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<h4 class="subsection">21.1.6 Commands Specific to <span class="sc">gnu</span> Hurd Systems</h4>

<p><a name="index-g_t_0040sc_007bgnu_007d-Hurd-debugging-1231"></a>
This subsection describes <span class="sc">gdb</span> commands specific to the
<span class="sc">gnu</span> Hurd native debugging.

     <dl>
<dt><code>set signals</code><dt><code>set sigs</code><dd><a name="index-set-signals_0040r_007b_002c-Hurd-command_007d-1232"></a><a name="index-set-sigs_0040r_007b_002c-Hurd-command_007d-1233"></a>This command toggles the state of inferior signal interception by
<span class="sc">gdb</span>.  Mach exceptions, such as breakpoint traps, are not
affected by this command.  <code>sigs</code> is a shorthand alias for
<code>signals</code>.

     <br><dt><code>show signals</code><dt><code>show sigs</code><dd><a name="index-show-signals_0040r_007b_002c-Hurd-command_007d-1234"></a><a name="index-show-sigs_0040r_007b_002c-Hurd-command_007d-1235"></a>Show the current state of intercepting inferior's signals.

     <br><dt><code>set signal-thread</code><dt><code>set sigthread</code><dd><a name="index-set-signal_002dthread-1236"></a><a name="index-set-sigthread-1237"></a>This command tells <span class="sc">gdb</span> which thread is the <code>libc</code> signal
thread.  That thread is run when a signal is delivered to a running
process.  <code>set sigthread</code> is the shorthand alias of <code>set
signal-thread</code>.

     <br><dt><code>show signal-thread</code><dt><code>show sigthread</code><dd><a name="index-show-signal_002dthread-1238"></a><a name="index-show-sigthread-1239"></a>These two commands show which thread will run when the inferior is
delivered a signal.

     <br><dt><code>set stopped</code><dd><a name="index-set-stopped_0040r_007b_002c-Hurd-command_007d-1240"></a>This commands tells <span class="sc">gdb</span> that the inferior process is stopped,
as with the <code>SIGSTOP</code> signal.  The stopped process can be
continued by delivering a signal to it.

     <br><dt><code>show stopped</code><dd><a name="index-show-stopped_0040r_007b_002c-Hurd-command_007d-1241"></a>This command shows whether <span class="sc">gdb</span> thinks the debuggee is
stopped.

     <br><dt><code>set exceptions</code><dd><a name="index-set-exceptions_0040r_007b_002c-Hurd-command_007d-1242"></a>Use this command to turn off trapping of exceptions in the inferior. 
When exception trapping is off, neither breakpoints nor
single-stepping will work.  To restore the default, set exception
trapping on.

     <br><dt><code>show exceptions</code><dd><a name="index-show-exceptions_0040r_007b_002c-Hurd-command_007d-1243"></a>Show the current state of trapping exceptions in the inferior.

     <br><dt><code>set task pause</code><dd><a name="index-set-task_0040r_007b_002c-Hurd-commands_007d-1244"></a><a name="index-task-attributes-_0028_0040sc_007bgnu_007d-Hurd_0029-1245"></a><a name="index-pause-current-task-_0028_0040sc_007bgnu_007d-Hurd_0029-1246"></a>This command toggles task suspension when <span class="sc">gdb</span> has control. 
Setting it to on takes effect immediately, and the task is suspended
whenever <span class="sc">gdb</span> gets control.  Setting it to off will take
effect the next time the inferior is continued.  If this option is set
to off, you can use <code>set thread default pause on</code> or <code>set
thread pause on</code> (see below) to pause individual threads.

     <br><dt><code>show task pause</code><dd><a name="index-show-task_0040r_007b_002c-Hurd-commands_007d-1247"></a>Show the current state of task suspension.

     <br><dt><code>set task detach-suspend-count</code><dd><a name="index-task-suspend-count-1248"></a><a name="index-detach-from-task_002c-_0040sc_007bgnu_007d-Hurd-1249"></a>This command sets the suspend count the task will be left with when
<span class="sc">gdb</span> detaches from it.

     <br><dt><code>show task detach-suspend-count</code><dd>Show the suspend count the task will be left with when detaching.

     <br><dt><code>set task exception-port</code><dt><code>set task excp</code><dd><a name="index-task-exception-port_002c-_0040sc_007bgnu_007d-Hurd-1250"></a>This command sets the task exception port to which <span class="sc">gdb</span> will
forward exceptions.  The argument should be the value of the <dfn>send
rights</dfn> of the task.  <code>set task excp</code> is a shorthand alias.

     <br><dt><code>set noninvasive</code><dd><a name="index-noninvasive-task-options-1251"></a>This command switches <span class="sc">gdb</span> to a mode that is the least
invasive as far as interfering with the inferior is concerned.  This
is the same as using <code>set task pause</code>, <code>set exceptions</code>, and
<code>set signals</code> to values opposite to the defaults.

     <br><dt><code>info send-rights</code><dt><code>info receive-rights</code><dt><code>info port-rights</code><dt><code>info port-sets</code><dt><code>info dead-names</code><dt><code>info ports</code><dt><code>info psets</code><dd><a name="index-send-rights_002c-_0040sc_007bgnu_007d-Hurd-1252"></a><a name="index-receive-rights_002c-_0040sc_007bgnu_007d-Hurd-1253"></a><a name="index-port-rights_002c-_0040sc_007bgnu_007d-Hurd-1254"></a><a name="index-port-sets_002c-_0040sc_007bgnu_007d-Hurd-1255"></a><a name="index-dead-names_002c-_0040sc_007bgnu_007d-Hurd-1256"></a>These commands display information about, respectively, send rights,
receive rights, port rights, port sets, and dead names of a task. 
There are also shorthand aliases: <code>info ports</code> for <code>info
port-rights</code> and <code>info psets</code> for <code>info port-sets</code>.

     <br><dt><code>set thread pause</code><dd><a name="index-set-thread_0040r_007b_002c-Hurd-command_007d-1257"></a><a name="index-thread-properties_002c-_0040sc_007bgnu_007d-Hurd-1258"></a><a name="index-pause-current-thread-_0028_0040sc_007bgnu_007d-Hurd_0029-1259"></a>This command toggles current thread suspension when <span class="sc">gdb</span> has
control.  Setting it to on takes effect immediately, and the current
thread is suspended whenever <span class="sc">gdb</span> gets control.  Setting it to
off will take effect the next time the inferior is continued. 
Normally, this command has no effect, since when <span class="sc">gdb</span> has
control, the whole task is suspended.  However, if you used <code>set
task pause off</code> (see above), this command comes in handy to suspend
only the current thread.

     <br><dt><code>show thread pause</code><dd><a name="index-show-thread_0040r_007b_002c-Hurd-command_007d-1260"></a>This command shows the state of current thread suspension.

     <br><dt><code>set thread run</code><dd>This command sets whether the current thread is allowed to run.

     <br><dt><code>show thread run</code><dd>Show whether the current thread is allowed to run.

     <br><dt><code>set thread detach-suspend-count</code><dd><a name="index-thread-suspend-count_002c-_0040sc_007bgnu_007d-Hurd-1261"></a><a name="index-detach-from-thread_002c-_0040sc_007bgnu_007d-Hurd-1262"></a>This command sets the suspend count <span class="sc">gdb</span> will leave on a
thread when detaching.  This number is relative to the suspend count
found by <span class="sc">gdb</span> when it notices the thread; use <code>set thread
takeover-suspend-count</code> to force it to an absolute value.

     <br><dt><code>show thread detach-suspend-count</code><dd>Show the suspend count <span class="sc">gdb</span> will leave on the thread when
detaching.

     <br><dt><code>set thread exception-port</code><dt><code>set thread excp</code><dd>Set the thread exception port to which to forward exceptions.  This
overrides the port set by <code>set task exception-port</code> (see above). 
<code>set thread excp</code> is the shorthand alias.

     <br><dt><code>set thread takeover-suspend-count</code><dd>Normally, <span class="sc">gdb</span>'s thread suspend counts are relative to the
value <span class="sc">gdb</span> finds when it notices each thread.  This command
changes the suspend counts to be absolute instead.

     <br><dt><code>set thread default</code><dt><code>show thread default</code><dd><a name="index-thread-default-settings_002c-_0040sc_007bgnu_007d-Hurd-1263"></a>Each of the above <code>set thread</code> commands has a <code>set thread
default</code> counterpart (e.g., <code>set thread default pause</code>, <code>set
thread default exception-port</code>, etc.).  The <code>thread default</code>
variety of commands sets the default thread properties for all
threads; you can then change the properties of individual threads with
the non-default commands. 
</dl>

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