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<title>Debugging with GDB: Threads In Python</title>

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<a name="Threads-In-Python"></a>
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<hr>
<a name="Threads-In-Python-1"></a>
<h4 class="subsubsection">23.2.2.18 Threads In Python</h4>
<a name="index-threads-in-python"></a>

<a name="index-gdb_002eInferiorThread"></a>
<p>Python scripts can access information about, and manipulate inferior threads
controlled by <small>GDB</small>, via objects of the <code>gdb.InferiorThread</code> class.
</p>
<p>The following thread-related functions are available in the <code>gdb</code>
module:
</p>
<a name="index-gdb_002eselected_005fthread"></a>
<dl>
<dt><a name="index-gdb_002eselected_005fthread-1"></a>Function: <strong>gdb.selected_thread</strong> <em>()</em></dt>
<dd><p>This function returns the thread object for the selected thread.  If there
is no selected thread, this will return <code>None</code>.
</p></dd></dl>

<p>To get the list of threads for an inferior, use the <code>Inferior.threads()</code>
method.  See <a href="Inferiors-In-Python.html#Inferiors-In-Python">Inferiors In Python</a>.
</p>
<p>A <code>gdb.InferiorThread</code> object has the following attributes:
</p>
<dl>
<dt><a name="index-InferiorThread_002ename"></a>Variable: <strong>InferiorThread.name</strong></dt>
<dd><p>The name of the thread.  If the user specified a name using
<code>thread name</code>, then this returns that name.  Otherwise, if an
OS-supplied name is available, then it is returned.  Otherwise, this
returns <code>None</code>.
</p>
<p>This attribute can be assigned to.  The new value must be a string
object, which sets the new name, or <code>None</code>, which removes any
user-specified thread name.
</p></dd></dl>

<dl>
<dt><a name="index-InferiorThread_002enum"></a>Variable: <strong>InferiorThread.num</strong></dt>
<dd><p>The per-inferior number of the thread, as assigned by GDB.
</p></dd></dl>

<dl>
<dt><a name="index-InferiorThread_002eglobal_005fnum"></a>Variable: <strong>InferiorThread.global_num</strong></dt>
<dd><p>The global ID of the thread, as assigned by GDB.  You can use this to
make Python breakpoints thread-specific, for example
(see <a href="Breakpoints-In-Python.html#python_005fbreakpoint_005fthread">The Breakpoint.thread attribute</a>).
</p></dd></dl>

<dl>
<dt><a name="index-InferiorThread_002eptid"></a>Variable: <strong>InferiorThread.ptid</strong></dt>
<dd><p>ID of the thread, as assigned by the operating system.  This attribute is a
tuple containing three integers.  The first is the Process ID (PID); the second
is the Lightweight Process ID (LWPID), and the third is the Thread ID (TID).
Either the LWPID or TID may be 0, which indicates that the operating system
does not  use that identifier.
</p></dd></dl>

<dl>
<dt><a name="index-InferiorThread_002einferior"></a>Variable: <strong>InferiorThread.inferior</strong></dt>
<dd><p>The inferior this thread belongs to.  This attribute is represented as
a <code>gdb.Inferior</code> object.  This attribute is not writable.
</p></dd></dl>

<p>A <code>gdb.InferiorThread</code> object has the following methods:
</p>
<dl>
<dt><a name="index-InferiorThread_002eis_005fvalid"></a>Function: <strong>InferiorThread.is_valid</strong> <em>()</em></dt>
<dd><p>Returns <code>True</code> if the <code>gdb.InferiorThread</code> object is valid,
<code>False</code> if not.  A <code>gdb.InferiorThread</code> object will become
invalid if the thread exits, or the inferior that the thread belongs
is deleted.  All other <code>gdb.InferiorThread</code> methods will throw an
exception if it is invalid at the time the method is called.
</p></dd></dl>

<dl>
<dt><a name="index-InferiorThread_002eswitch"></a>Function: <strong>InferiorThread.switch</strong> <em>()</em></dt>
<dd><p>This changes <small>GDB</small>&rsquo;s currently selected thread to the one represented
by this object.
</p></dd></dl>

<dl>
<dt><a name="index-InferiorThread_002eis_005fstopped"></a>Function: <strong>InferiorThread.is_stopped</strong> <em>()</em></dt>
<dd><p>Return a Boolean indicating whether the thread is stopped.
</p></dd></dl>

<dl>
<dt><a name="index-InferiorThread_002eis_005frunning"></a>Function: <strong>InferiorThread.is_running</strong> <em>()</em></dt>
<dd><p>Return a Boolean indicating whether the thread is running.
</p></dd></dl>

<dl>
<dt><a name="index-InferiorThread_002eis_005fexited"></a>Function: <strong>InferiorThread.is_exited</strong> <em>()</em></dt>
<dd><p>Return a Boolean indicating whether the thread is exited.
</p></dd></dl>

<dl>
<dt><a name="index-InferiorThread_002ehandle"></a>Function: <strong>InferiorThread.handle</strong> <em>()</em></dt>
<dd><p>Return the thread object&rsquo;s handle, represented as a Python <code>bytes</code>
object.  A <code>gdb.Value</code> representation of the handle may be
constructed via <code>gdb.Value(bufobj, type)</code> where <var>bufobj</var> is
the Python <code>bytes</code> representation of the handle and <var>type</var> is
a <code>gdb.Type</code> for the handle type.
</p></dd></dl>

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