toolchain/share/doc/gdb/General-Query-Packets.html

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<h3 class="section">E.4 General Query Packets</h3>
<p><a name="index-remote-query-requests-3491"></a>
Packets starting with &lsquo;<samp><span class="samp">q</span></samp>&rsquo; are <dfn>general query packets</dfn>;
packets starting with &lsquo;<samp><span class="samp">Q</span></samp>&rsquo; are <dfn>general set packets</dfn>. General
query and set packets are a semi-unified form for retrieving and
sending information to and from the stub.
<p>The initial letter of a query or set packet is followed by a name
indicating what sort of thing the packet applies to. For example,
<span class="sc">gdb</span> may use a &lsquo;<samp><span class="samp">qSymbol</span></samp>&rsquo; packet to exchange symbol
definitions with the stub. These packet names follow some
conventions:
<ul>
<li>The name must not contain commas, colons or semicolons.
<li>Most <span class="sc">gdb</span> query and set packets have a leading upper case
letter.
<li>The names of custom vendor packets should use a company prefix, in
lower case, followed by a period. For example, packets designed at
the Acme Corporation might begin with &lsquo;<samp><span class="samp">qacme.foo</span></samp>&rsquo; (for querying
foos) or &lsquo;<samp><span class="samp">Qacme.bar</span></samp>&rsquo; (for setting bars).
</ul>
<p>The name of a query or set packet should be separated from any
parameters by a &lsquo;<samp><span class="samp">:</span></samp>&rsquo;; the parameters themselves should be
separated by &lsquo;<samp><span class="samp">,</span></samp>&rsquo; or &lsquo;<samp><span class="samp">;</span></samp>&rsquo;. Stubs must be careful to match the
full packet name, and check for a separator or the end of the packet,
in case two packet names share a common prefix. New packets should not begin
with &lsquo;<samp><span class="samp">qC</span></samp>&rsquo;, &lsquo;<samp><span class="samp">qP</span></samp>&rsquo;, or &lsquo;<samp><span class="samp">qL</span></samp>&rsquo;<a rel="footnote" href="#fn-1" name="fnd-1"><sup>1</sup></a>.
<p>Like the descriptions of the other packets, each description here
has a template showing the packet's overall syntax, followed by an
explanation of the packet's meaning. We include spaces in some of the
templates for clarity; these are not part of the packet's syntax. No
<span class="sc">gdb</span> packet uses spaces to separate its components.
<p>Here are the currently defined query and set packets:
<dl>
<dt>&lsquo;<samp><span class="samp">QAgent:1</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QAgent:0</span></samp>&rsquo;<dd>Turn on or off the agent as a helper to perform some debugging operations
delegated from <span class="sc">gdb</span> (see <a href="Control-Agent.html#Control-Agent">Control Agent</a>).
<br><dt>&lsquo;<samp><span class="samp">QAllow:</span><var>op</var><span class="samp">:</span><var>val</var><span class="samp">...</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bQAllow_007d-packet-3492"></a>Specify which operations <span class="sc">gdb</span> expects to request of the
target, as a semicolon-separated list of operation name and value
pairs. Possible values for <var>op</var> include &lsquo;<samp><span class="samp">WriteReg</span></samp>&rsquo;,
&lsquo;<samp><span class="samp">WriteMem</span></samp>&rsquo;, &lsquo;<samp><span class="samp">InsertBreak</span></samp>&rsquo;, &lsquo;<samp><span class="samp">InsertTrace</span></samp>&rsquo;,
&lsquo;<samp><span class="samp">InsertFastTrace</span></samp>&rsquo;, and &lsquo;<samp><span class="samp">Stop</span></samp>&rsquo;. <var>val</var> is either 0,
indicating that <span class="sc">gdb</span> will not request the operation, or 1,
indicating that it may. (The target can then use this to set up its
own internals optimally, for instance if the debugger never expects to
insert breakpoints, it may not need to install its own trap handler.)
<br><dt>&lsquo;<samp><span class="samp">qC</span></samp>&rsquo;<dd><a name="index-current-thread_002c-remote-request-3493"></a><a name="index-g_t_0040samp_007bqC_007d-packet-3494"></a>Return the current thread ID.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">QC </span><var>thread-id</var></samp>&rsquo;<dd>Where <var>thread-id</var> is a thread ID as documented in
<a href="thread_002did-syntax.html#thread_002did-syntax">thread-id syntax</a>.
<br><dt>&lsquo;<samp><span class="samp">(anything else)</span></samp>&rsquo;<dd>Any other reply implies the old thread ID.
</dl>
<br><dt>&lsquo;<samp><span class="samp">qCRC:</span><var>addr</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="index-CRC-of-memory-block_002c-remote-request-3495"></a><a name="index-g_t_0040samp_007bqCRC_007d-packet-3496"></a><a name="qCRC-packet"></a>Compute the CRC checksum of a block of memory using CRC-32 defined in
IEEE 802.3. The CRC is computed byte at a time, taking the most
significant bit of each byte first. The initial pattern code
<code>0xffffffff</code> is used to ensure leading zeros affect the CRC.
<p><em>Note:</em> This is the same CRC used in validating separate debug
files (see <a href="Separate-Debug-Files.html#Separate-Debug-Files">Debugging Information in Separate Files</a>). However the algorithm is slightly different. When validating
separate debug files, the CRC is computed taking the <em>least</em>
significant bit of each byte first, and the final result is inverted to
detect trailing zeros.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>An error (such as memory fault)
<br><dt>&lsquo;<samp><span class="samp">C </span><var>crc32</var></samp>&rsquo;<dd>The specified memory region's checksum is <var>crc32</var>.
</dl>
<br><dt>&lsquo;<samp><span class="samp">QDisableRandomization:</span><var>value</var></samp>&rsquo;<dd><a name="index-disable-address-space-randomization_002c-remote-request-3497"></a><a name="index-g_t_0040samp_007bQDisableRandomization_007d-packet-3498"></a>Some target operating systems will randomize the virtual address space
of the inferior process as a security feature, but provide a feature
to disable such randomization, e.g. to allow for a more deterministic
debugging experience. On such systems, this packet with a <var>value</var>
of 1 directs the target to disable address space randomization for
processes subsequently started via &lsquo;<samp><span class="samp">vRun</span></samp>&rsquo; packets, while a packet
with a <var>value</var> of 0 tells the target to enable address space
randomization.
<p>This packet is only available in extended mode (see <a href="extended-mode.html#extended-mode">extended mode</a>).
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The request succeeded.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>An error occurred. The error number <var>nn</var> is given as hex digits.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates that &lsquo;<samp><span class="samp">QDisableRandomization</span></samp>&rsquo; is not supported
by the stub.
</dl>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
This should only be done on targets that actually support disabling
address space randomization.
<br><dt>&lsquo;<samp><span class="samp">QStartupWithShell:</span><var>value</var></samp>&rsquo;<dd><a name="index-startup-with-shell_002c-remote-request-3499"></a><a name="index-g_t_0040samp_007bQStartupWithShell_007d-packet-3500"></a>On UNIX-like targets, it is possible to start the inferior using a
shell program. This is the default behavior on both <span class="sc">gdb</span> and
<samp><span class="command">gdbserver</span></samp> (see <a href="set-startup_002dwith_002dshell.html#set-startup_002dwith_002dshell">set startup-with-shell</a>). This packet is
used to inform <samp><span class="command">gdbserver</span></samp> whether it should start the
inferior using a shell or not.
<p>If <var>value</var> is &lsquo;<samp><span class="samp">0</span></samp>&rsquo;, <samp><span class="command">gdbserver</span></samp> will not use a shell
to start the inferior. If <var>value</var> is &lsquo;<samp><span class="samp">1</span></samp>&rsquo;,
<samp><span class="command">gdbserver</span></samp> will use a shell to start the inferior. All other
values are considered an error.
<p>This packet is only available in extended mode (see <a href="extended-mode.html#extended-mode">extended mode</a>).
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The request succeeded.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>An error occurred. The error number <var>nn</var> is given as hex digits.
</dl>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response
(see <a href="qSupported.html#qSupported">qSupported</a>). This should only be done on targets that
actually support starting the inferior using a shell.
<p>Use of this packet is controlled by the <code>set startup-with-shell</code>
command; see <a href="set-startup_002dwith_002dshell.html#set-startup_002dwith_002dshell">set startup-with-shell</a>.
<br><dt>&lsquo;<samp><span class="samp">QEnvironmentHexEncoded:</span><var>hex-value</var></samp>&rsquo;<dd><a name="QEnvironmentHexEncoded"></a><a name="index-set-environment-variable_002c-remote-request-3501"></a><a name="index-g_t_0040samp_007bQEnvironmentHexEncoded_007d-packet-3502"></a>On UNIX-like targets, it is possible to set environment variables that
will be passed to the inferior during the startup process. This
packet is used to inform <samp><span class="command">gdbserver</span></samp> of an environment
variable that has been defined by the user on <span class="sc">gdb</span> (see <a href="set-environment.html#set-environment">set environment</a>).
<p>The packet is composed by <var>hex-value</var>, an hex encoded
representation of the <var>name=value</var> format representing an
environment variable. The name of the environment variable is
represented by <var>name</var>, and the value to be assigned to the
environment variable is represented by <var>value</var>. If the variable
has no value (i.e., the value is <code>null</code>), then <var>value</var> will
not be present.
<p>This packet is only available in extended mode (see <a href="extended-mode.html#extended-mode">extended mode</a>).
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The request succeeded.
</dl>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response
(see <a href="qSupported.html#qSupported">qSupported</a>). This should only be done on targets that
actually support passing environment variables to the starting
inferior.
<p>This packet is related to the <code>set environment</code> command;
see <a href="set-environment.html#set-environment">set environment</a>.
<br><dt>&lsquo;<samp><span class="samp">QEnvironmentUnset:</span><var>hex-value</var></samp>&rsquo;<dd><a name="QEnvironmentUnset"></a><a name="index-unset-environment-variable_002c-remote-request-3503"></a><a name="index-g_t_0040samp_007bQEnvironmentUnset_007d-packet-3504"></a>On UNIX-like targets, it is possible to unset environment variables
before starting the inferior in the remote target. This packet is
used to inform <samp><span class="command">gdbserver</span></samp> of an environment variable that has
been unset by the user on <span class="sc">gdb</span> (see <a href="unset-environment.html#unset-environment">unset environment</a>).
<p>The packet is composed by <var>hex-value</var>, an hex encoded
representation of the name of the environment variable to be unset.
<p>This packet is only available in extended mode (see <a href="extended-mode.html#extended-mode">extended mode</a>).
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The request succeeded.
</dl>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response
(see <a href="qSupported.html#qSupported">qSupported</a>). This should only be done on targets that
actually support passing environment variables to the starting
inferior.
<p>This packet is related to the <code>unset environment</code> command;
see <a href="unset-environment.html#unset-environment">unset environment</a>.
<br><dt>&lsquo;<samp><span class="samp">QEnvironmentReset</span></samp>&rsquo;<dd><a name="QEnvironmentReset"></a><a name="index-reset-environment_002c-remote-request-3505"></a><a name="index-g_t_0040samp_007bQEnvironmentReset_007d-packet-3506"></a>On UNIX-like targets, this packet is used to reset the state of
environment variables in the remote target before starting the
inferior. In this context, reset means unsetting all environment
variables that were previously set by the user (i.e., were not
initially present in the environment). It is sent to
<samp><span class="command">gdbserver</span></samp> before the &lsquo;<samp><span class="samp">QEnvironmentHexEncoded</span></samp>&rsquo;
(see <a href="QEnvironmentHexEncoded.html#QEnvironmentHexEncoded">QEnvironmentHexEncoded</a>) and the &lsquo;<samp><span class="samp">QEnvironmentUnset</span></samp>&rsquo;
(see <a href="QEnvironmentUnset.html#QEnvironmentUnset">QEnvironmentUnset</a>) packets.
<p>This packet is only available in extended mode (see <a href="extended-mode.html#extended-mode">extended mode</a>).
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The request succeeded.
</dl>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response
(see <a href="qSupported.html#qSupported">qSupported</a>). This should only be done on targets that
actually support passing environment variables to the starting
inferior.
<br><dt>&lsquo;<samp><span class="samp">QSetWorkingDir:[</span><var>directory</var><span class="samp">]</span></samp>&rsquo;<dd><a name="QSetWorkingDir-packet"></a><a name="index-set-working-directory_002c-remote-request-3507"></a><a name="index-g_t_0040samp_007bQSetWorkingDir_007d-packet-3508"></a>This packet is used to inform the remote server of the intended
current working directory for programs that are going to be executed.
<p>The packet is composed by <var>directory</var>, an hex encoded
representation of the directory that the remote inferior will use as
its current working directory. If <var>directory</var> is an empty string,
the remote server should reset the inferior's current working
directory to its original, empty value.
<p>This packet is only available in extended mode (see <a href="extended-mode.html#extended-mode">extended mode</a>).
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The request succeeded.
</dl>
<br><dt>&lsquo;<samp><span class="samp">qfThreadInfo</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">qsThreadInfo</span></samp>&rsquo;<dd><a name="index-list-active-threads_002c-remote-request-3509"></a><a name="index-g_t_0040samp_007bqfThreadInfo_007d-packet-3510"></a><a name="index-g_t_0040samp_007bqsThreadInfo_007d-packet-3511"></a>Obtain a list of all active thread IDs from the target (OS). Since there
may be too many active threads to fit into one reply packet, this query
works iteratively: it may require more than one query/reply sequence to
obtain the entire list of threads. The first query of the sequence will
be the &lsquo;<samp><span class="samp">qfThreadInfo</span></samp>&rsquo; query; subsequent queries in the
sequence will be the &lsquo;<samp><span class="samp">qsThreadInfo</span></samp>&rsquo; query.
<p>NOTE: This packet replaces the &lsquo;<samp><span class="samp">qL</span></samp>&rsquo; query (see below).
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">m </span><var>thread-id</var></samp>&rsquo;<dd>A single thread ID
<br><dt>&lsquo;<samp><span class="samp">m </span><var>thread-id</var><span class="samp">,</span><var>thread-id</var><span class="samp">...</span></samp>&rsquo;<dd>a comma-separated list of thread IDs
<br><dt>&lsquo;<samp><span class="samp">l</span></samp>&rsquo;<dd>(lower case letter &lsquo;<samp><span class="samp">L</span></samp>&rsquo;) denotes end of list.
</dl>
<p>In response to each query, the target will reply with a list of one or
more thread IDs, separated by commas.
<span class="sc">gdb</span> will respond to each reply with a request for more thread
ids (using the &lsquo;<samp><span class="samp">qs</span></samp>&rsquo; form of the query), until the target responds
with &lsquo;<samp><span class="samp">l</span></samp>&rsquo; (lower-case ell, for <dfn>last</dfn>).
Refer to <a href="thread_002did-syntax.html#thread_002did-syntax">thread-id syntax</a>, for the format of the <var>thread-id</var>
fields.
<p><em>Note: </em><span class="sc">gdb</span><em> will send the </em><code>qfThreadInfo</code><em> query during the
initial connection with the remote target, and the very first thread ID
mentioned in the reply will be stopped by </em><span class="sc">gdb</span><em> in a subsequent
message. Therefore, the stub should ensure that the first thread ID in
the </em><code>qfThreadInfo</code><em> reply is suitable for being stopped by </em><span class="sc">gdb</span><em>.</em>
<br><dt>&lsquo;<samp><span class="samp">qGetTLSAddr:</span><var>thread-id</var><span class="samp">,</span><var>offset</var><span class="samp">,</span><var>lm</var></samp>&rsquo;<dd><a name="index-get-thread_002dlocal-storage-address_002c-remote-request-3512"></a><a name="index-g_t_0040samp_007bqGetTLSAddr_007d-packet-3513"></a>Fetch the address associated with thread local storage specified
by <var>thread-id</var>, <var>offset</var>, and <var>lm</var>.
<p><var>thread-id</var> is the thread ID associated with the
thread for which to fetch the TLS address. See <a href="thread_002did-syntax.html#thread_002did-syntax">thread-id syntax</a>.
<p><var>offset</var> is the (big endian, hex encoded) offset associated with the
thread local variable. (This offset is obtained from the debug
information associated with the variable.)
<p><var>lm</var> is the (big endian, hex encoded) OS/ABI-specific encoding of the
load module associated with the thread local storage. For example,
a <span class="sc">gnu</span>/Linux system will pass the link map address of the shared
object associated with the thread local storage under consideration.
Other operating environments may choose to represent the load module
differently, so the precise meaning of this parameter will vary.
<p>Reply:
<dl>
<dt>&lsquo;<samp><var>XX</var><span class="samp">...</span></samp>&rsquo;<dd>Hex encoded (big endian) bytes representing the address of the thread
local storage requested.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>An error occurred. The error number <var>nn</var> is given as hex digits.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates that &lsquo;<samp><span class="samp">qGetTLSAddr</span></samp>&rsquo; is not supported by the stub.
</dl>
<br><dt>&lsquo;<samp><span class="samp">qGetTIBAddr:</span><var>thread-id</var></samp>&rsquo;<dd><a name="index-get-thread-information-block-address-3514"></a><a name="index-g_t_0040samp_007bqGetTIBAddr_007d-packet-3515"></a>Fetch address of the Windows OS specific Thread Information Block.
<p><var>thread-id</var> is the thread ID associated with the thread.
<p>Reply:
<dl>
<dt>&lsquo;<samp><var>XX</var><span class="samp">...</span></samp>&rsquo;<dd>Hex encoded (big endian) bytes representing the linear address of the
thread information block.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>An error occured. This means that either the thread was not found, or the
address could not be retrieved.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates that &lsquo;<samp><span class="samp">qGetTIBAddr</span></samp>&rsquo; is not supported by the stub.
</dl>
<br><dt>&lsquo;<samp><span class="samp">qL </span><var>startflag</var> <var>threadcount</var> <var>nextthread</var></samp>&rsquo;<dd>Obtain thread information from RTOS. Where: <var>startflag</var> (one hex
digit) is one to indicate the first query and zero to indicate a
subsequent query; <var>threadcount</var> (two hex digits) is the maximum
number of threads the response packet can contain; and <var>nextthread</var>
(eight hex digits), for subsequent queries (<var>startflag</var> is zero), is
returned in the response as <var>argthread</var>.
<p>Don't use this packet; use the &lsquo;<samp><span class="samp">qfThreadInfo</span></samp>&rsquo; query instead (see above).
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">qM </span><var>count</var> <var>done</var> <var>argthread</var> <var>thread</var><span class="samp">...</span></samp>&rsquo;<dd>Where: <var>count</var> (two hex digits) is the number of threads being
returned; <var>done</var> (one hex digit) is zero to indicate more threads
and one indicates no further threads; <var>argthreadid</var> (eight hex
digits) is <var>nextthread</var> from the request packet; <var>thread</var><small class="dots">...</small>
is a sequence of thread IDs, <var>threadid</var> (eight hex
digits), from the target. See <code>remote.c:parse_threadlist_response()</code>.
</dl>
<br><dt>&lsquo;<samp><span class="samp">qOffsets</span></samp>&rsquo;<dd><a name="index-section-offsets_002c-remote-request-3516"></a><a name="index-g_t_0040samp_007bqOffsets_007d-packet-3517"></a>Get section offsets that the target used when relocating the downloaded
image.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">Text=</span><var>xxx</var><span class="samp">;Data=</span><var>yyy</var><span class="samp">[;Bss=</span><var>zzz</var><span class="samp">]</span></samp>&rsquo;<dd>Relocate the <code>Text</code> section by <var>xxx</var> from its original address.
Relocate the <code>Data</code> section by <var>yyy</var> from its original address.
If the object file format provides segment information (e.g. <span class="sc">elf</span>
&lsquo;<samp><span class="samp">PT_LOAD</span></samp>&rsquo; program headers), <span class="sc">gdb</span> will relocate entire
segments by the supplied offsets.
<p><em>Note: while a </em><code>Bss</code><em> offset may be included in the response,
</em><span class="sc">gdb</span><em> ignores this and instead applies the </em><code>Data</code><em> offset
to the </em><code>Bss</code><em> section.</em>
<br><dt>&lsquo;<samp><span class="samp">TextSeg=</span><var>xxx</var><span class="samp">[;DataSeg=</span><var>yyy</var><span class="samp">]</span></samp>&rsquo;<dd>Relocate the first segment of the object file, which conventionally
contains program code, to a starting address of <var>xxx</var>. If
&lsquo;<samp><span class="samp">DataSeg</span></samp>&rsquo; is specified, relocate the second segment, which
conventionally contains modifiable data, to a starting address of
<var>yyy</var>. <span class="sc">gdb</span> will report an error if the object file
does not contain segment information, or does not contain at least
as many segments as mentioned in the reply. Extra segments are
kept at fixed offsets relative to the last relocated segment.
</dl>
<br><dt>&lsquo;<samp><span class="samp">qP </span><var>mode</var> <var>thread-id</var></samp>&rsquo;<dd><a name="index-thread-information_002c-remote-request-3518"></a><a name="index-g_t_0040samp_007bqP_007d-packet-3519"></a>Returns information on <var>thread-id</var>. Where: <var>mode</var> is a hex
encoded 32 bit mode; <var>thread-id</var> is a thread ID
(see <a href="thread_002did-syntax.html#thread_002did-syntax">thread-id syntax</a>).
<p>Don't use this packet; use the &lsquo;<samp><span class="samp">qThreadExtraInfo</span></samp>&rsquo; query instead
(see below).
<p>Reply: see <code>remote.c:remote_unpack_thread_info_response()</code>.
<br><dt>&lsquo;<samp><span class="samp">QNonStop:1</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QNonStop:0</span></samp>&rsquo;<dd><a name="index-non_002dstop-mode_002c-remote-request-3520"></a><a name="index-g_t_0040samp_007bQNonStop_007d-packet-3521"></a><a name="QNonStop"></a>Enter non-stop (&lsquo;<samp><span class="samp">QNonStop:1</span></samp>&rsquo;) or all-stop (&lsquo;<samp><span class="samp">QNonStop:0</span></samp>&rsquo;) mode.
See <a href="Remote-Non_002dStop.html#Remote-Non_002dStop">Remote Non-Stop</a>, for more information.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The request succeeded.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>An error occurred. The error number <var>nn</var> is given as hex digits.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates that &lsquo;<samp><span class="samp">QNonStop</span></samp>&rsquo; is not supported by
the stub.
</dl>
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
Use of this packet is controlled by the <code>set non-stop</code> command;
see <a href="Non_002dStop-Mode.html#Non_002dStop-Mode">Non-Stop Mode</a>.
<br><dt>&lsquo;<samp><span class="samp">QCatchSyscalls:1 [;</span><var>sysno</var><span class="samp">]...</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QCatchSyscalls:0</span></samp>&rsquo;<dd><a name="index-catch-syscalls-from-inferior_002c-remote-request-3522"></a><a name="index-g_t_0040samp_007bQCatchSyscalls_007d-packet-3523"></a><a name="QCatchSyscalls"></a>Enable (&lsquo;<samp><span class="samp">QCatchSyscalls:1</span></samp>&rsquo;) or disable (&lsquo;<samp><span class="samp">QCatchSyscalls:0</span></samp>&rsquo;)
catching syscalls from the inferior process.
<p>For &lsquo;<samp><span class="samp">QCatchSyscalls:1</span></samp>&rsquo;, each listed syscall <var>sysno</var> (encoded
in hex) should be reported to <span class="sc">gdb</span>. If no syscall <var>sysno</var>
is listed, every system call should be reported.
<p>Note that if a syscall not in the list is reported, <span class="sc">gdb</span> will
still filter the event according to its own list from all corresponding
<code>catch syscall</code> commands. However, it is more efficient to only
report the requested syscalls.
<p>Multiple &lsquo;<samp><span class="samp">QCatchSyscalls:1</span></samp>&rsquo; packets do not combine; any earlier
&lsquo;<samp><span class="samp">QCatchSyscalls:1</span></samp>&rsquo; list is completely replaced by the new list.
<p>If the inferior process execs, the state of &lsquo;<samp><span class="samp">QCatchSyscalls</span></samp>&rsquo; is
kept for the new process too. On targets where exec may affect syscall
numbers, for example with exec between 32 and 64-bit processes, the
client should send a new packet with the new syscall list.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The request succeeded.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>An error occurred. <var>nn</var> are hex digits.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates that &lsquo;<samp><span class="samp">QCatchSyscalls</span></samp>&rsquo; is not supported by
the stub.
</dl>
<p>Use of this packet is controlled by the <code>set remote catch-syscalls</code>
command (see <a href="Remote-Configuration.html#Remote-Configuration">set remote catch-syscalls</a>).
This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">QPassSignals: </span><var>signal</var><span class="samp"> [;</span><var>signal</var><span class="samp">]...</span></samp>&rsquo;<dd><a name="index-pass-signals-to-inferior_002c-remote-request-3524"></a><a name="index-g_t_0040samp_007bQPassSignals_007d-packet-3525"></a><a name="QPassSignals"></a>Each listed <var>signal</var> should be passed directly to the inferior process.
Signals are numbered identically to continue packets and stop replies
(see <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>). Each <var>signal</var> list item should be
strictly greater than the previous item. These signals do not need to stop
the inferior, or be reported to <span class="sc">gdb</span>. All other signals should be
reported to <span class="sc">gdb</span>. Multiple &lsquo;<samp><span class="samp">QPassSignals</span></samp>&rsquo; packets do not
combine; any earlier &lsquo;<samp><span class="samp">QPassSignals</span></samp>&rsquo; list is completely replaced by the
new list. This packet improves performance when using &lsquo;<samp><span class="samp">handle
</span><var>signal</var><span class="samp"> nostop noprint pass</span></samp>&rsquo;.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The request succeeded.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>An error occurred. The error number <var>nn</var> is given as hex digits.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates that &lsquo;<samp><span class="samp">QPassSignals</span></samp>&rsquo; is not supported by
the stub.
</dl>
<p>Use of this packet is controlled by the <code>set remote pass-signals</code>
command (see <a href="Remote-Configuration.html#Remote-Configuration">set remote pass-signals</a>).
This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">QProgramSignals: </span><var>signal</var><span class="samp"> [;</span><var>signal</var><span class="samp">]...</span></samp>&rsquo;<dd><a name="index-signals-the-inferior-may-see_002c-remote-request-3526"></a><a name="index-g_t_0040samp_007bQProgramSignals_007d-packet-3527"></a><a name="QProgramSignals"></a>Each listed <var>signal</var> may be delivered to the inferior process.
Others should be silently discarded.
<p>In some cases, the remote stub may need to decide whether to deliver a
signal to the program or not without <span class="sc">gdb</span> involvement. One
example of that is while detaching &mdash; the program's threads may have
stopped for signals that haven't yet had a chance of being reported to
<span class="sc">gdb</span>, and so the remote stub can use the signal list specified
by this packet to know whether to deliver or ignore those pending
signals.
<p>This does not influence whether to deliver a signal as requested by a
resumption packet (see <a href="vCont-packet.html#vCont-packet">vCont packet</a>).
<p>Signals are numbered identically to continue packets and stop replies
(see <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>). Each <var>signal</var> list item should be
strictly greater than the previous item. Multiple
&lsquo;<samp><span class="samp">QProgramSignals</span></samp>&rsquo; packets do not combine; any earlier
&lsquo;<samp><span class="samp">QProgramSignals</span></samp>&rsquo; list is completely replaced by the new list.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The request succeeded.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>An error occurred. The error number <var>nn</var> is given as hex digits.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates that &lsquo;<samp><span class="samp">QProgramSignals</span></samp>&rsquo; is not supported
by the stub.
</dl>
<p>Use of this packet is controlled by the <code>set remote program-signals</code>
command (see <a href="Remote-Configuration.html#Remote-Configuration">set remote program-signals</a>).
This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<p><a name="QThreadEvents"></a><br><dt>&lsquo;<samp><span class="samp">QThreadEvents:1</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QThreadEvents:0</span></samp>&rsquo;<dd><a name="index-thread-create_002fexit-events_002c-remote-request-3528"></a><a name="index-g_t_0040samp_007bQThreadEvents_007d-packet-3529"></a>
Enable (&lsquo;<samp><span class="samp">QThreadEvents:1</span></samp>&rsquo;) or disable (&lsquo;<samp><span class="samp">QThreadEvents:0</span></samp>&rsquo;)
reporting of thread create and exit events. See <a href="thread-create-event.html#thread-create-event">thread create event</a>, for the reply specifications. For example, this is used in
non-stop mode when <span class="sc">gdb</span> stops a set of threads and
synchronously waits for the their corresponding stop replies. Without
exit events, if one of the threads exits, <span class="sc">gdb</span> would hang
forever not knowing that it should no longer expect a stop for that
same thread. <span class="sc">gdb</span> does not enable this feature unless the
stub reports that it supports it by including &lsquo;<samp><span class="samp">QThreadEvents+</span></samp>&rsquo; in
its &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; reply.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The request succeeded.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>An error occurred. The error number <var>nn</var> is given as hex digits.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates that &lsquo;<samp><span class="samp">QThreadEvents</span></samp>&rsquo; is not supported by
the stub.
</dl>
<p>Use of this packet is controlled by the <code>set remote thread-events</code>
command (see <a href="Remote-Configuration.html#Remote-Configuration">set remote thread-events</a>).
<br><dt>&lsquo;<samp><span class="samp">qRcmd,</span><var>command</var></samp>&rsquo;<dd><a name="index-execute-remote-command_002c-remote-request-3530"></a><a name="index-g_t_0040samp_007bqRcmd_007d-packet-3531"></a><var>command</var> (hex encoded) is passed to the local interpreter for
execution. Invalid commands should be reported using the output
string. Before the final result packet, the target may also respond
with a number of intermediate &lsquo;<samp><span class="samp">O</span><var>output</var></samp>&rsquo; console output
packets. <em>Implementors should note that providing access to a
stubs's interpreter may have security implications</em>.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>A command response with no output.
<br><dt>&lsquo;<samp><var>OUTPUT</var></samp>&rsquo;<dd>A command response with the hex encoded output string <var>OUTPUT</var>.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>Indicate a badly formed request.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates that &lsquo;<samp><span class="samp">qRcmd</span></samp>&rsquo; is not recognized.
</dl>
<p>(Note that the <code>qRcmd</code> packet's name is separated from the
command by a &lsquo;<samp><span class="samp">,</span></samp>&rsquo;, not a &lsquo;<samp><span class="samp">:</span></samp>&rsquo;, contrary to the naming
conventions above. Please don't use this packet as a model for new
packets.)
<br><dt>&lsquo;<samp><span class="samp">qSearch:memory:</span><var>address</var><span class="samp">;</span><var>length</var><span class="samp">;</span><var>search-pattern</var></samp>&rsquo;<dd><a name="index-searching-memory_002c-in-remote-debugging-3532"></a><a name="index-g_t_0040samp_007bqSearch_003amemory_007d-packet-3533"></a><a name="index-g_t_0040samp_007bqSearch-memory_007d-packet-3534"></a><a name="qSearch-memory"></a>Search <var>length</var> bytes at <var>address</var> for <var>search-pattern</var>.
Both <var>address</var> and <var>length</var> are encoded in hex;
<var>search-pattern</var> is a sequence of bytes, also hex encoded.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">0</span></samp>&rsquo;<dd>The pattern was not found.
<br><dt>&lsquo;<samp><span class="samp">1,address</span></samp>&rsquo;<dd>The pattern was found at <var>address</var>.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>A badly formed request or an error was encountered while searching memory.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates that &lsquo;<samp><span class="samp">qSearch:memory</span></samp>&rsquo; is not recognized.
</dl>
<br><dt>&lsquo;<samp><span class="samp">QStartNoAckMode</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bQStartNoAckMode_007d-packet-3535"></a><a name="QStartNoAckMode"></a>Request that the remote stub disable the normal &lsquo;<samp><span class="samp">+</span></samp>&rsquo;/&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
protocol acknowledgments (see <a href="Packet-Acknowledgment.html#Packet-Acknowledgment">Packet Acknowledgment</a>).
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The stub has switched to no-acknowledgment mode.
<span class="sc">gdb</span> acknowledges this reponse,
but neither the stub nor <span class="sc">gdb</span> shall send or expect further
&lsquo;<samp><span class="samp">+</span></samp>&rsquo;/&lsquo;<samp><span class="samp">-</span></samp>&rsquo; acknowledgments in the current connection.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates that the stub does not support no-acknowledgment mode.
</dl>
<br><dt>&lsquo;<samp><span class="samp">qSupported [:</span><var>gdbfeature</var><span class="samp"> [;</span><var>gdbfeature</var><span class="samp">]... ]</span></samp>&rsquo;<dd><a name="index-supported-packets_002c-remote-query-3536"></a><a name="index-features-of-the-remote-protocol-3537"></a><a name="index-g_t_0040samp_007bqSupported_007d-packet-3538"></a><a name="qSupported"></a>Tell the remote stub about features supported by <span class="sc">gdb</span>, and
query the stub for features it supports. This packet allows
<span class="sc">gdb</span> and the remote stub to take advantage of each others'
features. &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; also consolidates multiple feature probes
at startup, to improve <span class="sc">gdb</span> performance&mdash;a single larger
packet performs better than multiple smaller probe packets on
high-latency links. Some features may enable behavior which must not
be on by default, e.g. because it would confuse older clients or
stubs. Other features may describe packets which could be
automatically probed for, but are not. These features must be
reported before <span class="sc">gdb</span> will use them. This &ldquo;default
unsupported&rdquo; behavior is not appropriate for all packets, but it
helps to keep the initial connection time under control with new
versions of <span class="sc">gdb</span> which support increasing numbers of packets.
<p>Reply:
<dl>
<dt>&lsquo;<samp><var>stubfeature</var><span class="samp"> [;</span><var>stubfeature</var><span class="samp">]...</span></samp>&rsquo;<dd>The stub supports or does not support each returned <var>stubfeature</var>,
depending on the form of each <var>stubfeature</var> (see below for the
possible forms).
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates that &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; is not recognized,
or that no features needed to be reported to <span class="sc">gdb</span>.
</dl>
<p>The allowed forms for each feature (either a <var>gdbfeature</var> in the
&lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; packet, or a <var>stubfeature</var> in the response)
are:
<dl>
<dt>&lsquo;<samp><var>name</var><span class="samp">=</span><var>value</var></samp>&rsquo;<dd>The remote protocol feature <var>name</var> is supported, and associated
with the specified <var>value</var>. The format of <var>value</var> depends
on the feature, but it must not include a semicolon.
<br><dt>&lsquo;<samp><var>name</var><span class="samp">+</span></samp>&rsquo;<dd>The remote protocol feature <var>name</var> is supported, and does not
need an associated value.
<br><dt>&lsquo;<samp><var>name</var><span class="samp">-</span></samp>&rsquo;<dd>The remote protocol feature <var>name</var> is not supported.
<br><dt>&lsquo;<samp><var>name</var><span class="samp">?</span></samp>&rsquo;<dd>The remote protocol feature <var>name</var> may be supported, and
<span class="sc">gdb</span> should auto-detect support in some other way when it is
needed. This form will not be used for <var>gdbfeature</var> notifications,
but may be used for <var>stubfeature</var> responses.
</dl>
<p>Whenever the stub receives a &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; request, the
supplied set of <span class="sc">gdb</span> features should override any previous
request. This allows <span class="sc">gdb</span> to put the stub in a known
state, even if the stub had previously been communicating with
a different version of <span class="sc">gdb</span>.
<p>The following values of <var>gdbfeature</var> (for the packet sent by <span class="sc">gdb</span>)
are defined:
<dl>
<dt>&lsquo;<samp><span class="samp">multiprocess</span></samp>&rsquo;<dd>This feature indicates whether <span class="sc">gdb</span> supports multiprocess
extensions to the remote protocol. <span class="sc">gdb</span> does not use such
extensions unless the stub also reports that it supports them by
including &lsquo;<samp><span class="samp">multiprocess+</span></samp>&rsquo; in its &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; reply.
See <a href="multiprocess-extensions.html#multiprocess-extensions">multiprocess extensions</a>, for details.
<br><dt>&lsquo;<samp><span class="samp">xmlRegisters</span></samp>&rsquo;<dd>This feature indicates that <span class="sc">gdb</span> supports the XML target
description. If the stub sees &lsquo;<samp><span class="samp">xmlRegisters=</span></samp>&rsquo; with target
specific strings separated by a comma, it will report register
description.
<br><dt>&lsquo;<samp><span class="samp">qRelocInsn</span></samp>&rsquo;<dd>This feature indicates whether <span class="sc">gdb</span> supports the
&lsquo;<samp><span class="samp">qRelocInsn</span></samp>&rsquo; packet (see <a href="Tracepoint-Packets.html#Tracepoint-Packets">Relocate instruction reply packet</a>).
<br><dt>&lsquo;<samp><span class="samp">swbreak</span></samp>&rsquo;<dd>This feature indicates whether <span class="sc">gdb</span> supports the swbreak stop
reason in stop replies. See <a href="swbreak-stop-reason.html#swbreak-stop-reason">swbreak stop reason</a>, for details.
<br><dt>&lsquo;<samp><span class="samp">hwbreak</span></samp>&rsquo;<dd>This feature indicates whether <span class="sc">gdb</span> supports the hwbreak stop
reason in stop replies. See <a href="swbreak-stop-reason.html#swbreak-stop-reason">swbreak stop reason</a>, for details.
<br><dt>&lsquo;<samp><span class="samp">fork-events</span></samp>&rsquo;<dd>This feature indicates whether <span class="sc">gdb</span> supports fork event
extensions to the remote protocol. <span class="sc">gdb</span> does not use such
extensions unless the stub also reports that it supports them by
including &lsquo;<samp><span class="samp">fork-events+</span></samp>&rsquo; in its &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; reply.
<br><dt>&lsquo;<samp><span class="samp">vfork-events</span></samp>&rsquo;<dd>This feature indicates whether <span class="sc">gdb</span> supports vfork event
extensions to the remote protocol. <span class="sc">gdb</span> does not use such
extensions unless the stub also reports that it supports them by
including &lsquo;<samp><span class="samp">vfork-events+</span></samp>&rsquo; in its &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; reply.
<br><dt>&lsquo;<samp><span class="samp">exec-events</span></samp>&rsquo;<dd>This feature indicates whether <span class="sc">gdb</span> supports exec event
extensions to the remote protocol. <span class="sc">gdb</span> does not use such
extensions unless the stub also reports that it supports them by
including &lsquo;<samp><span class="samp">exec-events+</span></samp>&rsquo; in its &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; reply.
<br><dt>&lsquo;<samp><span class="samp">vContSupported</span></samp>&rsquo;<dd>This feature indicates whether <span class="sc">gdb</span> wants to know the
supported actions in the reply to &lsquo;<samp><span class="samp">vCont?</span></samp>&rsquo; packet.
</dl>
<p>Stubs should ignore any unknown values for
<var>gdbfeature</var>. Any <span class="sc">gdb</span> which sends a &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo;
packet supports receiving packets of unlimited length (earlier
versions of <span class="sc">gdb</span> may reject overly long responses). Additional values
for <var>gdbfeature</var> may be defined in the future to let the stub take
advantage of new features in <span class="sc">gdb</span>, e.g. incompatible
improvements in the remote protocol&mdash;the &lsquo;<samp><span class="samp">multiprocess</span></samp>&rsquo; feature is
an example of such a feature. The stub's reply should be independent
of the <var>gdbfeature</var> entries sent by <span class="sc">gdb</span>; first <span class="sc">gdb</span>
describes all the features it supports, and then the stub replies with
all the features it supports.
<p>Similarly, <span class="sc">gdb</span> will silently ignore unrecognized stub feature
responses, as long as each response uses one of the standard forms.
<p>Some features are flags. A stub which supports a flag feature
should respond with a &lsquo;<samp><span class="samp">+</span></samp>&rsquo; form response. Other features
require values, and the stub should respond with an &lsquo;<samp><span class="samp">=</span></samp>&rsquo;
form response.
<p>Each feature has a default value, which <span class="sc">gdb</span> will use if
&lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; is not available or if the feature is not mentioned
in the &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response. The default values are fixed; a
stub is free to omit any feature responses that match the defaults.
<p>Not all features can be probed, but for those which can, the probing
mechanism is useful: in some cases, a stub's internal
architecture may not allow the protocol layer to know some information
about the underlying target in advance. This is especially common in
stubs which may be configured for multiple targets.
<p>These are the currently defined stub features and their properties:
<p><table summary=""><!-- NOTE: The first row should be @headitem, but we do not yet require -->
<!-- a new enough version of Texinfo (4.7) to use @headitem. -->
<tr align="left"><td valign="top" width="35%">Feature Name
</td><td valign="top" width="20%">Value Required
</td><td valign="top" width="12%">Default
</td><td valign="top" width="20%">Probe Allowed
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">PacketSize</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:auxv:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:btrace:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:btrace-conf:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:exec-file:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:features:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:libraries:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:libraries-svr4:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">augmented-libraries-svr4-read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:memory-map:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:sdata:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:spu:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:spu:write</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:siginfo:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:siginfo:write</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:threads:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:traceframe-info:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:uib:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">qXfer:fdpic:read</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">Qbtrace:off</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">Qbtrace:bts</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">Qbtrace:pt</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">Qbtrace-conf:bts:size</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">Qbtrace-conf:pt:size</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">QNonStop</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">QCatchSyscalls</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">QPassSignals</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">QStartNoAckMode</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">Yes
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">multiprocess</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">ConditionalBreakpoints</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">ConditionalTracepoints</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">ReverseContinue</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">ReverseStep</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">TracepointSource</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">QAgent</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">QAllow</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">QDisableRandomization</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">EnableDisableTracepoints</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">QTBuffer:size</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">tracenz</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">BreakpointCommands</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">swbreak</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">hwbreak</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">fork-events</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">vfork-events</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">exec-events</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">QThreadEvents</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<p><br></td></tr><tr align="left"><td valign="top" width="35%">&lsquo;<samp><span class="samp">no-resumed</span></samp>&rsquo;
</td><td valign="top" width="20%">No
</td><td valign="top" width="12%">&lsquo;<samp><span class="samp">-</span></samp>&rsquo;
</td><td valign="top" width="20%">No
<br></td></tr></table>
<p>These are the currently defined stub features, in more detail:
<a name="index-packet-size_002c-remote-protocol-3539"></a>
<dl><dt>&lsquo;<samp><span class="samp">PacketSize=</span><var>bytes</var></samp>&rsquo;<dd>The remote stub can accept packets up to at least <var>bytes</var> in
length. <span class="sc">gdb</span> will send packets up to this size for bulk
transfers, and will never send larger packets. This is a limit on the
data characters in the packet, including the frame and checksum.
There is no trailing NUL byte in a remote protocol packet; if the stub
stores packets in a NUL-terminated format, it should allow an extra
byte in its buffer for the NUL. If this stub feature is not supported,
<span class="sc">gdb</span> guesses based on the size of the &lsquo;<samp><span class="samp">g</span></samp>&rsquo; packet response.
<br><dt>&lsquo;<samp><span class="samp">qXfer:auxv:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:auxv:read</span></samp>&rsquo; packet
(see <a href="qXfer-auxiliary-vector-read.html#qXfer-auxiliary-vector-read">qXfer auxiliary vector read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:btrace:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:btrace:read</span></samp>&rsquo;
packet (see <a href="qXfer-btrace-read.html#qXfer-btrace-read">qXfer btrace read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:btrace-conf:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:btrace-conf:read</span></samp>&rsquo;
packet (see <a href="qXfer-btrace_002dconf-read.html#qXfer-btrace_002dconf-read">qXfer btrace-conf read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:exec-file:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:exec-file:read</span></samp>&rsquo; packet
(see <a href="qXfer-executable-filename-read.html#qXfer-executable-filename-read">qXfer executable filename read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:features:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:features:read</span></samp>&rsquo; packet
(see <a href="qXfer-target-description-read.html#qXfer-target-description-read">qXfer target description read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:libraries:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:libraries:read</span></samp>&rsquo; packet
(see <a href="qXfer-library-list-read.html#qXfer-library-list-read">qXfer library list read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:libraries-svr4:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:libraries-svr4:read</span></samp>&rsquo; packet
(see <a href="qXfer-svr4-library-list-read.html#qXfer-svr4-library-list-read">qXfer svr4 library list read</a>).
<br><dt>&lsquo;<samp><span class="samp">augmented-libraries-svr4-read</span></samp>&rsquo;<dd>The remote stub understands the augmented form of the
&lsquo;<samp><span class="samp">qXfer:libraries-svr4:read</span></samp>&rsquo; packet
(see <a href="qXfer-svr4-library-list-read.html#qXfer-svr4-library-list-read">qXfer svr4 library list read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:memory-map:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:memory-map:read</span></samp>&rsquo; packet
(see <a href="qXfer-memory-map-read.html#qXfer-memory-map-read">qXfer memory map read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:sdata:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:sdata:read</span></samp>&rsquo; packet
(see <a href="qXfer-sdata-read.html#qXfer-sdata-read">qXfer sdata read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:spu:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:spu:read</span></samp>&rsquo; packet
(see <a href="qXfer-spu-read.html#qXfer-spu-read">qXfer spu read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:spu:write</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:spu:write</span></samp>&rsquo; packet
(see <a href="qXfer-spu-write.html#qXfer-spu-write">qXfer spu write</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:siginfo:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:siginfo:read</span></samp>&rsquo; packet
(see <a href="qXfer-siginfo-read.html#qXfer-siginfo-read">qXfer siginfo read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:siginfo:write</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:siginfo:write</span></samp>&rsquo; packet
(see <a href="qXfer-siginfo-write.html#qXfer-siginfo-write">qXfer siginfo write</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:threads:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:threads:read</span></samp>&rsquo; packet
(see <a href="qXfer-threads-read.html#qXfer-threads-read">qXfer threads read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:traceframe-info:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:traceframe-info:read</span></samp>&rsquo;
packet (see <a href="qXfer-traceframe-info-read.html#qXfer-traceframe-info-read">qXfer traceframe info read</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:uib:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:uib:read</span></samp>&rsquo;
packet (see <a href="qXfer-unwind-info-block.html#qXfer-unwind-info-block">qXfer unwind info block</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:fdpic:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:fdpic:read</span></samp>&rsquo;
packet (see <a href="qXfer-fdpic-loadmap-read.html#qXfer-fdpic-loadmap-read">qXfer fdpic loadmap read</a>).
<br><dt>&lsquo;<samp><span class="samp">QNonStop</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">QNonStop</span></samp>&rsquo; packet
(see <a href="QNonStop.html#QNonStop">QNonStop</a>).
<br><dt>&lsquo;<samp><span class="samp">QCatchSyscalls</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">QCatchSyscalls</span></samp>&rsquo; packet
(see <a href="QCatchSyscalls.html#QCatchSyscalls">QCatchSyscalls</a>).
<br><dt>&lsquo;<samp><span class="samp">QPassSignals</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">QPassSignals</span></samp>&rsquo; packet
(see <a href="QPassSignals.html#QPassSignals">QPassSignals</a>).
<br><dt>&lsquo;<samp><span class="samp">QStartNoAckMode</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">QStartNoAckMode</span></samp>&rsquo; packet and
prefers to operate in no-acknowledgment mode. See <a href="Packet-Acknowledgment.html#Packet-Acknowledgment">Packet Acknowledgment</a>.
<br><dt>&lsquo;<samp><span class="samp">multiprocess</span></samp>&rsquo;<dd><a name="multiprocess-extensions"></a><a name="index-multiprocess-extensions_002c-in-remote-protocol-3540"></a>The remote stub understands the multiprocess extensions to the remote
protocol syntax. The multiprocess extensions affect the syntax of
thread IDs in both packets and replies (see <a href="thread_002did-syntax.html#thread_002did-syntax">thread-id syntax</a>), and
add process IDs to the &lsquo;<samp><span class="samp">D</span></samp>&rsquo; packet and &lsquo;<samp><span class="samp">W</span></samp>&rsquo; and &lsquo;<samp><span class="samp">X</span></samp>&rsquo;
replies. Note that reporting this feature indicates support for the
syntactic extensions only, not that the stub necessarily supports
debugging of more than one process at a time. The stub must not use
multiprocess extensions in packet replies unless <span class="sc">gdb</span> has also
indicated it supports them in its &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; request.
<br><dt>&lsquo;<samp><span class="samp">qXfer:osdata:read</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">qXfer:osdata:read</span></samp>&rsquo; packet
((see <a href="qXfer-osdata-read.html#qXfer-osdata-read">qXfer osdata read</a>).
<br><dt>&lsquo;<samp><span class="samp">ConditionalBreakpoints</span></samp>&rsquo;<dd>The target accepts and implements evaluation of conditional expressions
defined for breakpoints. The target will only report breakpoint triggers
when such conditions are true (see <a href="Conditions.html#Conditions">Break Conditions</a>).
<br><dt>&lsquo;<samp><span class="samp">ConditionalTracepoints</span></samp>&rsquo;<dd>The remote stub accepts and implements conditional expressions defined
for tracepoints (see <a href="Tracepoint-Conditions.html#Tracepoint-Conditions">Tracepoint Conditions</a>).
<br><dt>&lsquo;<samp><span class="samp">ReverseContinue</span></samp>&rsquo;<dd>The remote stub accepts and implements the reverse continue packet
(see <a href="bc.html#bc">bc</a>).
<br><dt>&lsquo;<samp><span class="samp">ReverseStep</span></samp>&rsquo;<dd>The remote stub accepts and implements the reverse step packet
(see <a href="bs.html#bs">bs</a>).
<br><dt>&lsquo;<samp><span class="samp">TracepointSource</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">QTDPsrc</span></samp>&rsquo; packet that supplies
the source form of tracepoint definitions.
<br><dt>&lsquo;<samp><span class="samp">QAgent</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">QAgent</span></samp>&rsquo; packet.
<br><dt>&lsquo;<samp><span class="samp">QAllow</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">QAllow</span></samp>&rsquo; packet.
<br><dt>&lsquo;<samp><span class="samp">QDisableRandomization</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">QDisableRandomization</span></samp>&rsquo; packet.
<br><dt>&lsquo;<samp><span class="samp">StaticTracepoint</span></samp>&rsquo;<dd><a name="index-static-tracepoints_002c-in-remote-protocol-3541"></a>The remote stub supports static tracepoints.
<br><dt>&lsquo;<samp><span class="samp">InstallInTrace</span></samp>&rsquo;<dd><a name="install-tracepoint-in-tracing"></a>The remote stub supports installing tracepoint in tracing.
<br><dt>&lsquo;<samp><span class="samp">EnableDisableTracepoints</span></samp>&rsquo;<dd>The remote stub supports the &lsquo;<samp><span class="samp">QTEnable</span></samp>&rsquo; (see <a href="QTEnable.html#QTEnable">QTEnable</a>) and
&lsquo;<samp><span class="samp">QTDisable</span></samp>&rsquo; (see <a href="QTDisable.html#QTDisable">QTDisable</a>) packets that allow tracepoints
to be enabled and disabled while a trace experiment is running.
<br><dt>&lsquo;<samp><span class="samp">QTBuffer:size</span></samp>&rsquo;<dd>The remote stub supports the &lsquo;<samp><span class="samp">QTBuffer:size</span></samp>&rsquo; (see <a href="QTBuffer_002dsize.html#QTBuffer_002dsize">QTBuffer-size</a>)
packet that allows to change the size of the trace buffer.
<br><dt>&lsquo;<samp><span class="samp">tracenz</span></samp>&rsquo;<dd><a name="index-string-tracing_002c-in-remote-protocol-3542"></a>The remote stub supports the &lsquo;<samp><span class="samp">tracenz</span></samp>&rsquo; bytecode for collecting strings.
See <a href="Bytecode-Descriptions.html#Bytecode-Descriptions">Bytecode Descriptions</a> for details about the bytecode.
<br><dt>&lsquo;<samp><span class="samp">BreakpointCommands</span></samp>&rsquo;<dd><a name="index-breakpoint-commands_002c-in-remote-protocol-3543"></a>The remote stub supports running a breakpoint's command list itself,
rather than reporting the hit to <span class="sc">gdb</span>.
<br><dt>&lsquo;<samp><span class="samp">Qbtrace:off</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">Qbtrace:off</span></samp>&rsquo; packet.
<br><dt>&lsquo;<samp><span class="samp">Qbtrace:bts</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">Qbtrace:bts</span></samp>&rsquo; packet.
<br><dt>&lsquo;<samp><span class="samp">Qbtrace:pt</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">Qbtrace:pt</span></samp>&rsquo; packet.
<br><dt>&lsquo;<samp><span class="samp">Qbtrace-conf:bts:size</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">Qbtrace-conf:bts:size</span></samp>&rsquo; packet.
<br><dt>&lsquo;<samp><span class="samp">Qbtrace-conf:pt:size</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">Qbtrace-conf:pt:size</span></samp>&rsquo; packet.
<br><dt>&lsquo;<samp><span class="samp">swbreak</span></samp>&rsquo;<dd>The remote stub reports the &lsquo;<samp><span class="samp">swbreak</span></samp>&rsquo; stop reason for memory
breakpoints.
<br><dt>&lsquo;<samp><span class="samp">hwbreak</span></samp>&rsquo;<dd>The remote stub reports the &lsquo;<samp><span class="samp">hwbreak</span></samp>&rsquo; stop reason for hardware
breakpoints.
<br><dt>&lsquo;<samp><span class="samp">fork-events</span></samp>&rsquo;<dd>The remote stub reports the &lsquo;<samp><span class="samp">fork</span></samp>&rsquo; stop reason for fork events.
<br><dt>&lsquo;<samp><span class="samp">vfork-events</span></samp>&rsquo;<dd>The remote stub reports the &lsquo;<samp><span class="samp">vfork</span></samp>&rsquo; stop reason for vfork events
and vforkdone events.
<br><dt>&lsquo;<samp><span class="samp">exec-events</span></samp>&rsquo;<dd>The remote stub reports the &lsquo;<samp><span class="samp">exec</span></samp>&rsquo; stop reason for exec events.
<br><dt>&lsquo;<samp><span class="samp">vContSupported</span></samp>&rsquo;<dd>The remote stub reports the supported actions in the reply to
&lsquo;<samp><span class="samp">vCont?</span></samp>&rsquo; packet.
<br><dt>&lsquo;<samp><span class="samp">QThreadEvents</span></samp>&rsquo;<dd>The remote stub understands the &lsquo;<samp><span class="samp">QThreadEvents</span></samp>&rsquo; packet.
<br><dt>&lsquo;<samp><span class="samp">no-resumed</span></samp>&rsquo;<dd>The remote stub reports the &lsquo;<samp><span class="samp">N</span></samp>&rsquo; stop reply.
</dl>
<br><dt>&lsquo;<samp><span class="samp">qSymbol::</span></samp>&rsquo;<dd><a name="index-symbol-lookup_002c-remote-request-3544"></a><a name="index-g_t_0040samp_007bqSymbol_007d-packet-3545"></a>Notify the target that <span class="sc">gdb</span> is prepared to serve symbol lookup
requests. Accept requests from the target for the values of symbols.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The target does not need to look up any (more) symbols.
<br><dt>&lsquo;<samp><span class="samp">qSymbol:</span><var>sym_name</var></samp>&rsquo;<dd>The target requests the value of symbol <var>sym_name</var> (hex encoded).
<span class="sc">gdb</span> may provide the value by using the
&lsquo;<samp><span class="samp">qSymbol:</span><var>sym_value</var><span class="samp">:</span><var>sym_name</var></samp>&rsquo; message, described
below.
</dl>
<br><dt>&lsquo;<samp><span class="samp">qSymbol:</span><var>sym_value</var><span class="samp">:</span><var>sym_name</var></samp>&rsquo;<dd>Set the value of <var>sym_name</var> to <var>sym_value</var>.
<p><var>sym_name</var> (hex encoded) is the name of a symbol whose value the
target has previously requested.
<p><var>sym_value</var> (hex) is the value for symbol <var>sym_name</var>. If
<span class="sc">gdb</span> cannot supply a value for <var>sym_name</var>, then this field
will be empty.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The target does not need to look up any (more) symbols.
<br><dt>&lsquo;<samp><span class="samp">qSymbol:</span><var>sym_name</var></samp>&rsquo;<dd>The target requests the value of a new symbol <var>sym_name</var> (hex
encoded). <span class="sc">gdb</span> will continue to supply the values of symbols
(if available), until the target ceases to request them.
</dl>
<br><dt>&lsquo;<samp><span class="samp">qTBuffer</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTBuffer</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTDisconnected</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTDP</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTDPsrc</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTDV</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">qTfP</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">qTfV</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTFrame</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">qTMinFTPILen</span></samp>&rsquo;<dd>
See <a href="Tracepoint-Packets.html#Tracepoint-Packets">Tracepoint Packets</a>.
<br><dt>&lsquo;<samp><span class="samp">qThreadExtraInfo,</span><var>thread-id</var></samp>&rsquo;<dd><a name="index-thread-attributes-info_002c-remote-request-3546"></a><a name="index-g_t_0040samp_007bqThreadExtraInfo_007d-packet-3547"></a>Obtain from the target OS a printable string description of thread
attributes for the thread <var>thread-id</var>; see <a href="thread_002did-syntax.html#thread_002did-syntax">thread-id syntax</a>,
for the forms of <var>thread-id</var>. This
string may contain anything that the target OS thinks is interesting
for <span class="sc">gdb</span> to tell the user about the thread. The string is
displayed in <span class="sc">gdb</span>'s <code>info threads</code> display. Some
examples of possible thread extra info strings are &lsquo;<samp><span class="samp">Runnable</span></samp>&rsquo;, or
&lsquo;<samp><span class="samp">Blocked on Mutex</span></samp>&rsquo;.
<p>Reply:
<dl>
<dt>&lsquo;<samp><var>XX</var><span class="samp">...</span></samp>&rsquo;<dd>Where &lsquo;<samp><var>XX</var><span class="samp">...</span></samp>&rsquo; is a hex encoding of <span class="sc">ascii</span> data,
comprising the printable string containing the extra information about
the thread's attributes.
</dl>
<p>(Note that the <code>qThreadExtraInfo</code> packet's name is separated from
the command by a &lsquo;<samp><span class="samp">,</span></samp>&rsquo;, not a &lsquo;<samp><span class="samp">:</span></samp>&rsquo;, contrary to the naming
conventions above. Please don't use this packet as a model for new
packets.)
<br><dt>&lsquo;<samp><span class="samp">QTNotes</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">qTP</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTSave</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">qTsP</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">qTsV</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTStart</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTStop</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTEnable</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTDisable</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTinit</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">QTro</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">qTStatus</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">qTV</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">qTfSTM</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">qTsSTM</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">qTSTMat</span></samp>&rsquo;<dd>See <a href="Tracepoint-Packets.html#Tracepoint-Packets">Tracepoint Packets</a>.
<br><dt>&lsquo;<samp><span class="samp">qXfer:</span><var>object</var><span class="samp">:read:</span><var>annex</var><span class="samp">:</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="index-read-special-object_002c-remote-request-3548"></a><a name="index-g_t_0040samp_007bqXfer_007d-packet-3549"></a><a name="qXfer-read"></a>Read uninterpreted bytes from the target's special data area
identified by the keyword <var>object</var>. Request <var>length</var> bytes
starting at <var>offset</var> bytes into the data. The content and
encoding of <var>annex</var> is specific to <var>object</var>; it can supply
additional details about what data to access.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">m </span><var>data</var></samp>&rsquo;<dd>Data <var>data</var> (see <a href="Binary-Data.html#Binary-Data">Binary Data</a>) has been read from the
target. There may be more data at a higher address (although
it is permitted to return &lsquo;<samp><span class="samp">m</span></samp>&rsquo; even for the last valid
block of data, as long as at least one byte of data was read).
It is possible for <var>data</var> to have fewer bytes than the <var>length</var> in the
request.
<br><dt>&lsquo;<samp><span class="samp">l </span><var>data</var></samp>&rsquo;<dd>Data <var>data</var> (see <a href="Binary-Data.html#Binary-Data">Binary Data</a>) has been read from the target.
There is no more data to be read. It is possible for <var>data</var> to
have fewer bytes than the <var>length</var> in the request.
<br><dt>&lsquo;<samp><span class="samp">l</span></samp>&rsquo;<dd>The <var>offset</var> in the request is at the end of the data.
There is no more data to be read.
<br><dt>&lsquo;<samp><span class="samp">E00</span></samp>&rsquo;<dd>The request was malformed, or <var>annex</var> was invalid.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>The offset was invalid, or there was an error encountered reading the data.
The <var>nn</var> part is a hex-encoded <code>errno</code> value.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates the <var>object</var> string was not recognized by
the stub, or that the object does not support reading.
</dl>
<p>Here are the specific requests of this form defined so far. All the
&lsquo;<samp><span class="samp">qXfer:</span><var>object</var><span class="samp">:read:...</span></samp>&rsquo; requests use the same reply
formats, listed above.
<dl>
<dt>&lsquo;<samp><span class="samp">qXfer:auxv:read::</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-auxiliary-vector-read"></a>Access the target's <dfn>auxiliary vector</dfn>. See <a href="OS-Information.html#OS-Information">auxiliary vector</a>. Note <var>annex</var> must be empty.
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:btrace:read:</span><var>annex</var><span class="samp">:</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-btrace-read"></a>Return a description of the current branch trace.
See <a href="Branch-Trace-Format.html#Branch-Trace-Format">Branch Trace Format</a>. The annex part of the generic &lsquo;<samp><span class="samp">qXfer</span></samp>&rsquo;
packet may have one of the following values:
<dl>
<dt><code>all</code><dd>Returns all available branch trace.
<br><dt><code>new</code><dd>Returns all available branch trace if the branch trace changed since
the last read request.
<br><dt><code>delta</code><dd>Returns the new branch trace since the last read request. Adds a new
block to the end of the trace that begins at zero and ends at the source
location of the first branch in the trace buffer. This extra block is
used to stitch traces together.
<p>If the trace buffer overflowed, returns an error indicating the overflow.
</dl>
<p>This packet is not probed by default; the remote stub must request it
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:btrace-conf:read::</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-btrace_002dconf-read"></a>Return a description of the current branch trace configuration.
See <a href="Branch-Trace-Configuration-Format.html#Branch-Trace-Configuration-Format">Branch Trace Configuration Format</a>.
<p>This packet is not probed by default; the remote stub must request it
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:exec-file:read:</span><var>annex</var><span class="samp">:</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-executable-filename-read"></a>Return the full absolute name of the file that was executed to create
a process running on the remote system. The annex specifies the
numeric process ID of the process to query, encoded as a hexadecimal
number. If the annex part is empty the remote stub should return the
filename corresponding to the currently executing process.
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:features:read:</span><var>annex</var><span class="samp">:</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-target-description-read"></a>Access the <dfn>target description</dfn>. See <a href="Target-Descriptions.html#Target-Descriptions">Target Descriptions</a>. The
annex specifies which XML document to access. The main description is
always loaded from the &lsquo;<samp><span class="samp">target.xml</span></samp>&rsquo; annex.
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:libraries:read:</span><var>annex</var><span class="samp">:</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-library-list-read"></a>Access the target's list of loaded libraries. See <a href="Library-List-Format.html#Library-List-Format">Library List Format</a>.
The annex part of the generic &lsquo;<samp><span class="samp">qXfer</span></samp>&rsquo; packet must be empty
(see <a href="qXfer-read.html#qXfer-read">qXfer read</a>).
<p>Targets which maintain a list of libraries in the program's memory do
not need to implement this packet; it is designed for platforms where
the operating system manages the list of loaded libraries.
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:libraries-svr4:read:</span><var>annex</var><span class="samp">:</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-svr4-library-list-read"></a>Access the target's list of loaded libraries when the target is an SVR4
platform. See <a href="Library-List-Format-for-SVR4-Targets.html#Library-List-Format-for-SVR4-Targets">Library List Format for SVR4 Targets</a>. The annex part
of the generic &lsquo;<samp><span class="samp">qXfer</span></samp>&rsquo; packet must be empty unless the remote
stub indicated it supports the augmented form of this packet
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response
(see <a href="qXfer-read.html#qXfer-read">qXfer read</a>, <a href="qSupported.html#qSupported">qSupported</a>).
<p>This packet is optional for better performance on SVR4 targets.
<span class="sc">gdb</span> uses memory read packets to read the SVR4 library list otherwise.
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<p>If the remote stub indicates it supports the augmented form of this
packet then the annex part of the generic &lsquo;<samp><span class="samp">qXfer</span></samp>&rsquo; packet may
contain a semicolon-separated list of &lsquo;<samp><var>name</var><span class="samp">=</span><var>value</var></samp>&rsquo;
arguments. The currently supported arguments are:
<dl>
<dt><code>start=</code><var>address</var><dd>A hexadecimal number specifying the address of the &lsquo;<samp><span class="samp">struct
link_map</span></samp>&rsquo; to start reading the library list from. If unset or zero
then the first &lsquo;<samp><span class="samp">struct link_map</span></samp>&rsquo; in the library list will be
chosen as the starting point.
<br><dt><code>prev=</code><var>address</var><dd>A hexadecimal number specifying the address of the &lsquo;<samp><span class="samp">struct
link_map</span></samp>&rsquo; immediately preceding the &lsquo;<samp><span class="samp">struct link_map</span></samp>&rsquo;
specified by the &lsquo;<samp><span class="samp">start</span></samp>&rsquo; argument. If unset or zero then
the remote stub will expect that no &lsquo;<samp><span class="samp">struct link_map</span></samp>&rsquo;
exists prior to the starting point.
</dl>
<p>Arguments that are not understood by the remote stub will be silently
ignored.
<br><dt>&lsquo;<samp><span class="samp">qXfer:memory-map:read::</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-memory-map-read"></a>Access the target's <dfn>memory-map</dfn>. See <a href="Memory-Map-Format.html#Memory-Map-Format">Memory Map Format</a>. The
annex part of the generic &lsquo;<samp><span class="samp">qXfer</span></samp>&rsquo; packet must be empty
(see <a href="qXfer-read.html#qXfer-read">qXfer read</a>).
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:sdata:read::</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-sdata-read"></a>Read contents of the extra collected static tracepoint marker
information. The annex part of the generic &lsquo;<samp><span class="samp">qXfer</span></samp>&rsquo; packet must
be empty (see <a href="qXfer-read.html#qXfer-read">qXfer read</a>). See <a href="Tracepoint-Actions.html#Tracepoint-Actions">Tracepoint Action Lists</a>.
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response
(see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:siginfo:read::</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-siginfo-read"></a>Read contents of the extra signal information on the target
system. The annex part of the generic &lsquo;<samp><span class="samp">qXfer</span></samp>&rsquo; packet must be
empty (see <a href="qXfer-read.html#qXfer-read">qXfer read</a>).
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response
(see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:spu:read:</span><var>annex</var><span class="samp">:</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-spu-read"></a>Read contents of an <code>spufs</code> file on the target system. The
annex specifies which file to read; it must be of the form
<samp><var>id</var><span class="file">/</span><var>name</var></samp>, where <var>id</var> specifies an SPU context ID
in the target process, and <var>name</var> identifes the <code>spufs</code> file
in that context to be accessed.
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response
(see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:threads:read::</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-threads-read"></a>Access the list of threads on target. See <a href="Thread-List-Format.html#Thread-List-Format">Thread List Format</a>. The
annex part of the generic &lsquo;<samp><span class="samp">qXfer</span></samp>&rsquo; packet must be empty
(see <a href="qXfer-read.html#qXfer-read">qXfer read</a>).
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:traceframe-info:read::</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-traceframe-info-read"></a>Return a description of the current traceframe's contents.
See <a href="Traceframe-Info-Format.html#Traceframe-Info-Format">Traceframe Info Format</a>. The annex part of the generic
&lsquo;<samp><span class="samp">qXfer</span></samp>&rsquo; packet must be empty (see <a href="qXfer-read.html#qXfer-read">qXfer read</a>).
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:uib:read:</span><var>pc</var><span class="samp">:</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-unwind-info-block"></a>Return the unwind information block for <var>pc</var>. This packet is used
on OpenVMS/ia64 to ask the kernel unwind information.
<p>This packet is not probed by default.
<br><dt>&lsquo;<samp><span class="samp">qXfer:fdpic:read:</span><var>annex</var><span class="samp">:</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-fdpic-loadmap-read"></a>Read contents of <code>loadmap</code>s on the target system. The
annex, either &lsquo;<samp><span class="samp">exec</span></samp>&rsquo; or &lsquo;<samp><span class="samp">interp</span></samp>&rsquo;, specifies which <code>loadmap</code>,
executable <code>loadmap</code> or interpreter <code>loadmap</code> to read.
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:osdata:read::</span><var>offset</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="qXfer-osdata-read"></a>Access the target's <dfn>operating system information</dfn>.
See <a href="Operating-System-Information.html#Operating-System-Information">Operating System Information</a>.
</dl>
<br><dt>&lsquo;<samp><span class="samp">qXfer:</span><var>object</var><span class="samp">:write:</span><var>annex</var><span class="samp">:</span><var>offset</var><span class="samp">:</span><var>data</var><span class="samp">...</span></samp>&rsquo;<dd><a name="index-write-data-into-object_002c-remote-request-3550"></a><a name="qXfer-write"></a>Write uninterpreted bytes into the target's special data area
identified by the keyword <var>object</var>, starting at <var>offset</var> bytes
into the data. The binary-encoded data (see <a href="Binary-Data.html#Binary-Data">Binary Data</a>) to be
written is given by <var>data</var><small class="dots">...</small>. The content and encoding of <var>annex</var>
is specific to <var>object</var>; it can supply additional details about what data
to access.
<p>Reply:
<dl>
<dt>&lsquo;<samp><var>nn</var></samp>&rsquo;<dd><var>nn</var> (hex encoded) is the number of bytes written.
This may be fewer bytes than supplied in the request.
<br><dt>&lsquo;<samp><span class="samp">E00</span></samp>&rsquo;<dd>The request was malformed, or <var>annex</var> was invalid.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>The offset was invalid, or there was an error encountered writing the data.
The <var>nn</var> part is a hex-encoded <code>errno</code> value.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>An empty reply indicates the <var>object</var> string was not
recognized by the stub, or that the object does not support writing.
</dl>
<p>Here are the specific requests of this form defined so far. All the
&lsquo;<samp><span class="samp">qXfer:</span><var>object</var><span class="samp">:write:...</span></samp>&rsquo; requests use the same reply
formats, listed above.
<dl>
<dt>&lsquo;<samp><span class="samp">qXfer:siginfo:write::</span><var>offset</var><span class="samp">:</span><var>data</var><span class="samp">...</span></samp>&rsquo;<dd><a name="qXfer-siginfo-write"></a>Write <var>data</var> to the extra signal information on the target system.
The annex part of the generic &lsquo;<samp><span class="samp">qXfer</span></samp>&rsquo; packet must be
empty (see <a href="qXfer-write.html#qXfer-write">qXfer write</a>).
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response
(see <a href="qSupported.html#qSupported">qSupported</a>).
<br><dt>&lsquo;<samp><span class="samp">qXfer:spu:write:</span><var>annex</var><span class="samp">:</span><var>offset</var><span class="samp">:</span><var>data</var><span class="samp">...</span></samp>&rsquo;<dd><a name="qXfer-spu-write"></a>Write <var>data</var> to an <code>spufs</code> file on the target system. The
annex specifies which file to write; it must be of the form
<samp><var>id</var><span class="file">/</span><var>name</var></samp>, where <var>id</var> specifies an SPU context ID
in the target process, and <var>name</var> identifes the <code>spufs</code> file
in that context to be accessed.
<p>This packet is not probed by default; the remote stub must request it,
by supplying an appropriate &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo; response (see <a href="qSupported.html#qSupported">qSupported</a>).
</dl>
<br><dt>&lsquo;<samp><span class="samp">qXfer:</span><var>object</var><span class="samp">:</span><var>operation</var><span class="samp">:...</span></samp>&rsquo;<dd>Requests of this form may be added in the future. When a stub does
not recognize the <var>object</var> keyword, or its support for
<var>object</var> does not recognize the <var>operation</var> keyword, the stub
must respond with an empty packet.
<br><dt>&lsquo;<samp><span class="samp">qAttached:</span><var>pid</var></samp>&rsquo;<dd><a name="index-query-attached_002c-remote-request-3551"></a><a name="index-g_t_0040samp_007bqAttached_007d-packet-3552"></a>Return an indication of whether the remote server attached to an
existing process or created a new process. When the multiprocess
protocol extensions are supported (see <a href="multiprocess-extensions.html#multiprocess-extensions">multiprocess extensions</a>),
<var>pid</var> is an integer in hexadecimal format identifying the target
process. Otherwise, <span class="sc">gdb</span> will omit the <var>pid</var> field and
the query packet will be simplified as &lsquo;<samp><span class="samp">qAttached</span></samp>&rsquo;.
<p>This query is used, for example, to know whether the remote process
should be detached or killed when a <span class="sc">gdb</span> session is ended with
the <code>quit</code> command.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">1</span></samp>&rsquo;<dd>The remote server attached to an existing process.
<br><dt>&lsquo;<samp><span class="samp">0</span></samp>&rsquo;<dd>The remote server created a new process.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>A badly formed request or an error was encountered.
</dl>
<br><dt>&lsquo;<samp><span class="samp">Qbtrace:bts</span></samp>&rsquo;<dd>Enable branch tracing for the current thread using Branch Trace Store.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>Branch tracing has been enabled.
<br><dt>&lsquo;<samp><span class="samp">E.errtext</span></samp>&rsquo;<dd>A badly formed request or an error was encountered.
</dl>
<br><dt>&lsquo;<samp><span class="samp">Qbtrace:pt</span></samp>&rsquo;<dd>Enable branch tracing for the current thread using Intel Processor Trace.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>Branch tracing has been enabled.
<br><dt>&lsquo;<samp><span class="samp">E.errtext</span></samp>&rsquo;<dd>A badly formed request or an error was encountered.
</dl>
<br><dt>&lsquo;<samp><span class="samp">Qbtrace:off</span></samp>&rsquo;<dd>Disable branch tracing for the current thread.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>Branch tracing has been disabled.
<br><dt>&lsquo;<samp><span class="samp">E.errtext</span></samp>&rsquo;<dd>A badly formed request or an error was encountered.
</dl>
<br><dt>&lsquo;<samp><span class="samp">Qbtrace-conf:bts:size=</span><var>value</var></samp>&rsquo;<dd>Set the requested ring buffer size for new threads that use the
btrace recording method in bts format.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The ring buffer size has been set.
<br><dt>&lsquo;<samp><span class="samp">E.errtext</span></samp>&rsquo;<dd>A badly formed request or an error was encountered.
</dl>
<br><dt>&lsquo;<samp><span class="samp">Qbtrace-conf:pt:size=</span><var>value</var></samp>&rsquo;<dd>Set the requested ring buffer size for new threads that use the
btrace recording method in pt format.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The ring buffer size has been set.
<br><dt>&lsquo;<samp><span class="samp">E.errtext</span></samp>&rsquo;<dd>A badly formed request or an error was encountered.
</dl>
</dl>
<div class="footnote">
<hr>
<h4>Footnotes</h4><p class="footnote"><small>[<a name="fn-1" href="#fnd-1">1</a>]</small> The &lsquo;<samp><span class="samp">qP</span></samp>&rsquo; and &lsquo;<samp><span class="samp">qL</span></samp>&rsquo;
packets predate these conventions, and have arguments without any terminator
for the packet name; we suspect they are in widespread use in places that
are difficult to upgrade. The &lsquo;<samp><span class="samp">qC</span></samp>&rsquo; packet has no arguments, but some
existing stubs (e.g. RedBoot) are known to not check for the end of the
packet.</p>
<hr></div>
</body></html>