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<h3 class="section">17.3 Giving your Program a Signal</h3>

<p><a name="index-deliver-a-signal-to-a-program-1170"></a>
     
<a name="index-signal-1171"></a>
<dl><dt><code>signal </code><var>signal</var><dd>Resume execution where your program is stopped, but immediately give it the
signal <var>signal</var>.  The <var>signal</var> can be the name or the number of a
signal.  For example, on many systems <code>signal 2</code> and <code>signal
SIGINT</code> are both ways of sending an interrupt signal.

     <p>Alternatively, if <var>signal</var> is zero, continue execution without
giving a signal.  This is useful when your program stopped on account of
a signal and would ordinarily see the signal when resumed with the
<code>continue</code> command; &lsquo;<samp><span class="samp">signal 0</span></samp>&rsquo; causes it to resume without a
signal.

     <p><em>Note:</em> When resuming a multi-threaded program, <var>signal</var> is
delivered to the currently selected thread, not the thread that last
reported a stop.  This includes the situation where a thread was
stopped due to a signal.  So if you want to continue execution
suppressing the signal that stopped a thread, you should select that
same thread before issuing the &lsquo;<samp><span class="samp">signal 0</span></samp>&rsquo; command.  If you issue
the &lsquo;<samp><span class="samp">signal 0</span></samp>&rsquo; command with another thread as the selected one,
<span class="sc">gdb</span> detects that and asks for confirmation.

     <p>Invoking the <code>signal</code> command is not the same as invoking the
<code>kill</code> utility from the shell.  Sending a signal with <code>kill</code>
causes <span class="sc">gdb</span> to decide what to do with the signal depending on
the signal handling tables (see <a href="Signals.html#Signals">Signals</a>).  The <code>signal</code> command
passes the signal directly to your program.

     <p><code>signal</code> does not repeat when you press &lt;RET&gt; a second time
after executing the command.

     <p><a name="index-queue_002dsignal-1172"></a><br><dt><code>queue-signal </code><var>signal</var><dd>Queue <var>signal</var> to be delivered immediately to the current thread
when execution of the thread resumes.  The <var>signal</var> can be the name or
the number of a signal.  For example, on many systems <code>signal 2</code> and
<code>signal SIGINT</code> are both ways of sending an interrupt signal. 
The handling of the signal must be set to pass the signal to the program,
otherwise <span class="sc">gdb</span> will report an error. 
You can control the handling of signals from <span class="sc">gdb</span> with the
<code>handle</code> command (see <a href="Signals.html#Signals">Signals</a>).

     <p>Alternatively, if <var>signal</var> is zero, any currently queued signal
for the current thread is discarded and when execution resumes no signal
will be delivered.  This is useful when your program stopped on account
of a signal and would ordinarily see the signal when resumed with the
<code>continue</code> command.

     <p>This command differs from the <code>signal</code> command in that the signal
is just queued, execution is not resumed.  And <code>queue-signal</code> cannot
be used to pass a signal whose handling state has been set to <code>nopass</code>
(see <a href="Signals.html#Signals">Signals</a>). 
</dl>
   <!-- @end group -->

   <p>See <a href="stepping-into-signal-handlers.html#stepping-into-signal-handlers">stepping into signal handlers</a>, for information on how stepping
commands behave when the thread has a signal queued.

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