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<a name="Packets"></a>
<p>
Next:&nbsp;<a rel="next" accesskey="n" href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>,
Previous:&nbsp;<a rel="previous" accesskey="p" href="Overview.html#Overview">Overview</a>,
Up:&nbsp;<a rel="up" accesskey="u" href="Remote-Protocol.html#Remote-Protocol">Remote Protocol</a>
<hr>
</div>
<h3 class="section">E.2 Packets</h3>
<p>The following table provides a complete list of all currently defined
<var>command</var>s and their corresponding response <var>data</var>.
See <a href="File_002dI_002fO-Remote-Protocol-Extension.html#File_002dI_002fO-Remote-Protocol-Extension">File-I/O Remote Protocol Extension</a>, for details about the File
I/O extension of the remote protocol.
<p>Each packet's description 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. For example, a template like &lsquo;<samp><span class="samp">foo
</span><var>bar</var> <var>baz</var></samp>&rsquo; describes a packet beginning with the three ASCII
bytes &lsquo;<samp><span class="samp">foo</span></samp>&rsquo;, followed by a <var>bar</var>, followed directly by a
<var>baz</var>. <span class="sc">gdb</span> does not transmit a space character between the
&lsquo;<samp><span class="samp">foo</span></samp>&rsquo; and the <var>bar</var>, or between the <var>bar</var> and the
<var>baz</var>.
<p><a name="index-g_t_0040var_007bthread_002did_007d_002c-in-remote-protocol-3422"></a><a name="thread_002did-syntax"></a>Several packets and replies include a <var>thread-id</var> field to identify
a thread. Normally these are positive numbers with a target-specific
interpretation, formatted as big-endian hex strings. A <var>thread-id</var>
can also be a literal &lsquo;<samp><span class="samp">-1</span></samp>&rsquo; to indicate all threads, or &lsquo;<samp><span class="samp">0</span></samp>&rsquo; to
pick any thread.
<p>In addition, the remote protocol supports a multiprocess feature in
which the <var>thread-id</var> syntax is extended to optionally include both
process and thread ID fields, as &lsquo;<samp><span class="samp">p</span><var>pid</var><span class="samp">.</span><var>tid</var></samp>&rsquo;.
The <var>pid</var> (process) and <var>tid</var> (thread) components each have the
format described above: a positive number with target-specific
interpretation formatted as a big-endian hex string, literal &lsquo;<samp><span class="samp">-1</span></samp>&rsquo;
to indicate all processes or threads (respectively), or &lsquo;<samp><span class="samp">0</span></samp>&rsquo; to
indicate an arbitrary process or thread. Specifying just a process, as
&lsquo;<samp><span class="samp">p</span><var>pid</var></samp>&rsquo;, is equivalent to &lsquo;<samp><span class="samp">p</span><var>pid</var><span class="samp">.-1</span></samp>&rsquo;. It is an
error to specify all processes but a specific thread, such as
&lsquo;<samp><span class="samp">p-1.</span><var>tid</var></samp>&rsquo;. Note that the &lsquo;<samp><span class="samp">p</span></samp>&rsquo; prefix is <em>not</em> used
for those packets and replies explicitly documented to include a process
ID, rather than a <var>thread-id</var>.
<p>The multiprocess <var>thread-id</var> syntax extensions are only used if both
<span class="sc">gdb</span> and the stub report support for the &lsquo;<samp><span class="samp">multiprocess</span></samp>&rsquo;
feature using &lsquo;<samp><span class="samp">qSupported</span></samp>&rsquo;. See <a href="multiprocess-extensions.html#multiprocess-extensions">multiprocess extensions</a>, for
more information.
<p>Note that all packet forms beginning with an upper- or lower-case
letter, other than those described here, are reserved for future use.
<p>Here are the packet descriptions.
<dl>
<dt>&lsquo;<samp><span class="samp">!</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007b_0021_007d-packet-3423"></a><a name="extended-mode"></a>Enable extended mode. In extended mode, the remote server is made
persistent. The &lsquo;<samp><span class="samp">R</span></samp>&rsquo; packet is used to restart the program being
debugged.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The remote target both supports and has enabled extended mode.
</dl>
<br><dt>&lsquo;<samp><span class="samp">?</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007b_003f_007d-packet-3424"></a><a name="g_t_003f-packet"></a>Indicate the reason the target halted. The reply is the same as for
step and continue. This packet has a special interpretation when the
target is in non-stop mode; see <a href="Remote-Non_002dStop.html#Remote-Non_002dStop">Remote Non-Stop</a>.
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
<br><dt>&lsquo;<samp><span class="samp">A </span><var>arglen</var><span class="samp">,</span><var>argnum</var><span class="samp">,</span><var>arg</var><span class="samp">,...</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bA_007d-packet-3425"></a>Initialized <code>argv[]</code> array passed into program. <var>arglen</var>
specifies the number of bytes in the hex encoded byte stream
<var>arg</var>. See <code>gdbserver</code> for more details.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>The arguments were set.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>An error occurred.
</dl>
<br><dt>&lsquo;<samp><span class="samp">b </span><var>baud</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bb_007d-packet-3426"></a>(Don't use this packet; its behavior is not well-defined.)
Change the serial line speed to <var>baud</var>.
<p>JTC: <em>When does the transport layer state change? When it's
received, or after the ACK is transmitted. In either case, there are
problems if the command or the acknowledgment packet is dropped.</em>
<p>Stan: <em>If people really wanted to add something like this, and get
it working for the first time, they ought to modify ser-unix.c to send
some kind of out-of-band message to a specially-setup stub and have the
switch happen "in between" packets, so that from remote protocol's point
of view, nothing actually happened.</em>
<br><dt>&lsquo;<samp><span class="samp">B </span><var>addr</var><span class="samp">,</span><var>mode</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bB_007d-packet-3427"></a>Set (<var>mode</var> is &lsquo;<samp><span class="samp">S</span></samp>&rsquo;) or clear (<var>mode</var> is &lsquo;<samp><span class="samp">C</span></samp>&rsquo;) a
breakpoint at <var>addr</var>.
<p>Don't use this packet. Use the &lsquo;<samp><span class="samp">Z</span></samp>&rsquo; and &lsquo;<samp><span class="samp">z</span></samp>&rsquo; packets instead
(see <a href="insert-breakpoint-or-watchpoint-packet.html#insert-breakpoint-or-watchpoint-packet">insert breakpoint or watchpoint packet</a>).
<p><a name="index-g_t_0040samp_007bbc_007d-packet-3428"></a><a name="bc"></a><br><dt>&lsquo;<samp><span class="samp">bc</span></samp>&rsquo;<dd>Backward continue. Execute the target system in reverse. No parameter.
See <a href="Reverse-Execution.html#Reverse-Execution">Reverse Execution</a>, for more information.
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
<p><a name="index-g_t_0040samp_007bbs_007d-packet-3429"></a><a name="bs"></a><br><dt>&lsquo;<samp><span class="samp">bs</span></samp>&rsquo;<dd>Backward single step. Execute one instruction in reverse. No parameter.
See <a href="Reverse-Execution.html#Reverse-Execution">Reverse Execution</a>, for more information.
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
<br><dt>&lsquo;<samp><span class="samp">c [</span><var>addr</var><span class="samp">]</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bc_007d-packet-3430"></a>Continue at <var>addr</var>, which is the address to resume. If <var>addr</var>
is omitted, resume at current address.
<p>This packet is deprecated for multi-threading support. See <a href="vCont-packet.html#vCont-packet">vCont packet</a>.
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
<br><dt>&lsquo;<samp><span class="samp">C </span><var>sig</var><span class="samp">[;</span><var>addr</var><span class="samp">]</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bC_007d-packet-3431"></a>Continue with signal <var>sig</var> (hex signal number). If
&lsquo;<samp><span class="samp">;</span><var>addr</var></samp>&rsquo; is omitted, resume at same address.
<p>This packet is deprecated for multi-threading support. See <a href="vCont-packet.html#vCont-packet">vCont packet</a>.
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
<br><dt>&lsquo;<samp><span class="samp">d</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bd_007d-packet-3432"></a>Toggle debug flag.
<p>Don't use this packet; instead, define a general set packet
(see <a href="General-Query-Packets.html#General-Query-Packets">General Query Packets</a>).
<br><dt>&lsquo;<samp><span class="samp">D</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">D;</span><var>pid</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bD_007d-packet-3433"></a>The first form of the packet is used to detach <span class="sc">gdb</span> from the
remote system. It is sent to the remote target
before <span class="sc">gdb</span> disconnects via the <code>detach</code> command.
<p>The second form, including a process ID, is used when multiprocess
protocol extensions are enabled (see <a href="multiprocess-extensions.html#multiprocess-extensions">multiprocess extensions</a>), to
detach only a specific process. The <var>pid</var> is specified as a
big-endian hex string.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>for success
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
</dl>
<br><dt>&lsquo;<samp><span class="samp">F </span><var>RC</var><span class="samp">,</span><var>EE</var><span class="samp">,</span><var>CF</var><span class="samp">;</span><var>XX</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bF_007d-packet-3434"></a>A reply from <span class="sc">gdb</span> to an &lsquo;<samp><span class="samp">F</span></samp>&rsquo; packet sent by the target.
This is part of the File-I/O protocol extension. See <a href="File_002dI_002fO-Remote-Protocol-Extension.html#File_002dI_002fO-Remote-Protocol-Extension">File-I/O Remote Protocol Extension</a>, for the specification.
<br><dt>&lsquo;<samp><span class="samp">g</span></samp>&rsquo;<dd><a name="read-registers-packet"></a><a name="index-g_t_0040samp_007bg_007d-packet-3435"></a>Read general registers.
<p>Reply:
<dl>
<dt>&lsquo;<samp><var>XX<small class="dots">...</small></var></samp>&rsquo;<dd>Each byte of register data is described by two hex digits. The bytes
with the register are transmitted in target byte order. The size of
each register and their position within the &lsquo;<samp><span class="samp">g</span></samp>&rsquo; packet are
determined by the <span class="sc">gdb</span> internal gdbarch functions
<code>DEPRECATED_REGISTER_RAW_SIZE</code> and <code>gdbarch_register_name</code>.
<p>When reading registers from a trace frame (see <a href="Analyze-Collected-Data.html#Analyze-Collected-Data">Using the Collected Data</a>), the stub may also return a string of
literal &lsquo;<samp><span class="samp">x</span></samp>&rsquo;'s in place of the register data digits, to indicate
that the corresponding register has not been collected, thus its value
is unavailable. For example, for an architecture with 4 registers of
4 bytes each, the following reply indicates to <span class="sc">gdb</span> that
registers 0 and 2 have not been collected, while registers 1 and 3
have been collected, and both have zero value:
<pre class="smallexample"> -&gt; <code>g</code>
&lt;- <code>xxxxxxxx00000000xxxxxxxx00000000</code>
</pre>
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error.
</dl>
<br><dt>&lsquo;<samp><span class="samp">G </span><var>XX<small class="dots">...</small></var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bG_007d-packet-3436"></a>Write general registers. See <a href="read-registers-packet.html#read-registers-packet">read registers packet</a>, for a
description of the <var>XX<small class="dots">...</small></var> data.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>for success
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
</dl>
<br><dt>&lsquo;<samp><span class="samp">H </span><var>op</var> <var>thread-id</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bH_007d-packet-3437"></a>Set thread for subsequent operations (&lsquo;<samp><span class="samp">m</span></samp>&rsquo;, &lsquo;<samp><span class="samp">M</span></samp>&rsquo;, &lsquo;<samp><span class="samp">g</span></samp>&rsquo;,
&lsquo;<samp><span class="samp">G</span></samp>&rsquo;, et.al.). Depending on the operation to be performed, <var>op</var>
should be &lsquo;<samp><span class="samp">c</span></samp>&rsquo; for step and continue operations (note that this
is deprecated, supporting the &lsquo;<samp><span class="samp">vCont</span></samp>&rsquo; command is a better
option), and &lsquo;<samp><span class="samp">g</span></samp>&rsquo; for other operations. The thread designator
<var>thread-id</var> has the format and interpretation described in
<a href="thread_002did-syntax.html#thread_002did-syntax">thread-id syntax</a>.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>for success
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
</dl>
<!-- FIXME: JTC: -->
<!-- 'H': How restrictive (or permissive) is the thread model. If a -->
<!-- thread is selected and stopped, are other threads allowed -->
<!-- to continue to execute? As I mentioned above, I think the -->
<!-- semantics of each command when a thread is selected must be -->
<!-- described. For example: -->
<!-- 'g': If the stub supports threads and a specific thread is -->
<!-- selected, returns the register block from that thread; -->
<!-- otherwise returns current registers. -->
<!-- 'G' If the stub supports threads and a specific thread is -->
<!-- selected, sets the registers of the register block of -->
<!-- that thread; otherwise sets current registers. -->
<br><dt>&lsquo;<samp><span class="samp">i [</span><var>addr</var><span class="samp">[,</span><var>nnn</var><span class="samp">]]</span></samp>&rsquo;<dd><a name="cycle-step-packet"></a><a name="index-g_t_0040samp_007bi_007d-packet-3438"></a>Step the remote target by a single clock cycle. If &lsquo;<samp><span class="samp">,</span><var>nnn</var></samp>&rsquo; is
present, cycle step <var>nnn</var> cycles. If <var>addr</var> is present, cycle
step starting at that address.
<br><dt>&lsquo;<samp><span class="samp">I</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bI_007d-packet-3439"></a>Signal, then cycle step. See <a href="step-with-signal-packet.html#step-with-signal-packet">step with signal packet</a>. See <a href="cycle-step-packet.html#cycle-step-packet">cycle step packet</a>.
<br><dt>&lsquo;<samp><span class="samp">k</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bk_007d-packet-3440"></a>Kill request.
<p>The exact effect of this packet is not specified.
<p>For a bare-metal target, it may power cycle or reset the target
system. For that reason, the &lsquo;<samp><span class="samp">k</span></samp>&rsquo; packet has no reply.
<p>For a single-process target, it may kill that process if possible.
<p>A multiple-process target may choose to kill just one process, or all
that are under <span class="sc">gdb</span>'s control. For more precise control, use
the vKill packet (see <a href="vKill-packet.html#vKill-packet">vKill packet</a>).
<p>If the target system immediately closes the connection in response to
&lsquo;<samp><span class="samp">k</span></samp>&rsquo;, <span class="sc">gdb</span> does not consider the lack of packet
acknowledgment to be an error, and assumes the kill was successful.
<p>If connected using <kbd>target extended-remote</kbd>, and the target does
not close the connection in response to a kill request, <span class="sc">gdb</span>
probes the target state as if a new connection was opened
(see <a href="_003f-packet.html#g_t_003f-packet">? packet</a>).
<br><dt>&lsquo;<samp><span class="samp">m </span><var>addr</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bm_007d-packet-3441"></a>Read <var>length</var> addressable memory units starting at address <var>addr</var>
(see <a href="addressable-memory-unit.html#addressable-memory-unit">addressable memory unit</a>). Note that <var>addr</var> may not be aligned to
any particular boundary.
<p>The stub need not use any particular size or alignment when gathering
data from memory for the response; even if <var>addr</var> is word-aligned
and <var>length</var> is a multiple of the word size, the stub is free to
use byte accesses, or not. For this reason, this packet may not be
suitable for accessing memory-mapped I/O devices.
<a name="index-alignment-of-remote-memory-accesses-3442"></a><a name="index-size-of-remote-memory-accesses-3443"></a><a name="index-memory_002c-alignment-and-size-of-remote-accesses-3444"></a>
Reply:
<dl>
<dt>&lsquo;<samp><var>XX<small class="dots">...</small></var></samp>&rsquo;<dd>Memory contents; each byte is transmitted as a two-digit hexadecimal number.
The reply may contain fewer addressable memory units than requested if the
server was able to read only part of the region of memory.
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd><var>NN</var> is errno
</dl>
<br><dt>&lsquo;<samp><span class="samp">M </span><var>addr</var><span class="samp">,</span><var>length</var><span class="samp">:</span><var>XX<small class="dots">...</small></var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bM_007d-packet-3445"></a>Write <var>length</var> addressable memory units starting at address <var>addr</var>
(see <a href="addressable-memory-unit.html#addressable-memory-unit">addressable memory unit</a>). The data is given by <var>XX<small class="dots">...</small></var>; each
byte is transmitted as a two-digit hexadecimal number.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>for success
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error (this includes the case where only part of the data was
written).
</dl>
<br><dt>&lsquo;<samp><span class="samp">p </span><var>n</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bp_007d-packet-3446"></a>Read the value of register <var>n</var>; <var>n</var> is in hex.
See <a href="read-registers-packet.html#read-registers-packet">read registers packet</a>, for a description of how the returned
register value is encoded.
<p>Reply:
<dl>
<dt>&lsquo;<samp><var>XX<small class="dots">...</small></var></samp>&rsquo;<dd>the register's value
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>Indicating an unrecognized <var>query</var>.
</dl>
<br><dt>&lsquo;<samp><span class="samp">P </span><var>n<small class="dots">...</small></var><span class="samp">=</span><var>r<small class="dots">...</small></var></samp>&rsquo;<dd><a name="write-register-packet"></a><a name="index-g_t_0040samp_007bP_007d-packet-3447"></a>Write register <var>n<small class="dots">...</small></var> with value <var>r<small class="dots">...</small></var>. The register
number <var>n</var> is in hexadecimal, and <var>r<small class="dots">...</small></var> contains two hex
digits for each byte in the register (target byte order).
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>for success
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
</dl>
<br><dt>&lsquo;<samp><span class="samp">q </span><var>name</var> <var>params</var><span class="samp">...</span></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">Q </span><var>name</var> <var>params</var><span class="samp">...</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bq_007d-packet-3448"></a><a name="index-g_t_0040samp_007bQ_007d-packet-3449"></a>General query (&lsquo;<samp><span class="samp">q</span></samp>&rsquo;) and set (&lsquo;<samp><span class="samp">Q</span></samp>&rsquo;). These packets are
described fully in <a href="General-Query-Packets.html#General-Query-Packets">General Query Packets</a>.
<br><dt>&lsquo;<samp><span class="samp">r</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007br_007d-packet-3450"></a>Reset the entire system.
<p>Don't use this packet; use the &lsquo;<samp><span class="samp">R</span></samp>&rsquo; packet instead.
<br><dt>&lsquo;<samp><span class="samp">R </span><var>XX</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bR_007d-packet-3451"></a>Restart the program being debugged. The <var>XX</var>, while needed, is ignored.
This packet is only available in extended mode (see <a href="extended-mode.html#extended-mode">extended mode</a>).
<p>The &lsquo;<samp><span class="samp">R</span></samp>&rsquo; packet has no reply.
<br><dt>&lsquo;<samp><span class="samp">s [</span><var>addr</var><span class="samp">]</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bs_007d-packet-3452"></a>Single step, resuming at <var>addr</var>. If
<var>addr</var> is omitted, resume at same address.
<p>This packet is deprecated for multi-threading support. See <a href="vCont-packet.html#vCont-packet">vCont packet</a>.
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
<br><dt>&lsquo;<samp><span class="samp">S </span><var>sig</var><span class="samp">[;</span><var>addr</var><span class="samp">]</span></samp>&rsquo;<dd><a name="step-with-signal-packet"></a><a name="index-g_t_0040samp_007bS_007d-packet-3453"></a>Step with signal. This is analogous to the &lsquo;<samp><span class="samp">C</span></samp>&rsquo; packet, but
requests a single-step, rather than a normal resumption of execution.
<p>This packet is deprecated for multi-threading support. See <a href="vCont-packet.html#vCont-packet">vCont packet</a>.
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
<br><dt>&lsquo;<samp><span class="samp">t </span><var>addr</var><span class="samp">:</span><var>PP</var><span class="samp">,</span><var>MM</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bt_007d-packet-3454"></a>Search backwards starting at address <var>addr</var> for a match with pattern
<var>PP</var> and mask <var>MM</var>, both of which are are 4 byte long.
There must be at least 3 digits in <var>addr</var>.
<br><dt>&lsquo;<samp><span class="samp">T </span><var>thread-id</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bT_007d-packet-3455"></a>Find out if the thread <var>thread-id</var> is alive. See <a href="thread_002did-syntax.html#thread_002did-syntax">thread-id syntax</a>.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>thread is still alive
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>thread is dead
</dl>
<br><dt>&lsquo;<samp><span class="samp">v</span></samp>&rsquo;<dd>Packets starting with &lsquo;<samp><span class="samp">v</span></samp>&rsquo; are identified by a multi-letter name,
up to the first &lsquo;<samp><span class="samp">;</span></samp>&rsquo; or &lsquo;<samp><span class="samp">?</span></samp>&rsquo; (or the end of the packet).
<br><dt>&lsquo;<samp><span class="samp">vAttach;</span><var>pid</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bvAttach_007d-packet-3456"></a>Attach to a new process with the specified process ID <var>pid</var>.
The process ID is a
hexadecimal integer identifying the process. In all-stop mode, all
threads in the attached process are stopped; in non-stop mode, it may be
attached without being stopped if that is supported by the target.
<!-- In non-stop mode, on a successful vAttach, the stub should set the -->
<!-- current thread to a thread of the newly-attached process. After -->
<!-- attaching, GDB queries for the attached process's thread ID with qC. -->
<!-- Also note that, from a user perspective, whether or not the -->
<!-- target is stopped on attach in non-stop mode depends on whether you -->
<!-- use the foreground or background version of the attach command, not -->
<!-- on what vAttach does; GDB does the right thing with respect to either -->
<!-- stopping or restarting threads. -->
<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">E </span><var>nn</var></samp>&rsquo;<dd>for an error
<br><dt>&lsquo;<samp><span class="samp">Any stop packet</span></samp>&rsquo;<dd>for success in all-stop mode (see <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>)
<br><dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>for success in non-stop mode (see <a href="Remote-Non_002dStop.html#Remote-Non_002dStop">Remote Non-Stop</a>)
</dl>
<br><dt>&lsquo;<samp><span class="samp">vCont[;</span><var>action</var><span class="samp">[:</span><var>thread-id</var><span class="samp">]]...</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bvCont_007d-packet-3457"></a><a name="vCont-packet"></a>Resume the inferior, specifying different actions for each thread.
<p>For each inferior thread, the leftmost action with a matching
<var>thread-id</var> is applied. Threads that don't match any action
remain in their current state. Thread IDs are specified using the
syntax described in <a href="thread_002did-syntax.html#thread_002did-syntax">thread-id syntax</a>. If multiprocess
extensions (see <a href="multiprocess-extensions.html#multiprocess-extensions">multiprocess extensions</a>) are supported, actions
can be specified to match all threads in a process by using the
&lsquo;<samp><span class="samp">p</span><var>pid</var><span class="samp">.-1</span></samp>&rsquo; form of the <var>thread-id</var>. An action with no
<var>thread-id</var> matches all threads. Specifying no actions is an
error.
<p>Currently supported actions are:
<dl>
<dt>&lsquo;<samp><span class="samp">c</span></samp>&rsquo;<dd>Continue.
<br><dt>&lsquo;<samp><span class="samp">C </span><var>sig</var></samp>&rsquo;<dd>Continue with signal <var>sig</var>. The signal <var>sig</var> should be two hex digits.
<br><dt>&lsquo;<samp><span class="samp">s</span></samp>&rsquo;<dd>Step.
<br><dt>&lsquo;<samp><span class="samp">S </span><var>sig</var></samp>&rsquo;<dd>Step with signal <var>sig</var>. The signal <var>sig</var> should be two hex digits.
<br><dt>&lsquo;<samp><span class="samp">t</span></samp>&rsquo;<dd>Stop.
<br><dt>&lsquo;<samp><span class="samp">r </span><var>start</var><span class="samp">,</span><var>end</var></samp>&rsquo;<dd>Step once, and then keep stepping as long as the thread stops at
addresses between <var>start</var> (inclusive) and <var>end</var> (exclusive).
The remote stub reports a stop reply when either the thread goes out
of the range or is stopped due to an unrelated reason, such as hitting
a breakpoint. See <a href="range-stepping.html#range-stepping">range stepping</a>.
<p>If the range is empty (<var>start</var> == <var>end</var>), then the action
becomes equivalent to the &lsquo;<samp><span class="samp">s</span></samp>&rsquo; action. In other words,
single-step once, and report the stop (even if the stepped instruction
jumps to <var>start</var>).
<p>(A stop reply may be sent at any point even if the PC is still within
the stepping range; for example, it is valid to implement this packet
in a degenerate way as a single instruction step operation.)
</dl>
<p>The optional argument <var>addr</var> normally associated with the
&lsquo;<samp><span class="samp">c</span></samp>&rsquo;, &lsquo;<samp><span class="samp">C</span></samp>&rsquo;, &lsquo;<samp><span class="samp">s</span></samp>&rsquo;, and &lsquo;<samp><span class="samp">S</span></samp>&rsquo; packets is
not supported in &lsquo;<samp><span class="samp">vCont</span></samp>&rsquo;.
<p>The &lsquo;<samp><span class="samp">t</span></samp>&rsquo; action is only relevant in non-stop mode
(see <a href="Remote-Non_002dStop.html#Remote-Non_002dStop">Remote Non-Stop</a>) and may be ignored by the stub otherwise.
A stop reply should be generated for any affected thread not already stopped.
When a thread is stopped by means of a &lsquo;<samp><span class="samp">t</span></samp>&rsquo; action,
the corresponding stop reply should indicate that the thread has stopped with
signal &lsquo;<samp><span class="samp">0</span></samp>&rsquo;, regardless of whether the target uses some other signal
as an implementation detail.
<p>The server must ignore &lsquo;<samp><span class="samp">c</span></samp>&rsquo;, &lsquo;<samp><span class="samp">C</span></samp>&rsquo;, &lsquo;<samp><span class="samp">s</span></samp>&rsquo;, &lsquo;<samp><span class="samp">S</span></samp>&rsquo;, and
&lsquo;<samp><span class="samp">r</span></samp>&rsquo; actions for threads that are already running. Conversely,
the server must ignore &lsquo;<samp><span class="samp">t</span></samp>&rsquo; actions for threads that are already
stopped.
<p><em>Note:</em> In non-stop mode, a thread is considered running until
<span class="sc">gdb</span> acknowleges an asynchronous stop notification for it with
the &lsquo;<samp><span class="samp">vStopped</span></samp>&rsquo; packet (see <a href="Remote-Non_002dStop.html#Remote-Non_002dStop">Remote Non-Stop</a>).
<p>The stub must support &lsquo;<samp><span class="samp">vCont</span></samp>&rsquo; if it reports support for
multiprocess extensions (see <a href="multiprocess-extensions.html#multiprocess-extensions">multiprocess extensions</a>).
<p>Reply:
See <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>, for the reply specifications.
<br><dt>&lsquo;<samp><span class="samp">vCont?</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bvCont_003f_007d-packet-3458"></a>Request a list of actions supported by the &lsquo;<samp><span class="samp">vCont</span></samp>&rsquo; packet.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">vCont[;</span><var>action</var><span class="samp">...]</span></samp>&rsquo;<dd>The &lsquo;<samp><span class="samp">vCont</span></samp>&rsquo; packet is supported. Each <var>action</var> is a supported
command in the &lsquo;<samp><span class="samp">vCont</span></samp>&rsquo; packet.
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>The &lsquo;<samp><span class="samp">vCont</span></samp>&rsquo; packet is not supported.
</dl>
<p><a name="vCtrlC-packet"></a><br><dt>&lsquo;<samp><span class="samp">vCtrlC</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bvCtrlC_007d-packet-3459"></a>Interrupt remote target as if a control-C was pressed on the remote
terminal. This is the equivalent to reacting to the <code>^C</code>
(&lsquo;<samp><span class="samp">\003</span></samp>&rsquo;, the control-C character) character in all-stop mode
while the target is running, except this works in non-stop mode.
See <a href="interrupting-remote-targets.html#interrupting-remote-targets">interrupting remote targets</a>, for more info on the all-stop
variant.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>for an error
<br><dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>for success
</dl>
<br><dt>&lsquo;<samp><span class="samp">vFile:</span><var>operation</var><span class="samp">:</span><var>parameter</var><span class="samp">...</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bvFile_007d-packet-3460"></a>Perform a file operation on the target system. For details,
see <a href="Host-I_002fO-Packets.html#Host-I_002fO-Packets">Host I/O Packets</a>.
<br><dt>&lsquo;<samp><span class="samp">vFlashErase:</span><var>addr</var><span class="samp">,</span><var>length</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bvFlashErase_007d-packet-3461"></a>Direct the stub to erase <var>length</var> bytes of flash starting at
<var>addr</var>. The region may enclose any number of flash blocks, but
its start and end must fall on block boundaries, as indicated by the
flash block size appearing in the memory map (see <a href="Memory-Map-Format.html#Memory-Map-Format">Memory Map Format</a>). <span class="sc">gdb</span> groups flash memory programming operations
together, and sends a &lsquo;<samp><span class="samp">vFlashDone</span></samp>&rsquo; request after each group; the
stub is allowed to delay erase operation until the &lsquo;<samp><span class="samp">vFlashDone</span></samp>&rsquo;
packet is received.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>for success
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
</dl>
<br><dt>&lsquo;<samp><span class="samp">vFlashWrite:</span><var>addr</var><span class="samp">:</span><var>XX<small class="dots">...</small></var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bvFlashWrite_007d-packet-3462"></a>Direct the stub to write data to flash address <var>addr</var>. The data
is passed in binary form using the same encoding as for the &lsquo;<samp><span class="samp">X</span></samp>&rsquo;
packet (see <a href="Binary-Data.html#Binary-Data">Binary Data</a>). The memory ranges specified by
&lsquo;<samp><span class="samp">vFlashWrite</span></samp>&rsquo; packets preceding a &lsquo;<samp><span class="samp">vFlashDone</span></samp>&rsquo; packet must
not overlap, and must appear in order of increasing addresses
(although &lsquo;<samp><span class="samp">vFlashErase</span></samp>&rsquo; packets for higher addresses may already
have been received; the ordering is guaranteed only between
&lsquo;<samp><span class="samp">vFlashWrite</span></samp>&rsquo; packets). If a packet writes to an address that was
neither erased by a preceding &lsquo;<samp><span class="samp">vFlashErase</span></samp>&rsquo; packet nor by some other
target-specific method, the results are unpredictable.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>for success
<br><dt>&lsquo;<samp><span class="samp">E.memtype</span></samp>&rsquo;<dd>for vFlashWrite addressing non-flash memory
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
</dl>
<br><dt>&lsquo;<samp><span class="samp">vFlashDone</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bvFlashDone_007d-packet-3463"></a>Indicate to the stub that flash programming operation is finished.
The stub is permitted to delay or batch the effects of a group of
&lsquo;<samp><span class="samp">vFlashErase</span></samp>&rsquo; and &lsquo;<samp><span class="samp">vFlashWrite</span></samp>&rsquo; packets until a
&lsquo;<samp><span class="samp">vFlashDone</span></samp>&rsquo; packet is received. The contents of the affected
regions of flash memory are unpredictable until the &lsquo;<samp><span class="samp">vFlashDone</span></samp>&rsquo;
request is completed.
<br><dt>&lsquo;<samp><span class="samp">vKill;</span><var>pid</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bvKill_007d-packet-3464"></a><a name="vKill-packet"></a>Kill the process with the specified process ID <var>pid</var>, which is a
hexadecimal integer identifying the process. This packet is used in
preference to &lsquo;<samp><span class="samp">k</span></samp>&rsquo; when multiprocess protocol extensions are
supported; see <a href="multiprocess-extensions.html#multiprocess-extensions">multiprocess extensions</a>.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">E </span><var>nn</var></samp>&rsquo;<dd>for an error
<br><dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>for success
</dl>
<br><dt>&lsquo;<samp><span class="samp">vMustReplyEmpty</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bvMustReplyEmpty_007d-packet-3465"></a>The correct reply to an unknown &lsquo;<samp><span class="samp">v</span></samp>&rsquo; packet is to return the empty
string, however, some older versions of <samp><span class="command">gdbserver</span></samp> would
incorrectly return &lsquo;<samp><span class="samp">OK</span></samp>&rsquo; for unknown &lsquo;<samp><span class="samp">v</span></samp>&rsquo; packets.
<p>The &lsquo;<samp><span class="samp">vMustReplyEmpty</span></samp>&rsquo; is used as a feature test to check how
<samp><span class="command">gdbserver</span></samp> handles unknown packets, it is important that this
packet be handled in the same way as other unknown &lsquo;<samp><span class="samp">v</span></samp>&rsquo; packets.
If this packet is handled differently to other unknown &lsquo;<samp><span class="samp">v</span></samp>&rsquo;
packets then it is possile that <span class="sc">gdb</span> may run into problems in
other areas, specifically around use of &lsquo;<samp><span class="samp">vFile:setfs:</span></samp>&rsquo;.
<br><dt>&lsquo;<samp><span class="samp">vRun;</span><var>filename</var><span class="samp">[;</span><var>argument</var><span class="samp">]...</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bvRun_007d-packet-3466"></a>Run the program <var>filename</var>, passing it each <var>argument</var> on its
command line. The file and arguments are hex-encoded strings. If
<var>filename</var> is an empty string, the stub may use a default program
(e.g. the last program run). The program is created in the stopped
state.
<!-- FIXME: What about non-stop mode? -->
<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">E </span><var>nn</var></samp>&rsquo;<dd>for an error
<br><dt>&lsquo;<samp><span class="samp">Any stop packet</span></samp>&rsquo;<dd>for success (see <a href="Stop-Reply-Packets.html#Stop-Reply-Packets">Stop Reply Packets</a>)
</dl>
<br><dt>&lsquo;<samp><span class="samp">vStopped</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bvStopped_007d-packet-3467"></a>See <a href="Notification-Packets.html#Notification-Packets">Notification Packets</a>.
<br><dt>&lsquo;<samp><span class="samp">X </span><var>addr</var><span class="samp">,</span><var>length</var><span class="samp">:</span><var>XX<small class="dots">...</small></var></samp>&rsquo;<dd><a name="X-packet"></a><a name="index-g_t_0040samp_007bX_007d-packet-3468"></a>Write data to memory, where the data is transmitted in binary.
Memory is specified by its address <var>addr</var> and number of addressable memory
units <var>length</var> (see <a href="addressable-memory-unit.html#addressable-memory-unit">addressable memory unit</a>);
&lsquo;<samp><var>XX</var><span class="samp">...</span></samp>&rsquo; is binary data (see <a href="Binary-Data.html#Binary-Data">Binary Data</a>).
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>for success
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
</dl>
<br><dt>&lsquo;<samp><span class="samp">z </span><var>type</var><span class="samp">,</span><var>addr</var><span class="samp">,</span><var>kind</var></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">Z </span><var>type</var><span class="samp">,</span><var>addr</var><span class="samp">,</span><var>kind</var></samp>&rsquo;<dd><a name="insert-breakpoint-or-watchpoint-packet"></a><a name="index-g_t_0040samp_007bz_007d-packet-3469"></a><a name="index-g_t_0040samp_007bZ_007d-packets-3470"></a>Insert (&lsquo;<samp><span class="samp">Z</span></samp>&rsquo;) or remove (&lsquo;<samp><span class="samp">z</span></samp>&rsquo;) a <var>type</var> breakpoint or
watchpoint starting at address <var>address</var> of kind <var>kind</var>.
<p>Each breakpoint and watchpoint packet <var>type</var> is documented
separately.
<p><em>Implementation notes: A remote target shall return an empty string
for an unrecognized breakpoint or watchpoint packet </em><var>type</var><em>. A
remote target shall support either both or neither of a given
&lsquo;</em><samp><span class="samp">Z</span><var>type</var><span class="samp">...</span></samp><em>&rsquo; and &lsquo;</em><samp><span class="samp">z</span><var>type</var><span class="samp">...</span></samp><em>&rsquo; packet pair. To
avoid potential problems with duplicate packets, the operations should
be implemented in an idempotent way.</em>
<br><dt>&lsquo;<samp><span class="samp">z0,</span><var>addr</var><span class="samp">,</span><var>kind</var></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">Z0,</span><var>addr</var><span class="samp">,</span><var>kind</var><span class="samp">[;</span><var>cond_list</var><span class="samp">...][;cmds:</span><var>persist</var><span class="samp">,</span><var>cmd_list</var><span class="samp">...]</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bz0_007d-packet-3471"></a><a name="index-g_t_0040samp_007bZ0_007d-packet-3472"></a>Insert (&lsquo;<samp><span class="samp">Z0</span></samp>&rsquo;) or remove (&lsquo;<samp><span class="samp">z0</span></samp>&rsquo;) a software breakpoint at address
<var>addr</var> of type <var>kind</var>.
<p>A software breakpoint is implemented by replacing the instruction at
<var>addr</var> with a software breakpoint or trap instruction. The
<var>kind</var> is target-specific and typically indicates the size of the
breakpoint in bytes that should be inserted. E.g., the <span class="sc">arm</span> and
<span class="sc">mips</span> can insert either a 2 or 4 byte breakpoint. Some
architectures have additional meanings for <var>kind</var>
(see <a href="Architecture_002dSpecific-Protocol-Details.html#Architecture_002dSpecific-Protocol-Details">Architecture-Specific Protocol Details</a>); if no
architecture-specific value is being used, it should be &lsquo;<samp><span class="samp">0</span></samp>&rsquo;.
<var>kind</var> is hex-encoded. <var>cond_list</var> is an optional list of
conditional expressions in bytecode form that should be evaluated on
the target's side. These are the conditions that should be taken into
consideration when deciding if the breakpoint trigger should be
reported back to <span class="sc">gdb</span>.
<p>See also the &lsquo;<samp><span class="samp">swbreak</span></samp>&rsquo; stop reason (see <a href="swbreak-stop-reason.html#swbreak-stop-reason">swbreak stop reason</a>)
for how to best report a software breakpoint event to <span class="sc">gdb</span>.
<p>The <var>cond_list</var> parameter is comprised of a series of expressions,
concatenated without separators. Each expression has the following form:
<dl>
<dt>&lsquo;<samp><span class="samp">X </span><var>len</var><span class="samp">,</span><var>expr</var></samp>&rsquo;<dd><var>len</var> is the length of the bytecode expression and <var>expr</var> is the
actual conditional expression in bytecode form.
</dl>
<p>The optional <var>cmd_list</var> parameter introduces commands that may be
run on the target, rather than being reported back to <span class="sc">gdb</span>.
The parameter starts with a numeric flag <var>persist</var>; if the flag is
nonzero, then the breakpoint may remain active and the commands
continue to be run even when <span class="sc">gdb</span> disconnects from the target.
Following this flag is a series of expressions concatenated with no
separators. Each expression has the following form:
<dl>
<dt>&lsquo;<samp><span class="samp">X </span><var>len</var><span class="samp">,</span><var>expr</var></samp>&rsquo;<dd><var>len</var> is the length of the bytecode expression and <var>expr</var> is the
actual commands expression in bytecode form.
</dl>
<p><em>Implementation note: It is possible for a target to copy or move
code that contains software breakpoints (e.g., when implementing
overlays). The behavior of this packet, in the presence of such a
target, is not defined.</em>
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>success
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>not supported
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
</dl>
<br><dt>&lsquo;<samp><span class="samp">z1,</span><var>addr</var><span class="samp">,</span><var>kind</var></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">Z1,</span><var>addr</var><span class="samp">,</span><var>kind</var><span class="samp">[;</span><var>cond_list</var><span class="samp">...][;cmds:</span><var>persist</var><span class="samp">,</span><var>cmd_list</var><span class="samp">...]</span></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bz1_007d-packet-3473"></a><a name="index-g_t_0040samp_007bZ1_007d-packet-3474"></a>Insert (&lsquo;<samp><span class="samp">Z1</span></samp>&rsquo;) or remove (&lsquo;<samp><span class="samp">z1</span></samp>&rsquo;) a hardware breakpoint at
address <var>addr</var>.
<p>A hardware breakpoint is implemented using a mechanism that is not
dependent on being able to modify the target's memory. The
<var>kind</var>, <var>cond_list</var>, and <var>cmd_list</var> arguments have the
same meaning as in &lsquo;<samp><span class="samp">Z0</span></samp>&rsquo; packets.
<p><em>Implementation note: A hardware breakpoint is not affected by code
movement.</em>
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>success
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>not supported
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
</dl>
<br><dt>&lsquo;<samp><span class="samp">z2,</span><var>addr</var><span class="samp">,</span><var>kind</var></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">Z2,</span><var>addr</var><span class="samp">,</span><var>kind</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bz2_007d-packet-3475"></a><a name="index-g_t_0040samp_007bZ2_007d-packet-3476"></a>Insert (&lsquo;<samp><span class="samp">Z2</span></samp>&rsquo;) or remove (&lsquo;<samp><span class="samp">z2</span></samp>&rsquo;) a write watchpoint at <var>addr</var>.
The number of bytes to watch is specified by <var>kind</var>.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>success
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>not supported
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
</dl>
<br><dt>&lsquo;<samp><span class="samp">z3,</span><var>addr</var><span class="samp">,</span><var>kind</var></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">Z3,</span><var>addr</var><span class="samp">,</span><var>kind</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bz3_007d-packet-3477"></a><a name="index-g_t_0040samp_007bZ3_007d-packet-3478"></a>Insert (&lsquo;<samp><span class="samp">Z3</span></samp>&rsquo;) or remove (&lsquo;<samp><span class="samp">z3</span></samp>&rsquo;) a read watchpoint at <var>addr</var>.
The number of bytes to watch is specified by <var>kind</var>.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>success
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>not supported
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
</dl>
<br><dt>&lsquo;<samp><span class="samp">z4,</span><var>addr</var><span class="samp">,</span><var>kind</var></samp>&rsquo;<dt>&lsquo;<samp><span class="samp">Z4,</span><var>addr</var><span class="samp">,</span><var>kind</var></samp>&rsquo;<dd><a name="index-g_t_0040samp_007bz4_007d-packet-3479"></a><a name="index-g_t_0040samp_007bZ4_007d-packet-3480"></a>Insert (&lsquo;<samp><span class="samp">Z4</span></samp>&rsquo;) or remove (&lsquo;<samp><span class="samp">z4</span></samp>&rsquo;) an access watchpoint at <var>addr</var>.
The number of bytes to watch is specified by <var>kind</var>.
<p>Reply:
<dl>
<dt>&lsquo;<samp><span class="samp">OK</span></samp>&rsquo;<dd>success
<br><dt>&lsquo;<samp><span class="samp"><!-- /@w --></span></samp>&rsquo;<dd>not supported
<br><dt>&lsquo;<samp><span class="samp">E </span><var>NN</var></samp>&rsquo;<dd>for an error
</dl>
</dl>
</body></html>