path: root/specs/recordlib.xml

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<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
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<!-- lifted from troff+ms+XMan by doclifter -->
<book id="recordlib">

<bookinfo>
   <title>X Record Extension Library</title>
   <subtitle>X Consortium Standard</subtitle>
   <releaseinfo>X Version 11, Release 6.7</releaseinfo>
   <authorgroup>
      <author>
         <firstname>Martha</firstname><surname>Zimet</surname>
      </author>
   </authorgroup>
   <corpname>Network Computing Devices, Inc.</corpname>
   <copyright><year>1994</year><holder>Network Computing Devices, Inc.</holder></copyright>
   <copyright><year>1995</year><holder>X Consortium</holder></copyright>
   <releaseinfo>Version 1.13</releaseinfo>
   <affiliation><orgname>X Consortium</orgname></affiliation>
   <productnumber>X Version 11, Release 6.7</productnumber>
   <editor>
         <firstname>Stephen</firstname><surname>Gildea</surname>
         <affiliation><orgname>X Consortium</orgname></affiliation>
   </editor>

<legalnotice>

<para>
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 "as is" without express or implied warranty.
</para>

<para>
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files
(the "Software"), 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:
</para>

<para>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 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.
</para>

<para>
Except as contained in this notice, the name of the X Consortium 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.
</para>

<para>X Window System is a trademark of The Open Group.</para>
</legalnotice>
</bookinfo>

<chapter id="record_extension_overview">
<title>Record Extension Overview</title>
<para>
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.
</para>

<sect1 id="synchronous_playback">
<title>Synchronous Playback</title>
<para>
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
<function>MotionNotify</function>, <function>ButtonPress</function>,
and <function>ButtonRelease</function> 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
<function>ImageText8</function> and <function>PolyLine</function> to the
X server, or the X server could send non-device events such as
<function>Expose</function> and <function>MapNotify</function> to the
client window. Both the
requests and non-device events that result from user actions are known
as consequences, 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)
</para>
<para>
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.
</para>
</sect1>

<sect1 id="design_approach">
<title>Design Approach</title>
<para>
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.
</para>
</sect1>

<sect1 id="record_clients">
<title>Record Clients</title>
<para>
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.
</para>
<para>
Information about recording (for example, what clients to record, what
protocol to record for each client, and so on) is stored in resources
called record contexts (type <function>XRecordContext</function>). 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.
</para>
<para>
A client that wishes to record X protocol does so through the library
functions defined in
<link linkend="library_extension_requests">
<xref linkend="library_extension_requests"></xref></link>
A typical sequence of requests that a client would make is as follows:
</para>
<itemizedlist>
  <listitem>
    <para>
<function>XRecordQueryVersion</function>
    </para>
    <para>
query the extension protocol version.
    </para>
</listitem>
<listitem>
    <para>
<function>XRecordCreateContext</function>
    </para>
    <para>
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 <function>XRecord-Context</function>, which is an XID that is
used by most other extension requests to identify the specified context.
    </para>
  </listitem>
  <listitem>
    <para>
<function>XRecordEnableContext</function>
    </para>
    <para>
begin the recording and reporting of protocol data.
    </para>
  </listitem>
  <listitem>
    <para>
<function>XRecordDisableContext</function>
    </para>
    <para>
end the recording and reporting of protocol data.
    </para>
  </listitem>
  <listitem>
    <para>
<function>XRecordFreeContext</function>
    </para>
    <para>
free the record context.
    </para>
  </listitem>
</itemizedlist>

<para>
The header for this library is
&lt;<function>X11/extensions/record.h</function>&gt;. All identifiers defined
in the interface are supplied by this header and are prefixed with "XRecord".
The <function>Xtst</function> library contains the
<function>XRecord</function> functions.
</para>

</sect1>
</chapter>

<chapter id="common_arguments">
<title>Common Arguments</title>
<para>
The Record extension functions <function>XRecordCreateContext</function>
 and <function>XRecordRegisterClients</function> allow applications to
specify the following:
</para>
<itemizedlist>
  <listitem>
    <para>
Individual clients or sets of clients to record
    </para>
  </listitem>
  <listitem>
    <para>
Ranges of core X protocol and X extension protocol to record for each client
    </para>
  </listitem>
</itemizedlist>
<para>
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
<link linkend="protocol_ranges">
<xref linkend="protocol_ranges"></xref></link>
</para>


<para>
The Record extension functions <function>XRecordCreateContext</function>
 and <function>XRecordRegisterClients</function> 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.
</para>

<sect1 id="datum_flags">
<title>Datum Flags</title>
<para>
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.
</para>

<para>
The <function>XRecordFromServerTime</function> flag specifies that
<function>XRecordInterceptData</function> structures with a category of
<function>XRecordFromServer</function> will have a server_time field specific to each
protocol element.
</para>

<para>
The <function>XRecordFromClientTime</function> flag specifies that
<function>XRecordInterceptData</function> structures with a category of
<function>XRecordFromClient</function> will have a server_time field specific
to each protocol element.
</para>

<para>
The <function>XRecordFromClientSequence</function> flag specifies that
<function>XRecordInterceptData</function> structures with a category of
<function>XRecordFromClient</function> or
<function>XRecordClientDied</function> will have a valid client_seq field.
</para>
</sect1>

<sect1 id="selecting_clients">
<title>Selecting Clients</title>

<para>
The clients argument is a pointer to an array of
<function>XRecordClientSpec</function>.
<function>XRecordClientSpec</function> is an integral type that holds a
resource ID, a client resource ID base, or one of the client set constants
defined below.
</para>
<para>
Duplicate elements in the array are ignored by the functions, and if any
element in the array is not valid, a
<function>BadMatch</function>
error results. A resource ID references the client that created that
resource. The client set may be one of the following constants:
<function>XRecordCurrentClients</function>,
<function>XRecordFutureClients</function>, or
<function>XRecordAllClients</function>.
</para>
<para>
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
<link linkend="data_transfer">
<xref linkend="data_transfer"></xref></link>
</para>
<para>
If the element is <function>XRecordCurrentClients</function>, the protocol
ranges specified by the ranges argument, except for device_events, are
associated with each current client connection. If the element is
<function>XRecordFutureClients</function>, the
protocol ranges specified by the ranges argument are associated with each new
client connection. If the element is
<function>XRecordAllClients</function>,
the protocol ranges specified by the ranges argument are associated with
each current client connection and with each new client connection.
When the context is enabled, the data connection is unregistered if it
was registered. If the context is enabled,
<function>XRecordCurrentClients</function> and
<function>XRecordAllClients</function>
silently exclude the recording data connection. It is an error to explicitly
register the data connection.
</para>
</sect1>
<sect1 id="protocol_ranges">
<title>Protocol Ranges</title>

<para>
The functions <function>XRecordCreateContext</function> and
<function>XRecordRegisterClients</function> have another common argument,
ranges, which is an array of pointers to <function>XRecordRange</function>
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 <function>XRecordRange</function> structure must be
allocated by the Record library using the
<function>XRecordAllocRange</function> function.
</para>
<para>
The <function>XRecordRange</function> typedef is a structure with the
following members:
</para>

<literallayout remap='Ds'>
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 */
</literallayout>

<para>
The types used in
<function>XRecordRange</function>
members are defined as follows.  The
<function>XRecordRange8</function>
typedef is a structure with the following members:
</para>

<literallayout remap='Ds'>
XRecordRange8:
     unsigned char first
     unsigned char last
</literallayout>

<para>
The
<function>XRecordRange16</function>
typedef is a structure with the following members:
</para>

<literallayout remap='Ds'>
XRecordRange16:
     unsigned short first
     unsigned short last
</literallayout>

<para>
The
<function>XRecordExtRange</function>
typedef is a structure with the following members:
</para>

<literallayout remap='Ds'>
XRecordExtRange:
     XRecordRange8  ext_major
     XRecordRange16 ext_minor
</literallayout>

<para>
If any of the values specified in
<function>XRecordRange</function>
is invalid, a
<function>BadValue</function>
error results.
</para>

<para>
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
<function>BadValue</function>
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.
</para>

<para>
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
<function>BadValue</function>
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.
</para>

<para>
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
<function>BadValue</function>
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.
</para>

<para>
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
<function>BadValue</function>
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.
</para>

<para>
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
<function>BadValue</function>
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.
</para>

<para>
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
<function>BadValue</function>
error results if the value of first is greater than the value of last.  A
<function>BadValue</function>
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.
</para>

<para>
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
<function>BadValue</function>
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.
</para>

<para>
A value of
<function>True</function>
for the client_started member specifies the
connection setup reply from the server to new clients.  If
<function>False</function>
the connection setup reply is not specified by this
<function>XRecordRange</function>
</para>

<para>
A value of
<function>True</function>
for the client_died member specifies
notification when a client disconnects.  If
<function>False</function>
notification when a client disconnects is not specified by this
<function>XRecordRange</function>
</para>
</sect1>
</chapter>

<chapter id='library_extension_requests'>
<title>Library Extension Requests</title>

<para>
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
<function>BadAlloc</function>
or
<function>BadLength</function>
errors.
</para>

<sect1 id='query_extension_version'>
<title>Query Extension Version</title>

<para>
An application uses the
<function>XRecordQueryVersion</function>
function to determine
the version of the Record extension protocol supported by an X server.
</para>

<funcsynopsis>
<funcprototype>
  <funcdef>Status <function>XRecordQueryVersion</function></funcdef>
    <paramdef>Display <parameter> *display</parameter></paramdef>
    <paramdef>int <parameter> cmajor_return</parameter></paramdef>
    <paramdef>int <parameter> cminor_return</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>display</emphasis></term>
    <listitem><para>Returns the connection to the X server.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>cmajor_return</emphasis></term>
    <listitem><para>Returns the extension protocol major version in use.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>cminor_return</emphasis></term>
    <listitem><para>Returns the extension protocol minor version in use.</para></listitem>
  </varlistentry>
</variablelist>

<para>
The
<function>XRecordQueryVersion</function>
function returns the major and minor protocol version numbers supported by
the server.
<function>XRecordQueryVersion</function>
returns nonzero (success) only if the returned version numbers are
common to both the library and the server; otherwise, it returns zero.
</para>
</sect1>

<sect1 id='create_and_modify_context'>
<title>Create and Modify Context</title>

<para>
An application uses the
<function>XRecordCreateContext</function>
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.
</para>

<funcsynopsis>
<funcprototype>
  <funcdef>XRecordContext <function>XRecordCreateContext</function></funcdef>
    <paramdef>Display <parameter> *display</parameter></paramdef>
    <paramdef>int <parameter> datum_flags</parameter></paramdef>
    <paramdef>XRecordClientSpec <parameter> *clients</parameter></paramdef>
    <paramdef>int <parameter> nclients</parameter></paramdef>
    <paramdef>XRecordRange <parameter> *ranges</parameter></paramdef>
    <paramdef>int <parameter> nranges</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>display</emphasis></term>
    <listitem><para>Returns the connection to the X server.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>datum_flags</emphasis></term>
    <listitem><para>Specifies whether detailed time or sequence info should be sent.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>clients</emphasis></term>
    <listitem><para>Specifies the clients to record.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>nclients</emphasis></term>
    <listitem><para>Specifies the number of clients.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>ranges</emphasis></term>
    <listitem><para>Specifies the protocol ranges to record.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>nranges</emphasis></term>
    <listitem><para>Specifies the number of protocol ranges.</para></listitem>
  </varlistentry>
</variablelist>

<para>
The
<function>XRecordCreateContext</function>
function creates a record context and returns an
<function>XRecordContext</function>
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 (
<link linkend="datum_flags">
<xref linkend="datum_flags"></xref></link>
).  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
<function>XRecordCurrentClients</function>
<function>XRecordFutureClients</function>
or
<function>XRecordAllClients</function>
the actions described in
<link linkend="selecting_clients">
<xref linkend="selecting_clients"></xref></link>
are performed.
</para>

<para>
<function>XRecordCreateContext</function>
returns zero if the request failed.
<function>XRecordCreateContext</function>
can generate
<function>BadIDChoice</function>
<function>BadMatch</function>
and
<function>BadValue</function>
errors.
</para>

<para>The ranges argument is an
<function>XRecordRange</function>
array, that is, an array
of pointers.  The structures the elements point to shall be allocated
by calling
<function>XRecordAllocRange</function></para>

<literallayout remap='FD'>
XRecordRange *
XRecordAllocRange(void)
</literallayout> <!-- remap='FN' -->

<para>
The
<function>XRecordAllocRange</function>
function
allocates and returns an
<function>XRecordRange</function>
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
<function>XFree</function>
</para>

<sect2 id='additions'>
<title>Additions</title>

<para>
An application uses the
<function>XRecordRegisterClients</function>
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.
</para>

<funcsynopsis>
<funcprototype>
  <funcdef>Status <function>XRecordRegisterClients</function></funcdef>
    <paramdef>Display <parameter> *display</parameter></paramdef>
    <paramdef>XRecordContext <parameter> context</parameter></paramdef>
    <paramdef>int <parameter> datum_flags</parameter></paramdef>
    <paramdef>XRecordClientSpec <parameter> *clients</parameter></paramdef>
    <paramdef>int <parameter> nclients</parameter></paramdef>
    <paramdef>XRecordRange <parameter> *ranges</parameter></paramdef>
    <paramdef>int <parameter> nranges</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>display</emphasis></term>
    <listitem><para>Returns the connection to the X server.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>context</emphasis></term>
    <listitem><para>Specifies the record context to modify.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>datum_flags</emphasis></term>
    <listitem><para>Specifies whether detailed time or sequence info should be sent.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>clients</emphasis></term>
    <listitem><para>Specifies the clients to record.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>nclients</emphasis></term>
    <listitem><para>Specifies the number of clients.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>ranges</emphasis></term>
    <listitem><para>Specifies the protocol ranges to record.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>nranges</emphasis></term>
    <listitem><para>Specifies the number of protocol ranges.</para></listitem>
  </varlistentry>
</variablelist>

<para>
The datum_flags specifies whether server time and/or client sequence number
should precede protocol elements for all clients recorded by context (See
<link linkend="datum_flags">
<xref linkend="datum_flags"></xref></link>
).  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
<function>XRecordCurrentClients</function>
<function>XRecordFutureClients</function>
or
<function>XRecordAllClients</function>
the actions described in
<link linkend="selecting_clients">
<xref linkend="selecting_clients"></xref></link>
are performed.
</para>

<para>
<function>XRecordRegisterClients</function>
returns zero if the request failed; otherwise, it
returns nonzero.
</para>

<para>
<function>XRecordRegisterClients</function>
can generate
<function>XRecordBadContext</function>
<function>BadMatch</function>
and
<function>BadValue</function>
errors.
</para>
</sect2>

<sect2 id='deletions'>
<title>Deletions</title>

<para>
An application uses the
<function>XRecordUnregisterClients</function>
function to delete clients from a previously created
record context, typically over its control connection to the X server.
</para>

<funcsynopsis>
<funcprototype>
  <funcdef>Status <function>XRecordUnRegisterClients</function></funcdef>
    <paramdef>Display <parameter> *display</parameter></paramdef>
    <paramdef>XRecordContext <parameter> context</parameter></paramdef>
    <paramdef>XRecordClientSpec <parameter> *clients</parameter></paramdef>
    <paramdef>int <parameter> nclients</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>display</emphasis></term>
    <listitem><para>Returns the connection to the X server.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>context</emphasis></term>
    <listitem><para>Specifies the record context to modify.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>clients</emphasis></term>
    <listitem><para>Specifies the clients to stop recording.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>nclients</emphasis></term>
    <listitem><para>Specifies the number of clients.</para></listitem>
  </varlistentry>
</variablelist>

<para>
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.
</para>

<para>
When the element is
<function>XRecordCurrentClients</function>
all clients currently targeted for recording in context and their
corresponding sets of protocol to record are deleted from context.
</para>

<para>
When the item is
<function>XRecordFutureClients</function>
any future client connections will not automatically be targeted for
recording in context.
</para>

<para>
When the element is
<function>XRecordAllClients</function>
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.
</para>

<para>
<function>XRecordUnregisterClients</function>
returns zero if the request failed; otherwise, it returns nonzero.
</para>

<para>
<function>XRecordUnregisterClients</function>
can generate
<function>XRecordBadContext</function>
<function>BadMatch</function>
and
<function>BadValue</function>
errors.</para>
</sect2>
</sect1>

<sect1 id='query_context_state'>
<title>Query Context State</title>

<para>
An application uses the
<function>XRecordGetContext</function>
function to query the current state of a record context, typically over
its control connection to the X server.
</para>

<funcsynopsis>
<funcprototype>
  <funcdef>Status <function>XRecordGetContext</function></funcdef>
    <paramdef>Display <parameter> *display</parameter></paramdef>
    <paramdef>XRecordContext <parameter> context</parameter></paramdef>
    <paramdef>XRecordState <parameter> **state_return</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>display</emphasis></term>
    <listitem><para>Specifies the connection to the X server.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>context</emphasis></term>
    <listitem><para>Specifies the record context to query.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>state_return</emphasis></term>
    <listitem><para>Specifies the address of a variable into which
the function stores a pointer to the current state of the record context.
    </para></listitem>
  </varlistentry>
</variablelist>

<para>
The
<function>XRecordState</function>
typedef returned by
<function>XRecordGetContext</function>
is a structure with the following members:
</para>

<literallayout remap='Ds'>
XRecordState:
     Bool              enabled
     int               datum_flags
     unsigned long     nclients
     XRecordClientInfo **client_info
</literallayout>

<para>
The enabled member is set to the state of data transfer and is
<function>True</function>
when the recording client has asked that recorded data be sent;
otherwise it is
<function>False</function>
The datum_flags member is set to the value of these flags for this context.
The nclients member is set to the number of
<function>XRecordClientInfo</function>
structures returned.  The client_info member is an array of pointers to
<function>XRecordClientInfo</function>
structures that contain the protocol to record for each targeted client.  The
<function>XRecordClientInfo</function>
typedef is a structure with the following members:
</para>

<literallayout remap='Ds'>
XRecordClientInfo:
     XRecordClientSpec client
     unsigned long nranges
     XRecordRange **ranges
</literallayout>

<para>
The client member either identifies a client targeted for recording
or is set to
<function>XRecordFutureClients</function>
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
<function>XRecordRange</function>
structures, which specify the protocol ranges to record.
</para>

<para>
<function>XRecordGetContext</function>
returns zero if the request failed; otherwise, it returns nonzero.
The context argument must specify a valid
<function>XRecordContext</function>
or a
<function>XRecordBadContext</function>
error results.
</para>

<para>
Recording clients should use the
<function>XRecordFreeState</function>
function to free the state data returned by
<function>XRecordGetContext</function>
</para>

<funcsynopsis>
<funcprototype>
  <funcdef>void <function>XRecordFreeState</function></funcdef>
    <paramdef>XRecordState <parameter> *state</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>state</emphasis></term>
    <listitem><para>Specifies the structure that is to be freed.</para></listitem>
  </varlistentry>
</variablelist>

<para>
<function>XRecordFreeState</function>
frees the data pointed to by state.  If the argument does not match an
<function>XRecordState</function>
pointer returned from a successful call to
<function>XRecordGetContext</function>
or if
<function>XRecordFreeState</function>
has already been called with it, the behavior is undefined.
</para>
</sect1>

<sect1 id='data_transfer'>
<title>Data Transfer</title>

<para>
An application uses the
<function>XRecordEnableContext</function>
and
<function>XRecordDisableContext</function>
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.
</para>

<sect2 id='enable_context'>
<title>Enable Context</title>

<para>
To direct the X server to record and report protocol, a program uses
<function>XRecordEnableContext</function>
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
<function>XRecordInterceptData</function>
typedef, a structure with the following members:
</para>

<literallayout remap='Ds'>
XRecordInterceptData:
     XID              id_base
     Time             server_time
     unsigned long    client_seq
     int              category
     Bool             client_swapped
     unsigned char    *data
     unsigned long    data_len
</literallayout>

<para>
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:
<function>XRecordStartOfData</function>
<function>XRecordFromServer</function>
<function>XRecordFromClient</function>
<function>XRecordClientStarted</function>
<function>XRecordClientDied</function>
or
<function>XRecordEndOfData</function>
<function>XRecordStartOfData</function>
is immediately sent as the first reply to confirm that the context is enabled.
<function>XRecordFromClient</function>
indicates the protocol
data is from the recorded client to the server (requests).
<function>XRecordFromServer</function>
indicates the protocol data is from the server to the recorded client
(replies, errors, events, or device events).
<function>XRecordClientStarted</function>
indicates that the protocol data is the connection setup reply from the server.
<function>XRecordClientDied</function>
indicates that the recorded client has closed its connection
to the X server; there is no protocol data.
<function>XRecordEndOfData</function>
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.
</para>

<para>
The client_swapped member is set to
<function>True</function>
if the byte order of the client being recorded is swapped relative to
the recording client; otherwise, it is set to
<function>False</function>
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
<function>XRecordStartOfData</function>
and
<function>XRecordEndOfData</function>
client_swapped is set according
to the byte order of the server relative to the recording client.
</para>

<para>
The data member contains the actual recorded protocol data.
When category is set to
<function>XRecordStartOfData</function>
<function>XRecordClientDied</function>
or
<function>XRecordEndOfData</function>
no protocol data are contained in data.
</para>


<!--  copied exactly from the protocol document -->
<para>
For the core X events
<function>KeyPress</function>
<function>KeyRelease</function>
<function>ButtonPress</function>
and
<function>ButtonRelease</function>,
the fields of a device event that contain
valid information are time and detail.  For the core X event
<function>MotionNotify</function>
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.
</para>

<para>For the extension input device events
<function>DeviceKeyPress</function>
<function>DeviceKeyRelease</function>
<function>DeviceButtonPress</function>
and
<function>DeviceButtonRelease</function>
the fields of a device event that contain valid information are
device, time, and detail.  For
<function>DeviceMotionNotify</function>
the valid device event fields are device and time.
For the extension input device events
<function>ProximityIn</function>
and
<function>ProximityOut</function>
the fields of a device event that contain valid
information are device and time.  For the extension input device event
<function>DeviceValuator</function>
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.
</para>


<para>
The data_len member is set to the length of the actual recorded protocol
data in 4-byte units.
</para>

<para>
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
<function>XRecordInterceptProc</function>
is called for each protocol element in the reply.
</para>

<funcsynopsis>
<funcprototype>
  <funcdef>typedef void <function>(*XRecordInterceptProc)</function></funcdef>
    <paramdef>XPointer<parameter> closure</parameter></paramdef>
    <paramdef>XRecordInterceptData<parameter> *recorded_data</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>closure</emphasis></term>
    <listitem><para>Pointer that was passed in when the context was enabled.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>recorded_data</emphasis></term>
    <listitem><para>A protocol element recorded by the server extension.</para></listitem>
  </varlistentry>
</variablelist>

<para>
This callback may use the control display connection (or any display
connection other than the data connection).
</para>

<para>
Recording clients should use the
<function>XRecordFreeData</function>
function to free the
<function>XRecordInterceptData</function>
structure.
</para>

<funcsynopsis>
<funcprototype>
  <funcdef>Status <function>XRecordEnableContext</function></funcdef>
    <paramdef>Display<parameter> *display</parameter></paramdef>
    <paramdef>XRecordContext<parameter> context</parameter></paramdef>
    <paramdef>XRecordInterceptProc<parameter> callback</parameter></paramdef>
    <paramdef>XPointer<parameter> closure</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>display</emphasis></term>
    <listitem><para>Specifies the connection to the X server.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>context</emphasis></term>
    <listitem><para>Specifies the record context to enable.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>callback</emphasis></term>
    <listitem><para>Specifies the function to be called for each protocol element received.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>closure</emphasis></term>
    <listitem><para>Specifies data passed to callback.</para></listitem>
  </varlistentry>
</variablelist>


<para>
<function>XRecordEnableContext</function>
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.
</para>

<para>
<function>XRecordEnableContext</function>
returns zero if the request failed; otherwise, it
returns nonzero.  The context argument must specify a valid
<function>XRecordContext</function>
or a
<function>XRecordBadContext</function>
error results.  The error
<function>BadMatch</function>
results when data transfer is already enabled on the given context.
</para>
</sect2>

<sect2 id='enable_context_asynchronously'>
<title>Enable Context Asynchronously</title>

<para>Because
<function>XRecordEnableContext</function>
does not return until
<function>XRecordDisableContext</function>
is executed on the control connection, a nonblocking interface in
addition to
<function>XRecordEnableContext</function>
is provided.  This interface also
enables data transfer; however, it does not block.
</para>

<para>
This interface is defined as follows:
</para>

<funcsynopsis>
<funcprototype>
  <funcdef>Status <function>XRecordEnableContextAsync</function></funcdef>
    <paramdef>Display<parameter> *display</parameter></paramdef>
    <paramdef>XRecordContext<parameter> context</parameter></paramdef>
    <paramdef>XRecordInterceptProc<parameter> callback</parameter></paramdef>
    <paramdef>XPointer<parameter> closure</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>display</emphasis></term>
    <listitem><para>Specifies the connection to the X server.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>context</emphasis></term>
    <listitem><para>Specifies the record context to enable.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>callback</emphasis></term>
    <listitem><para>Specifies the function to be called for each protocol element received.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>closure</emphasis></term>
    <listitem><para>Specifies data passed to callback.</para></listitem>
  </varlistentry>
</variablelist>

<para>
<function>XRecordEnableContextAsync</function>
enables data transfer between the recording
client and the X server just as
<function>XRecordEnableContext</function>
does.  Unlike
<function>XRecordEnableContext</function>
it does not wait for the context to be disabled
before returning;
<function>XRecordEnableContextAsync</function>
returns as soon as the
<function>XRecordStartOfData</function>
reply has been received and processed.
</para>

<para>
<function>XRecordEnableContextAsync</function>
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
<function>XRecordContext</function>
or a
<function>XRecordBadContext</function>
error results.  The error
<function>BadMatch</function>
results when data transfer is already enabled.
</para>

<para>
Each time it reads data from the server connection, Xlib will check
for incoming replies and call <emphasis remap='I'>callback</emphasis>
as necessary.  The application may direct Xlib explicitly to check
for Record data with the
<function>XRecordProcessReplies</function>
function.
</para>

<funcsynopsis>
<funcprototype>
  <funcdef>void <function>XRecordProcessReplies</function></funcdef>
    <paramdef>Display<parameter> *display</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>display</emphasis></term>
    <listitem><para>Specifies the connection to the X server.</para></listitem>
  </varlistentry>
</variablelist>

<para>
<function>XRecordProcessReplies</function>
will check for any replies that have not yet
been processed by the application.  The asynchronous callback will be called
as appropriate.
<function>XRecordProcessReplies</function>
returns when all immediately
available replies have been processed.  It does not block.
</para>

<para>To free the data passed to the
<function>XRecordInterceptProc</function>
callback, use
<function>XRecordFreeData</function></para>

<funcsynopsis>
<funcprototype>
  <funcdef>void <function>XRecordFreeData</function></funcdef>
    <paramdef>XRecordInterceptData<parameter> *data</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>data</emphasis></term>
    <listitem><para>Specifies the structure that is to be freed.</para></listitem>
  </varlistentry>
</variablelist>


<para>
<function>XRecordFreeData</function>
frees the data pointed to by data.  If the argument does not match an
<function>XRecordInterceptData</function>
pointer earlier passed to an
<function>XRecordInterceptProc</function>
callback or if
<function>XRecordFreeData</function>
has already been called with it, the behavior is undefined.
</para>
</sect2>

<sect2 id='disable_context'>
<title>Disable Context</title>

<para>
To direct the X server to halt the reporting of recorded protocol, the
program executes
<function>XRecordDisableContext</function>
typically over its control connection to the X server.
</para>

<funcsynopsis>
<funcprototype>
  <funcdef>Status <function>XRecordDisableContext</function></funcdef>
    <paramdef>Display<parameter> *display</parameter></paramdef>
    <paramdef>XRecordContext<parameter> context</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>display</emphasis></term>
    <listitem><para>Specifies the connection to the X server.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>context</emphasis></term>
    <listitem><para>Specifies the record context to disable.</para></listitem>
  </varlistentry>
</variablelist>


<para>
The
<function>XRecordDisableContext</function>
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
<function>XRecordContext</function>
that has not been enabled, no action will take place.
</para>

<para>
<function>XRecordDisableContext</function>
returns zero if the request failed; otherwise, it
returns nonzero.  The context argument must specify a valid
<function>XRecordContext</function>
or an
<function>XRecordBadContext</function>
error results.
</para>
</sect2>
</sect1>

<sect1 id='id_base_mask'><title>ID Base Mask</title>

<para>
To determine the mask the server uses for the client ID base, use
<function>XRecordIdBaseMask</function></para>

<funcsynopsis>
<funcprototype>
  <funcdef>XID <function>XRecordIdBaseMask</function></funcdef>
    <paramdef>Display<parameter> *display</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>display</emphasis></term>
    <listitem><para>Specifies the connection to the X server.</para></listitem>
  </varlistentry>
</variablelist>

<para>
The
<function>XRecordIdBaseMask</function>
function returns the resource ID mask passed to the client by the
server at connection setup.
</para>

</sect1>

<sect1 id='free_context'>
<title>Free Context</title>

<para>
Before terminating, the program should request that the server
free the record context.  This is done with the
<function>XRecordFreeContext</function>
function, typically over the record client's control connection
to the X server.
</para>

<funcsynopsis>
<funcprototype>
  <funcdef>Status <function>XRecordFreeContext</function></funcdef>
    <paramdef>Display<parameter> *display</parameter></paramdef>
    <paramdef>XRecordContext<parameter> context</parameter></paramdef>
</funcprototype>
</funcsynopsis>

<variablelist remap='IP'>
  <varlistentry>
    <term><emphasis remap='I'>display</emphasis></term>
    <listitem><para>Specifies the connection to the X server.</para></listitem>
  </varlistentry>
  <varlistentry>
    <term><emphasis remap='I'>context</emphasis></term>
    <listitem><para>Specifies the record context to free.</para></listitem>
  </varlistentry>
</variablelist>

<para>
The
<function>XRecordFreeContext</function>
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
<function>XRecordDisableContext</function>
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.
</para>

<para>
<function>XRecordFreeContext</function>
returns zero if the request failed; otherwise,it
returns nonzero.  The context argument must specify a valid
<function>XRecordContext</function>
or a
<function>XRecordBadContext</function>
error results.
</para>

</sect1>
</chapter>
</book>