visus
/
toolchain-gcc-arm-embedded

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Copyright (C) 1988-2020 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being "Free Software" and "Free Software Needs
Free Documentation", with the Front-Cover Texts being "A GNU Manual,"
and with the Back-Cover Texts as in (a) below.

(a) The FSF's Back-Cover Text is: "You are free to copy and modify
this GNU Manual.  Buying copies from GNU Press supports the FSF in
developing GNU and promoting software freedom." -->
<!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>General Query Packets (Debugging with GDB)</title>

<meta name="description" content="General Query Packets (Debugging with GDB)">
<meta name="keywords" content="General Query Packets (Debugging with GDB)">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<link href="index.html#Top" rel="start" title="Top">
<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="Remote-Protocol.html#Remote-Protocol" rel="up" title="Remote Protocol">
<link href="Architecture_002dSpecific-Protocol-Details.html#Architecture_002dSpecific-Protocol-Details" rel="next" title="Architecture-Specific Protocol Details">
<link href="Stop-Reply-Packets.html#Stop-Reply-Packets" rel="prev" title="Stop Reply Packets">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.indentedblock {margin-right: 0em}
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
blockquote.smallquotation {font-size: smaller}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.lisp {margin-left: 3.2em}
div.smalldisplay {margin-left: 3.2em}
div.smallexample {margin-left: 3.2em}
div.smalllisp {margin-left: 3.2em}
kbd {font-style: oblique}
pre.display {font-family: inherit}
pre.format {font-family: inherit}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
pre.smalldisplay {font-family: inherit; font-size: smaller}
pre.smallexample {font-size: smaller}
pre.smallformat {font-family: inherit; font-size: smaller}
pre.smalllisp {font-size: smaller}
span.nolinebreak {white-space: nowrap}
span.roman {font-family: initial; font-weight: normal}
span.sansserif {font-family: sans-serif; font-weight: normal}
ul.no-bullet {list-style: none}
-->
</style>


</head>

<body lang="en">
<a name="General-Query-Packets"></a>
<div class="header">
<p>
Next: <a href="Architecture_002dSpecific-Protocol-Details.html#Architecture_002dSpecific-Protocol-Details" accesskey="n" rel="next">Architecture-Specific Protocol Details</a>, Previous: <a href="Stop-Reply-Packets.html#Stop-Reply-Packets" accesskey="p" rel="prev">Stop Reply Packets</a>, Up: <a href="Remote-Protocol.html#Remote-Protocol" accesskey="u" rel="up">Remote Protocol</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="General-Query-Packets-1"></a>
<h3 class="section">E.4 General Query Packets</h3>
<a name="index-remote-query-requests"></a>

<p>Packets starting with &lsquo;<samp>q</samp>&rsquo; are <em>general query packets</em>;
packets starting with &lsquo;<samp>Q</samp>&rsquo; are <em>general set packets</em>.  General
query and set packets are a semi-unified form for retrieving and
sending information to and from the stub.
</p>
<p>The initial letter of a query or set packet is followed by a name
indicating what sort of thing the packet applies to.  For example,
<small>GDB</small> may use a &lsquo;<samp>qSymbol</samp>&rsquo; packet to exchange symbol
definitions with the stub.  These packet names follow some
conventions:
</p>
<ul>
<li> The name must not contain commas, colons or semicolons.
</li><li> Most <small>GDB</small> query and set packets have a leading upper case
letter.
</li><li> The names of custom vendor packets should use a company prefix, in
lower case, followed by a period.  For example, packets designed at
the Acme Corporation might begin with &lsquo;<samp>qacme.foo</samp>&rsquo; (for querying
foos) or &lsquo;<samp>Qacme.bar</samp>&rsquo; (for setting bars).
</li></ul>

<p>The name of a query or set packet should be separated from any
parameters by a &lsquo;<samp>:</samp>&rsquo;; the parameters themselves should be
separated by &lsquo;<samp>,</samp>&rsquo; or &lsquo;<samp>;</samp>&rsquo;.  Stubs must be careful to match the
full packet name, and check for a separator or the end of the packet,
in case two packet names share a common prefix.  New packets should not begin
with &lsquo;<samp>qC</samp>&rsquo;, &lsquo;<samp>qP</samp>&rsquo;, or &lsquo;<samp>qL</samp>&rsquo;<a name="DOCF20" href="#FOOT20"><sup>20</sup></a>.
</p>
<p>Like the descriptions of the other packets, each description here
has a template showing the packet&rsquo;s overall syntax, followed by an
explanation of the packet&rsquo;s meaning.  We include spaces in some of the
templates for clarity; these are not part of the packet&rsquo;s syntax.  No
<small>GDB</small> packet uses spaces to separate its components.
</p>
<p>Here are the currently defined query and set packets:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>QAgent:1</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QAgent:0</samp>&rsquo;</dt>
<dd><p>Turn on or off the agent as a helper to perform some debugging operations
delegated from <small>GDB</small> (see <a href="In_002dProcess-Agent.html#Control-Agent">Control Agent</a>).
</p>
</dd>
<dt>&lsquo;<samp>QAllow:<var>op</var>:<var>val</var>&hellip;</samp>&rsquo;</dt>
<dd><a name="index-QAllow-packet"></a>
<p>Specify which operations <small>GDB</small> expects to request of the
target, as a semicolon-separated list of operation name and value
pairs.  Possible values for <var>op</var> include &lsquo;<samp>WriteReg</samp>&rsquo;,
&lsquo;<samp>WriteMem</samp>&rsquo;, &lsquo;<samp>InsertBreak</samp>&rsquo;, &lsquo;<samp>InsertTrace</samp>&rsquo;,
&lsquo;<samp>InsertFastTrace</samp>&rsquo;, and &lsquo;<samp>Stop</samp>&rsquo;. <var>val</var> is either 0,
indicating that <small>GDB</small> will not request the operation, or 1,
indicating that it may.  (The target can then use this to set up its
own internals optimally, for instance if the debugger never expects to
insert breakpoints, it may not need to install its own trap handler.)
</p>
</dd>
<dt>&lsquo;<samp>qC</samp>&rsquo;</dt>
<dd><a name="index-current-thread_002c-remote-request"></a>
<a name="index-qC-packet"></a>
<p>Return the current thread ID.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>QC <var>thread-id</var></samp>&rsquo;</dt>
<dd><p>Where <var>thread-id</var> is a thread ID as documented in 
<a href="Packets.html#thread_002did-syntax">thread-id syntax</a>.
</p></dd>
<dt>&lsquo;<samp><span class="roman">(anything else)</span></samp>&rsquo;</dt>
<dd><p>Any other reply implies the old thread ID.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>qCRC:<var>addr</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="index-CRC-of-memory-block_002c-remote-request"></a>
<a name="index-qCRC-packet"></a>
<a name="qCRC-packet"></a><p>Compute the CRC checksum of a block of memory using CRC-32 defined in
IEEE 802.3.  The CRC is computed byte at a time, taking the most
significant bit of each byte first.  The initial pattern code
<code>0xffffffff</code> is used to ensure leading zeros affect the CRC.
</p>
<p><em>Note:</em> This is the same CRC used in validating separate debug
files (see <a href="Separate-Debug-Files.html#Separate-Debug-Files">Debugging Information in Separate
Files</a>).  However the algorithm is slightly different.  When validating
separate debug files, the CRC is computed taking the <em>least</em>
significant bit of each byte first, and the final result is inverted to
detect trailing zeros.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>An error (such as memory fault)
</p></dd>
<dt>&lsquo;<samp>C <var>crc32</var></samp>&rsquo;</dt>
<dd><p>The specified memory region&rsquo;s checksum is <var>crc32</var>.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>QDisableRandomization:<var>value</var></samp>&rsquo;</dt>
<dd><a name="index-disable-address-space-randomization_002c-remote-request"></a>
<a name="index-QDisableRandomization-packet"></a>
<p>Some target operating systems will randomize the virtual address space
of the inferior process as a security feature, but provide a feature
to disable such randomization, e.g. to allow for a more deterministic
debugging experience.  On such systems, this packet with a <var>value</var>
of 1 directs the target to disable address space randomization for
processes subsequently started via &lsquo;<samp>vRun</samp>&rsquo; packets, while a packet
with a <var>value</var> of 0 tells the target to enable address space
randomization.
</p>
<p>This packet is only available in extended mode (see <a href="Packets.html#extended-mode">extended mode</a>).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The request succeeded.
</p>
</dd>
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
</p>
</dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates that &lsquo;<samp>QDisableRandomization</samp>&rsquo; is not supported
by the stub.
</p></dd>
</dl>

<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
This should only be done on targets that actually support disabling
address space randomization.
</p>
</dd>
<dt>&lsquo;<samp>QStartupWithShell:<var>value</var></samp>&rsquo;</dt>
<dd><a name="index-startup-with-shell_002c-remote-request"></a>
<a name="index-QStartupWithShell-packet"></a>
<p>On UNIX-like targets, it is possible to start the inferior using a
shell program.  This is the default behavior on both <small>GDB</small> and
<code>gdbserver</code> (see <a href="Starting.html#set-startup_002dwith_002dshell">set startup-with-shell</a>).  This packet is
used to inform <code>gdbserver</code> whether it should start the
inferior using a shell or not.
</p>
<p>If <var>value</var> is &lsquo;<samp>0</samp>&rsquo;, <code>gdbserver</code> will not use a shell
to start the inferior.  If <var>value</var> is &lsquo;<samp>1</samp>&rsquo;,
<code>gdbserver</code> will use a shell to start the inferior.  All other
values are considered an error.
</p>
<p>This packet is only available in extended mode (see <a href="Packets.html#extended-mode">extended mode</a>).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The request succeeded.
</p>
</dd>
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
</p></dd>
</dl>

<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
(see <a href="#qSupported">qSupported</a>).  This should only be done on targets that
actually support starting the inferior using a shell.
</p>
<p>Use of this packet is controlled by the <code>set startup-with-shell</code>
command; see <a href="Starting.html#set-startup_002dwith_002dshell">set startup-with-shell</a>.
</p>
</dd>
<dt>&lsquo;<samp>QEnvironmentHexEncoded:<var>hex-value</var></samp>&rsquo;</dt>
<dd><a name="QEnvironmentHexEncoded"></a><a name="index-set-environment-variable_002c-remote-request"></a>
<a name="index-QEnvironmentHexEncoded-packet"></a>
<p>On UNIX-like targets, it is possible to set environment variables that
will be passed to the inferior during the startup process.  This
packet is used to inform <code>gdbserver</code> of an environment
variable that has been defined by the user on <small>GDB</small> (see <a href="Environment.html#set-environment">set environment</a>).
</p>
<p>The packet is composed by <var>hex-value</var>, an hex encoded
representation of the <var>name=value</var> format representing an
environment variable.  The name of the environment variable is
represented by <var>name</var>, and the value to be assigned to the
environment variable is represented by <var>value</var>.  If the variable
has no value (i.e., the value is <code>null</code>), then <var>value</var> will
not be present.
</p>
<p>This packet is only available in extended mode (see <a href="Packets.html#extended-mode">extended mode</a>).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The request succeeded.
</p></dd>
</dl>

<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
(see <a href="#qSupported">qSupported</a>).  This should only be done on targets that
actually support passing environment variables to the starting
inferior.
</p>
<p>This packet is related to the <code>set environment</code> command;
see <a href="Environment.html#set-environment">set environment</a>.
</p>
</dd>
<dt>&lsquo;<samp>QEnvironmentUnset:<var>hex-value</var></samp>&rsquo;</dt>
<dd><a name="QEnvironmentUnset"></a><a name="index-unset-environment-variable_002c-remote-request"></a>
<a name="index-QEnvironmentUnset-packet"></a>
<p>On UNIX-like targets, it is possible to unset environment variables
before starting the inferior in the remote target.  This packet is
used to inform <code>gdbserver</code> of an environment variable that has
been unset by the user on <small>GDB</small> (see <a href="Environment.html#unset-environment">unset environment</a>).
</p>
<p>The packet is composed by <var>hex-value</var>, an hex encoded
representation of the name of the environment variable to be unset.
</p>
<p>This packet is only available in extended mode (see <a href="Packets.html#extended-mode">extended mode</a>).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The request succeeded.
</p></dd>
</dl>

<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
(see <a href="#qSupported">qSupported</a>).  This should only be done on targets that
actually support passing environment variables to the starting
inferior.
</p>
<p>This packet is related to the <code>unset environment</code> command;
see <a href="Environment.html#unset-environment">unset environment</a>.
</p>
</dd>
<dt>&lsquo;<samp>QEnvironmentReset</samp>&rsquo;</dt>
<dd><a name="QEnvironmentReset"></a><a name="index-reset-environment_002c-remote-request"></a>
<a name="index-QEnvironmentReset-packet"></a>
<p>On UNIX-like targets, this packet is used to reset the state of
environment variables in the remote target before starting the
inferior.  In this context, reset means unsetting all environment
variables that were previously set by the user (i.e., were not
initially present in the environment).  It is sent to
<code>gdbserver</code> before the &lsquo;<samp>QEnvironmentHexEncoded</samp>&rsquo;
(see <a href="#QEnvironmentHexEncoded">QEnvironmentHexEncoded</a>) and the &lsquo;<samp>QEnvironmentUnset</samp>&rsquo;
(see <a href="#QEnvironmentUnset">QEnvironmentUnset</a>) packets.
</p>
<p>This packet is only available in extended mode (see <a href="Packets.html#extended-mode">extended mode</a>).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The request succeeded.
</p></dd>
</dl>

<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
(see <a href="#qSupported">qSupported</a>).  This should only be done on targets that
actually support passing environment variables to the starting
inferior.
</p>
</dd>
<dt>&lsquo;<samp>QSetWorkingDir:<span class="roman">[</span><var>directory</var><span class="roman">]</span></samp>&rsquo;</dt>
<dd><a name="QSetWorkingDir-packet"></a><a name="index-set-working-directory_002c-remote-request"></a>
<a name="index-QSetWorkingDir-packet"></a>
<p>This packet is used to inform the remote server of the intended
current working directory for programs that are going to be executed.
</p>
<p>The packet is composed by <var>directory</var>, an hex encoded
representation of the directory that the remote inferior will use as
its current working directory.  If <var>directory</var> is an empty string,
the remote server should reset the inferior&rsquo;s current working
directory to its original, empty value.
</p>
<p>This packet is only available in extended mode (see <a href="Packets.html#extended-mode">extended mode</a>).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The request succeeded.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>qfThreadInfo</samp>&rsquo;</dt>
<dt>&lsquo;<samp>qsThreadInfo</samp>&rsquo;</dt>
<dd><a name="index-list-active-threads_002c-remote-request"></a>
<a name="index-qfThreadInfo-packet"></a>
<a name="index-qsThreadInfo-packet"></a>
<p>Obtain a list of all active thread IDs from the target (OS).  Since there
may be too many active threads to fit into one reply packet, this query
works iteratively: it may require more than one query/reply sequence to
obtain the entire list of threads.  The first query of the sequence will
be the &lsquo;<samp>qfThreadInfo</samp>&rsquo; query; subsequent queries in the
sequence will be the &lsquo;<samp>qsThreadInfo</samp>&rsquo; query.
</p>
<p>NOTE: This packet replaces the &lsquo;<samp>qL</samp>&rsquo; query (see below).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>m <var>thread-id</var></samp>&rsquo;</dt>
<dd><p>A single thread ID
</p></dd>
<dt>&lsquo;<samp>m <var>thread-id</var>,<var>thread-id</var>&hellip;</samp>&rsquo;</dt>
<dd><p>a comma-separated list of thread IDs
</p></dd>
<dt>&lsquo;<samp>l</samp>&rsquo;</dt>
<dd><p>(lower case letter &lsquo;<samp>L</samp>&rsquo;) denotes end of list.
</p></dd>
</dl>

<p>In response to each query, the target will reply with a list of one or
more thread IDs, separated by commas.
<small>GDB</small> will respond to each reply with a request for more thread
ids (using the &lsquo;<samp>qs</samp>&rsquo; form of the query), until the target responds
with &lsquo;<samp>l</samp>&rsquo; (lower-case ell, for <em>last</em>).
Refer to <a href="Packets.html#thread_002did-syntax">thread-id syntax</a>, for the format of the <var>thread-id</var>
fields.
</p>
<p><em>Note: <small>GDB</small> will send the <code>qfThreadInfo</code> query during the
initial connection with the remote target, and the very first thread ID
mentioned in the reply will be stopped by <small>GDB</small> in a subsequent
message.  Therefore, the stub should ensure that the first thread ID in
the <code>qfThreadInfo</code> reply is suitable for being stopped by <small>GDB</small>.</em>
</p>
</dd>
<dt>&lsquo;<samp>qGetTLSAddr:<var>thread-id</var>,<var>offset</var>,<var>lm</var></samp>&rsquo;</dt>
<dd><a name="index-get-thread_002dlocal-storage-address_002c-remote-request"></a>
<a name="index-qGetTLSAddr-packet"></a>
<p>Fetch the address associated with thread local storage specified
by <var>thread-id</var>, <var>offset</var>, and <var>lm</var>.
</p>
<p><var>thread-id</var> is the thread ID associated with the
thread for which to fetch the TLS address.  See <a href="Packets.html#thread_002did-syntax">thread-id syntax</a>.
</p>
<p><var>offset</var> is the (big endian, hex encoded) offset associated with the
thread local variable.  (This offset is obtained from the debug
information associated with the variable.)
</p>
<p><var>lm</var> is the (big endian, hex encoded) OS/ABI-specific encoding of the
load module associated with the thread local storage.  For example,
a <small>GNU</small>/Linux system will pass the link map address of the shared
object associated with the thread local storage under consideration. 
Other operating environments may choose to represent the load module
differently, so the precise meaning of this parameter will vary.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp><var>XX</var>&hellip;</samp>&rsquo;</dt>
<dd><p>Hex encoded (big endian) bytes representing the address of the thread
local storage requested.
</p>
</dd>
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
</p>
</dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates that &lsquo;<samp>qGetTLSAddr</samp>&rsquo; is not supported by the stub.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>qGetTIBAddr:<var>thread-id</var></samp>&rsquo;</dt>
<dd><a name="index-get-thread-information-block-address"></a>
<a name="index-qGetTIBAddr-packet"></a>
<p>Fetch address of the Windows OS specific Thread Information Block.
</p>
<p><var>thread-id</var> is the thread ID associated with the thread.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp><var>XX</var>&hellip;</samp>&rsquo;</dt>
<dd><p>Hex encoded (big endian) bytes representing the linear address of the
thread information block.
</p>
</dd>
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>An error occured.  This means that either the thread was not found, or the
address could not be retrieved.
</p>
</dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates that &lsquo;<samp>qGetTIBAddr</samp>&rsquo; is not supported by the stub.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>qL <var>startflag</var> <var>threadcount</var> <var>nextthread</var></samp>&rsquo;</dt>
<dd><p>Obtain thread information from RTOS.  Where: <var>startflag</var> (one hex
digit) is one to indicate the first query and zero to indicate a
subsequent query; <var>threadcount</var> (two hex digits) is the maximum
number of threads the response packet can contain; and <var>nextthread</var>
(eight hex digits), for subsequent queries (<var>startflag</var> is zero), is
returned in the response as <var>argthread</var>.
</p>
<p>Don&rsquo;t use this packet; use the &lsquo;<samp>qfThreadInfo</samp>&rsquo; query instead (see above).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>qM <var>count</var> <var>done</var> <var>argthread</var> <var>thread</var>&hellip;</samp>&rsquo;</dt>
<dd><p>Where: <var>count</var> (two hex digits) is the number of threads being
returned; <var>done</var> (one hex digit) is zero to indicate more threads
and one indicates no further threads; <var>argthreadid</var> (eight hex
digits) is <var>nextthread</var> from the request packet; <var>thread</var>&hellip;
is a sequence of thread IDs, <var>threadid</var> (eight hex
digits), from the target.  See <code>remote.c:parse_threadlist_response()</code>.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>qOffsets</samp>&rsquo;</dt>
<dd><a name="index-section-offsets_002c-remote-request"></a>
<a name="index-qOffsets-packet"></a>
<p>Get section offsets that the target used when relocating the downloaded
image.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>Text=<var>xxx</var>;Data=<var>yyy</var><span class="roman">[</span>;Bss=<var>zzz</var><span class="roman">]</span></samp>&rsquo;</dt>
<dd><p>Relocate the <code>Text</code> section by <var>xxx</var> from its original address.
Relocate the <code>Data</code> section by <var>yyy</var> from its original address.
If the object file format provides segment information (e.g. <small>ELF</small>
&lsquo;<samp>PT_LOAD</samp>&rsquo; program headers), <small>GDB</small> will relocate entire
segments by the supplied offsets.
</p>
<p><em>Note: while a <code>Bss</code> offset may be included in the response,
<small>GDB</small> ignores this and instead applies the <code>Data</code> offset
to the <code>Bss</code> section.</em>
</p>
</dd>
<dt>&lsquo;<samp>TextSeg=<var>xxx</var><span class="roman">[</span>;DataSeg=<var>yyy</var><span class="roman">]</span></samp>&rsquo;</dt>
<dd><p>Relocate the first segment of the object file, which conventionally
contains program code, to a starting address of <var>xxx</var>.  If
&lsquo;<samp>DataSeg</samp>&rsquo; is specified, relocate the second segment, which
conventionally contains modifiable data, to a starting address of
<var>yyy</var>.  <small>GDB</small> will report an error if the object file
does not contain segment information, or does not contain at least
as many segments as mentioned in the reply.  Extra segments are
kept at fixed offsets relative to the last relocated segment.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>qP <var>mode</var> <var>thread-id</var></samp>&rsquo;</dt>
<dd><a name="index-thread-information_002c-remote-request"></a>
<a name="index-qP-packet"></a>
<p>Returns information on <var>thread-id</var>.  Where: <var>mode</var> is a hex
encoded 32 bit mode; <var>thread-id</var> is a thread ID 
(see <a href="Packets.html#thread_002did-syntax">thread-id syntax</a>).
</p>
<p>Don&rsquo;t use this packet; use the &lsquo;<samp>qThreadExtraInfo</samp>&rsquo; query instead
(see below).
</p>
<p>Reply: see <code>remote.c:remote_unpack_thread_info_response()</code>.
</p>
</dd>
<dt>&lsquo;<samp>QNonStop:1</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QNonStop:0</samp>&rsquo;</dt>
<dd><a name="index-non_002dstop-mode_002c-remote-request"></a>
<a name="index-QNonStop-packet"></a>
<a name="QNonStop"></a><p>Enter non-stop (&lsquo;<samp>QNonStop:1</samp>&rsquo;) or all-stop (&lsquo;<samp>QNonStop:0</samp>&rsquo;) mode.
See <a href="Remote-Non_002dStop.html#Remote-Non_002dStop">Remote Non-Stop</a>, for more information.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The request succeeded.
</p>
</dd>
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
</p>
</dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates that &lsquo;<samp>QNonStop</samp>&rsquo; is not supported by
the stub.
</p></dd>
</dl>

<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
Use of this packet is controlled by the <code>set non-stop</code> command; 
see <a href="Non_002dStop-Mode.html#Non_002dStop-Mode">Non-Stop Mode</a>.
</p>
</dd>
<dt>&lsquo;<samp>QCatchSyscalls:1 <span class="roman">[</span>;<var>sysno</var><span class="roman">]</span>&hellip;</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QCatchSyscalls:0</samp>&rsquo;</dt>
<dd><a name="index-catch-syscalls-from-inferior_002c-remote-request"></a>
<a name="index-QCatchSyscalls-packet"></a>
<a name="QCatchSyscalls"></a><p>Enable (&lsquo;<samp>QCatchSyscalls:1</samp>&rsquo;) or disable (&lsquo;<samp>QCatchSyscalls:0</samp>&rsquo;)
catching syscalls from the inferior process.
</p>
<p>For &lsquo;<samp>QCatchSyscalls:1</samp>&rsquo;, each listed syscall <var>sysno</var> (encoded
in hex) should be reported to <small>GDB</small>.  If no syscall <var>sysno</var>
is listed, every system call should be reported.
</p>
<p>Note that if a syscall not in the list is reported, <small>GDB</small> will
still filter the event according to its own list from all corresponding
<code>catch syscall</code> commands.  However, it is more efficient to only
report the requested syscalls.
</p>
<p>Multiple &lsquo;<samp>QCatchSyscalls:1</samp>&rsquo; packets do not combine; any earlier
&lsquo;<samp>QCatchSyscalls:1</samp>&rsquo; list is completely replaced by the new list.
</p>
<p>If the inferior process execs, the state of &lsquo;<samp>QCatchSyscalls</samp>&rsquo; is
kept for the new process too.  On targets where exec may affect syscall
numbers, for example with exec between 32 and 64-bit processes, the
client should send a new packet with the new syscall list.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The request succeeded.
</p>
</dd>
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>An error occurred.  <var>nn</var> are hex digits.
</p>
</dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates that &lsquo;<samp>QCatchSyscalls</samp>&rsquo; is not supported by
the stub.
</p></dd>
</dl>

<p>Use of this packet is controlled by the <code>set remote catch-syscalls</code>
command (see <a href="Remote-Configuration.html#Remote-Configuration">set remote catch-syscalls</a>).
This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>QPassSignals: <var>signal</var> <span class="roman">[</span>;<var>signal</var><span class="roman">]</span>&hellip;</samp>&rsquo;</dt>
<dd><a name="index-pass-signals-to-inferior_002c-remote-request"></a>
<a name="index-QPassSignals-packet"></a>
<a name="QPassSignals"></a><p>Each listed <var>signal</var> should be passed directly to the inferior process. 
Signals are numbered identically to continue packets and stop replies
(see <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>).  Each <var>signal</var> list item should be
strictly greater than the previous item.  These signals do not need to stop
the inferior, or be reported to <small>GDB</small>.  All other signals should be
reported to <small>GDB</small>.  Multiple &lsquo;<samp>QPassSignals</samp>&rsquo; packets do not
combine; any earlier &lsquo;<samp>QPassSignals</samp>&rsquo; list is completely replaced by the
new list.  This packet improves performance when using &lsquo;<samp>handle
<var>signal</var> nostop noprint pass</samp>&rsquo;.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The request succeeded.
</p>
</dd>
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
</p>
</dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates that &lsquo;<samp>QPassSignals</samp>&rsquo; is not supported by
the stub.
</p></dd>
</dl>

<p>Use of this packet is controlled by the <code>set remote pass-signals</code>
command (see <a href="Remote-Configuration.html#Remote-Configuration">set remote pass-signals</a>).
This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>QProgramSignals: <var>signal</var> <span class="roman">[</span>;<var>signal</var><span class="roman">]</span>&hellip;</samp>&rsquo;</dt>
<dd><a name="index-signals-the-inferior-may-see_002c-remote-request"></a>
<a name="index-QProgramSignals-packet"></a>
<a name="QProgramSignals"></a><p>Each listed <var>signal</var> may be delivered to the inferior process.
Others should be silently discarded.
</p>
<p>In some cases, the remote stub may need to decide whether to deliver a
signal to the program or not without <small>GDB</small> involvement.  One
example of that is while detaching &mdash; the program&rsquo;s threads may have
stopped for signals that haven&rsquo;t yet had a chance of being reported to
<small>GDB</small>, and so the remote stub can use the signal list specified
by this packet to know whether to deliver or ignore those pending
signals.
</p>
<p>This does not influence whether to deliver a signal as requested by a
resumption packet (see <a href="Packets.html#vCont-packet">vCont packet</a>).
</p>
<p>Signals are numbered identically to continue packets and stop replies
(see <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>).  Each <var>signal</var> list item should be
strictly greater than the previous item.  Multiple
&lsquo;<samp>QProgramSignals</samp>&rsquo; packets do not combine; any earlier
&lsquo;<samp>QProgramSignals</samp>&rsquo; list is completely replaced by the new list.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The request succeeded.
</p>
</dd>
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
</p>
</dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates that &lsquo;<samp>QProgramSignals</samp>&rsquo; is not supported
by the stub.
</p></dd>
</dl>

<p>Use of this packet is controlled by the <code>set remote program-signals</code>
command (see <a href="Remote-Configuration.html#Remote-Configuration">set remote program-signals</a>).
This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
<a name="QThreadEvents"></a></dd>
<dt>&lsquo;<samp>QThreadEvents:1</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QThreadEvents:0</samp>&rsquo;</dt>
<dd><a name="index-thread-create_002fexit-events_002c-remote-request"></a>
<a name="index-QThreadEvents-packet"></a>

<p>Enable (&lsquo;<samp>QThreadEvents:1</samp>&rsquo;) or disable (&lsquo;<samp>QThreadEvents:0</samp>&rsquo;)
reporting of thread create and exit events.  See <a href="Stop-Reply-Packets.html#thread-create-event">thread create event</a>, for the reply specifications.  For example, this is used in
non-stop mode when <small>GDB</small> stops a set of threads and
synchronously waits for the their corresponding stop replies.  Without
exit events, if one of the threads exits, <small>GDB</small> would hang
forever not knowing that it should no longer expect a stop for that
same thread.  <small>GDB</small> does not enable this feature unless the
stub reports that it supports it by including &lsquo;<samp>QThreadEvents+</samp>&rsquo; in
its &lsquo;<samp>qSupported</samp>&rsquo; reply.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The request succeeded.
</p>
</dd>
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
</p>
</dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates that &lsquo;<samp>QThreadEvents</samp>&rsquo; is not supported by
the stub.
</p></dd>
</dl>

<p>Use of this packet is controlled by the <code>set remote thread-events</code>
command (see <a href="Remote-Configuration.html#Remote-Configuration">set remote thread-events</a>).
</p>
</dd>
<dt>&lsquo;<samp>qRcmd,<var>command</var></samp>&rsquo;</dt>
<dd><a name="index-execute-remote-command_002c-remote-request"></a>
<a name="index-qRcmd-packet"></a>
<p><var>command</var> (hex encoded) is passed to the local interpreter for
execution.  Invalid commands should be reported using the output
string.  Before the final result packet, the target may also respond
with a number of intermediate &lsquo;<samp>O<var>output</var></samp>&rsquo; console output
packets.  <em>Implementors should note that providing access to a
stubs&rsquo;s interpreter may have security implications</em>.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>A command response with no output.
</p></dd>
<dt>&lsquo;<samp><var>OUTPUT</var></samp>&rsquo;</dt>
<dd><p>A command response with the hex encoded output string <var>OUTPUT</var>.
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>Indicate a badly formed request.
</p></dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates that &lsquo;<samp>qRcmd</samp>&rsquo; is not recognized.
</p></dd>
</dl>

<p>(Note that the <code>qRcmd</code> packet&rsquo;s name is separated from the
command by a &lsquo;<samp>,</samp>&rsquo;, not a &lsquo;<samp>:</samp>&rsquo;, contrary to the naming
conventions above.  Please don&rsquo;t use this packet as a model for new
packets.)
</p>
</dd>
<dt>&lsquo;<samp>qSearch:memory:<var>address</var>;<var>length</var>;<var>search-pattern</var></samp>&rsquo;</dt>
<dd><a name="index-searching-memory_002c-in-remote-debugging"></a>
<a name="index-qSearch_003amemory-packet"></a>
<a name="index-qSearch-memory-packet"></a>
<a name="qSearch-memory"></a><p>Search <var>length</var> bytes at <var>address</var> for <var>search-pattern</var>.
Both <var>address</var> and <var>length</var> are encoded in hex;
<var>search-pattern</var> is a sequence of bytes, also hex encoded.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>0</samp>&rsquo;</dt>
<dd><p>The pattern was not found.
</p></dd>
<dt>&lsquo;<samp>1,address</samp>&rsquo;</dt>
<dd><p>The pattern was found at <var>address</var>.
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>A badly formed request or an error was encountered while searching memory.
</p></dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates that &lsquo;<samp>qSearch:memory</samp>&rsquo; is not recognized.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>QStartNoAckMode</samp>&rsquo;</dt>
<dd><a name="index-QStartNoAckMode-packet"></a>
<a name="QStartNoAckMode"></a><p>Request that the remote stub disable the normal &lsquo;<samp>+</samp>&rsquo;/&lsquo;<samp>-</samp>&rsquo;
protocol acknowledgments (see <a href="Packet-Acknowledgment.html#Packet-Acknowledgment">Packet Acknowledgment</a>).
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The stub has switched to no-acknowledgment mode.
<small>GDB</small> acknowledges this response,
but neither the stub nor <small>GDB</small> shall send or expect further
&lsquo;<samp>+</samp>&rsquo;/&lsquo;<samp>-</samp>&rsquo; acknowledgments in the current connection.
</p></dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates that the stub does not support no-acknowledgment mode.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>qSupported <span class="roman">[</span>:<var>gdbfeature</var> <span class="roman">[</span>;<var>gdbfeature</var><span class="roman">]</span>&hellip; <span class="roman">]</span></samp>&rsquo;</dt>
<dd><a name="index-supported-packets_002c-remote-query"></a>
<a name="index-features-of-the-remote-protocol"></a>
<a name="index-qSupported-packet"></a>
<a name="qSupported"></a><p>Tell the remote stub about features supported by <small>GDB</small>, and
query the stub for features it supports.  This packet allows
<small>GDB</small> and the remote stub to take advantage of each others&rsquo;
features.  &lsquo;<samp>qSupported</samp>&rsquo; also consolidates multiple feature probes
at startup, to improve <small>GDB</small> performance&mdash;a single larger
packet performs better than multiple smaller probe packets on
high-latency links.  Some features may enable behavior which must not
be on by default, e.g. because it would confuse older clients or
stubs.  Other features may describe packets which could be
automatically probed for, but are not.  These features must be
reported before <small>GDB</small> will use them.  This &ldquo;default
unsupported&rdquo; behavior is not appropriate for all packets, but it
helps to keep the initial connection time under control with new
versions of <small>GDB</small> which support increasing numbers of packets.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp><var>stubfeature</var> <span class="roman">[</span>;<var>stubfeature</var><span class="roman">]</span>&hellip;</samp>&rsquo;</dt>
<dd><p>The stub supports or does not support each returned <var>stubfeature</var>,
depending on the form of each <var>stubfeature</var> (see below for the
possible forms).
</p></dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates that &lsquo;<samp>qSupported</samp>&rsquo; is not recognized,
or that no features needed to be reported to <small>GDB</small>.
</p></dd>
</dl>

<p>The allowed forms for each feature (either a <var>gdbfeature</var> in the
&lsquo;<samp>qSupported</samp>&rsquo; packet, or a <var>stubfeature</var> in the response)
are:
</p>
<dl compact="compact">
<dt>&lsquo;<samp><var>name</var>=<var>value</var></samp>&rsquo;</dt>
<dd><p>The remote protocol feature <var>name</var> is supported, and associated
with the specified <var>value</var>.  The format of <var>value</var> depends
on the feature, but it must not include a semicolon.
</p></dd>
<dt>&lsquo;<samp><var>name</var>+</samp>&rsquo;</dt>
<dd><p>The remote protocol feature <var>name</var> is supported, and does not
need an associated value.
</p></dd>
<dt>&lsquo;<samp><var>name</var>-</samp>&rsquo;</dt>
<dd><p>The remote protocol feature <var>name</var> is not supported.
</p></dd>
<dt>&lsquo;<samp><var>name</var>?</samp>&rsquo;</dt>
<dd><p>The remote protocol feature <var>name</var> may be supported, and
<small>GDB</small> should auto-detect support in some other way when it is
needed.  This form will not be used for <var>gdbfeature</var> notifications,
but may be used for <var>stubfeature</var> responses.
</p></dd>
</dl>

<p>Whenever the stub receives a &lsquo;<samp>qSupported</samp>&rsquo; request, the
supplied set of <small>GDB</small> features should override any previous
request.  This allows <small>GDB</small> to put the stub in a known
state, even if the stub had previously been communicating with
a different version of <small>GDB</small>.
</p>
<p>The following values of <var>gdbfeature</var> (for the packet sent by <small>GDB</small>)
are defined:  
</p>
<dl compact="compact">
<dt>&lsquo;<samp>multiprocess</samp>&rsquo;</dt>
<dd><p>This feature indicates whether <small>GDB</small> supports multiprocess 
extensions to the remote protocol.  <small>GDB</small> does not use such
extensions unless the stub also reports that it supports them by
including &lsquo;<samp>multiprocess+</samp>&rsquo; in its &lsquo;<samp>qSupported</samp>&rsquo; reply.
See <a href="#multiprocess-extensions">multiprocess extensions</a>, for details.
</p>
</dd>
<dt>&lsquo;<samp>xmlRegisters</samp>&rsquo;</dt>
<dd><p>This feature indicates that <small>GDB</small> supports the XML target
description.  If the stub sees &lsquo;<samp>xmlRegisters=</samp>&rsquo; with target
specific strings separated by a comma, it will report register
description.
</p>
</dd>
<dt>&lsquo;<samp>qRelocInsn</samp>&rsquo;</dt>
<dd><p>This feature indicates whether <small>GDB</small> supports the
&lsquo;<samp>qRelocInsn</samp>&rsquo; packet (see <a href="Tracepoint-Packets.html#Tracepoint-Packets">Relocate
instruction reply packet</a>).
</p>
</dd>
<dt>&lsquo;<samp>swbreak</samp>&rsquo;</dt>
<dd><p>This feature indicates whether <small>GDB</small> supports the swbreak stop
reason in stop replies.  See <a href="Stop-Reply-Packets.html#swbreak-stop-reason">swbreak stop reason</a>, for details.
</p>
</dd>
<dt>&lsquo;<samp>hwbreak</samp>&rsquo;</dt>
<dd><p>This feature indicates whether <small>GDB</small> supports the hwbreak stop
reason in stop replies.  See <a href="Stop-Reply-Packets.html#swbreak-stop-reason">swbreak stop reason</a>, for details.
</p>
</dd>
<dt>&lsquo;<samp>fork-events</samp>&rsquo;</dt>
<dd><p>This feature indicates whether <small>GDB</small> supports fork event
extensions to the remote protocol.  <small>GDB</small> does not use such
extensions unless the stub also reports that it supports them by
including &lsquo;<samp>fork-events+</samp>&rsquo; in its &lsquo;<samp>qSupported</samp>&rsquo; reply.
</p>
</dd>
<dt>&lsquo;<samp>vfork-events</samp>&rsquo;</dt>
<dd><p>This feature indicates whether <small>GDB</small> supports vfork event
extensions to the remote protocol.  <small>GDB</small> does not use such
extensions unless the stub also reports that it supports them by
including &lsquo;<samp>vfork-events+</samp>&rsquo; in its &lsquo;<samp>qSupported</samp>&rsquo; reply.
</p>
</dd>
<dt>&lsquo;<samp>exec-events</samp>&rsquo;</dt>
<dd><p>This feature indicates whether <small>GDB</small> supports exec event
extensions to the remote protocol.  <small>GDB</small> does not use such
extensions unless the stub also reports that it supports them by
including &lsquo;<samp>exec-events+</samp>&rsquo; in its &lsquo;<samp>qSupported</samp>&rsquo; reply.
</p>
</dd>
<dt>&lsquo;<samp>vContSupported</samp>&rsquo;</dt>
<dd><p>This feature indicates whether <small>GDB</small> wants to know the
supported actions in the reply to &lsquo;<samp>vCont?</samp>&rsquo; packet.
</p></dd>
</dl>

<p>Stubs should ignore any unknown values for
<var>gdbfeature</var>.  Any <small>GDB</small> which sends a &lsquo;<samp>qSupported</samp>&rsquo;
packet supports receiving packets of unlimited length (earlier
versions of <small>GDB</small> may reject overly long responses).  Additional values
for <var>gdbfeature</var> may be defined in the future to let the stub take
advantage of new features in <small>GDB</small>, e.g. incompatible
improvements in the remote protocol&mdash;the &lsquo;<samp>multiprocess</samp>&rsquo; feature is
an example of such a feature.  The stub&rsquo;s reply should be independent
of the <var>gdbfeature</var> entries sent by <small>GDB</small>; first <small>GDB</small>
describes all the features it supports, and then the stub replies with
all the features it supports.
</p>
<p>Similarly, <small>GDB</small> will silently ignore unrecognized stub feature
responses, as long as each response uses one of the standard forms.
</p>
<p>Some features are flags.  A stub which supports a flag feature
should respond with a &lsquo;<samp>+</samp>&rsquo; form response.  Other features
require values, and the stub should respond with an &lsquo;<samp>=</samp>&rsquo;
form response.
</p>
<p>Each feature has a default value, which <small>GDB</small> will use if
&lsquo;<samp>qSupported</samp>&rsquo; is not available or if the feature is not mentioned
in the &lsquo;<samp>qSupported</samp>&rsquo; response.  The default values are fixed; a
stub is free to omit any feature responses that match the defaults.
</p>
<p>Not all features can be probed, but for those which can, the probing
mechanism is useful: in some cases, a stub&rsquo;s internal
architecture may not allow the protocol layer to know some information
about the underlying target in advance.  This is especially common in
stubs which may be configured for multiple targets.
</p>
<p>These are the currently defined stub features and their properties:
</p>
<table>
<tr><td width="35%">Feature Name</td><td width="20%">Value Required</td><td width="12%">Default</td><td width="20%">Probe Allowed</td></tr>
<tr><td width="35%">&lsquo;<samp>PacketSize</samp>&rsquo;</td><td width="20%">Yes</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:auxv:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:btrace:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:btrace-conf:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:exec-file:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:features:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:libraries:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:libraries-svr4:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>augmented-libraries-svr4-read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:memory-map:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:sdata:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:siginfo:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:siginfo:write</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:threads:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:traceframe-info:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:uib:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>qXfer:fdpic:read</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>Qbtrace:off</samp>&rsquo;</td><td width="20%">Yes</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>Qbtrace:bts</samp>&rsquo;</td><td width="20%">Yes</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>Qbtrace:pt</samp>&rsquo;</td><td width="20%">Yes</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>Qbtrace-conf:bts:size</samp>&rsquo;</td><td width="20%">Yes</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>Qbtrace-conf:pt:size</samp>&rsquo;</td><td width="20%">Yes</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>QNonStop</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>QCatchSyscalls</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>QPassSignals</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>QStartNoAckMode</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">Yes</td></tr>
<tr><td width="35%">&lsquo;<samp>multiprocess</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>ConditionalBreakpoints</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>ConditionalTracepoints</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>ReverseContinue</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>ReverseStep</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>TracepointSource</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>QAgent</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>QAllow</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>QDisableRandomization</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>EnableDisableTracepoints</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>QTBuffer:size</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>tracenz</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>BreakpointCommands</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>swbreak</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>hwbreak</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>fork-events</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>vfork-events</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>exec-events</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>QThreadEvents</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
<tr><td width="35%">&lsquo;<samp>no-resumed</samp>&rsquo;</td><td width="20%">No</td><td width="12%">&lsquo;<samp>-</samp>&rsquo;</td><td width="20%">No</td></tr>
</table>

<p>These are the currently defined stub features, in more detail:
</p>
<dl compact="compact">
<dd><a name="index-packet-size_002c-remote-protocol"></a>
</dd>
<dt>&lsquo;<samp>PacketSize=<var>bytes</var></samp>&rsquo;</dt>
<dd><p>The remote stub can accept packets up to at least <var>bytes</var> in
length.  <small>GDB</small> will send packets up to this size for bulk
transfers, and will never send larger packets.  This is a limit on the
data characters in the packet, including the frame and checksum.
There is no trailing NUL byte in a remote protocol packet; if the stub
stores packets in a NUL-terminated format, it should allow an extra
byte in its buffer for the NUL.  If this stub feature is not supported,
<small>GDB</small> guesses based on the size of the &lsquo;<samp>g</samp>&rsquo; packet response.
</p>
</dd>
<dt>&lsquo;<samp>qXfer:auxv:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:auxv:read</samp>&rsquo; packet
(see <a href="#qXfer-auxiliary-vector-read">qXfer auxiliary vector read</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:btrace:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:btrace:read</samp>&rsquo;
packet (see <a href="#qXfer-btrace-read">qXfer btrace read</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:btrace-conf:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:btrace-conf:read</samp>&rsquo;
packet (see <a href="#qXfer-btrace_002dconf-read">qXfer btrace-conf read</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:exec-file:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:exec-file:read</samp>&rsquo; packet
(see <a href="#qXfer-executable-filename-read">qXfer executable filename read</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:features:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:features:read</samp>&rsquo; packet
(see <a href="#qXfer-target-description-read">qXfer target description read</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:libraries:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:libraries:read</samp>&rsquo; packet
(see <a href="#qXfer-library-list-read">qXfer library list read</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:libraries-svr4:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:libraries-svr4:read</samp>&rsquo; packet
(see <a href="#qXfer-svr4-library-list-read">qXfer svr4 library list read</a>).
</p>
</dd>
<dt>&lsquo;<samp>augmented-libraries-svr4-read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the augmented form of the
&lsquo;<samp>qXfer:libraries-svr4:read</samp>&rsquo; packet
(see <a href="#qXfer-svr4-library-list-read">qXfer svr4 library list read</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:memory-map:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:memory-map:read</samp>&rsquo; packet
(see <a href="#qXfer-memory-map-read">qXfer memory map read</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:sdata:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:sdata:read</samp>&rsquo; packet
(see <a href="#qXfer-sdata-read">qXfer sdata read</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:siginfo:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:siginfo:read</samp>&rsquo; packet
(see <a href="#qXfer-siginfo-read">qXfer siginfo read</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:siginfo:write</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:siginfo:write</samp>&rsquo; packet
(see <a href="#qXfer-siginfo-write">qXfer siginfo write</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:threads:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:threads:read</samp>&rsquo; packet
(see <a href="#qXfer-threads-read">qXfer threads read</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:traceframe-info:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:traceframe-info:read</samp>&rsquo;
packet (see <a href="#qXfer-traceframe-info-read">qXfer traceframe info read</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:uib:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:uib:read</samp>&rsquo;
packet (see <a href="#qXfer-unwind-info-block">qXfer unwind info block</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:fdpic:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:fdpic:read</samp>&rsquo;
packet (see <a href="#qXfer-fdpic-loadmap-read">qXfer fdpic loadmap read</a>).
</p>
</dd>
<dt>&lsquo;<samp>QNonStop</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>QNonStop</samp>&rsquo; packet
(see <a href="#QNonStop">QNonStop</a>).
</p>
</dd>
<dt>&lsquo;<samp>QCatchSyscalls</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>QCatchSyscalls</samp>&rsquo; packet
(see <a href="#QCatchSyscalls">QCatchSyscalls</a>).
</p>
</dd>
<dt>&lsquo;<samp>QPassSignals</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>QPassSignals</samp>&rsquo; packet
(see <a href="#QPassSignals">QPassSignals</a>).
</p>
</dd>
<dt>&lsquo;<samp>QStartNoAckMode</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>QStartNoAckMode</samp>&rsquo; packet and
prefers to operate in no-acknowledgment mode.  See <a href="Packet-Acknowledgment.html#Packet-Acknowledgment">Packet Acknowledgment</a>.
</p>
</dd>
<dt>&lsquo;<samp>multiprocess</samp>&rsquo;</dt>
<dd><a name="multiprocess-extensions"></a><a name="index-multiprocess-extensions_002c-in-remote-protocol"></a>
<p>The remote stub understands the multiprocess extensions to the remote
protocol syntax.  The multiprocess extensions affect the syntax of
thread IDs in both packets and replies (see <a href="Packets.html#thread_002did-syntax">thread-id syntax</a>), and
add process IDs to the &lsquo;<samp>D</samp>&rsquo; packet and &lsquo;<samp>W</samp>&rsquo; and &lsquo;<samp>X</samp>&rsquo;
replies.  Note that reporting this feature indicates support for the
syntactic extensions only, not that the stub necessarily supports
debugging of more than one process at a time.  The stub must not use
multiprocess extensions in packet replies unless <small>GDB</small> has also
indicated it supports them in its &lsquo;<samp>qSupported</samp>&rsquo; request.
</p>
</dd>
<dt>&lsquo;<samp>qXfer:osdata:read</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>qXfer:osdata:read</samp>&rsquo; packet
((see <a href="#qXfer-osdata-read">qXfer osdata read</a>).
</p>
</dd>
<dt>&lsquo;<samp>ConditionalBreakpoints</samp>&rsquo;</dt>
<dd><p>The target accepts and implements evaluation of conditional expressions
defined for breakpoints.  The target will only report breakpoint triggers
when such conditions are true (see <a href="Conditions.html#Conditions">Break Conditions</a>).
</p>
</dd>
<dt>&lsquo;<samp>ConditionalTracepoints</samp>&rsquo;</dt>
<dd><p>The remote stub accepts and implements conditional expressions defined
for tracepoints (see <a href="Tracepoint-Conditions.html#Tracepoint-Conditions">Tracepoint Conditions</a>).
</p>
</dd>
<dt>&lsquo;<samp>ReverseContinue</samp>&rsquo;</dt>
<dd><p>The remote stub accepts and implements the reverse continue packet
(see <a href="Packets.html#bc">bc</a>).
</p>
</dd>
<dt>&lsquo;<samp>ReverseStep</samp>&rsquo;</dt>
<dd><p>The remote stub accepts and implements the reverse step packet
(see <a href="Packets.html#bs">bs</a>).
</p>
</dd>
<dt>&lsquo;<samp>TracepointSource</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>QTDPsrc</samp>&rsquo; packet that supplies
the source form of tracepoint definitions.
</p>
</dd>
<dt>&lsquo;<samp>QAgent</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>QAgent</samp>&rsquo; packet.
</p>
</dd>
<dt>&lsquo;<samp>QAllow</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>QAllow</samp>&rsquo; packet.
</p>
</dd>
<dt>&lsquo;<samp>QDisableRandomization</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>QDisableRandomization</samp>&rsquo; packet.
</p>
</dd>
<dt>&lsquo;<samp>StaticTracepoint</samp>&rsquo;</dt>
<dd><a name="index-static-tracepoints_002c-in-remote-protocol"></a>
<p>The remote stub supports static tracepoints.
</p>
</dd>
<dt>&lsquo;<samp>InstallInTrace</samp>&rsquo;</dt>
<dd><a name="install-tracepoint-in-tracing"></a><p>The remote stub supports installing tracepoint in tracing.
</p>
</dd>
<dt>&lsquo;<samp>EnableDisableTracepoints</samp>&rsquo;</dt>
<dd><p>The remote stub supports the &lsquo;<samp>QTEnable</samp>&rsquo; (see <a href="Tracepoint-Packets.html#QTEnable">QTEnable</a>) and
&lsquo;<samp>QTDisable</samp>&rsquo; (see <a href="Tracepoint-Packets.html#QTDisable">QTDisable</a>) packets that allow tracepoints
to be enabled and disabled while a trace experiment is running.
</p>
</dd>
<dt>&lsquo;<samp>QTBuffer:size</samp>&rsquo;</dt>
<dd><p>The remote stub supports the &lsquo;<samp>QTBuffer:size</samp>&rsquo; (see <a href="Tracepoint-Packets.html#QTBuffer_002dsize">QTBuffer-size</a>)
packet that allows to change the size of the trace buffer.
</p>
</dd>
<dt>&lsquo;<samp>tracenz</samp>&rsquo;</dt>
<dd><a name="index-string-tracing_002c-in-remote-protocol"></a>
<p>The remote stub supports the &lsquo;<samp>tracenz</samp>&rsquo; bytecode for collecting strings.
See <a href="Bytecode-Descriptions.html#Bytecode-Descriptions">Bytecode Descriptions</a> for details about the bytecode.
</p>
</dd>
<dt>&lsquo;<samp>BreakpointCommands</samp>&rsquo;</dt>
<dd><a name="index-breakpoint-commands_002c-in-remote-protocol"></a>
<p>The remote stub supports running a breakpoint&rsquo;s command list itself,
rather than reporting the hit to <small>GDB</small>.
</p>
</dd>
<dt>&lsquo;<samp>Qbtrace:off</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>Qbtrace:off</samp>&rsquo; packet.
</p>
</dd>
<dt>&lsquo;<samp>Qbtrace:bts</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>Qbtrace:bts</samp>&rsquo; packet.
</p>
</dd>
<dt>&lsquo;<samp>Qbtrace:pt</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>Qbtrace:pt</samp>&rsquo; packet.
</p>
</dd>
<dt>&lsquo;<samp>Qbtrace-conf:bts:size</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>Qbtrace-conf:bts:size</samp>&rsquo; packet.
</p>
</dd>
<dt>&lsquo;<samp>Qbtrace-conf:pt:size</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>Qbtrace-conf:pt:size</samp>&rsquo; packet.
</p>
</dd>
<dt>&lsquo;<samp>swbreak</samp>&rsquo;</dt>
<dd><p>The remote stub reports the &lsquo;<samp>swbreak</samp>&rsquo; stop reason for memory
breakpoints.
</p>
</dd>
<dt>&lsquo;<samp>hwbreak</samp>&rsquo;</dt>
<dd><p>The remote stub reports the &lsquo;<samp>hwbreak</samp>&rsquo; stop reason for hardware
breakpoints.
</p>
</dd>
<dt>&lsquo;<samp>fork-events</samp>&rsquo;</dt>
<dd><p>The remote stub reports the &lsquo;<samp>fork</samp>&rsquo; stop reason for fork events.
</p>
</dd>
<dt>&lsquo;<samp>vfork-events</samp>&rsquo;</dt>
<dd><p>The remote stub reports the &lsquo;<samp>vfork</samp>&rsquo; stop reason for vfork events
and vforkdone events.
</p>
</dd>
<dt>&lsquo;<samp>exec-events</samp>&rsquo;</dt>
<dd><p>The remote stub reports the &lsquo;<samp>exec</samp>&rsquo; stop reason for exec events.
</p>
</dd>
<dt>&lsquo;<samp>vContSupported</samp>&rsquo;</dt>
<dd><p>The remote stub reports the supported actions in the reply to
&lsquo;<samp>vCont?</samp>&rsquo; packet.
</p>
</dd>
<dt>&lsquo;<samp>QThreadEvents</samp>&rsquo;</dt>
<dd><p>The remote stub understands the &lsquo;<samp>QThreadEvents</samp>&rsquo; packet.
</p>
</dd>
<dt>&lsquo;<samp>no-resumed</samp>&rsquo;</dt>
<dd><p>The remote stub reports the &lsquo;<samp>N</samp>&rsquo; stop reply.
</p>
</dd>
</dl>

</dd>
<dt>&lsquo;<samp>qSymbol::</samp>&rsquo;</dt>
<dd><a name="index-symbol-lookup_002c-remote-request"></a>
<a name="index-qSymbol-packet"></a>
<p>Notify the target that <small>GDB</small> is prepared to serve symbol lookup
requests.  Accept requests from the target for the values of symbols.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The target does not need to look up any (more) symbols.
</p></dd>
<dt>&lsquo;<samp>qSymbol:<var>sym_name</var></samp>&rsquo;</dt>
<dd><p>The target requests the value of symbol <var>sym_name</var> (hex encoded).
<small>GDB</small> may provide the value by using the
&lsquo;<samp>qSymbol:<var>sym_value</var>:<var>sym_name</var></samp>&rsquo; message, described
below.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>qSymbol:<var>sym_value</var>:<var>sym_name</var></samp>&rsquo;</dt>
<dd><p>Set the value of <var>sym_name</var> to <var>sym_value</var>.
</p>
<p><var>sym_name</var> (hex encoded) is the name of a symbol whose value the
target has previously requested.
</p>
<p><var>sym_value</var> (hex) is the value for symbol <var>sym_name</var>.  If
<small>GDB</small> cannot supply a value for <var>sym_name</var>, then this field
will be empty.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The target does not need to look up any (more) symbols.
</p></dd>
<dt>&lsquo;<samp>qSymbol:<var>sym_name</var></samp>&rsquo;</dt>
<dd><p>The target requests the value of a new symbol <var>sym_name</var> (hex
encoded).  <small>GDB</small> will continue to supply the values of symbols
(if available), until the target ceases to request them.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>qTBuffer</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTBuffer</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTDisconnected</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTDP</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTDPsrc</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTDV</samp>&rsquo;</dt>
<dt>&lsquo;<samp>qTfP</samp>&rsquo;</dt>
<dt>&lsquo;<samp>qTfV</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTFrame</samp>&rsquo;</dt>
<dt>&lsquo;<samp>qTMinFTPILen</samp>&rsquo;</dt>
<dd>
<p>See <a href="Tracepoint-Packets.html#Tracepoint-Packets">Tracepoint Packets</a>.
</p>
</dd>
<dt>&lsquo;<samp>qThreadExtraInfo,<var>thread-id</var></samp>&rsquo;</dt>
<dd><a name="index-thread-attributes-info_002c-remote-request"></a>
<a name="index-qThreadExtraInfo-packet"></a>
<p>Obtain from the target OS a printable string description of thread
attributes for the thread <var>thread-id</var>; see <a href="Packets.html#thread_002did-syntax">thread-id syntax</a>,
for the forms of <var>thread-id</var>.  This
string may contain anything that the target OS thinks is interesting
for <small>GDB</small> to tell the user about the thread.  The string is
displayed in <small>GDB</small>&rsquo;s <code>info threads</code> display.  Some
examples of possible thread extra info strings are &lsquo;<samp>Runnable</samp>&rsquo;, or
&lsquo;<samp>Blocked on Mutex</samp>&rsquo;.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp><var>XX</var>&hellip;</samp>&rsquo;</dt>
<dd><p>Where &lsquo;<samp><var>XX</var>&hellip;</samp>&rsquo; is a hex encoding of <small>ASCII</small> data,
comprising the printable string containing the extra information about
the thread&rsquo;s attributes.
</p></dd>
</dl>

<p>(Note that the <code>qThreadExtraInfo</code> packet&rsquo;s name is separated from
the command by a &lsquo;<samp>,</samp>&rsquo;, not a &lsquo;<samp>:</samp>&rsquo;, contrary to the naming
conventions above.  Please don&rsquo;t use this packet as a model for new
packets.)
</p>
</dd>
<dt>&lsquo;<samp>QTNotes</samp>&rsquo;</dt>
<dt>&lsquo;<samp>qTP</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTSave</samp>&rsquo;</dt>
<dt>&lsquo;<samp>qTsP</samp>&rsquo;</dt>
<dt>&lsquo;<samp>qTsV</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTStart</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTStop</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTEnable</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTDisable</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTinit</samp>&rsquo;</dt>
<dt>&lsquo;<samp>QTro</samp>&rsquo;</dt>
<dt>&lsquo;<samp>qTStatus</samp>&rsquo;</dt>
<dt>&lsquo;<samp>qTV</samp>&rsquo;</dt>
<dt>&lsquo;<samp>qTfSTM</samp>&rsquo;</dt>
<dt>&lsquo;<samp>qTsSTM</samp>&rsquo;</dt>
<dt>&lsquo;<samp>qTSTMat</samp>&rsquo;</dt>
<dd><p>See <a href="Tracepoint-Packets.html#Tracepoint-Packets">Tracepoint Packets</a>.
</p>
</dd>
<dt>&lsquo;<samp>qXfer:<var>object</var>:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="index-read-special-object_002c-remote-request"></a>
<a name="index-qXfer-packet"></a>
<a name="qXfer-read"></a><p>Read uninterpreted bytes from the target&rsquo;s special data area
identified by the keyword <var>object</var>.  Request <var>length</var> bytes
starting at <var>offset</var> bytes into the data.  The content and
encoding of <var>annex</var> is specific to <var>object</var>; it can supply
additional details about what data to access.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>m <var>data</var></samp>&rsquo;</dt>
<dd><p>Data <var>data</var> (see <a href="Overview.html#Binary-Data">Binary Data</a>) has been read from the
target.  There may be more data at a higher address (although
it is permitted to return &lsquo;<samp>m</samp>&rsquo; even for the last valid
block of data, as long as at least one byte of data was read).
It is possible for <var>data</var> to have fewer bytes than the <var>length</var> in the
request.
</p>
</dd>
<dt>&lsquo;<samp>l <var>data</var></samp>&rsquo;</dt>
<dd><p>Data <var>data</var> (see <a href="Overview.html#Binary-Data">Binary Data</a>) has been read from the target.
There is no more data to be read.  It is possible for <var>data</var> to
have fewer bytes than the <var>length</var> in the request.
</p>
</dd>
<dt>&lsquo;<samp>l</samp>&rsquo;</dt>
<dd><p>The <var>offset</var> in the request is at the end of the data.
There is no more data to be read.
</p>
</dd>
<dt>&lsquo;<samp>E00</samp>&rsquo;</dt>
<dd><p>The request was malformed, or <var>annex</var> was invalid.
</p>
</dd>
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>The offset was invalid, or there was an error encountered reading the data.
The <var>nn</var> part is a hex-encoded <code>errno</code> value.
</p>
</dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates the <var>object</var> string was not recognized by
the stub, or that the object does not support reading.
</p></dd>
</dl>

<p>Here are the specific requests of this form defined so far.  All the
&lsquo;<samp>qXfer:<var>object</var>:read:&hellip;</samp>&rsquo; requests use the same reply
formats, listed above.
</p>
<dl compact="compact">
<dt>&lsquo;<samp>qXfer:auxv:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-auxiliary-vector-read"></a><p>Access the target&rsquo;s <em>auxiliary vector</em>.  See <a href="OS-Information.html#OS-Information">auxiliary vector</a>.  Note <var>annex</var> must be empty.
</p>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:btrace:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-btrace-read"></a>
<p>Return a description of the current branch trace.
See <a href="Branch-Trace-Format.html#Branch-Trace-Format">Branch Trace Format</a>.  The annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo;
packet may have one of the following values:
</p>
<dl compact="compact">
<dt><code>all</code></dt>
<dd><p>Returns all available branch trace.
</p>
</dd>
<dt><code>new</code></dt>
<dd><p>Returns all available branch trace if the branch trace changed since
the last read request.
</p>
</dd>
<dt><code>delta</code></dt>
<dd><p>Returns the new branch trace since the last read request.  Adds a new
block to the end of the trace that begins at zero and ends at the source
location of the first branch in the trace buffer.  This extra block is
used to stitch traces together.
</p>
<p>If the trace buffer overflowed, returns an error indicating the overflow.
</p></dd>
</dl>

<p>This packet is not probed by default; the remote stub must request it
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:btrace-conf:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-btrace_002dconf-read"></a>
<p>Return a description of the current branch trace configuration.
See <a href="Branch-Trace-Configuration-Format.html#Branch-Trace-Configuration-Format">Branch Trace Configuration Format</a>.
</p>
<p>This packet is not probed by default; the remote stub must request it
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:exec-file:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-executable-filename-read"></a><p>Return the full absolute name of the file that was executed to create
a process running on the remote system.  The annex specifies the
numeric process ID of the process to query, encoded as a hexadecimal
number.  If the annex part is empty the remote stub should return the
filename corresponding to the currently executing process.
</p>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:features:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-target-description-read"></a><p>Access the <em>target description</em>.  See <a href="Target-Descriptions.html#Target-Descriptions">Target Descriptions</a>.  The
annex specifies which XML document to access.  The main description is
always loaded from the &lsquo;<samp>target.xml</samp>&rsquo; annex.
</p>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:libraries:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-library-list-read"></a><p>Access the target&rsquo;s list of loaded libraries.  See <a href="Library-List-Format.html#Library-List-Format">Library List Format</a>.
The annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must be empty
(see <a href="#qXfer-read">qXfer read</a>).
</p>
<p>Targets which maintain a list of libraries in the program&rsquo;s memory do
not need to implement this packet; it is designed for platforms where
the operating system manages the list of loaded libraries.
</p>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:libraries-svr4:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-svr4-library-list-read"></a><p>Access the target&rsquo;s list of loaded libraries when the target is an SVR4
platform.  See <a href="Library-List-Format-for-SVR4-Targets.html#Library-List-Format-for-SVR4-Targets">Library List Format for SVR4 Targets</a>.  The annex part
of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must be empty unless the remote
stub indicated it supports the augmented form of this packet
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
(see <a href="#qXfer-read">qXfer read</a>, <a href="#qSupported">qSupported</a>).
</p>
<p>This packet is optional for better performance on SVR4 targets.  
<small>GDB</small> uses memory read packets to read the SVR4 library list otherwise.
</p>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
<p>If the remote stub indicates it supports the augmented form of this
packet then the annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet may
contain a semicolon-separated list of &lsquo;<samp><var>name</var>=<var>value</var></samp>&rsquo;
arguments.  The currently supported arguments are:
</p>
<dl compact="compact">
<dt><code>start=<var>address</var></code></dt>
<dd><p>A hexadecimal number specifying the address of the &lsquo;<samp>struct
link_map</samp>&rsquo; to start reading the library list from.  If unset or zero
then the first &lsquo;<samp>struct link_map</samp>&rsquo; in the library list will be
chosen as the starting point.
</p>
</dd>
<dt><code>prev=<var>address</var></code></dt>
<dd><p>A hexadecimal number specifying the address of the &lsquo;<samp>struct
link_map</samp>&rsquo; immediately preceding the &lsquo;<samp>struct link_map</samp>&rsquo;
specified by the &lsquo;<samp>start</samp>&rsquo; argument.  If unset or zero then
the remote stub will expect that no &lsquo;<samp>struct link_map</samp>&rsquo;
exists prior to the starting point.
</p>
</dd>
</dl>

<p>Arguments that are not understood by the remote stub will be silently
ignored.
</p>
</dd>
<dt>&lsquo;<samp>qXfer:memory-map:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-memory-map-read"></a><p>Access the target&rsquo;s <em>memory-map</em>.  See <a href="Memory-Map-Format.html#Memory-Map-Format">Memory Map Format</a>.  The
annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must be empty
(see <a href="#qXfer-read">qXfer read</a>).
</p>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:sdata:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-sdata-read"></a>
<p>Read contents of the extra collected static tracepoint marker
information.  The annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must
be empty (see <a href="#qXfer-read">qXfer read</a>).  See <a href="Tracepoint-Actions.html#Tracepoint-Actions">Tracepoint
Action Lists</a>.
</p>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
(see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:siginfo:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-siginfo-read"></a><p>Read contents of the extra signal information on the target
system.  The annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must be
empty (see <a href="#qXfer-read">qXfer read</a>).
</p>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
(see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:threads:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-threads-read"></a><p>Access the list of threads on target.  See <a href="Thread-List-Format.html#Thread-List-Format">Thread List Format</a>.  The
annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must be empty
(see <a href="#qXfer-read">qXfer read</a>).
</p>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:traceframe-info:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-traceframe-info-read"></a>
<p>Return a description of the current traceframe&rsquo;s contents.
See <a href="Traceframe-Info-Format.html#Traceframe-Info-Format">Traceframe Info Format</a>.  The annex part of the generic
&lsquo;<samp>qXfer</samp>&rsquo; packet must be empty (see <a href="#qXfer-read">qXfer read</a>).
</p>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:uib:read:<var>pc</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-unwind-info-block"></a>
<p>Return the unwind information block for <var>pc</var>.  This packet is used
on OpenVMS/ia64 to ask the kernel unwind information.
</p>
<p>This packet is not probed by default.
</p>
</dd>
<dt>&lsquo;<samp>qXfer:fdpic:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-fdpic-loadmap-read"></a><p>Read contents of <code>loadmap</code>s on the target system.  The
annex, either &lsquo;<samp>exec</samp>&rsquo; or &lsquo;<samp>interp</samp>&rsquo;, specifies which <code>loadmap</code>,
executable <code>loadmap</code> or interpreter <code>loadmap</code> to read.
</p>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
</p>
</dd>
<dt>&lsquo;<samp>qXfer:osdata:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
<dd><a name="qXfer-osdata-read"></a><p>Access the target&rsquo;s <em>operating system information</em>.
See <a href="Operating-System-Information.html#Operating-System-Information">Operating System Information</a>.
</p>
</dd>
</dl>

</dd>
<dt>&lsquo;<samp>qXfer:<var>object</var>:write:<var>annex</var>:<var>offset</var>:<var>data</var>&hellip;</samp>&rsquo;</dt>
<dd><a name="index-write-data-into-object_002c-remote-request"></a>
<a name="qXfer-write"></a><p>Write uninterpreted bytes into the target&rsquo;s special data area
identified by the keyword <var>object</var>, starting at <var>offset</var> bytes
into the data.  The binary-encoded data (see <a href="Overview.html#Binary-Data">Binary Data</a>) to be
written is given by <var>data</var>&hellip;.  The content and encoding of <var>annex</var>
is specific to <var>object</var>; it can supply additional details about what data
to access.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp><var>nn</var></samp>&rsquo;</dt>
<dd><p><var>nn</var> (hex encoded) is the number of bytes written.
This may be fewer bytes than supplied in the request.
</p>
</dd>
<dt>&lsquo;<samp>E00</samp>&rsquo;</dt>
<dd><p>The request was malformed, or <var>annex</var> was invalid.
</p>
</dd>
<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
<dd><p>The offset was invalid, or there was an error encountered writing the data.
The <var>nn</var> part is a hex-encoded <code>errno</code> value.
</p>
</dd>
<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
<dd><p>An empty reply indicates the <var>object</var> string was not
recognized by the stub, or that the object does not support writing.
</p></dd>
</dl>

<p>Here are the specific requests of this form defined so far.  All the
&lsquo;<samp>qXfer:<var>object</var>:write:&hellip;</samp>&rsquo; requests use the same reply
formats, listed above.
</p>
<dl compact="compact">
<dt>&lsquo;<samp>qXfer:siginfo:write::<var>offset</var>:<var>data</var>&hellip;</samp>&rsquo;</dt>
<dd><a name="qXfer-siginfo-write"></a><p>Write <var>data</var> to the extra signal information on the target system.
The annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must be
empty (see <a href="#qXfer-write">qXfer write</a>).
</p>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
(see <a href="#qSupported">qSupported</a>).
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>qXfer:<var>object</var>:<var>operation</var>:&hellip;</samp>&rsquo;</dt>
<dd><p>Requests of this form may be added in the future.  When a stub does
not recognize the <var>object</var> keyword, or its support for
<var>object</var> does not recognize the <var>operation</var> keyword, the stub
must respond with an empty packet.
</p>
</dd>
<dt>&lsquo;<samp>qAttached:<var>pid</var></samp>&rsquo;</dt>
<dd><a name="index-query-attached_002c-remote-request"></a>
<a name="index-qAttached-packet"></a>
<p>Return an indication of whether the remote server attached to an
existing process or created a new process.  When the multiprocess
protocol extensions are supported (see <a href="#multiprocess-extensions">multiprocess extensions</a>),
<var>pid</var> is an integer in hexadecimal format identifying the target
process.  Otherwise, <small>GDB</small> will omit the <var>pid</var> field and
the query packet will be simplified as &lsquo;<samp>qAttached</samp>&rsquo;.
</p>
<p>This query is used, for example, to know whether the remote process
should be detached or killed when a <small>GDB</small> session is ended with
the <code>quit</code> command.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>1</samp>&rsquo;</dt>
<dd><p>The remote server attached to an existing process.
</p></dd>
<dt>&lsquo;<samp>0</samp>&rsquo;</dt>
<dd><p>The remote server created a new process.
</p></dd>
<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
<dd><p>A badly formed request or an error was encountered.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>Qbtrace:bts</samp>&rsquo;</dt>
<dd><p>Enable branch tracing for the current thread using Branch Trace Store.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>Branch tracing has been enabled.
</p></dd>
<dt>&lsquo;<samp>E.errtext</samp>&rsquo;</dt>
<dd><p>A badly formed request or an error was encountered.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>Qbtrace:pt</samp>&rsquo;</dt>
<dd><p>Enable branch tracing for the current thread using Intel Processor Trace.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>Branch tracing has been enabled.
</p></dd>
<dt>&lsquo;<samp>E.errtext</samp>&rsquo;</dt>
<dd><p>A badly formed request or an error was encountered.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>Qbtrace:off</samp>&rsquo;</dt>
<dd><p>Disable branch tracing for the current thread.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>Branch tracing has been disabled.
</p></dd>
<dt>&lsquo;<samp>E.errtext</samp>&rsquo;</dt>
<dd><p>A badly formed request or an error was encountered.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>Qbtrace-conf:bts:size=<var>value</var></samp>&rsquo;</dt>
<dd><p>Set the requested ring buffer size for new threads that use the
btrace recording method in bts format.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The ring buffer size has been set.
</p></dd>
<dt>&lsquo;<samp>E.errtext</samp>&rsquo;</dt>
<dd><p>A badly formed request or an error was encountered.
</p></dd>
</dl>

</dd>
<dt>&lsquo;<samp>Qbtrace-conf:pt:size=<var>value</var></samp>&rsquo;</dt>
<dd><p>Set the requested ring buffer size for new threads that use the
btrace recording method in pt format.
</p>
<p>Reply:
</p><dl compact="compact">
<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
<dd><p>The ring buffer size has been set.
</p></dd>
<dt>&lsquo;<samp>E.errtext</samp>&rsquo;</dt>
<dd><p>A badly formed request or an error was encountered.
</p></dd>
</dl>

</dd>
</dl>

<div class="footnote">
<hr>
<h4 class="footnotes-heading">Footnotes</h4>

<h3><a name="FOOT20" href="#DOCF20">(20)</a></h3>
<p>The &lsquo;<samp>qP</samp>&rsquo; and &lsquo;<samp>qL</samp>&rsquo;
packets predate these conventions, and have arguments without any terminator
for the packet name; we suspect they are in widespread use in places that
are difficult to upgrade.  The &lsquo;<samp>qC</samp>&rsquo; packet has no arguments, but some
existing stubs (e.g. RedBoot) are known to not check for the end of the
packet.</p>
</div>
<hr>
<div class="header">
<p>
Next: <a href="Architecture_002dSpecific-Protocol-Details.html#Architecture_002dSpecific-Protocol-Details" accesskey="n" rel="next">Architecture-Specific Protocol Details</a>, Previous: <a href="Stop-Reply-Packets.html#Stop-Reply-Packets" accesskey="p" rel="prev">Stop Reply Packets</a>, Up: <a href="Remote-Protocol.html#Remote-Protocol" accesskey="u" rel="up">Remote Protocol</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
</div>


</body>
</html>