1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
2<html>
3<!-- Copyright (C) 1988-2021 Free Software Foundation, Inc.
4
5Permission is granted to copy, distribute and/or modify this document
6under the terms of the GNU Free Documentation License, Version 1.3 or
7any later version published by the Free Software Foundation; with the
8Invariant Sections being "Free Software" and "Free Software Needs
9Free Documentation", with the Front-Cover Texts being "A GNU Manual,"
10and with the Back-Cover Texts as in (a) below.
11
12(a) The FSF's Back-Cover Text is: "You are free to copy and modify
13this GNU Manual.  Buying copies from GNU Press supports the FSF in
14developing GNU and promoting software freedom." -->
15<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ -->
16<head>
17<title>Debugging with GDB: General Query Packets</title>
18
19<meta name="description" content="Debugging with GDB: General Query Packets">
20<meta name="keywords" content="Debugging with GDB: General Query Packets">
21<meta name="resource-type" content="document">
22<meta name="distribution" content="global">
23<meta name="Generator" content="makeinfo">
24<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
25<link href="index.html#Top" rel="start" title="Top">
26<link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
27<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
28<link href="Remote-Protocol.html#Remote-Protocol" rel="up" title="Remote Protocol">
29<link href="Architecture_002dSpecific-Protocol-Details.html#Architecture_002dSpecific-Protocol-Details" rel="next" title="Architecture-Specific Protocol Details">
30<link href="Stop-Reply-Packets.html#Stop-Reply-Packets" rel="previous" title="Stop Reply Packets">
31<style type="text/css">
32<!--
33a.summary-letter {text-decoration: none}
34blockquote.smallquotation {font-size: smaller}
35div.display {margin-left: 3.2em}
36div.example {margin-left: 3.2em}
37div.indentedblock {margin-left: 3.2em}
38div.lisp {margin-left: 3.2em}
39div.smalldisplay {margin-left: 3.2em}
40div.smallexample {margin-left: 3.2em}
41div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
42div.smalllisp {margin-left: 3.2em}
43kbd {font-style:oblique}
44pre.display {font-family: inherit}
45pre.format {font-family: inherit}
46pre.menu-comment {font-family: serif}
47pre.menu-preformatted {font-family: serif}
48pre.smalldisplay {font-family: inherit; font-size: smaller}
49pre.smallexample {font-size: smaller}
50pre.smallformat {font-family: inherit; font-size: smaller}
51pre.smalllisp {font-size: smaller}
52span.nocodebreak {white-space:nowrap}
53span.nolinebreak {white-space:nowrap}
54span.roman {font-family:serif; font-weight:normal}
55span.sansserif {font-family:sans-serif; font-weight:normal}
56ul.no-bullet {list-style: none}
57-->
58</style>
59
60
61</head>
62
63<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
64<a name="General-Query-Packets"></a>
65<div class="header">
66<p>
67Next: <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="previous">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>
68</div>
69<hr>
70<a name="General-Query-Packets-1"></a>
71<h3 class="section">E.4 General Query Packets</h3>
72<a name="index-remote-query-requests"></a>
73
74<p>Packets starting with &lsquo;<samp>q</samp>&rsquo; are <em>general query packets</em>;
75packets starting with &lsquo;<samp>Q</samp>&rsquo; are <em>general set packets</em>.  General
76query and set packets are a semi-unified form for retrieving and
77sending information to and from the stub.
78</p>
79<p>The initial letter of a query or set packet is followed by a name
80indicating what sort of thing the packet applies to.  For example,
81<small>GDB</small> may use a &lsquo;<samp>qSymbol</samp>&rsquo; packet to exchange symbol
82definitions with the stub.  These packet names follow some
83conventions:
84</p>
85<ul>
86<li> The name must not contain commas, colons or semicolons.
87</li><li> Most <small>GDB</small> query and set packets have a leading upper case
88letter.
89</li><li> The names of custom vendor packets should use a company prefix, in
90lower case, followed by a period.  For example, packets designed at
91the Acme Corporation might begin with &lsquo;<samp>qacme.foo</samp>&rsquo; (for querying
92foos) or &lsquo;<samp>Qacme.bar</samp>&rsquo; (for setting bars).
93</li></ul>
94
95<p>The name of a query or set packet should be separated from any
96parameters by a &lsquo;<samp>:</samp>&rsquo;; the parameters themselves should be
97separated by &lsquo;<samp>,</samp>&rsquo; or &lsquo;<samp>;</samp>&rsquo;.  Stubs must be careful to match the
98full packet name, and check for a separator or the end of the packet,
99in case two packet names share a common prefix.  New packets should not begin
100with &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>.
101</p>
102<p>Like the descriptions of the other packets, each description here
103has a template showing the packet&rsquo;s overall syntax, followed by an
104explanation of the packet&rsquo;s meaning.  We include spaces in some of the
105templates for clarity; these are not part of the packet&rsquo;s syntax.  No
106<small>GDB</small> packet uses spaces to separate its components.
107</p>
108<p>Here are the currently defined query and set packets:
109</p>
110<dl compact="compact">
111<dt>&lsquo;<samp>QAgent:1</samp>&rsquo;</dt>
112<dt>&lsquo;<samp>QAgent:0</samp>&rsquo;</dt>
113<dd><p>Turn on or off the agent as a helper to perform some debugging operations
114delegated from <small>GDB</small> (see <a href="In_002dprocess-Agent.html#Control-Agent">Control Agent</a>).
115</p>
116</dd>
117<dt>&lsquo;<samp>QAllow:<var>op</var>:<var>val</var>&hellip;</samp>&rsquo;</dt>
118<dd><a name="index-QAllow-packet"></a>
119<p>Specify which operations <small>GDB</small> expects to request of the
120target, as a semicolon-separated list of operation name and value
121pairs.  Possible values for <var>op</var> include &lsquo;<samp>WriteReg</samp>&rsquo;,
122&lsquo;<samp>WriteMem</samp>&rsquo;, &lsquo;<samp>InsertBreak</samp>&rsquo;, &lsquo;<samp>InsertTrace</samp>&rsquo;,
123&lsquo;<samp>InsertFastTrace</samp>&rsquo;, and &lsquo;<samp>Stop</samp>&rsquo;. <var>val</var> is either 0,
124indicating that <small>GDB</small> will not request the operation, or 1,
125indicating that it may.  (The target can then use this to set up its
126own internals optimally, for instance if the debugger never expects to
127insert breakpoints, it may not need to install its own trap handler.)
128</p>
129</dd>
130<dt>&lsquo;<samp>qC</samp>&rsquo;</dt>
131<dd><a name="index-current-thread_002c-remote-request"></a>
132<a name="index-qC-packet"></a>
133<p>Return the current thread ID.
134</p>
135<p>Reply:
136</p><dl compact="compact">
137<dt>&lsquo;<samp>QC <var>thread-id</var></samp>&rsquo;</dt>
138<dd><p>Where <var>thread-id</var> is a thread ID as documented in
139<a href="Packets.html#thread_002did-syntax">thread-id syntax</a>.
140</p></dd>
141<dt>&lsquo;<samp><span class="roman">(anything else)</span></samp>&rsquo;</dt>
142<dd><p>Any other reply implies the old thread ID.
143</p></dd>
144</dl>
145
146</dd>
147<dt>&lsquo;<samp>qCRC:<var>addr</var>,<var>length</var></samp>&rsquo;</dt>
148<dd><a name="index-CRC-of-memory-block_002c-remote-request"></a>
149<a name="index-qCRC-packet"></a>
150<a name="qCRC-packet"></a><p>Compute the CRC checksum of a block of memory using CRC-32 defined in
151IEEE 802.3.  The CRC is computed byte at a time, taking the most
152significant bit of each byte first.  The initial pattern code
153<code>0xffffffff</code> is used to ensure leading zeros affect the CRC.
154</p>
155<p><em>Note:</em> This is the same CRC used in validating separate debug
156files (see <a href="Separate-Debug-Files.html#Separate-Debug-Files">Debugging Information in Separate
157Files</a>).  However the algorithm is slightly different.  When validating
158separate debug files, the CRC is computed taking the <em>least</em>
159significant bit of each byte first, and the final result is inverted to
160detect trailing zeros.
161</p>
162<p>Reply:
163</p><dl compact="compact">
164<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
165<dd><p>An error (such as memory fault)
166</p></dd>
167<dt>&lsquo;<samp>C <var>crc32</var></samp>&rsquo;</dt>
168<dd><p>The specified memory region&rsquo;s checksum is <var>crc32</var>.
169</p></dd>
170</dl>
171
172</dd>
173<dt>&lsquo;<samp>QDisableRandomization:<var>value</var></samp>&rsquo;</dt>
174<dd><a name="index-disable-address-space-randomization_002c-remote-request"></a>
175<a name="index-QDisableRandomization-packet"></a>
176<p>Some target operating systems will randomize the virtual address space
177of the inferior process as a security feature, but provide a feature
178to disable such randomization, e.g. to allow for a more deterministic
179debugging experience.  On such systems, this packet with a <var>value</var>
180of 1 directs the target to disable address space randomization for
181processes subsequently started via &lsquo;<samp>vRun</samp>&rsquo; packets, while a packet
182with a <var>value</var> of 0 tells the target to enable address space
183randomization.
184</p>
185<p>This packet is only available in extended mode (see <a href="Packets.html#extended-mode">extended mode</a>).
186</p>
187<p>Reply:
188</p><dl compact="compact">
189<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
190<dd><p>The request succeeded.
191</p>
192</dd>
193<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
194<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
195</p>
196</dd>
197<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
198<dd><p>An empty reply indicates that &lsquo;<samp>QDisableRandomization</samp>&rsquo; is not supported
199by the stub.
200</p></dd>
201</dl>
202
203<p>This packet is not probed by default; the remote stub must request it,
204by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
205This should only be done on targets that actually support disabling
206address space randomization.
207</p>
208</dd>
209<dt>&lsquo;<samp>QStartupWithShell:<var>value</var></samp>&rsquo;</dt>
210<dd><a name="index-startup-with-shell_002c-remote-request"></a>
211<a name="index-QStartupWithShell-packet"></a>
212<p>On UNIX-like targets, it is possible to start the inferior using a
213shell program.  This is the default behavior on both <small>GDB</small> and
214<code>gdbserver</code> (see <a href="Starting.html#set-startup_002dwith_002dshell">set startup-with-shell</a>).  This packet is
215used to inform <code>gdbserver</code> whether it should start the
216inferior using a shell or not.
217</p>
218<p>If <var>value</var> is &lsquo;<samp>0</samp>&rsquo;, <code>gdbserver</code> will not use a shell
219to start the inferior.  If <var>value</var> is &lsquo;<samp>1</samp>&rsquo;,
220<code>gdbserver</code> will use a shell to start the inferior.  All other
221values are considered an error.
222</p>
223<p>This packet is only available in extended mode (see <a href="Packets.html#extended-mode">extended mode</a>).
224</p>
225<p>Reply:
226</p><dl compact="compact">
227<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
228<dd><p>The request succeeded.
229</p>
230</dd>
231<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
232<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
233</p></dd>
234</dl>
235
236<p>This packet is not probed by default; the remote stub must request it,
237by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
238(see <a href="#qSupported">qSupported</a>).  This should only be done on targets that
239actually support starting the inferior using a shell.
240</p>
241<p>Use of this packet is controlled by the <code>set startup-with-shell</code>
242command; see <a href="Starting.html#set-startup_002dwith_002dshell">set startup-with-shell</a>.
243</p>
244</dd>
245<dt>&lsquo;<samp>QEnvironmentHexEncoded:<var>hex-value</var></samp>&rsquo;</dt>
246<dd><a name="QEnvironmentHexEncoded"></a><a name="index-set-environment-variable_002c-remote-request"></a>
247<a name="index-QEnvironmentHexEncoded-packet"></a>
248<p>On UNIX-like targets, it is possible to set environment variables that
249will be passed to the inferior during the startup process.  This
250packet is used to inform <code>gdbserver</code> of an environment
251variable that has been defined by the user on <small>GDB</small> (see <a href="Environment.html#set-environment">set environment</a>).
252</p>
253<p>The packet is composed by <var>hex-value</var>, an hex encoded
254representation of the <var>name=value</var> format representing an
255environment variable.  The name of the environment variable is
256represented by <var>name</var>, and the value to be assigned to the
257environment variable is represented by <var>value</var>.  If the variable
258has no value (i.e., the value is <code>null</code>), then <var>value</var> will
259not be present.
260</p>
261<p>This packet is only available in extended mode (see <a href="Packets.html#extended-mode">extended mode</a>).
262</p>
263<p>Reply:
264</p><dl compact="compact">
265<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
266<dd><p>The request succeeded.
267</p></dd>
268</dl>
269
270<p>This packet is not probed by default; the remote stub must request it,
271by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
272(see <a href="#qSupported">qSupported</a>).  This should only be done on targets that
273actually support passing environment variables to the starting
274inferior.
275</p>
276<p>This packet is related to the <code>set environment</code> command;
277see <a href="Environment.html#set-environment">set environment</a>.
278</p>
279</dd>
280<dt>&lsquo;<samp>QEnvironmentUnset:<var>hex-value</var></samp>&rsquo;</dt>
281<dd><a name="QEnvironmentUnset"></a><a name="index-unset-environment-variable_002c-remote-request"></a>
282<a name="index-QEnvironmentUnset-packet"></a>
283<p>On UNIX-like targets, it is possible to unset environment variables
284before starting the inferior in the remote target.  This packet is
285used to inform <code>gdbserver</code> of an environment variable that has
286been unset by the user on <small>GDB</small> (see <a href="Environment.html#unset-environment">unset environment</a>).
287</p>
288<p>The packet is composed by <var>hex-value</var>, an hex encoded
289representation of the name of the environment variable to be unset.
290</p>
291<p>This packet is only available in extended mode (see <a href="Packets.html#extended-mode">extended mode</a>).
292</p>
293<p>Reply:
294</p><dl compact="compact">
295<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
296<dd><p>The request succeeded.
297</p></dd>
298</dl>
299
300<p>This packet is not probed by default; the remote stub must request it,
301by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
302(see <a href="#qSupported">qSupported</a>).  This should only be done on targets that
303actually support passing environment variables to the starting
304inferior.
305</p>
306<p>This packet is related to the <code>unset environment</code> command;
307see <a href="Environment.html#unset-environment">unset environment</a>.
308</p>
309</dd>
310<dt>&lsquo;<samp>QEnvironmentReset</samp>&rsquo;</dt>
311<dd><a name="QEnvironmentReset"></a><a name="index-reset-environment_002c-remote-request"></a>
312<a name="index-QEnvironmentReset-packet"></a>
313<p>On UNIX-like targets, this packet is used to reset the state of
314environment variables in the remote target before starting the
315inferior.  In this context, reset means unsetting all environment
316variables that were previously set by the user (i.e., were not
317initially present in the environment).  It is sent to
318<code>gdbserver</code> before the &lsquo;<samp>QEnvironmentHexEncoded</samp>&rsquo;
319(see <a href="#QEnvironmentHexEncoded">QEnvironmentHexEncoded</a>) and the &lsquo;<samp>QEnvironmentUnset</samp>&rsquo;
320(see <a href="#QEnvironmentUnset">QEnvironmentUnset</a>) packets.
321</p>
322<p>This packet is only available in extended mode (see <a href="Packets.html#extended-mode">extended mode</a>).
323</p>
324<p>Reply:
325</p><dl compact="compact">
326<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
327<dd><p>The request succeeded.
328</p></dd>
329</dl>
330
331<p>This packet is not probed by default; the remote stub must request it,
332by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
333(see <a href="#qSupported">qSupported</a>).  This should only be done on targets that
334actually support passing environment variables to the starting
335inferior.
336</p>
337</dd>
338<dt>&lsquo;<samp>QSetWorkingDir:<span class="roman">[</span><var>directory</var><span class="roman">]</span></samp>&rsquo;</dt>
339<dd><a name="QSetWorkingDir-packet"></a><a name="index-set-working-directory_002c-remote-request"></a>
340<a name="index-QSetWorkingDir-packet"></a>
341<p>This packet is used to inform the remote server of the intended
342current working directory for programs that are going to be executed.
343</p>
344<p>The packet is composed by <var>directory</var>, an hex encoded
345representation of the directory that the remote inferior will use as
346its current working directory.  If <var>directory</var> is an empty string,
347the remote server should reset the inferior&rsquo;s current working
348directory to its original, empty value.
349</p>
350<p>This packet is only available in extended mode (see <a href="Packets.html#extended-mode">extended mode</a>).
351</p>
352<p>Reply:
353</p><dl compact="compact">
354<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
355<dd><p>The request succeeded.
356</p></dd>
357</dl>
358
359</dd>
360<dt>&lsquo;<samp>qfThreadInfo</samp>&rsquo;</dt>
361<dt>&lsquo;<samp>qsThreadInfo</samp>&rsquo;</dt>
362<dd><a name="index-list-active-threads_002c-remote-request"></a>
363<a name="index-qfThreadInfo-packet"></a>
364<a name="index-qsThreadInfo-packet"></a>
365<p>Obtain a list of all active thread IDs from the target (OS).  Since there
366may be too many active threads to fit into one reply packet, this query
367works iteratively: it may require more than one query/reply sequence to
368obtain the entire list of threads.  The first query of the sequence will
369be the &lsquo;<samp>qfThreadInfo</samp>&rsquo; query; subsequent queries in the
370sequence will be the &lsquo;<samp>qsThreadInfo</samp>&rsquo; query.
371</p>
372<p>NOTE: This packet replaces the &lsquo;<samp>qL</samp>&rsquo; query (see below).
373</p>
374<p>Reply:
375</p><dl compact="compact">
376<dt>&lsquo;<samp>m <var>thread-id</var></samp>&rsquo;</dt>
377<dd><p>A single thread ID
378</p></dd>
379<dt>&lsquo;<samp>m <var>thread-id</var>,<var>thread-id</var>&hellip;</samp>&rsquo;</dt>
380<dd><p>a comma-separated list of thread IDs
381</p></dd>
382<dt>&lsquo;<samp>l</samp>&rsquo;</dt>
383<dd><p>(lower case letter &lsquo;<samp>L</samp>&rsquo;) denotes end of list.
384</p></dd>
385</dl>
386
387<p>In response to each query, the target will reply with a list of one or
388more thread IDs, separated by commas.
389<small>GDB</small> will respond to each reply with a request for more thread
390ids (using the &lsquo;<samp>qs</samp>&rsquo; form of the query), until the target responds
391with &lsquo;<samp>l</samp>&rsquo; (lower-case ell, for <em>last</em>).
392Refer to <a href="Packets.html#thread_002did-syntax">thread-id syntax</a>, for the format of the <var>thread-id</var>
393fields.
394</p>
395<p><em>Note: <small>GDB</small> will send the <code>qfThreadInfo</code> query during the
396initial connection with the remote target, and the very first thread ID
397mentioned in the reply will be stopped by <small>GDB</small> in a subsequent
398message.  Therefore, the stub should ensure that the first thread ID in
399the <code>qfThreadInfo</code> reply is suitable for being stopped by <small>GDB</small>.</em>
400</p>
401</dd>
402<dt>&lsquo;<samp>qGetTLSAddr:<var>thread-id</var>,<var>offset</var>,<var>lm</var></samp>&rsquo;</dt>
403<dd><a name="index-get-thread_002dlocal-storage-address_002c-remote-request"></a>
404<a name="index-qGetTLSAddr-packet"></a>
405<p>Fetch the address associated with thread local storage specified
406by <var>thread-id</var>, <var>offset</var>, and <var>lm</var>.
407</p>
408<p><var>thread-id</var> is the thread ID associated with the
409thread for which to fetch the TLS address.  See <a href="Packets.html#thread_002did-syntax">thread-id syntax</a>.
410</p>
411<p><var>offset</var> is the (big endian, hex encoded) offset associated with the
412thread local variable.  (This offset is obtained from the debug
413information associated with the variable.)
414</p>
415<p><var>lm</var> is the (big endian, hex encoded) OS/ABI-specific encoding of the
416load module associated with the thread local storage.  For example,
417a <small>GNU</small>/Linux system will pass the link map address of the shared
418object associated with the thread local storage under consideration.
419Other operating environments may choose to represent the load module
420differently, so the precise meaning of this parameter will vary.
421</p>
422<p>Reply:
423</p><dl compact="compact">
424<dt>&lsquo;<samp><var>XX</var>&hellip;</samp>&rsquo;</dt>
425<dd><p>Hex encoded (big endian) bytes representing the address of the thread
426local storage requested.
427</p>
428</dd>
429<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
430<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
431</p>
432</dd>
433<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
434<dd><p>An empty reply indicates that &lsquo;<samp>qGetTLSAddr</samp>&rsquo; is not supported by the stub.
435</p></dd>
436</dl>
437
438</dd>
439<dt>&lsquo;<samp>qGetTIBAddr:<var>thread-id</var></samp>&rsquo;</dt>
440<dd><a name="index-get-thread-information-block-address"></a>
441<a name="index-qGetTIBAddr-packet"></a>
442<p>Fetch address of the Windows OS specific Thread Information Block.
443</p>
444<p><var>thread-id</var> is the thread ID associated with the thread.
445</p>
446<p>Reply:
447</p><dl compact="compact">
448<dt>&lsquo;<samp><var>XX</var>&hellip;</samp>&rsquo;</dt>
449<dd><p>Hex encoded (big endian) bytes representing the linear address of the
450thread information block.
451</p>
452</dd>
453<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
454<dd><p>An error occured.  This means that either the thread was not found, or the
455address could not be retrieved.
456</p>
457</dd>
458<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
459<dd><p>An empty reply indicates that &lsquo;<samp>qGetTIBAddr</samp>&rsquo; is not supported by the stub.
460</p></dd>
461</dl>
462
463</dd>
464<dt>&lsquo;<samp>qL <var>startflag</var> <var>threadcount</var> <var>nextthread</var></samp>&rsquo;</dt>
465<dd><p>Obtain thread information from RTOS.  Where: <var>startflag</var> (one hex
466digit) is one to indicate the first query and zero to indicate a
467subsequent query; <var>threadcount</var> (two hex digits) is the maximum
468number of threads the response packet can contain; and <var>nextthread</var>
469(eight hex digits), for subsequent queries (<var>startflag</var> is zero), is
470returned in the response as <var>argthread</var>.
471</p>
472<p>Don&rsquo;t use this packet; use the &lsquo;<samp>qfThreadInfo</samp>&rsquo; query instead (see above).
473</p>
474<p>Reply:
475</p><dl compact="compact">
476<dt>&lsquo;<samp>qM <var>count</var> <var>done</var> <var>argthread</var> <var>thread</var>&hellip;</samp>&rsquo;</dt>
477<dd><p>Where: <var>count</var> (two hex digits) is the number of threads being
478returned; <var>done</var> (one hex digit) is zero to indicate more threads
479and one indicates no further threads; <var>argthreadid</var> (eight hex
480digits) is <var>nextthread</var> from the request packet; <var>thread</var>&hellip;
481is a sequence of thread IDs, <var>threadid</var> (eight hex
482digits), from the target.  See <code>remote.c:parse_threadlist_response()</code>.
483</p></dd>
484</dl>
485
486</dd>
487<dt>&lsquo;<samp>qOffsets</samp>&rsquo;</dt>
488<dd><a name="index-section-offsets_002c-remote-request"></a>
489<a name="index-qOffsets-packet"></a>
490<p>Get section offsets that the target used when relocating the downloaded
491image.
492</p>
493<p>Reply:
494</p><dl compact="compact">
495<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>
496<dd><p>Relocate the <code>Text</code> section by <var>xxx</var> from its original address.
497Relocate the <code>Data</code> section by <var>yyy</var> from its original address.
498If the object file format provides segment information (e.g. <small>ELF</small>
499&lsquo;<samp>PT_LOAD</samp>&rsquo; program headers), <small>GDB</small> will relocate entire
500segments by the supplied offsets.
501</p>
502<p><em>Note: while a <code>Bss</code> offset may be included in the response,
503<small>GDB</small> ignores this and instead applies the <code>Data</code> offset
504to the <code>Bss</code> section.</em>
505</p>
506</dd>
507<dt>&lsquo;<samp>TextSeg=<var>xxx</var><span class="roman">[</span>;DataSeg=<var>yyy</var><span class="roman">]</span></samp>&rsquo;</dt>
508<dd><p>Relocate the first segment of the object file, which conventionally
509contains program code, to a starting address of <var>xxx</var>.  If
510&lsquo;<samp>DataSeg</samp>&rsquo; is specified, relocate the second segment, which
511conventionally contains modifiable data, to a starting address of
512<var>yyy</var>.  <small>GDB</small> will report an error if the object file
513does not contain segment information, or does not contain at least
514as many segments as mentioned in the reply.  Extra segments are
515kept at fixed offsets relative to the last relocated segment.
516</p></dd>
517</dl>
518
519</dd>
520<dt>&lsquo;<samp>qP <var>mode</var> <var>thread-id</var></samp>&rsquo;</dt>
521<dd><a name="index-thread-information_002c-remote-request"></a>
522<a name="index-qP-packet"></a>
523<p>Returns information on <var>thread-id</var>.  Where: <var>mode</var> is a hex
524encoded 32 bit mode; <var>thread-id</var> is a thread ID
525(see <a href="Packets.html#thread_002did-syntax">thread-id syntax</a>).
526</p>
527<p>Don&rsquo;t use this packet; use the &lsquo;<samp>qThreadExtraInfo</samp>&rsquo; query instead
528(see below).
529</p>
530<p>Reply: see <code>remote.c:remote_unpack_thread_info_response()</code>.
531</p>
532</dd>
533<dt>&lsquo;<samp>QNonStop:1</samp>&rsquo;</dt>
534<dt>&lsquo;<samp>QNonStop:0</samp>&rsquo;</dt>
535<dd><a name="index-non_002dstop-mode_002c-remote-request"></a>
536<a name="index-QNonStop-packet"></a>
537<a name="QNonStop"></a><p>Enter non-stop (&lsquo;<samp>QNonStop:1</samp>&rsquo;) or all-stop (&lsquo;<samp>QNonStop:0</samp>&rsquo;) mode.
538See <a href="Remote-Non_002dStop.html#Remote-Non_002dStop">Remote Non-Stop</a>, for more information.
539</p>
540<p>Reply:
541</p><dl compact="compact">
542<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
543<dd><p>The request succeeded.
544</p>
545</dd>
546<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
547<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
548</p>
549</dd>
550<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
551<dd><p>An empty reply indicates that &lsquo;<samp>QNonStop</samp>&rsquo; is not supported by
552the stub.
553</p></dd>
554</dl>
555
556<p>This packet is not probed by default; the remote stub must request it,
557by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
558Use of this packet is controlled by the <code>set non-stop</code> command;
559see <a href="Non_002dStop-Mode.html#Non_002dStop-Mode">Non-Stop Mode</a>.
560</p>
561</dd>
562<dt>&lsquo;<samp>QCatchSyscalls:1 <span class="roman">[</span>;<var>sysno</var><span class="roman">]</span>&hellip;</samp>&rsquo;</dt>
563<dt>&lsquo;<samp>QCatchSyscalls:0</samp>&rsquo;</dt>
564<dd><a name="index-catch-syscalls-from-inferior_002c-remote-request"></a>
565<a name="index-QCatchSyscalls-packet"></a>
566<a name="QCatchSyscalls"></a><p>Enable (&lsquo;<samp>QCatchSyscalls:1</samp>&rsquo;) or disable (&lsquo;<samp>QCatchSyscalls:0</samp>&rsquo;)
567catching syscalls from the inferior process.
568</p>
569<p>For &lsquo;<samp>QCatchSyscalls:1</samp>&rsquo;, each listed syscall <var>sysno</var> (encoded
570in hex) should be reported to <small>GDB</small>.  If no syscall <var>sysno</var>
571is listed, every system call should be reported.
572</p>
573<p>Note that if a syscall not in the list is reported, <small>GDB</small> will
574still filter the event according to its own list from all corresponding
575<code>catch syscall</code> commands.  However, it is more efficient to only
576report the requested syscalls.
577</p>
578<p>Multiple &lsquo;<samp>QCatchSyscalls:1</samp>&rsquo; packets do not combine; any earlier
579&lsquo;<samp>QCatchSyscalls:1</samp>&rsquo; list is completely replaced by the new list.
580</p>
581<p>If the inferior process execs, the state of &lsquo;<samp>QCatchSyscalls</samp>&rsquo; is
582kept for the new process too.  On targets where exec may affect syscall
583numbers, for example with exec between 32 and 64-bit processes, the
584client should send a new packet with the new syscall list.
585</p>
586<p>Reply:
587</p><dl compact="compact">
588<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
589<dd><p>The request succeeded.
590</p>
591</dd>
592<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
593<dd><p>An error occurred.  <var>nn</var> are hex digits.
594</p>
595</dd>
596<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
597<dd><p>An empty reply indicates that &lsquo;<samp>QCatchSyscalls</samp>&rsquo; is not supported by
598the stub.
599</p></dd>
600</dl>
601
602<p>Use of this packet is controlled by the <code>set remote catch-syscalls</code>
603command (see <a href="Remote-Configuration.html#Remote-Configuration">set remote catch-syscalls</a>).
604This packet is not probed by default; the remote stub must request it,
605by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
606</p>
607</dd>
608<dt>&lsquo;<samp>QPassSignals: <var>signal</var> <span class="roman">[</span>;<var>signal</var><span class="roman">]</span>&hellip;</samp>&rsquo;</dt>
609<dd><a name="index-pass-signals-to-inferior_002c-remote-request"></a>
610<a name="index-QPassSignals-packet"></a>
611<a name="QPassSignals"></a><p>Each listed <var>signal</var> should be passed directly to the inferior process.
612Signals are numbered identically to continue packets and stop replies
613(see <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>).  Each <var>signal</var> list item should be
614strictly greater than the previous item.  These signals do not need to stop
615the inferior, or be reported to <small>GDB</small>.  All other signals should be
616reported to <small>GDB</small>.  Multiple &lsquo;<samp>QPassSignals</samp>&rsquo; packets do not
617combine; any earlier &lsquo;<samp>QPassSignals</samp>&rsquo; list is completely replaced by the
618new list.  This packet improves performance when using &lsquo;<samp>handle
619<var>signal</var> nostop noprint pass</samp>&rsquo;.
620</p>
621<p>Reply:
622</p><dl compact="compact">
623<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
624<dd><p>The request succeeded.
625</p>
626</dd>
627<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
628<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
629</p>
630</dd>
631<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
632<dd><p>An empty reply indicates that &lsquo;<samp>QPassSignals</samp>&rsquo; is not supported by
633the stub.
634</p></dd>
635</dl>
636
637<p>Use of this packet is controlled by the <code>set remote pass-signals</code>
638command (see <a href="Remote-Configuration.html#Remote-Configuration">set remote pass-signals</a>).
639This packet is not probed by default; the remote stub must request it,
640by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
641</p>
642</dd>
643<dt>&lsquo;<samp>QProgramSignals: <var>signal</var> <span class="roman">[</span>;<var>signal</var><span class="roman">]</span>&hellip;</samp>&rsquo;</dt>
644<dd><a name="index-signals-the-inferior-may-see_002c-remote-request"></a>
645<a name="index-QProgramSignals-packet"></a>
646<a name="QProgramSignals"></a><p>Each listed <var>signal</var> may be delivered to the inferior process.
647Others should be silently discarded.
648</p>
649<p>In some cases, the remote stub may need to decide whether to deliver a
650signal to the program or not without <small>GDB</small> involvement.  One
651example of that is while detaching &mdash; the program&rsquo;s threads may have
652stopped for signals that haven&rsquo;t yet had a chance of being reported to
653<small>GDB</small>, and so the remote stub can use the signal list specified
654by this packet to know whether to deliver or ignore those pending
655signals.
656</p>
657<p>This does not influence whether to deliver a signal as requested by a
658resumption packet (see <a href="Packets.html#vCont-packet">vCont packet</a>).
659</p>
660<p>Signals are numbered identically to continue packets and stop replies
661(see <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>).  Each <var>signal</var> list item should be
662strictly greater than the previous item.  Multiple
663&lsquo;<samp>QProgramSignals</samp>&rsquo; packets do not combine; any earlier
664&lsquo;<samp>QProgramSignals</samp>&rsquo; list is completely replaced by the new list.
665</p>
666<p>Reply:
667</p><dl compact="compact">
668<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
669<dd><p>The request succeeded.
670</p>
671</dd>
672<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
673<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
674</p>
675</dd>
676<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
677<dd><p>An empty reply indicates that &lsquo;<samp>QProgramSignals</samp>&rsquo; is not supported
678by the stub.
679</p></dd>
680</dl>
681
682<p>Use of this packet is controlled by the <code>set remote program-signals</code>
683command (see <a href="Remote-Configuration.html#Remote-Configuration">set remote program-signals</a>).
684This packet is not probed by default; the remote stub must request it,
685by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
686</p>
687<a name="QThreadEvents"></a></dd>
688<dt>&lsquo;<samp>QThreadEvents:1</samp>&rsquo;</dt>
689<dt>&lsquo;<samp>QThreadEvents:0</samp>&rsquo;</dt>
690<dd><a name="index-thread-create_002fexit-events_002c-remote-request"></a>
691<a name="index-QThreadEvents-packet"></a>
692
693<p>Enable (&lsquo;<samp>QThreadEvents:1</samp>&rsquo;) or disable (&lsquo;<samp>QThreadEvents:0</samp>&rsquo;)
694reporting 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
695non-stop mode when <small>GDB</small> stops a set of threads and
696synchronously waits for the their corresponding stop replies.  Without
697exit events, if one of the threads exits, <small>GDB</small> would hang
698forever not knowing that it should no longer expect a stop for that
699same thread.  <small>GDB</small> does not enable this feature unless the
700stub reports that it supports it by including &lsquo;<samp>QThreadEvents+</samp>&rsquo; in
701its &lsquo;<samp>qSupported</samp>&rsquo; reply.
702</p>
703<p>Reply:
704</p><dl compact="compact">
705<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
706<dd><p>The request succeeded.
707</p>
708</dd>
709<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
710<dd><p>An error occurred.  The error number <var>nn</var> is given as hex digits.
711</p>
712</dd>
713<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
714<dd><p>An empty reply indicates that &lsquo;<samp>QThreadEvents</samp>&rsquo; is not supported by
715the stub.
716</p></dd>
717</dl>
718
719<p>Use of this packet is controlled by the <code>set remote thread-events</code>
720command (see <a href="Remote-Configuration.html#Remote-Configuration">set remote thread-events</a>).
721</p>
722</dd>
723<dt>&lsquo;<samp>qRcmd,<var>command</var></samp>&rsquo;</dt>
724<dd><a name="index-execute-remote-command_002c-remote-request"></a>
725<a name="index-qRcmd-packet"></a>
726<p><var>command</var> (hex encoded) is passed to the local interpreter for
727execution.  Invalid commands should be reported using the output
728string.  Before the final result packet, the target may also respond
729with a number of intermediate &lsquo;<samp>O<var>output</var></samp>&rsquo; console output
730packets.  <em>Implementors should note that providing access to a
731stubs&rsquo;s interpreter may have security implications</em>.
732</p>
733<p>Reply:
734</p><dl compact="compact">
735<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
736<dd><p>A command response with no output.
737</p></dd>
738<dt>&lsquo;<samp><var>OUTPUT</var></samp>&rsquo;</dt>
739<dd><p>A command response with the hex encoded output string <var>OUTPUT</var>.
740</p></dd>
741<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
742<dd><p>Indicate a badly formed request.
743</p></dd>
744<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
745<dd><p>An empty reply indicates that &lsquo;<samp>qRcmd</samp>&rsquo; is not recognized.
746</p></dd>
747</dl>
748
749<p>(Note that the <code>qRcmd</code> packet&rsquo;s name is separated from the
750command by a &lsquo;<samp>,</samp>&rsquo;, not a &lsquo;<samp>:</samp>&rsquo;, contrary to the naming
751conventions above.  Please don&rsquo;t use this packet as a model for new
752packets.)
753</p>
754</dd>
755<dt>&lsquo;<samp>qSearch:memory:<var>address</var>;<var>length</var>;<var>search-pattern</var></samp>&rsquo;</dt>
756<dd><a name="index-searching-memory_002c-in-remote-debugging"></a>
757<a name="index-qSearch_003amemory-packet"></a>
758<a name="index-qSearch-memory-packet"></a>
759<a name="qSearch-memory"></a><p>Search <var>length</var> bytes at <var>address</var> for <var>search-pattern</var>.
760Both <var>address</var> and <var>length</var> are encoded in hex;
761<var>search-pattern</var> is a sequence of bytes, also hex encoded.
762</p>
763<p>Reply:
764</p><dl compact="compact">
765<dt>&lsquo;<samp>0</samp>&rsquo;</dt>
766<dd><p>The pattern was not found.
767</p></dd>
768<dt>&lsquo;<samp>1,address</samp>&rsquo;</dt>
769<dd><p>The pattern was found at <var>address</var>.
770</p></dd>
771<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
772<dd><p>A badly formed request or an error was encountered while searching memory.
773</p></dd>
774<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
775<dd><p>An empty reply indicates that &lsquo;<samp>qSearch:memory</samp>&rsquo; is not recognized.
776</p></dd>
777</dl>
778
779</dd>
780<dt>&lsquo;<samp>QStartNoAckMode</samp>&rsquo;</dt>
781<dd><a name="index-QStartNoAckMode-packet"></a>
782<a name="QStartNoAckMode"></a><p>Request that the remote stub disable the normal &lsquo;<samp>+</samp>&rsquo;/&lsquo;<samp>-</samp>&rsquo;
783protocol acknowledgments (see <a href="Packet-Acknowledgment.html#Packet-Acknowledgment">Packet Acknowledgment</a>).
784</p>
785<p>Reply:
786</p><dl compact="compact">
787<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
788<dd><p>The stub has switched to no-acknowledgment mode.
789<small>GDB</small> acknowledges this response,
790but neither the stub nor <small>GDB</small> shall send or expect further
791&lsquo;<samp>+</samp>&rsquo;/&lsquo;<samp>-</samp>&rsquo; acknowledgments in the current connection.
792</p></dd>
793<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
794<dd><p>An empty reply indicates that the stub does not support no-acknowledgment mode.
795</p></dd>
796</dl>
797
798</dd>
799<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>
800<dd><a name="index-supported-packets_002c-remote-query"></a>
801<a name="index-features-of-the-remote-protocol"></a>
802<a name="index-qSupported-packet"></a>
803<a name="qSupported"></a><p>Tell the remote stub about features supported by <small>GDB</small>, and
804query the stub for features it supports.  This packet allows
805<small>GDB</small> and the remote stub to take advantage of each others&rsquo;
806features.  &lsquo;<samp>qSupported</samp>&rsquo; also consolidates multiple feature probes
807at startup, to improve <small>GDB</small> performance&mdash;a single larger
808packet performs better than multiple smaller probe packets on
809high-latency links.  Some features may enable behavior which must not
810be on by default, e.g. because it would confuse older clients or
811stubs.  Other features may describe packets which could be
812automatically probed for, but are not.  These features must be
813reported before <small>GDB</small> will use them.  This &ldquo;default
814unsupported&rdquo; behavior is not appropriate for all packets, but it
815helps to keep the initial connection time under control with new
816versions of <small>GDB</small> which support increasing numbers of packets.
817</p>
818<p>Reply:
819</p><dl compact="compact">
820<dt>&lsquo;<samp><var>stubfeature</var> <span class="roman">[</span>;<var>stubfeature</var><span class="roman">]</span>&hellip;</samp>&rsquo;</dt>
821<dd><p>The stub supports or does not support each returned <var>stubfeature</var>,
822depending on the form of each <var>stubfeature</var> (see below for the
823possible forms).
824</p></dd>
825<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
826<dd><p>An empty reply indicates that &lsquo;<samp>qSupported</samp>&rsquo; is not recognized,
827or that no features needed to be reported to <small>GDB</small>.
828</p></dd>
829</dl>
830
831<p>The allowed forms for each feature (either a <var>gdbfeature</var> in the
832&lsquo;<samp>qSupported</samp>&rsquo; packet, or a <var>stubfeature</var> in the response)
833are:
834</p>
835<dl compact="compact">
836<dt>&lsquo;<samp><var>name</var>=<var>value</var></samp>&rsquo;</dt>
837<dd><p>The remote protocol feature <var>name</var> is supported, and associated
838with the specified <var>value</var>.  The format of <var>value</var> depends
839on the feature, but it must not include a semicolon.
840</p></dd>
841<dt>&lsquo;<samp><var>name</var>+</samp>&rsquo;</dt>
842<dd><p>The remote protocol feature <var>name</var> is supported, and does not
843need an associated value.
844</p></dd>
845<dt>&lsquo;<samp><var>name</var>-</samp>&rsquo;</dt>
846<dd><p>The remote protocol feature <var>name</var> is not supported.
847</p></dd>
848<dt>&lsquo;<samp><var>name</var>?</samp>&rsquo;</dt>
849<dd><p>The remote protocol feature <var>name</var> may be supported, and
850<small>GDB</small> should auto-detect support in some other way when it is
851needed.  This form will not be used for <var>gdbfeature</var> notifications,
852but may be used for <var>stubfeature</var> responses.
853</p></dd>
854</dl>
855
856<p>Whenever the stub receives a &lsquo;<samp>qSupported</samp>&rsquo; request, the
857supplied set of <small>GDB</small> features should override any previous
858request.  This allows <small>GDB</small> to put the stub in a known
859state, even if the stub had previously been communicating with
860a different version of <small>GDB</small>.
861</p>
862<p>The following values of <var>gdbfeature</var> (for the packet sent by <small>GDB</small>)
863are defined:
864</p>
865<dl compact="compact">
866<dt>&lsquo;<samp>multiprocess</samp>&rsquo;</dt>
867<dd><p>This feature indicates whether <small>GDB</small> supports multiprocess
868extensions to the remote protocol.  <small>GDB</small> does not use such
869extensions unless the stub also reports that it supports them by
870including &lsquo;<samp>multiprocess+</samp>&rsquo; in its &lsquo;<samp>qSupported</samp>&rsquo; reply.
871See <a href="#multiprocess-extensions">multiprocess extensions</a>, for details.
872</p>
873</dd>
874<dt>&lsquo;<samp>xmlRegisters</samp>&rsquo;</dt>
875<dd><p>This feature indicates that <small>GDB</small> supports the XML target
876description.  If the stub sees &lsquo;<samp>xmlRegisters=</samp>&rsquo; with target
877specific strings separated by a comma, it will report register
878description.
879</p>
880</dd>
881<dt>&lsquo;<samp>qRelocInsn</samp>&rsquo;</dt>
882<dd><p>This feature indicates whether <small>GDB</small> supports the
883&lsquo;<samp>qRelocInsn</samp>&rsquo; packet (see <a href="Tracepoint-Packets.html#Tracepoint-Packets">Relocate
884instruction reply packet</a>).
885</p>
886</dd>
887<dt>&lsquo;<samp>swbreak</samp>&rsquo;</dt>
888<dd><p>This feature indicates whether <small>GDB</small> supports the swbreak stop
889reason in stop replies.  See <a href="Stop-Reply-Packets.html#swbreak-stop-reason">swbreak stop reason</a>, for details.
890</p>
891</dd>
892<dt>&lsquo;<samp>hwbreak</samp>&rsquo;</dt>
893<dd><p>This feature indicates whether <small>GDB</small> supports the hwbreak stop
894reason in stop replies.  See <a href="Stop-Reply-Packets.html#swbreak-stop-reason">swbreak stop reason</a>, for details.
895</p>
896</dd>
897<dt>&lsquo;<samp>fork-events</samp>&rsquo;</dt>
898<dd><p>This feature indicates whether <small>GDB</small> supports fork event
899extensions to the remote protocol.  <small>GDB</small> does not use such
900extensions unless the stub also reports that it supports them by
901including &lsquo;<samp>fork-events+</samp>&rsquo; in its &lsquo;<samp>qSupported</samp>&rsquo; reply.
902</p>
903</dd>
904<dt>&lsquo;<samp>vfork-events</samp>&rsquo;</dt>
905<dd><p>This feature indicates whether <small>GDB</small> supports vfork event
906extensions to the remote protocol.  <small>GDB</small> does not use such
907extensions unless the stub also reports that it supports them by
908including &lsquo;<samp>vfork-events+</samp>&rsquo; in its &lsquo;<samp>qSupported</samp>&rsquo; reply.
909</p>
910</dd>
911<dt>&lsquo;<samp>exec-events</samp>&rsquo;</dt>
912<dd><p>This feature indicates whether <small>GDB</small> supports exec event
913extensions to the remote protocol.  <small>GDB</small> does not use such
914extensions unless the stub also reports that it supports them by
915including &lsquo;<samp>exec-events+</samp>&rsquo; in its &lsquo;<samp>qSupported</samp>&rsquo; reply.
916</p>
917</dd>
918<dt>&lsquo;<samp>vContSupported</samp>&rsquo;</dt>
919<dd><p>This feature indicates whether <small>GDB</small> wants to know the
920supported actions in the reply to &lsquo;<samp>vCont?</samp>&rsquo; packet.
921</p></dd>
922</dl>
923
924<p>Stubs should ignore any unknown values for
925<var>gdbfeature</var>.  Any <small>GDB</small> which sends a &lsquo;<samp>qSupported</samp>&rsquo;
926packet supports receiving packets of unlimited length (earlier
927versions of <small>GDB</small> may reject overly long responses).  Additional values
928for <var>gdbfeature</var> may be defined in the future to let the stub take
929advantage of new features in <small>GDB</small>, e.g. incompatible
930improvements in the remote protocol&mdash;the &lsquo;<samp>multiprocess</samp>&rsquo; feature is
931an example of such a feature.  The stub&rsquo;s reply should be independent
932of the <var>gdbfeature</var> entries sent by <small>GDB</small>; first <small>GDB</small>
933describes all the features it supports, and then the stub replies with
934all the features it supports.
935</p>
936<p>Similarly, <small>GDB</small> will silently ignore unrecognized stub feature
937responses, as long as each response uses one of the standard forms.
938</p>
939<p>Some features are flags.  A stub which supports a flag feature
940should respond with a &lsquo;<samp>+</samp>&rsquo; form response.  Other features
941require values, and the stub should respond with an &lsquo;<samp>=</samp>&rsquo;
942form response.
943</p>
944<p>Each feature has a default value, which <small>GDB</small> will use if
945&lsquo;<samp>qSupported</samp>&rsquo; is not available or if the feature is not mentioned
946in the &lsquo;<samp>qSupported</samp>&rsquo; response.  The default values are fixed; a
947stub is free to omit any feature responses that match the defaults.
948</p>
949<p>Not all features can be probed, but for those which can, the probing
950mechanism is useful: in some cases, a stub&rsquo;s internal
951architecture may not allow the protocol layer to know some information
952about the underlying target in advance.  This is especially common in
953stubs which may be configured for multiple targets.
954</p>
955<p>These are the currently defined stub features and their properties:
956</p>
957<table>
958<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>
959<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>
960<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>
961<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>
962<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>
963<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>
964<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>
965<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>
966<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>
967<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>
968<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>
969<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>
970<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>
971<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>
972<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>
973<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>
974<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>
975<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>
976<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>
977<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>
978<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>
979<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>
980<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>
981<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>
982<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>
983<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>
984<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>
985<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>
986<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>
987<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>
988<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>
989<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>
990<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>
991<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>
992<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>
993<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>
994<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>
995<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>
996<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>
997<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>
998<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>
999<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>
1000<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>
1001<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>
1002<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>
1003<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>
1004<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>
1005</table>
1006
1007<p>These are the currently defined stub features, in more detail:
1008</p>
1009<dl compact="compact">
1010<dd><a name="index-packet-size_002c-remote-protocol"></a>
1011</dd>
1012<dt>&lsquo;<samp>PacketSize=<var>bytes</var></samp>&rsquo;</dt>
1013<dd><p>The remote stub can accept packets up to at least <var>bytes</var> in
1014length.  <small>GDB</small> will send packets up to this size for bulk
1015transfers, and will never send larger packets.  This is a limit on the
1016data characters in the packet, including the frame and checksum.
1017There is no trailing NUL byte in a remote protocol packet; if the stub
1018stores packets in a NUL-terminated format, it should allow an extra
1019byte in its buffer for the NUL.  If this stub feature is not supported,
1020<small>GDB</small> guesses based on the size of the &lsquo;<samp>g</samp>&rsquo; packet response.
1021</p>
1022</dd>
1023<dt>&lsquo;<samp>qXfer:auxv:read</samp>&rsquo;</dt>
1024<dd><p>The remote stub understands the &lsquo;<samp>qXfer:auxv:read</samp>&rsquo; packet
1025(see <a href="#qXfer-auxiliary-vector-read">qXfer auxiliary vector read</a>).
1026</p>
1027</dd>
1028<dt>&lsquo;<samp>qXfer:btrace:read</samp>&rsquo;</dt>
1029<dd><p>The remote stub understands the &lsquo;<samp>qXfer:btrace:read</samp>&rsquo;
1030packet (see <a href="#qXfer-btrace-read">qXfer btrace read</a>).
1031</p>
1032</dd>
1033<dt>&lsquo;<samp>qXfer:btrace-conf:read</samp>&rsquo;</dt>
1034<dd><p>The remote stub understands the &lsquo;<samp>qXfer:btrace-conf:read</samp>&rsquo;
1035packet (see <a href="#qXfer-btrace_002dconf-read">qXfer btrace-conf read</a>).
1036</p>
1037</dd>
1038<dt>&lsquo;<samp>qXfer:exec-file:read</samp>&rsquo;</dt>
1039<dd><p>The remote stub understands the &lsquo;<samp>qXfer:exec-file:read</samp>&rsquo; packet
1040(see <a href="#qXfer-executable-filename-read">qXfer executable filename read</a>).
1041</p>
1042</dd>
1043<dt>&lsquo;<samp>qXfer:features:read</samp>&rsquo;</dt>
1044<dd><p>The remote stub understands the &lsquo;<samp>qXfer:features:read</samp>&rsquo; packet
1045(see <a href="#qXfer-target-description-read">qXfer target description read</a>).
1046</p>
1047</dd>
1048<dt>&lsquo;<samp>qXfer:libraries:read</samp>&rsquo;</dt>
1049<dd><p>The remote stub understands the &lsquo;<samp>qXfer:libraries:read</samp>&rsquo; packet
1050(see <a href="#qXfer-library-list-read">qXfer library list read</a>).
1051</p>
1052</dd>
1053<dt>&lsquo;<samp>qXfer:libraries-svr4:read</samp>&rsquo;</dt>
1054<dd><p>The remote stub understands the &lsquo;<samp>qXfer:libraries-svr4:read</samp>&rsquo; packet
1055(see <a href="#qXfer-svr4-library-list-read">qXfer svr4 library list read</a>).
1056</p>
1057</dd>
1058<dt>&lsquo;<samp>augmented-libraries-svr4-read</samp>&rsquo;</dt>
1059<dd><p>The remote stub understands the augmented form of the
1060&lsquo;<samp>qXfer:libraries-svr4:read</samp>&rsquo; packet
1061(see <a href="#qXfer-svr4-library-list-read">qXfer svr4 library list read</a>).
1062</p>
1063</dd>
1064<dt>&lsquo;<samp>qXfer:memory-map:read</samp>&rsquo;</dt>
1065<dd><p>The remote stub understands the &lsquo;<samp>qXfer:memory-map:read</samp>&rsquo; packet
1066(see <a href="#qXfer-memory-map-read">qXfer memory map read</a>).
1067</p>
1068</dd>
1069<dt>&lsquo;<samp>qXfer:sdata:read</samp>&rsquo;</dt>
1070<dd><p>The remote stub understands the &lsquo;<samp>qXfer:sdata:read</samp>&rsquo; packet
1071(see <a href="#qXfer-sdata-read">qXfer sdata read</a>).
1072</p>
1073</dd>
1074<dt>&lsquo;<samp>qXfer:siginfo:read</samp>&rsquo;</dt>
1075<dd><p>The remote stub understands the &lsquo;<samp>qXfer:siginfo:read</samp>&rsquo; packet
1076(see <a href="#qXfer-siginfo-read">qXfer siginfo read</a>).
1077</p>
1078</dd>
1079<dt>&lsquo;<samp>qXfer:siginfo:write</samp>&rsquo;</dt>
1080<dd><p>The remote stub understands the &lsquo;<samp>qXfer:siginfo:write</samp>&rsquo; packet
1081(see <a href="#qXfer-siginfo-write">qXfer siginfo write</a>).
1082</p>
1083</dd>
1084<dt>&lsquo;<samp>qXfer:threads:read</samp>&rsquo;</dt>
1085<dd><p>The remote stub understands the &lsquo;<samp>qXfer:threads:read</samp>&rsquo; packet
1086(see <a href="#qXfer-threads-read">qXfer threads read</a>).
1087</p>
1088</dd>
1089<dt>&lsquo;<samp>qXfer:traceframe-info:read</samp>&rsquo;</dt>
1090<dd><p>The remote stub understands the &lsquo;<samp>qXfer:traceframe-info:read</samp>&rsquo;
1091packet (see <a href="#qXfer-traceframe-info-read">qXfer traceframe info read</a>).
1092</p>
1093</dd>
1094<dt>&lsquo;<samp>qXfer:uib:read</samp>&rsquo;</dt>
1095<dd><p>The remote stub understands the &lsquo;<samp>qXfer:uib:read</samp>&rsquo;
1096packet (see <a href="#qXfer-unwind-info-block">qXfer unwind info block</a>).
1097</p>
1098</dd>
1099<dt>&lsquo;<samp>qXfer:fdpic:read</samp>&rsquo;</dt>
1100<dd><p>The remote stub understands the &lsquo;<samp>qXfer:fdpic:read</samp>&rsquo;
1101packet (see <a href="#qXfer-fdpic-loadmap-read">qXfer fdpic loadmap read</a>).
1102</p>
1103</dd>
1104<dt>&lsquo;<samp>QNonStop</samp>&rsquo;</dt>
1105<dd><p>The remote stub understands the &lsquo;<samp>QNonStop</samp>&rsquo; packet
1106(see <a href="#QNonStop">QNonStop</a>).
1107</p>
1108</dd>
1109<dt>&lsquo;<samp>QCatchSyscalls</samp>&rsquo;</dt>
1110<dd><p>The remote stub understands the &lsquo;<samp>QCatchSyscalls</samp>&rsquo; packet
1111(see <a href="#QCatchSyscalls">QCatchSyscalls</a>).
1112</p>
1113</dd>
1114<dt>&lsquo;<samp>QPassSignals</samp>&rsquo;</dt>
1115<dd><p>The remote stub understands the &lsquo;<samp>QPassSignals</samp>&rsquo; packet
1116(see <a href="#QPassSignals">QPassSignals</a>).
1117</p>
1118</dd>
1119<dt>&lsquo;<samp>QStartNoAckMode</samp>&rsquo;</dt>
1120<dd><p>The remote stub understands the &lsquo;<samp>QStartNoAckMode</samp>&rsquo; packet and
1121prefers to operate in no-acknowledgment mode.  See <a href="Packet-Acknowledgment.html#Packet-Acknowledgment">Packet Acknowledgment</a>.
1122</p>
1123</dd>
1124<dt>&lsquo;<samp>multiprocess</samp>&rsquo;</dt>
1125<dd><a name="multiprocess-extensions"></a><a name="index-multiprocess-extensions_002c-in-remote-protocol"></a>
1126<p>The remote stub understands the multiprocess extensions to the remote
1127protocol syntax.  The multiprocess extensions affect the syntax of
1128thread IDs in both packets and replies (see <a href="Packets.html#thread_002did-syntax">thread-id syntax</a>), and
1129add process IDs to the &lsquo;<samp>D</samp>&rsquo; packet and &lsquo;<samp>W</samp>&rsquo; and &lsquo;<samp>X</samp>&rsquo;
1130replies.  Note that reporting this feature indicates support for the
1131syntactic extensions only, not that the stub necessarily supports
1132debugging of more than one process at a time.  The stub must not use
1133multiprocess extensions in packet replies unless <small>GDB</small> has also
1134indicated it supports them in its &lsquo;<samp>qSupported</samp>&rsquo; request.
1135</p>
1136</dd>
1137<dt>&lsquo;<samp>qXfer:osdata:read</samp>&rsquo;</dt>
1138<dd><p>The remote stub understands the &lsquo;<samp>qXfer:osdata:read</samp>&rsquo; packet
1139((see <a href="#qXfer-osdata-read">qXfer osdata read</a>).
1140</p>
1141</dd>
1142<dt>&lsquo;<samp>ConditionalBreakpoints</samp>&rsquo;</dt>
1143<dd><p>The target accepts and implements evaluation of conditional expressions
1144defined for breakpoints.  The target will only report breakpoint triggers
1145when such conditions are true (see <a href="Conditions.html#Conditions">Break Conditions</a>).
1146</p>
1147</dd>
1148<dt>&lsquo;<samp>ConditionalTracepoints</samp>&rsquo;</dt>
1149<dd><p>The remote stub accepts and implements conditional expressions defined
1150for tracepoints (see <a href="Tracepoint-Conditions.html#Tracepoint-Conditions">Tracepoint Conditions</a>).
1151</p>
1152</dd>
1153<dt>&lsquo;<samp>ReverseContinue</samp>&rsquo;</dt>
1154<dd><p>The remote stub accepts and implements the reverse continue packet
1155(see <a href="Packets.html#bc">bc</a>).
1156</p>
1157</dd>
1158<dt>&lsquo;<samp>ReverseStep</samp>&rsquo;</dt>
1159<dd><p>The remote stub accepts and implements the reverse step packet
1160(see <a href="Packets.html#bs">bs</a>).
1161</p>
1162</dd>
1163<dt>&lsquo;<samp>TracepointSource</samp>&rsquo;</dt>
1164<dd><p>The remote stub understands the &lsquo;<samp>QTDPsrc</samp>&rsquo; packet that supplies
1165the source form of tracepoint definitions.
1166</p>
1167</dd>
1168<dt>&lsquo;<samp>QAgent</samp>&rsquo;</dt>
1169<dd><p>The remote stub understands the &lsquo;<samp>QAgent</samp>&rsquo; packet.
1170</p>
1171</dd>
1172<dt>&lsquo;<samp>QAllow</samp>&rsquo;</dt>
1173<dd><p>The remote stub understands the &lsquo;<samp>QAllow</samp>&rsquo; packet.
1174</p>
1175</dd>
1176<dt>&lsquo;<samp>QDisableRandomization</samp>&rsquo;</dt>
1177<dd><p>The remote stub understands the &lsquo;<samp>QDisableRandomization</samp>&rsquo; packet.
1178</p>
1179</dd>
1180<dt>&lsquo;<samp>StaticTracepoint</samp>&rsquo;</dt>
1181<dd><a name="index-static-tracepoints_002c-in-remote-protocol"></a>
1182<p>The remote stub supports static tracepoints.
1183</p>
1184</dd>
1185<dt>&lsquo;<samp>InstallInTrace</samp>&rsquo;</dt>
1186<dd><a name="install-tracepoint-in-tracing"></a><p>The remote stub supports installing tracepoint in tracing.
1187</p>
1188</dd>
1189<dt>&lsquo;<samp>EnableDisableTracepoints</samp>&rsquo;</dt>
1190<dd><p>The remote stub supports the &lsquo;<samp>QTEnable</samp>&rsquo; (see <a href="Tracepoint-Packets.html#QTEnable">QTEnable</a>) and
1191&lsquo;<samp>QTDisable</samp>&rsquo; (see <a href="Tracepoint-Packets.html#QTDisable">QTDisable</a>) packets that allow tracepoints
1192to be enabled and disabled while a trace experiment is running.
1193</p>
1194</dd>
1195<dt>&lsquo;<samp>QTBuffer:size</samp>&rsquo;</dt>
1196<dd><p>The remote stub supports the &lsquo;<samp>QTBuffer:size</samp>&rsquo; (see <a href="Tracepoint-Packets.html#QTBuffer_002dsize">QTBuffer-size</a>)
1197packet that allows to change the size of the trace buffer.
1198</p>
1199</dd>
1200<dt>&lsquo;<samp>tracenz</samp>&rsquo;</dt>
1201<dd><a name="index-string-tracing_002c-in-remote-protocol"></a>
1202<p>The remote stub supports the &lsquo;<samp>tracenz</samp>&rsquo; bytecode for collecting strings.
1203See <a href="Bytecode-Descriptions.html#Bytecode-Descriptions">Bytecode Descriptions</a> for details about the bytecode.
1204</p>
1205</dd>
1206<dt>&lsquo;<samp>BreakpointCommands</samp>&rsquo;</dt>
1207<dd><a name="index-breakpoint-commands_002c-in-remote-protocol"></a>
1208<p>The remote stub supports running a breakpoint&rsquo;s command list itself,
1209rather than reporting the hit to <small>GDB</small>.
1210</p>
1211</dd>
1212<dt>&lsquo;<samp>Qbtrace:off</samp>&rsquo;</dt>
1213<dd><p>The remote stub understands the &lsquo;<samp>Qbtrace:off</samp>&rsquo; packet.
1214</p>
1215</dd>
1216<dt>&lsquo;<samp>Qbtrace:bts</samp>&rsquo;</dt>
1217<dd><p>The remote stub understands the &lsquo;<samp>Qbtrace:bts</samp>&rsquo; packet.
1218</p>
1219</dd>
1220<dt>&lsquo;<samp>Qbtrace:pt</samp>&rsquo;</dt>
1221<dd><p>The remote stub understands the &lsquo;<samp>Qbtrace:pt</samp>&rsquo; packet.
1222</p>
1223</dd>
1224<dt>&lsquo;<samp>Qbtrace-conf:bts:size</samp>&rsquo;</dt>
1225<dd><p>The remote stub understands the &lsquo;<samp>Qbtrace-conf:bts:size</samp>&rsquo; packet.
1226</p>
1227</dd>
1228<dt>&lsquo;<samp>Qbtrace-conf:pt:size</samp>&rsquo;</dt>
1229<dd><p>The remote stub understands the &lsquo;<samp>Qbtrace-conf:pt:size</samp>&rsquo; packet.
1230</p>
1231</dd>
1232<dt>&lsquo;<samp>swbreak</samp>&rsquo;</dt>
1233<dd><p>The remote stub reports the &lsquo;<samp>swbreak</samp>&rsquo; stop reason for memory
1234breakpoints.
1235</p>
1236</dd>
1237<dt>&lsquo;<samp>hwbreak</samp>&rsquo;</dt>
1238<dd><p>The remote stub reports the &lsquo;<samp>hwbreak</samp>&rsquo; stop reason for hardware
1239breakpoints.
1240</p>
1241</dd>
1242<dt>&lsquo;<samp>fork-events</samp>&rsquo;</dt>
1243<dd><p>The remote stub reports the &lsquo;<samp>fork</samp>&rsquo; stop reason for fork events.
1244</p>
1245</dd>
1246<dt>&lsquo;<samp>vfork-events</samp>&rsquo;</dt>
1247<dd><p>The remote stub reports the &lsquo;<samp>vfork</samp>&rsquo; stop reason for vfork events
1248and vforkdone events.
1249</p>
1250</dd>
1251<dt>&lsquo;<samp>exec-events</samp>&rsquo;</dt>
1252<dd><p>The remote stub reports the &lsquo;<samp>exec</samp>&rsquo; stop reason for exec events.
1253</p>
1254</dd>
1255<dt>&lsquo;<samp>vContSupported</samp>&rsquo;</dt>
1256<dd><p>The remote stub reports the supported actions in the reply to
1257&lsquo;<samp>vCont?</samp>&rsquo; packet.
1258</p>
1259</dd>
1260<dt>&lsquo;<samp>QThreadEvents</samp>&rsquo;</dt>
1261<dd><p>The remote stub understands the &lsquo;<samp>QThreadEvents</samp>&rsquo; packet.
1262</p>
1263</dd>
1264<dt>&lsquo;<samp>no-resumed</samp>&rsquo;</dt>
1265<dd><p>The remote stub reports the &lsquo;<samp>N</samp>&rsquo; stop reply.
1266</p>
1267</dd>
1268</dl>
1269
1270</dd>
1271<dt>&lsquo;<samp>qSymbol::</samp>&rsquo;</dt>
1272<dd><a name="index-symbol-lookup_002c-remote-request"></a>
1273<a name="index-qSymbol-packet"></a>
1274<p>Notify the target that <small>GDB</small> is prepared to serve symbol lookup
1275requests.  Accept requests from the target for the values of symbols.
1276</p>
1277<p>Reply:
1278</p><dl compact="compact">
1279<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
1280<dd><p>The target does not need to look up any (more) symbols.
1281</p></dd>
1282<dt>&lsquo;<samp>qSymbol:<var>sym_name</var></samp>&rsquo;</dt>
1283<dd><p>The target requests the value of symbol <var>sym_name</var> (hex encoded).
1284<small>GDB</small> may provide the value by using the
1285&lsquo;<samp>qSymbol:<var>sym_value</var>:<var>sym_name</var></samp>&rsquo; message, described
1286below.
1287</p></dd>
1288</dl>
1289
1290</dd>
1291<dt>&lsquo;<samp>qSymbol:<var>sym_value</var>:<var>sym_name</var></samp>&rsquo;</dt>
1292<dd><p>Set the value of <var>sym_name</var> to <var>sym_value</var>.
1293</p>
1294<p><var>sym_name</var> (hex encoded) is the name of a symbol whose value the
1295target has previously requested.
1296</p>
1297<p><var>sym_value</var> (hex) is the value for symbol <var>sym_name</var>.  If
1298<small>GDB</small> cannot supply a value for <var>sym_name</var>, then this field
1299will be empty.
1300</p>
1301<p>Reply:
1302</p><dl compact="compact">
1303<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
1304<dd><p>The target does not need to look up any (more) symbols.
1305</p></dd>
1306<dt>&lsquo;<samp>qSymbol:<var>sym_name</var></samp>&rsquo;</dt>
1307<dd><p>The target requests the value of a new symbol <var>sym_name</var> (hex
1308encoded).  <small>GDB</small> will continue to supply the values of symbols
1309(if available), until the target ceases to request them.
1310</p></dd>
1311</dl>
1312
1313</dd>
1314<dt>&lsquo;<samp>qTBuffer</samp>&rsquo;</dt>
1315<dt>&lsquo;<samp>QTBuffer</samp>&rsquo;</dt>
1316<dt>&lsquo;<samp>QTDisconnected</samp>&rsquo;</dt>
1317<dt>&lsquo;<samp>QTDP</samp>&rsquo;</dt>
1318<dt>&lsquo;<samp>QTDPsrc</samp>&rsquo;</dt>
1319<dt>&lsquo;<samp>QTDV</samp>&rsquo;</dt>
1320<dt>&lsquo;<samp>qTfP</samp>&rsquo;</dt>
1321<dt>&lsquo;<samp>qTfV</samp>&rsquo;</dt>
1322<dt>&lsquo;<samp>QTFrame</samp>&rsquo;</dt>
1323<dt>&lsquo;<samp>qTMinFTPILen</samp>&rsquo;</dt>
1324<dd>
1325<p>See <a href="Tracepoint-Packets.html#Tracepoint-Packets">Tracepoint Packets</a>.
1326</p>
1327</dd>
1328<dt>&lsquo;<samp>qThreadExtraInfo,<var>thread-id</var></samp>&rsquo;</dt>
1329<dd><a name="index-thread-attributes-info_002c-remote-request"></a>
1330<a name="index-qThreadExtraInfo-packet"></a>
1331<p>Obtain from the target OS a printable string description of thread
1332attributes for the thread <var>thread-id</var>; see <a href="Packets.html#thread_002did-syntax">thread-id syntax</a>,
1333for the forms of <var>thread-id</var>.  This
1334string may contain anything that the target OS thinks is interesting
1335for <small>GDB</small> to tell the user about the thread.  The string is
1336displayed in <small>GDB</small>&rsquo;s <code>info threads</code> display.  Some
1337examples of possible thread extra info strings are &lsquo;<samp>Runnable</samp>&rsquo;, or
1338&lsquo;<samp>Blocked on Mutex</samp>&rsquo;.
1339</p>
1340<p>Reply:
1341</p><dl compact="compact">
1342<dt>&lsquo;<samp><var>XX</var>&hellip;</samp>&rsquo;</dt>
1343<dd><p>Where &lsquo;<samp><var>XX</var>&hellip;</samp>&rsquo; is a hex encoding of <small>ASCII</small> data,
1344comprising the printable string containing the extra information about
1345the thread&rsquo;s attributes.
1346</p></dd>
1347</dl>
1348
1349<p>(Note that the <code>qThreadExtraInfo</code> packet&rsquo;s name is separated from
1350the command by a &lsquo;<samp>,</samp>&rsquo;, not a &lsquo;<samp>:</samp>&rsquo;, contrary to the naming
1351conventions above.  Please don&rsquo;t use this packet as a model for new
1352packets.)
1353</p>
1354</dd>
1355<dt>&lsquo;<samp>QTNotes</samp>&rsquo;</dt>
1356<dt>&lsquo;<samp>qTP</samp>&rsquo;</dt>
1357<dt>&lsquo;<samp>QTSave</samp>&rsquo;</dt>
1358<dt>&lsquo;<samp>qTsP</samp>&rsquo;</dt>
1359<dt>&lsquo;<samp>qTsV</samp>&rsquo;</dt>
1360<dt>&lsquo;<samp>QTStart</samp>&rsquo;</dt>
1361<dt>&lsquo;<samp>QTStop</samp>&rsquo;</dt>
1362<dt>&lsquo;<samp>QTEnable</samp>&rsquo;</dt>
1363<dt>&lsquo;<samp>QTDisable</samp>&rsquo;</dt>
1364<dt>&lsquo;<samp>QTinit</samp>&rsquo;</dt>
1365<dt>&lsquo;<samp>QTro</samp>&rsquo;</dt>
1366<dt>&lsquo;<samp>qTStatus</samp>&rsquo;</dt>
1367<dt>&lsquo;<samp>qTV</samp>&rsquo;</dt>
1368<dt>&lsquo;<samp>qTfSTM</samp>&rsquo;</dt>
1369<dt>&lsquo;<samp>qTsSTM</samp>&rsquo;</dt>
1370<dt>&lsquo;<samp>qTSTMat</samp>&rsquo;</dt>
1371<dd><p>See <a href="Tracepoint-Packets.html#Tracepoint-Packets">Tracepoint Packets</a>.
1372</p>
1373</dd>
1374<dt>&lsquo;<samp>qXfer:<var>object</var>:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1375<dd><a name="index-read-special-object_002c-remote-request"></a>
1376<a name="index-qXfer-packet"></a>
1377<a name="qXfer-read"></a><p>Read uninterpreted bytes from the target&rsquo;s special data area
1378identified by the keyword <var>object</var>.  Request <var>length</var> bytes
1379starting at <var>offset</var> bytes into the data.  The content and
1380encoding of <var>annex</var> is specific to <var>object</var>; it can supply
1381additional details about what data to access.
1382</p>
1383<p>Reply:
1384</p><dl compact="compact">
1385<dt>&lsquo;<samp>m <var>data</var></samp>&rsquo;</dt>
1386<dd><p>Data <var>data</var> (see <a href="Overview.html#Binary-Data">Binary Data</a>) has been read from the
1387target.  There may be more data at a higher address (although
1388it is permitted to return &lsquo;<samp>m</samp>&rsquo; even for the last valid
1389block of data, as long as at least one byte of data was read).
1390It is possible for <var>data</var> to have fewer bytes than the <var>length</var> in the
1391request.
1392</p>
1393</dd>
1394<dt>&lsquo;<samp>l <var>data</var></samp>&rsquo;</dt>
1395<dd><p>Data <var>data</var> (see <a href="Overview.html#Binary-Data">Binary Data</a>) has been read from the target.
1396There is no more data to be read.  It is possible for <var>data</var> to
1397have fewer bytes than the <var>length</var> in the request.
1398</p>
1399</dd>
1400<dt>&lsquo;<samp>l</samp>&rsquo;</dt>
1401<dd><p>The <var>offset</var> in the request is at the end of the data.
1402There is no more data to be read.
1403</p>
1404</dd>
1405<dt>&lsquo;<samp>E00</samp>&rsquo;</dt>
1406<dd><p>The request was malformed, or <var>annex</var> was invalid.
1407</p>
1408</dd>
1409<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
1410<dd><p>The offset was invalid, or there was an error encountered reading the data.
1411The <var>nn</var> part is a hex-encoded <code>errno</code> value.
1412</p>
1413</dd>
1414<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
1415<dd><p>An empty reply indicates the <var>object</var> string was not recognized by
1416the stub, or that the object does not support reading.
1417</p></dd>
1418</dl>
1419
1420<p>Here are the specific requests of this form defined so far.  All the
1421&lsquo;<samp>qXfer:<var>object</var>:read:&hellip;</samp>&rsquo; requests use the same reply
1422formats, listed above.
1423</p>
1424<dl compact="compact">
1425<dt>&lsquo;<samp>qXfer:auxv:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1426<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.
1427</p>
1428<p>This packet is not probed by default; the remote stub must request it,
1429by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
1430</p>
1431</dd>
1432<dt>&lsquo;<samp>qXfer:btrace:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1433<dd><a name="qXfer-btrace-read"></a>
1434<p>Return a description of the current branch trace.
1435See <a href="Branch-Trace-Format.html#Branch-Trace-Format">Branch Trace Format</a>.  The annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo;
1436packet may have one of the following values:
1437</p>
1438<dl compact="compact">
1439<dt><code>all</code></dt>
1440<dd><p>Returns all available branch trace.
1441</p>
1442</dd>
1443<dt><code>new</code></dt>
1444<dd><p>Returns all available branch trace if the branch trace changed since
1445the last read request.
1446</p>
1447</dd>
1448<dt><code>delta</code></dt>
1449<dd><p>Returns the new branch trace since the last read request.  Adds a new
1450block to the end of the trace that begins at zero and ends at the source
1451location of the first branch in the trace buffer.  This extra block is
1452used to stitch traces together.
1453</p>
1454<p>If the trace buffer overflowed, returns an error indicating the overflow.
1455</p></dd>
1456</dl>
1457
1458<p>This packet is not probed by default; the remote stub must request it
1459by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
1460</p>
1461</dd>
1462<dt>&lsquo;<samp>qXfer:btrace-conf:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1463<dd><a name="qXfer-btrace_002dconf-read"></a>
1464<p>Return a description of the current branch trace configuration.
1465See <a href="Branch-Trace-Configuration-Format.html#Branch-Trace-Configuration-Format">Branch Trace Configuration Format</a>.
1466</p>
1467<p>This packet is not probed by default; the remote stub must request it
1468by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
1469</p>
1470</dd>
1471<dt>&lsquo;<samp>qXfer:exec-file:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1472<dd><a name="qXfer-executable-filename-read"></a><p>Return the full absolute name of the file that was executed to create
1473a process running on the remote system.  The annex specifies the
1474numeric process ID of the process to query, encoded as a hexadecimal
1475number.  If the annex part is empty the remote stub should return the
1476filename corresponding to the currently executing process.
1477</p>
1478<p>This packet is not probed by default; the remote stub must request it,
1479by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
1480</p>
1481</dd>
1482<dt>&lsquo;<samp>qXfer:features:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1483<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
1484annex specifies which XML document to access.  The main description is
1485always loaded from the &lsquo;<samp>target.xml</samp>&rsquo; annex.
1486</p>
1487<p>This packet is not probed by default; the remote stub must request it,
1488by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
1489</p>
1490</dd>
1491<dt>&lsquo;<samp>qXfer:libraries:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1492<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>.
1493The annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must be empty
1494(see <a href="#qXfer-read">qXfer read</a>).
1495</p>
1496<p>Targets which maintain a list of libraries in the program&rsquo;s memory do
1497not need to implement this packet; it is designed for platforms where
1498the operating system manages the list of loaded libraries.
1499</p>
1500<p>This packet is not probed by default; the remote stub must request it,
1501by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
1502</p>
1503</dd>
1504<dt>&lsquo;<samp>qXfer:libraries-svr4:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1505<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
1506platform.  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
1507of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must be empty unless the remote
1508stub indicated it supports the augmented form of this packet
1509by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
1510(see <a href="#qXfer-read">qXfer read</a>, <a href="#qSupported">qSupported</a>).
1511</p>
1512<p>This packet is optional for better performance on SVR4 targets.
1513<small>GDB</small> uses memory read packets to read the SVR4 library list otherwise.
1514</p>
1515<p>This packet is not probed by default; the remote stub must request it,
1516by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
1517</p>
1518<p>If the remote stub indicates it supports the augmented form of this
1519packet then the annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet may
1520contain a semicolon-separated list of &lsquo;<samp><var>name</var>=<var>value</var></samp>&rsquo;
1521arguments.  The currently supported arguments are:
1522</p>
1523<dl compact="compact">
1524<dt><code>start=<var>address</var></code></dt>
1525<dd><p>A hexadecimal number specifying the address of the &lsquo;<samp>struct
1526link_map</samp>&rsquo; to start reading the library list from.  If unset or zero
1527then the first &lsquo;<samp>struct link_map</samp>&rsquo; in the library list will be
1528chosen as the starting point.
1529</p>
1530</dd>
1531<dt><code>prev=<var>address</var></code></dt>
1532<dd><p>A hexadecimal number specifying the address of the &lsquo;<samp>struct
1533link_map</samp>&rsquo; immediately preceding the &lsquo;<samp>struct link_map</samp>&rsquo;
1534specified by the &lsquo;<samp>start</samp>&rsquo; argument.  If unset or zero then
1535the remote stub will expect that no &lsquo;<samp>struct link_map</samp>&rsquo;
1536exists prior to the starting point.
1537</p>
1538</dd>
1539</dl>
1540
1541<p>Arguments that are not understood by the remote stub will be silently
1542ignored.
1543</p>
1544</dd>
1545<dt>&lsquo;<samp>qXfer:memory-map:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1546<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
1547annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must be empty
1548(see <a href="#qXfer-read">qXfer read</a>).
1549</p>
1550<p>This packet is not probed by default; the remote stub must request it,
1551by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
1552</p>
1553</dd>
1554<dt>&lsquo;<samp>qXfer:sdata:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1555<dd><a name="qXfer-sdata-read"></a>
1556<p>Read contents of the extra collected static tracepoint marker
1557information.  The annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must
1558be empty (see <a href="#qXfer-read">qXfer read</a>).  See <a href="Tracepoint-Actions.html#Tracepoint-Actions">Tracepoint
1559Action Lists</a>.
1560</p>
1561<p>This packet is not probed by default; the remote stub must request it,
1562by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
1563(see <a href="#qSupported">qSupported</a>).
1564</p>
1565</dd>
1566<dt>&lsquo;<samp>qXfer:siginfo:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1567<dd><a name="qXfer-siginfo-read"></a><p>Read contents of the extra signal information on the target
1568system.  The annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must be
1569empty (see <a href="#qXfer-read">qXfer read</a>).
1570</p>
1571<p>This packet is not probed by default; the remote stub must request it,
1572by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
1573(see <a href="#qSupported">qSupported</a>).
1574</p>
1575</dd>
1576<dt>&lsquo;<samp>qXfer:threads:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1577<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
1578annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must be empty
1579(see <a href="#qXfer-read">qXfer read</a>).
1580</p>
1581<p>This packet is not probed by default; the remote stub must request it,
1582by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
1583</p>
1584</dd>
1585<dt>&lsquo;<samp>qXfer:traceframe-info:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1586<dd><a name="qXfer-traceframe-info-read"></a>
1587<p>Return a description of the current traceframe&rsquo;s contents.
1588See <a href="Traceframe-Info-Format.html#Traceframe-Info-Format">Traceframe Info Format</a>.  The annex part of the generic
1589&lsquo;<samp>qXfer</samp>&rsquo; packet must be empty (see <a href="#qXfer-read">qXfer read</a>).
1590</p>
1591<p>This packet is not probed by default; the remote stub must request it,
1592by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
1593</p>
1594</dd>
1595<dt>&lsquo;<samp>qXfer:uib:read:<var>pc</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1596<dd><a name="qXfer-unwind-info-block"></a>
1597<p>Return the unwind information block for <var>pc</var>.  This packet is used
1598on OpenVMS/ia64 to ask the kernel unwind information.
1599</p>
1600<p>This packet is not probed by default.
1601</p>
1602</dd>
1603<dt>&lsquo;<samp>qXfer:fdpic:read:<var>annex</var>:<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1604<dd><a name="qXfer-fdpic-loadmap-read"></a><p>Read contents of <code>loadmap</code>s on the target system.  The
1605annex, either &lsquo;<samp>exec</samp>&rsquo; or &lsquo;<samp>interp</samp>&rsquo;, specifies which <code>loadmap</code>,
1606executable <code>loadmap</code> or interpreter <code>loadmap</code> to read.
1607</p>
1608<p>This packet is not probed by default; the remote stub must request it,
1609by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response (see <a href="#qSupported">qSupported</a>).
1610</p>
1611</dd>
1612<dt>&lsquo;<samp>qXfer:osdata:read::<var>offset</var>,<var>length</var></samp>&rsquo;</dt>
1613<dd><a name="qXfer-osdata-read"></a><p>Access the target&rsquo;s <em>operating system information</em>.
1614See <a href="Operating-System-Information.html#Operating-System-Information">Operating System Information</a>.
1615</p>
1616</dd>
1617</dl>
1618
1619</dd>
1620<dt>&lsquo;<samp>qXfer:<var>object</var>:write:<var>annex</var>:<var>offset</var>:<var>data</var>&hellip;</samp>&rsquo;</dt>
1621<dd><a name="index-write-data-into-object_002c-remote-request"></a>
1622<a name="qXfer-write"></a><p>Write uninterpreted bytes into the target&rsquo;s special data area
1623identified by the keyword <var>object</var>, starting at <var>offset</var> bytes
1624into the data.  The binary-encoded data (see <a href="Overview.html#Binary-Data">Binary Data</a>) to be
1625written is given by <var>data</var>&hellip;.  The content and encoding of <var>annex</var>
1626is specific to <var>object</var>; it can supply additional details about what data
1627to access.
1628</p>
1629<p>Reply:
1630</p><dl compact="compact">
1631<dt>&lsquo;<samp><var>nn</var></samp>&rsquo;</dt>
1632<dd><p><var>nn</var> (hex encoded) is the number of bytes written.
1633This may be fewer bytes than supplied in the request.
1634</p>
1635</dd>
1636<dt>&lsquo;<samp>E00</samp>&rsquo;</dt>
1637<dd><p>The request was malformed, or <var>annex</var> was invalid.
1638</p>
1639</dd>
1640<dt>&lsquo;<samp>E <var>nn</var></samp>&rsquo;</dt>
1641<dd><p>The offset was invalid, or there was an error encountered writing the data.
1642The <var>nn</var> part is a hex-encoded <code>errno</code> value.
1643</p>
1644</dd>
1645<dt>&lsquo;<samp><!-- /@w --></samp>&rsquo;</dt>
1646<dd><p>An empty reply indicates the <var>object</var> string was not
1647recognized by the stub, or that the object does not support writing.
1648</p></dd>
1649</dl>
1650
1651<p>Here are the specific requests of this form defined so far.  All the
1652&lsquo;<samp>qXfer:<var>object</var>:write:&hellip;</samp>&rsquo; requests use the same reply
1653formats, listed above.
1654</p>
1655<dl compact="compact">
1656<dt>&lsquo;<samp>qXfer:siginfo:write::<var>offset</var>:<var>data</var>&hellip;</samp>&rsquo;</dt>
1657<dd><a name="qXfer-siginfo-write"></a><p>Write <var>data</var> to the extra signal information on the target system.
1658The annex part of the generic &lsquo;<samp>qXfer</samp>&rsquo; packet must be
1659empty (see <a href="#qXfer-write">qXfer write</a>).
1660</p>
1661<p>This packet is not probed by default; the remote stub must request it,
1662by supplying an appropriate &lsquo;<samp>qSupported</samp>&rsquo; response
1663(see <a href="#qSupported">qSupported</a>).
1664</p></dd>
1665</dl>
1666
1667</dd>
1668<dt>&lsquo;<samp>qXfer:<var>object</var>:<var>operation</var>:&hellip;</samp>&rsquo;</dt>
1669<dd><p>Requests of this form may be added in the future.  When a stub does
1670not recognize the <var>object</var> keyword, or its support for
1671<var>object</var> does not recognize the <var>operation</var> keyword, the stub
1672must respond with an empty packet.
1673</p>
1674</dd>
1675<dt>&lsquo;<samp>qAttached:<var>pid</var></samp>&rsquo;</dt>
1676<dd><a name="index-query-attached_002c-remote-request"></a>
1677<a name="index-qAttached-packet"></a>
1678<p>Return an indication of whether the remote server attached to an
1679existing process or created a new process.  When the multiprocess
1680protocol extensions are supported (see <a href="#multiprocess-extensions">multiprocess extensions</a>),
1681<var>pid</var> is an integer in hexadecimal format identifying the target
1682process.  Otherwise, <small>GDB</small> will omit the <var>pid</var> field and
1683the query packet will be simplified as &lsquo;<samp>qAttached</samp>&rsquo;.
1684</p>
1685<p>This query is used, for example, to know whether the remote process
1686should be detached or killed when a <small>GDB</small> session is ended with
1687the <code>quit</code> command.
1688</p>
1689<p>Reply:
1690</p><dl compact="compact">
1691<dt>&lsquo;<samp>1</samp>&rsquo;</dt>
1692<dd><p>The remote server attached to an existing process.
1693</p></dd>
1694<dt>&lsquo;<samp>0</samp>&rsquo;</dt>
1695<dd><p>The remote server created a new process.
1696</p></dd>
1697<dt>&lsquo;<samp>E <var>NN</var></samp>&rsquo;</dt>
1698<dd><p>A badly formed request or an error was encountered.
1699</p></dd>
1700</dl>
1701
1702</dd>
1703<dt>&lsquo;<samp>Qbtrace:bts</samp>&rsquo;</dt>
1704<dd><p>Enable branch tracing for the current thread using Branch Trace Store.
1705</p>
1706<p>Reply:
1707</p><dl compact="compact">
1708<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
1709<dd><p>Branch tracing has been enabled.
1710</p></dd>
1711<dt>&lsquo;<samp>E.errtext</samp>&rsquo;</dt>
1712<dd><p>A badly formed request or an error was encountered.
1713</p></dd>
1714</dl>
1715
1716</dd>
1717<dt>&lsquo;<samp>Qbtrace:pt</samp>&rsquo;</dt>
1718<dd><p>Enable branch tracing for the current thread using Intel Processor Trace.
1719</p>
1720<p>Reply:
1721</p><dl compact="compact">
1722<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
1723<dd><p>Branch tracing has been enabled.
1724</p></dd>
1725<dt>&lsquo;<samp>E.errtext</samp>&rsquo;</dt>
1726<dd><p>A badly formed request or an error was encountered.
1727</p></dd>
1728</dl>
1729
1730</dd>
1731<dt>&lsquo;<samp>Qbtrace:off</samp>&rsquo;</dt>
1732<dd><p>Disable branch tracing for the current thread.
1733</p>
1734<p>Reply:
1735</p><dl compact="compact">
1736<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
1737<dd><p>Branch tracing has been disabled.
1738</p></dd>
1739<dt>&lsquo;<samp>E.errtext</samp>&rsquo;</dt>
1740<dd><p>A badly formed request or an error was encountered.
1741</p></dd>
1742</dl>
1743
1744</dd>
1745<dt>&lsquo;<samp>Qbtrace-conf:bts:size=<var>value</var></samp>&rsquo;</dt>
1746<dd><p>Set the requested ring buffer size for new threads that use the
1747btrace recording method in bts format.
1748</p>
1749<p>Reply:
1750</p><dl compact="compact">
1751<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
1752<dd><p>The ring buffer size has been set.
1753</p></dd>
1754<dt>&lsquo;<samp>E.errtext</samp>&rsquo;</dt>
1755<dd><p>A badly formed request or an error was encountered.
1756</p></dd>
1757</dl>
1758
1759</dd>
1760<dt>&lsquo;<samp>Qbtrace-conf:pt:size=<var>value</var></samp>&rsquo;</dt>
1761<dd><p>Set the requested ring buffer size for new threads that use the
1762btrace recording method in pt format.
1763</p>
1764<p>Reply:
1765</p><dl compact="compact">
1766<dt>&lsquo;<samp>OK</samp>&rsquo;</dt>
1767<dd><p>The ring buffer size has been set.
1768</p></dd>
1769<dt>&lsquo;<samp>E.errtext</samp>&rsquo;</dt>
1770<dd><p>A badly formed request or an error was encountered.
1771</p></dd>
1772</dl>
1773
1774</dd>
1775</dl>
1776
1777<div class="footnote">
1778<hr>
1779<h4 class="footnotes-heading">Footnotes</h4>
1780
1781<h3><a name="FOOT20" href="#DOCF20">(20)</a></h3>
1782<p>The &lsquo;<samp>qP</samp>&rsquo; and &lsquo;<samp>qL</samp>&rsquo;
1783packets predate these conventions, and have arguments without any terminator
1784for the packet name; we suspect they are in widespread use in places that
1785are difficult to upgrade.  The &lsquo;<samp>qC</samp>&rsquo; packet has no arguments, but some
1786existing stubs (e.g. RedBoot) are known to not check for the end of the
1787packet.</p>
1788</div>
1789<hr>
1790<div class="header">
1791<p>
1792Next: <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="previous">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>
1793</div>
1794
1795
1796
1797</body>
1798</html>
1799