If the values of both
ext_major.first and ext_major.last
are zero, no X extension
replies will be recorded.
.LP
The delivered_events member specifies the range of both core
X events and X extension events to record.  These events are
delivered to at least one client.  Core X events and X extension events
with a code value between first and
last inclusive will be recorded.  A
.PN "BadValue"
error results
if the value of first
is greater than the value of last.  If the values of first
and last are zero, no events will be recorded.
.LP
The device_events member specifies the range of
both core X device events and X extension device events
to record.  These events may or may not be delivered to a client.
Core X device events and X extension device events with a code value
between first and last inclusive that are not delivered to any
clients will be recorded.  A
.PN "BadValue"
error results
if the value of first
is greater than the value of last.  A
.PN "BadValue"
error results
if first
is less than two or last is less than two, except that if
first and last are zero, no events will be
recorded.
.LP
The errors member specifies the range of both core X errors and X
extension errors to record.  Core X errors and X extension errors with
a code value between first and last inclusive will be
recorded.  A
.PN "BadValue"
error results
if the value of first
is greater than the value of last.  If the values of first and
last are zero, no errors will be recorded.
.LP
A value of
.PN True
for the client_started member specifies the
connection setup reply from the server to new clients.
If
.PN False ,
the connection setup reply is
not specified by this
.PN XRecordRange .
.LP
A value of
.PN True
for the client_died member specifies
notification when a client disconnects.
If
.PN False ,
notification when a client disconnects is
not specified by this
.PN XRecordRange .
.NH 1
Library Extension Requests
.XS
\*(SN Library Extension Requests
.XE
.LP
Recording operations are accessed by programs through the use of
new protocol requests.  The following functions are provided as extensions
to Xlib.  An Xlib error results if
an extension request is made to an X server that does not support the
Record extension.  Note that any of the extension protocol requests may generate
.PN BadAlloc
or
.PN BadLength
errors.
.NH 2
Query Extension Version
.XS
\*(SN Query Extension Version
.XE
.LP
An application uses the
.PN XRecordQueryVersion
function to determine
the version of the Record extension protocol supported by an X server.
.sM
.FD 0
Status
XRecordQueryVersion\^(Display *\fIdisplay\fP, int *\fIcmajor_return\fP, \
int *\fIcminor_return\fP)
.FN
.IP \fIdisplay\fP 1i
Specifies the connection to the X server.
.IP "\fIcmajor_return\fP" 1i  
Returns the extension protocol major version in use.
.IP "\fIcminor_return\fP" 1i 
Returns the extension protocol minor version in use.
.LP
.eM
The
.PN XRecordQueryVersion
function returns the major and minor
protocol version numbers supported by the server.
.PN XRecordQueryVersion
returns nonzero (success) only if the returned version numbers are
common to both the library and the
server; otherwise, it returns zero.
.NH 2
Create and Modify Context
.XS
\*(SN Create and Modify Context
.XE
.LP
An application uses the
.PN XRecordCreateContext
function to create a
record context.  At the time the record context is
created by the recording client, the clients to be recorded and the
protocol to record for each client may be specified.
.LP
.sM
.FD 0
XRecordContext
XRecordCreateContext\^(Display *\fIdisplay\fP, int \fIdatum_flags\fP, \
XRecordClientSpec *\fIclients\fP, int \fInclients\fP,
.br
                      XRecordRange **\fIranges\fP, int \fInranges\fP)
.FN
.IP "\fIdisplay\fP" 1i
Specifies the connection to the X server.
.IP \fIdatum_flags\fP 1i
Specifies whether detailed time or sequence info should be sent.
.IP "\fIclients\fP" 1i
Specifies the clients to record.
.IP "\fInclients\fP" 1i
Specifies the number of clients.
.IP "\fIranges\fP" 1i
Specifies the protocol ranges to record.
.IP "\fInranges\fP" 1i
Specifies the number of protocol ranges.
.LP
.eM
The
.PN XRecordCreateContext
function creates a record context and returns an
.PN XRecordContext ,
which is then used
in the other Record library calls.  This request is typically
executed by the recording client over its control connection to
the X server.
The datum_flags specifies whether server time and/or client
sequence number should precede protocol elements recorded by context
(see section 2.1).
When a clients element identifies
a particular client, the client is added to the context and
the protocol to record for that client is set to the union of
all ranges.  When a clients element is
.PN XRecordCurrentClients ,
.PN XRecordFutureClients ,
or
.PN XRecordAllClients ,
the actions described in section 2.2 \*QSelecting Clients\*U
are performed.
.LP
.PN XRecordCreateContext
returns zero if the request failed.
.PN XRecordCreateContext
can generate
.PN BadIDChoice ,
.PN BadMatch ,
and
.PN BadValue
errors.
.LP
The ranges argument is an
.PN XRecordRange *
array, that is, an array
of pointers.  The structures the elements point to shall be allocated
by calling
.PN XRecordAllocRange .
.LP
.sM
.FD 0
XRecordRange *
XRecordAllocRange\^(void)
.FN
.LP
.eM
The
.PN XRecordAllocRange
function
allocates and returns an
.PN XRecordRange
structure.
The structure is initialized to specify no protocol.
The function returns NULL if the structure allocation fails.
The application can free the structure by calling
.PN XFree .
.NH 3
Additions
.LP
An application uses the
.PN XRecordRegisterClients
function to modify a previously created
record context, by adding clients or modifying the recorded protocol,
typically over its control connection to the X server.
.LP
.sM
.FD 0
Status
XRecordRegisterClients\^(Display *\fIdisplay\fP, XRecordContext \fIcontext\fP, \
int \fIdatum_flags\fP, 
.br
                XRecordClientSpec *\fIclients\fP, int \fInclients\fP, \
XRecordRange **\fIranges\fP, int \fInranges\fP)
.FN
.IP "\fIdisplay\fP " 1i
Specifies the connection to the X server.
.IP "\fIcontext\fP" 1i
Specifies the record context to modify.
.IP \fIdatum_flags\fP 1i
Specifies whether detailed time or sequence info should be sent.
.IP "\fIclients\fP" 1i
Specifies the clients to record.
.IP "\fInclients\fP" 1i
Specifies the number of clients.
.IP "\fIranges\fP" 1i
Specifies the protocol ranges to record.
.IP "\fInranges\fP" 1i
Specifies the number of protocol ranges.
.LP
.eM
The datum_flags specifies whether server time and/or client
sequence number should precede protocol elements
for all clients
recorded by context
(see section 2.1).
When a clients element identifies a particular client and the
client is not yet
targeted for recording in the given context,
the client is added to the set of clients to record, and the protocol
to record for that client is set to the union of all ranges.
When the client is
already targeted for recording, the protocol to record for that client
is set to the union of all ranges.  When the element is
.PN XRecordCurrentClients ,
.PN XRecordFutureClients ,
or
.PN XRecordAllClients ,
the actions described
in section 2.2 \*QSelecting Clients\*U
are performed.
.LP
.PN XRecordRegisterClients
returns zero if the request failed; otherwise, it
returns nonzero.
.LP
.PN XRecordRegisterClients
can generate
.PN XRecordBadContext ,
.PN BadMatch ,
and
.PN BadValue
errors.
.NH 3
Deletions
.LP
An application uses
the
.PN XRecordUnregisterClients
function to delete clients from a
previously created
record context, typically over its control connection to the X server.
.LP
.sM
.FD 0
Status
XRecordUnregisterClients\^(Display *\fIdisplay\fP, XRecordContext \fIcontext\fP, \
RecordClientSpec *\fIclients\fP,
.br
                  int \fInclients\fP\^)
.FN
.IP "\fIdisplay\fP " 1i
Specifies the connection to the X server.
.IP "\fIcontext\fP" 1i
Specifies the record context to modify.
.IP "\fIclients\fP" 1i 
Specifies the clients to stop recording.
.IP "\fInclients\fP" 1i  
Specifies the number of clients.
.LP
.eM
When an element in clients identifies a particular client, and the
specified client is already targeted for recording in the given
context, the client and the set of protocol to record for that
client are deleted from the context.  If the specified client is not
targeted for recording, then no action is performed.
.LP
When the element is
.PN XRecordCurrentClients ,
all clients currently targeted
for recording in context and their corresponding sets of
protocol to record are deleted from context.
.LP
When the item is
.PN XRecordFutureClients ,
any future client connections will
not automatically be targeted for recording in context.
.LP
When the element is
.PN XRecordAllClients ,
all clients currently targeted
for recording in context and their corresponding sets of
protocol to record are deleted from context.  Any future
client connections will not automatically be targeted for recording
in context.
.LP
.PN XRecordUnregisterClients
returns zero if the request failed; otherwise,
it returns nonzero.
.LP
.PN XRecordUnregisterClients
can generate
.PN XRecordBadContext ,
.PN BadMatch ,
and
.PN BadValue
errors.
.NH 2
Query Context State
.XS
\*(SN Query Context State
.XE
.LP
An application uses the
.PN XRecordGetContext
function to query the
current state of a record context, typically over its control connection
to the X server.
.LP
.sM
.FD 0
Status
XRecordGetContext\^(Display *\fIdisplay\fP, XRecordContext \fIcontext\fP, \
	XRecordState **\fIstate_return\fP)
.FN
.IP \fIdisplay\fP 1i
Specifies the connection to the X server.
.IP "\fIcontext\fP" 1i
Specifies the record context to query.
.IP "\fIstate_return\fP" 1i
Specifies the address of a variable into which the function stores a
pointer to the current state of the record context.
.LP
.eM
The
.PN XRecordState
typedef returned by
.PN XRecordGetContext
is a structure
with the following members:
.LP
.sM
.Ds 0
.TA .5i
.ta .5i
XRecordState:
	Bool enabled
	int datum_flags
	unsigned long nclients
	XRecordClientInfo **client_info
.De
.LP
.eM
The enabled member is set to the state of data transfer and is
.PN True
when the recording client has asked that recorded data be sent;
otherwise it is
.PN False .
The datum_flags member is set to the value of these flags for
this context.
The nclients member is set to the
number of
.PN XRecordClientInfo
structures returned.  The client_info member
is an array of pointers to
.PN XRecordClientInfo
structures that contain
the protocol
to record for each targeted client.
The
.PN XRecordClientInfo
typedef is a structure with the following members:
.LP
.sM
.Ds 0
.TA .5i
.ta .5i
XRecordClientInfo:
	XRecordClientSpec client
	unsigned long nranges
	XRecordRange **ranges
.De
.LP
.eM
The client member either identifies a client targeted for recording
or is set to
.PN XRecordFutureClients
to describe how future clients
will be automatically targeted for recording.
The nranges member is set to the number of protocol
ranges to be recorded for the specified client.  The ranges member
is an array of pointers to
.PN XRecordRange
structures, which specify the
protocol ranges to record.
.LP
.PN XRecordGetContext
returns zero if the request failed; otherwise, it
returns nonzero.
The context argument must specify a valid
.PN XRecordContext
or a
.PN XRecordBadContext
error results.
.LP
Recording clients should use the
.PN XRecordFreeState
function to free the state data returned by
.PN XRecordGetContext .
.LP
.sM
.FD 0
void
XRecordFreeState\^(XRecordState *\fIstate\fP)
.FN
.IP "\fIstate\fP" 1i
Specifies the structure that is to be freed.
.LP
.eM
.PN XRecordFreeState
frees the data pointed to by state.
If the argument does not match an
.PN XRecordState
pointer
returned from a successful call to
.PN XRecordGetContext ,
or if
.PN XRecordFreeState
has already been
called with it, the behavior is undefined.
.NH 2
Data Transfer
.XS
\*(SN Data Transfer
.XE
.LP
An application uses the
.PN XRecordEnableContext
and
.PN XRecordDisableContext
functions to change the state of data transfer
between the X server and the recording client.  These functions allow
the application to start recording and reporting of protocol data
and to stop recording and reporting of protocol data, respectively.
.NH 3
Enable Context
.XS
\*(SN Enable Context
.XE
.LP
To direct the X server to record and report protocol, a program
uses
.PN XRecordEnableContext ,
typically over its data connection to the X
server.  The reporting of recorded protocol back to the recording client
is handled by the following data structures and procedure definitions.
Each recorded protocol element is reported
to the recording client through an
.PN XRecordInterceptData
typedef,
a structure with the following members:
.LP
.sM
.Ds 0
.TA .5i 
.ta .25i
XRecordInterceptData:
	XID id_base
	Time server_time
	unsigned long client_seq
	int category
	Bool client_swapped
	unsigned char *data
	unsigned long data_len
.De
.LP
.eM
The id_base member is set to the resource identifier base sent to the
client in the connection setup reply and therefore identifies the client
being recorded, except when the recorded protocol data is a device
event that may have not been delivered to a client.  In this case,
id_base is set to zero.  The server_time member
is set to the time of the server when the protocol was recorded.
It is the time that was attached to this protocol element in the reply,
if so specified by datum_flags,
or else the time from the header of the reply that contained
this protocol element.
The client_seq member is the sequence number of the recorded
client's most recent request processed by the server at the time this
protocol element was recorded, if this information were included in the
recorded data; otherwise client_seq is 0.
The category member is set to one of the following values:
.PN XRecordStartOfData ,
.PN XRecordFromServer ,
.PN XRecordFromClient ,
.PN XRecordClientStarted ,
.PN XRecordClientDied ,
or
.PN XRecordEndOfData .
.PN XRecordStartOfData
is immediately sent as the first reply to confirm
that the context is enabled.
.PN XRecordFromClient
indicates the protocol
data is from the recorded client to the server (requests).
.PN XRecordFromServer
indicates the protocol data is from the server to the recorded client
(replies, errors, events, or device events).
.PN XRecordClientStarted
indicates that the protocol data is the
connection setup reply from the server.
.PN XRecordClientDied
indicates that the recorded
client has closed its connection
to the X server; there is no protocol data.
.PN XRecordEndOfData
indicates that the context has been disabled and that
this is the last datum.  It does not correspond to any protocol or
state change in a recorded client.  There is no protocol data.
.LP
The client_swapped member is set to
.PN True
if the byte order of the client being recorded is swapped relative to
the recording client; otherwise, it is set to
.PN False .
All
recorded protocol data is returned in the byte order of the recorded
client.  Therefore, recording clients are responsible for all byte swapping,
if required.
Device events are in the byte order of the
recording client.
For replies of category
.PN XRecordStartOfData
and
.PN XRecordEndOfData ,
client_swapped is set
according
to the byte order of the server relative to the recording client.
.LP
The data member contains the actual recorded
protocol data.
When category is set to
.PN XRecordStartOfData ,
.PN XRecordClientDied ,
or
.PN XRecordEndOfData ,
no protocol
data are contained in data.
.\"
.LP
.\" copied exactly from the protocol document
For the core X events
.PN KeyPress ,
.PN KeyRelease ,
.PN ButtonPress ,
and
.PN ButtonRelease ,
the fields of a device event that contain
valid information are time and detail.
For the core X event
.PN MotionNotify ,
the fields of a device event that contain
valid information are time, root,
root-x and root-y.
The time field refers to the time the event was generated by the
device.
.LP
For the extension input device events
.PN DeviceKeyPress ,
.PN DeviceKeyRelease ,
.PN DeviceButtonPress ,
and
.PN DeviceButtonRelease ,
the fields of a device event that contain valid information are
device, time, and detail.
For
.PN DeviceMotionNotify ,
the valid device event fields are
device and time.
For the extension input device events
.PN ProximityIn
and
.PN ProximityOut ,
the fields of a device event that contain valid
information are device and time.
For the extension input device event
.PN DeviceValuator ,
the fields of a device event that contain valid information are
device,
num_valuators, first_valuator, and valuators.
The time field refers to the time the event was generated by the
device.
.\"
.LP
The data_len member is set to the
length of the actual recorded protocol data in 4-byte units.
.LP
When the context has been enabled, protocol data the recording client has
previously expressed interest in is recorded and returned to the
recording client via multiple replies.
Because
the X server batches
the recorded data, more than one protocol element may be contained
in the same reply packet.
When a reply is received, a procedure of type
.PN XRecordInterceptProc
is
called for each protocol
element in the reply.
.LP
.sM
.FD 0
typedef void\^(*XRecordInterceptProc)
.br
     (XPointer \fIclosure\fP, XRecordInterceptData *\fIrecorded_data\fP)
.FN
.IP "\fIclosure\fP" 1i
Pointer that was passed in when the context was enabled.
.IP "\fIrecorded_data\fP" 1i
A protocol element recorded by the server extension.
.LP
.eM 
This callback
may use the control display connection (or any display connection
other than the data connection).
.LP
Recording clients should use the
.PN XRecordFreeData
function
to free the
.PN XRecordInterceptData
structure.
.LP
.sM
.FD 0
Status
XRecordEnableContext\^(Display *\fIdisplay\fP, XRecordContext \fIcontext\fP, \
XRecordInterceptProc \fIcallback\fP,
.br
	               XPointer \fIclosure\fP)
.FN
.IP "\fIdisplay\fP" 1i
Specifies the connection to the X server.
.IP "\fIcontext\fP" 1i
Specifies the record context to enable.
.IP "\fIcallback\fP" 1i
Specifies the function to be called for each protocol element received.
.IP "\fIclosure\fP" 1i
Specifies data passed to \fIcallback.\fP
.LP
.eM
.PN XRecordEnableContext
enables data transfer between the recording client and
the X server.  All core and extension protocol received from or sent to
targeted clients that the recording client has expressed
interest in will be recorded and reported to the recording client.
.LP
.PN XRecordEnableContext
returns zero if the request failed; otherwise, it
returns nonzero.  The context argument must specify a valid
.PN XRecordContext
or a
.PN XRecordBadContext
error results.  The error
.PN BadMatch
results when data transfer is already enabled
on the given context.
.NH 3
Enable Context Asynchronously
.XS
\*(SN Enable Context Asynchronously
.XE
.LP
Because
.PN XRecordEnableContext
does not return until
.PN XRecordDisableContext
is executed on the control connection, a nonblocking interface in
addition to
.PN XRecordEnableContext
is provided.  This interface also
enables data transfer; however, it does not block.
.LP
This interface is defined as follows:
.LP
.sM
.FD 0
Status
XRecordEnableContextAsync\^(Display *\fIdisplay\fP, XRecordContext \fIcontext\fP,
.br
                           XRecordInterceptProc \fIcallback\fP, XPointer \fIclosure\fP)
.FN
.IP \fIdisplay\fP 1i
Specifies the connection to the X server.
.IP \fIcontext\fP 1i
Specifies the record context to enable.
.IP \fIcallback\fP 1i
Specifies the function to be called for each protocol element received.
.IP \fIclosure\fP 1i
Data passed to \fIcallback\fP.
.LP
.eM
.PN XRecordEnableContextAsync
enables data transfer between the recording
client and the X server just as
.PN XRecordEnableContext
does.
Unlike
.PN XRecordEnableContext ,
it does not wait for the context to be disabled
before returning;
.PN XRecordEnableContextAsync
returns as soon as the
.PN XRecordStartOfData
reply has been received and processed.
.LP
.PN XRecordEnableContextAsync
returns zero if it could not allocate the
necessary memory and nonzero if it sent the request successfully to
the server.  The context argument must specify a valid
.PN XRecordContext
or a
.PN XRecordBadContext
error results.  The error
.PN BadMatch
results when data transfer is already enabled.
.LP
Each time it reads data from the server connection, Xlib will check
for incoming replies and call \fIcallback\fP as necessary.  The
application may direct Xlib explicitly to check for Record data with
the
.PN XRecordProcessReplies
function.
.LP
.sM
.FD 0
void
XRecordProcessReplies\^(Display *\fIdisplay\fP)
.FN
.IP \fIdisplay\fP 11
Specifies the connection to the X server.
.LP
.eM
.PN XRecordProcessReplies
will check for any replies that have not yet
been processed by the application.  The asynchronous callback will be called
as appropriate.
.PN XRecordProcessReplies
returns when all immediately
available replies have been processed.  It does not block.
.LP
.sp
To free the data passed to the
.PN XRecordInterceptProc
callback,
use
.PN XRecordFreeData .
.LP
.sM
.FD 0
void
XRecordFreeData\^(XRecordInterceptData *\fIdata\fP)
.FN
.IP "\fIdata\fP" 1i
Specifies the structure that is to be freed.
.LP
.eM
.PN XRecordFreeData
frees the data pointed to by data.
If the argument does not match an
.PN XRecordInterceptData
pointer earlier
passed to an
.PN XRecordInterceptProc
callback or if
.PN XRecordFreeData
has
already been called with it, the behavior is undefined.
.NH 3
Disable Context
.XS
\*(SN Disable Context
.XE
.LP
To direct the X server to halt the reporting of recorded protocol, the
program executes
.PN XRecordDisableContext ,
typically over its
control connection to the X server.
.LP
.sM
.FD 0
Status
XRecordDisableContext\^(Display *\fIdisplay\fP, XRecordContext \fIcontext\fP)
.FN
.IP "\fIdisplay\fP" 1i
Specifies the connection to the X server.
.IP "\fIcontext\fP" 1i
Specifies the record context to disable.
.LP
.eM
The
.PN XRecordDisableContext
function disables context, stopping
all recording over its data connection.
Any complete protocol elements for context
that were buffered in the server will be sent to the
recording client rather than being discarded.
If a program attempts to disable an
.PN XRecordContext
that has not been enabled, no action will take place.
.LP
.PN XRecordDisableContext
returns zero if the request failed; otherwise, it
returns nonzero.  The context argument must specify a valid
.PN XRecordContext
or an
.PN XRecordBadContext
error results.
.NH 2
ID Base Mask
.XS
\*(SN ID Base Mask
.XE
.LP
To determine the mask the server uses for the client ID base, use
.PN XRecordIdBaseMask .
.LP
.sM
.FD 0
XID
XRecordIdBaseMask\^(Display *\fIdisplay\fP)
.FN
.IP "\fIdisplay\fP" 1i
Specifies the connection to the X server.
.LP
.eM
The
.PN XRecordIdBaseMask
function returns the resource ID mask passed to the client by the
server at connection setup.
.NH 2
Free Context
.XS
\*(SN Free Context
.XE
.LP
Before terminating, the program should request that the server
free the record context.  This is done with the
.PN XRecordFreeContext
function, typically over the record client's control connection
to the X server.
.LP
.sM
.FD 0
Status
XRecordFreeContext\^(Display *\fIdisplay\fP, XRecordContext \fIcontext\fP)
.FN
.IP "\fIdisplay\fP" 1i
Specifies the connection to the X server.
.IP "\fIcontext\fP" 1i 
Specifies the record context to free.
.LP
.eM
The
.PN XRecordFreeContext
function frees the given context for the
requesting client.  Freeing a record context releases the clients
targeted for recording and their respective protocol ranges to
record.  If protocol data is being reported to the recording client,
generally over the data connection to the X server, the reporting
ceases as if
.PN XRecordDisableContext
had been called on the given context.
When a program terminates without freeing
its record context, the X server will automatically free that context
on behalf of the client.
.LP
.PN XRecordFreeContext
returns zero if the request failed; otherwise,it
returns nonzero.  The context argument must specify a valid
.PN XRecordContext
or a
.PN XRecordBadContext
error results.
.\"
.\" Local Variables:
.\" time-stamp-start: "^\\.ds Ts "
.\" time-stamp-end: "\\\\\""
.\" time-stamp-format: "%d %3b %y (%H:%02M)"
.\" End: