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<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">sys.monitoring</span></code> — Execution event monitoring</a><ul>
<li><a class="reference internal" href="#tool-identifiers">Tool identifiers</a><ul>
<li><a class="reference internal" href="#registering-and-using-tools">Registering and using tools</a></li>
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<li><a class="reference internal" href="#setting-events-globally">Setting events globally</a></li>
<li><a class="reference internal" href="#per-code-object-events">Per code object events</a></li>
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  <section id="module-sys.monitoring">
<span id="sys-monitoring-execution-event-monitoring"></span><h1><code class="xref py py-mod docutils literal notranslate"><span class="pre">sys.monitoring</span></code> — Execution event monitoring<a class="headerlink" href="#module-sys.monitoring" title="Link to this heading">¶</a></h1>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.12.</span></p>
</div>
<hr class="docutils" />
<div class="admonition note">
<p class="admonition-title">Note</p>
<p><code class="xref py py-mod docutils literal notranslate"><span class="pre">sys.monitoring</span></code> is a namespace within the <a class="reference internal" href="sys.html#module-sys" title="sys: Access system-specific parameters and functions."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sys</span></code></a> module,
not an independent module, so there is no need to
<code class="docutils literal notranslate"><span class="pre">import</span> <span class="pre">sys.monitoring</span></code>, simply <code class="docutils literal notranslate"><span class="pre">import</span> <span class="pre">sys</span></code> and then use
<code class="docutils literal notranslate"><span class="pre">sys.monitoring</span></code>.</p>
</div>
<p>This namespace provides access to the functions and constants necessary to
activate and control event monitoring.</p>
<p>As programs execute, events occur that might be of interest to tools that
monitor execution. The <code class="xref py py-mod docutils literal notranslate"><span class="pre">sys.monitoring</span></code> namespace provides means to
receive callbacks when events of interest occur.</p>
<p>The monitoring API consists of three components:</p>
<ul class="simple">
<li><p><a class="reference internal" href="#tool-identifiers">Tool identifiers</a></p></li>
<li><p><a class="reference internal" href="#events">Events</a></p></li>
<li><p><a class="reference internal" href="#callbacks"><span class="std std-ref">Callbacks</span></a></p></li>
</ul>
<section id="tool-identifiers">
<h2>Tool identifiers<a class="headerlink" href="#tool-identifiers" title="Link to this heading">¶</a></h2>
<p>A tool identifier is an integer and the associated name.
Tool identifiers are used to discourage tools from interfering with each
other and to allow multiple tools to operate at the same time.
Currently tools are completely independent and cannot be used to
monitor each other. This restriction may be lifted in the future.</p>
<p>Before registering or activating events, a tool should choose an identifier.
Identifiers are integers in the range 0 to 5 inclusive.</p>
<section id="registering-and-using-tools">
<h3>Registering and using tools<a class="headerlink" href="#registering-and-using-tools" title="Link to this heading">¶</a></h3>
<dl class="py function">
<dt class="sig sig-object py" id="sys.monitoring.use_tool_id">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.</span></span><span class="sig-name descname"><span class="pre">use_tool_id</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">tool_id</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">name</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="stdtypes.html#str" title="str"><span class="pre">str</span></a></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">&#x2192;</span> <span class="sig-return-typehint"><a class="reference internal" href="constants.html#None" title="None"><span class="pre">None</span></a></span></span><a class="headerlink" href="#sys.monitoring.use_tool_id" title="Link to this definition">¶</a></dt>
<dd><p>Must be called before <em>tool_id</em> can be used.
<em>tool_id</em> must be in the range 0 to 5 inclusive.
Raises a <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> if <em>tool_id</em> is in use.</p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="sys.monitoring.clear_tool_id">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.</span></span><span class="sig-name descname"><span class="pre">clear_tool_id</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">tool_id</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">&#x2192;</span> <span class="sig-return-typehint"><a class="reference internal" href="constants.html#None" title="None"><span class="pre">None</span></a></span></span><a class="headerlink" href="#sys.monitoring.clear_tool_id" title="Link to this definition">¶</a></dt>
<dd><p>Unregister all events and callback functions associated with <em>tool_id</em>.</p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="sys.monitoring.free_tool_id">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.</span></span><span class="sig-name descname"><span class="pre">free_tool_id</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">tool_id</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">&#x2192;</span> <span class="sig-return-typehint"><a class="reference internal" href="constants.html#None" title="None"><span class="pre">None</span></a></span></span><a class="headerlink" href="#sys.monitoring.free_tool_id" title="Link to this definition">¶</a></dt>
<dd><p>Should be called once a tool no longer requires <em>tool_id</em>.
Will call <a class="reference internal" href="#sys.monitoring.clear_tool_id" title="sys.monitoring.clear_tool_id"><code class="xref py py-func docutils literal notranslate"><span class="pre">clear_tool_id()</span></code></a> before releasing <em>tool_id</em>.</p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="sys.monitoring.get_tool">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.</span></span><span class="sig-name descname"><span class="pre">get_tool</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">tool_id</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">&#x2192;</span> <span class="sig-return-typehint"><a class="reference internal" href="stdtypes.html#str" title="str"><span class="pre">str</span></a><span class="w"> </span><span class="p"><span class="pre">|</span></span><span class="w"> </span><a class="reference internal" href="constants.html#None" title="None"><span class="pre">None</span></a></span></span><a class="headerlink" href="#sys.monitoring.get_tool" title="Link to this definition">¶</a></dt>
<dd><p>Returns the name of the tool if <em>tool_id</em> is in use,
otherwise it returns <code class="docutils literal notranslate"><span class="pre">None</span></code>.
<em>tool_id</em> must be in the range 0 to 5 inclusive.</p>
</dd></dl>

<p>All IDs are treated the same by the VM with regard to events, but the
following IDs are pre-defined to make co-operation of tools easier:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">sys</span><span class="o">.</span><span class="n">monitoring</span><span class="o">.</span><span class="n">DEBUGGER_ID</span> <span class="o">=</span> <span class="mi">0</span>
<span class="n">sys</span><span class="o">.</span><span class="n">monitoring</span><span class="o">.</span><span class="n">COVERAGE_ID</span> <span class="o">=</span> <span class="mi">1</span>
<span class="n">sys</span><span class="o">.</span><span class="n">monitoring</span><span class="o">.</span><span class="n">PROFILER_ID</span> <span class="o">=</span> <span class="mi">2</span>
<span class="n">sys</span><span class="o">.</span><span class="n">monitoring</span><span class="o">.</span><span class="n">OPTIMIZER_ID</span> <span class="o">=</span> <span class="mi">5</span>
</pre></div>
</div>
</section>
</section>
<section id="events">
<h2>Events<a class="headerlink" href="#events" title="Link to this heading">¶</a></h2>
<p>The following events are supported:</p>
<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-BRANCH_LEFT">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">BRANCH_LEFT</span></span><a class="headerlink" href="#monitoring-event-BRANCH_LEFT" title="Link to this definition">¶</a></dt>
<dd><p>A conditional branch goes left.</p>
<p>It is up to the tool to determine how to present “left” and “right” branches.
There is no guarantee which branch is “left” and which is “right”, except
that it will be consistent for the duration of the program.</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-BRANCH_RIGHT">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">BRANCH_RIGHT</span></span><a class="headerlink" href="#monitoring-event-BRANCH_RIGHT" title="Link to this definition">¶</a></dt>
<dd><p>A conditional branch goes right.</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-CALL">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">CALL</span></span><a class="headerlink" href="#monitoring-event-CALL" title="Link to this definition">¶</a></dt>
<dd><p>A call in Python code (event occurs before the call).</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-C_RAISE">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">C_RAISE</span></span><a class="headerlink" href="#monitoring-event-C_RAISE" title="Link to this definition">¶</a></dt>
<dd><p>An exception raised from any callable, except for Python functions (event occurs after the exit).</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-C_RETURN">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">C_RETURN</span></span><a class="headerlink" href="#monitoring-event-C_RETURN" title="Link to this definition">¶</a></dt>
<dd><p>Return from any callable, except for Python functions (event occurs after the return).</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-EXCEPTION_HANDLED">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">EXCEPTION_HANDLED</span></span><a class="headerlink" href="#monitoring-event-EXCEPTION_HANDLED" title="Link to this definition">¶</a></dt>
<dd><p>An exception is handled.</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-INSTRUCTION">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">INSTRUCTION</span></span><a class="headerlink" href="#monitoring-event-INSTRUCTION" title="Link to this definition">¶</a></dt>
<dd><p>A VM instruction is about to be executed.</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-JUMP">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">JUMP</span></span><a class="headerlink" href="#monitoring-event-JUMP" title="Link to this definition">¶</a></dt>
<dd><p>An unconditional jump in the control flow graph is made.</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-LINE">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">LINE</span></span><a class="headerlink" href="#monitoring-event-LINE" title="Link to this definition">¶</a></dt>
<dd><p>An instruction is about to be executed that has a different line number from the preceding instruction.</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-PY_RESUME">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">PY_RESUME</span></span><a class="headerlink" href="#monitoring-event-PY_RESUME" title="Link to this definition">¶</a></dt>
<dd><p>Resumption of a Python function (for generator and coroutine functions), except for <code class="docutils literal notranslate"><span class="pre">throw()</span></code> calls.</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-PY_RETURN">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">PY_RETURN</span></span><a class="headerlink" href="#monitoring-event-PY_RETURN" title="Link to this definition">¶</a></dt>
<dd><p>Return from a Python function (occurs immediately before the return, the callee’s frame will be on the stack).</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-PY_START">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">PY_START</span></span><a class="headerlink" href="#monitoring-event-PY_START" title="Link to this definition">¶</a></dt>
<dd><p>Start of a Python function (occurs immediately after the call, the callee’s frame will be on the stack)</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-PY_THROW">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">PY_THROW</span></span><a class="headerlink" href="#monitoring-event-PY_THROW" title="Link to this definition">¶</a></dt>
<dd><p>A Python function is resumed by a <code class="docutils literal notranslate"><span class="pre">throw()</span></code> call.</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-PY_UNWIND">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">PY_UNWIND</span></span><a class="headerlink" href="#monitoring-event-PY_UNWIND" title="Link to this definition">¶</a></dt>
<dd><p>Exit from a Python function during exception unwinding. This includes exceptions raised directly within the
function and that are allowed to continue to propagate.</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-PY_YIELD">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">PY_YIELD</span></span><a class="headerlink" href="#monitoring-event-PY_YIELD" title="Link to this definition">¶</a></dt>
<dd><p>Yield from a Python function (occurs immediately before the yield, the callee’s frame will be on the stack).</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-RAISE">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">RAISE</span></span><a class="headerlink" href="#monitoring-event-RAISE" title="Link to this definition">¶</a></dt>
<dd><p>An exception is raised, except those that cause a <a class="reference internal" href="#monitoring-event-STOP_ITERATION"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">STOP_ITERATION</span></code></a> event.</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-RERAISE">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">RERAISE</span></span><a class="headerlink" href="#monitoring-event-RERAISE" title="Link to this definition">¶</a></dt>
<dd><p>An exception is re-raised, for example at the end of a <a class="reference internal" href="../reference/compound_stmts.html#finally"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">finally</span></code></a> block.</p>
</dd></dl>

<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-STOP_ITERATION">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">STOP_ITERATION</span></span><a class="headerlink" href="#monitoring-event-STOP_ITERATION" title="Link to this definition">¶</a></dt>
<dd><p>An artificial <a class="reference internal" href="exceptions.html#StopIteration" title="StopIteration"><code class="xref py py-exc docutils literal notranslate"><span class="pre">StopIteration</span></code></a> is raised; see <a class="reference internal" href="#the-stop-iteration-event">the STOP_ITERATION event</a>.</p>
</dd></dl>

<p>More events may be added in the future.</p>
<p>These events are attributes of the <code class="xref py py-mod docutils literal notranslate"><span class="pre">sys.monitoring.events</span></code> namespace.
Each event is represented as a power-of-2 integer constant.
To define a set of events, simply bitwise OR the individual events together.
For example, to specify both <a class="reference internal" href="#monitoring-event-PY_RETURN"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_RETURN</span></code></a> and <a class="reference internal" href="#monitoring-event-PY_START"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_START</span></code></a>
events, use the expression <code class="docutils literal notranslate"><span class="pre">PY_RETURN</span> <span class="pre">|</span> <span class="pre">PY_START</span></code>.</p>
<dl class="std monitoring-event">
<dt class="sig sig-object std" id="monitoring-event-NO_EVENTS">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.events.</span></span><span class="sig-name descname"><span class="pre">NO_EVENTS</span></span><a class="headerlink" href="#monitoring-event-NO_EVENTS" title="Link to this definition">¶</a></dt>
<dd><p>An alias for <code class="docutils literal notranslate"><span class="pre">0</span></code> so users can do explicit comparisons like:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">if</span> <span class="n">get_events</span><span class="p">(</span><span class="n">DEBUGGER_ID</span><span class="p">)</span> <span class="o">==</span> <span class="n">NO_EVENTS</span><span class="p">:</span>
    <span class="o">...</span>
</pre></div>
</div>
<p>Setting this event deactivates all events.</p>
</dd></dl>

<section id="local-events">
<span id="monitoring-event-local"></span><h3>Local events<a class="headerlink" href="#local-events" title="Link to this heading">¶</a></h3>
<p>Local events are associated with normal execution of the program and happen
at clearly defined locations. All local events can be disabled.
The local events are:</p>
<ul class="simple">
<li><p><a class="reference internal" href="#monitoring-event-PY_START"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_START</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-PY_RESUME"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_RESUME</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-PY_RETURN"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_RETURN</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-PY_YIELD"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_YIELD</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-CALL"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">CALL</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-LINE"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">LINE</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-INSTRUCTION"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">INSTRUCTION</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-JUMP"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">JUMP</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-BRANCH_LEFT"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">BRANCH_LEFT</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-BRANCH_RIGHT"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">BRANCH_RIGHT</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-STOP_ITERATION"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">STOP_ITERATION</span></code></a></p></li>
</ul>
</section>
<section id="deprecated-event">
<h3>Deprecated event<a class="headerlink" href="#deprecated-event" title="Link to this heading">¶</a></h3>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">BRANCH</span></code></p></li>
</ul>
<p>The <code class="docutils literal notranslate"><span class="pre">BRANCH</span></code> event is deprecated in 3.14.
Using <a class="reference internal" href="#monitoring-event-BRANCH_LEFT"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">BRANCH_LEFT</span></code></a> and <a class="reference internal" href="#monitoring-event-BRANCH_RIGHT"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">BRANCH_RIGHT</span></code></a>
events will give much better performance as they can be disabled
independently.</p>
</section>
<section id="ancillary-events">
<h3>Ancillary events<a class="headerlink" href="#ancillary-events" title="Link to this heading">¶</a></h3>
<p>Ancillary events can be monitored like other events, but are controlled
by another event:</p>
<ul class="simple">
<li><p><a class="reference internal" href="#monitoring-event-C_RAISE"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">C_RAISE</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-C_RETURN"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">C_RETURN</span></code></a></p></li>
</ul>
<p>The <a class="reference internal" href="#monitoring-event-C_RETURN"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">C_RETURN</span></code></a> and <a class="reference internal" href="#monitoring-event-C_RAISE"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">C_RAISE</span></code></a> events
are controlled by the <a class="reference internal" href="#monitoring-event-CALL"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">CALL</span></code></a> event.
<code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">C_RETURN</span></code> and <code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">C_RAISE</span></code> events will only be
seen if the corresponding <code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">CALL</span></code> event is being monitored.</p>
</section>
<section id="other-events">
<span id="monitoring-event-global"></span><h3>Other events<a class="headerlink" href="#other-events" title="Link to this heading">¶</a></h3>
<p>Other events are not necessarily tied to a specific location in the
program and cannot be individually disabled via <a class="reference internal" href="#sys.monitoring.DISABLE" title="sys.monitoring.DISABLE"><code class="xref py py-data docutils literal notranslate"><span class="pre">DISABLE</span></code></a>.</p>
<p>The other events that can be monitored are:</p>
<ul class="simple">
<li><p><a class="reference internal" href="#monitoring-event-PY_THROW"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_THROW</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-PY_UNWIND"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_UNWIND</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-RAISE"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">RAISE</span></code></a></p></li>
<li><p><a class="reference internal" href="#monitoring-event-EXCEPTION_HANDLED"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">EXCEPTION_HANDLED</span></code></a></p></li>
</ul>
</section>
<section id="the-stop-iteration-event">
<h3>The STOP_ITERATION event<a class="headerlink" href="#the-stop-iteration-event" title="Link to this heading">¶</a></h3>
<p><span class="target" id="index-0"></span><a class="pep reference external" href="https://peps.python.org/pep-0380/#use-of-stopiteration-to-return-values"><strong>PEP 380</strong></a>
specifies that a <a class="reference internal" href="exceptions.html#StopIteration" title="StopIteration"><code class="xref py py-exc docutils literal notranslate"><span class="pre">StopIteration</span></code></a> exception is raised when returning a value
from a generator or coroutine. However, this is a very inefficient way to
return a value, so some Python implementations, notably CPython 3.12+, do not
raise an exception unless it would be visible to other code.</p>
<p>To allow tools to monitor for real exceptions without slowing down generators
and coroutines, the <a class="reference internal" href="#monitoring-event-STOP_ITERATION"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">STOP_ITERATION</span></code></a> event is provided.
<code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">STOP_ITERATION</span></code> can be locally disabled, unlike
<a class="reference internal" href="#monitoring-event-RAISE"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">RAISE</span></code></a>.</p>
<p>Note that the <a class="reference internal" href="#monitoring-event-STOP_ITERATION"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">STOP_ITERATION</span></code></a> event and the
<a class="reference internal" href="#monitoring-event-RAISE"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">RAISE</span></code></a> event for a <a class="reference internal" href="exceptions.html#StopIteration" title="StopIteration"><code class="xref py py-exc docutils literal notranslate"><span class="pre">StopIteration</span></code></a> exception are
equivalent, and are treated as interchangeable when generating events.
Implementations will favor <code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">STOP_ITERATION</span></code> for performance
reasons, but may generate a <code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">RAISE</span></code> event with a
<code class="xref py py-exc docutils literal notranslate"><span class="pre">StopIteration</span></code>.</p>
</section>
</section>
<section id="turning-events-on-and-off">
<h2>Turning events on and off<a class="headerlink" href="#turning-events-on-and-off" title="Link to this heading">¶</a></h2>
<p>In order to monitor an event, it must be turned on and a corresponding callback
must be registered. Events can be turned on or off by setting the events either
globally and/or for a particular code object. An event will trigger only once,
even if it is turned on both globally and locally.</p>
<section id="setting-events-globally">
<h3>Setting events globally<a class="headerlink" href="#setting-events-globally" title="Link to this heading">¶</a></h3>
<p>Events can be controlled globally by modifying the set of events being monitored.</p>
<dl class="py function">
<dt class="sig sig-object py" id="sys.monitoring.get_events">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.</span></span><span class="sig-name descname"><span class="pre">get_events</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">tool_id</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">&#x2192;</span> <span class="sig-return-typehint"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></span><a class="headerlink" href="#sys.monitoring.get_events" title="Link to this definition">¶</a></dt>
<dd><p>Returns the <code class="docutils literal notranslate"><span class="pre">int</span></code> representing all the active events.</p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="sys.monitoring.set_events">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.</span></span><span class="sig-name descname"><span class="pre">set_events</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">tool_id</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">event_set</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">&#x2192;</span> <span class="sig-return-typehint"><a class="reference internal" href="constants.html#None" title="None"><span class="pre">None</span></a></span></span><a class="headerlink" href="#sys.monitoring.set_events" title="Link to this definition">¶</a></dt>
<dd><p>Activates all events which are set in <em>event_set</em>.
Raises a <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> if <em>tool_id</em> is not in use.</p>
</dd></dl>

<p>No events are active by default.</p>
</section>
<section id="per-code-object-events">
<h3>Per code object events<a class="headerlink" href="#per-code-object-events" title="Link to this heading">¶</a></h3>
<p>Events can also be controlled on a per code object basis. The functions
defined below which accept a <a class="reference internal" href="types.html#types.CodeType" title="types.CodeType"><code class="xref py py-class docutils literal notranslate"><span class="pre">types.CodeType</span></code></a> should be prepared
to accept a look-alike object from functions which are not defined
in Python (see <a class="reference internal" href="../c-api/monitoring.html#c-api-monitoring"><span class="std std-ref">Monitoring C API</span></a>).</p>
<dl class="py function">
<dt class="sig sig-object py" id="sys.monitoring.get_local_events">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.</span></span><span class="sig-name descname"><span class="pre">get_local_events</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">tool_id</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">code</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="types.html#types.CodeType" title="types.CodeType"><span class="pre">CodeType</span></a></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">&#x2192;</span> <span class="sig-return-typehint"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></span><a class="headerlink" href="#sys.monitoring.get_local_events" title="Link to this definition">¶</a></dt>
<dd><p>Returns all the <a class="reference internal" href="#monitoring-event-local"><span class="std std-ref">local events</span></a> for <em>code</em></p>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="sys.monitoring.set_local_events">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.</span></span><span class="sig-name descname"><span class="pre">set_local_events</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">tool_id</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">code</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="types.html#types.CodeType" title="types.CodeType"><span class="pre">CodeType</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">event_set</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">&#x2192;</span> <span class="sig-return-typehint"><a class="reference internal" href="constants.html#None" title="None"><span class="pre">None</span></a></span></span><a class="headerlink" href="#sys.monitoring.set_local_events" title="Link to this definition">¶</a></dt>
<dd><p>Activates all the <a class="reference internal" href="#monitoring-event-local"><span class="std std-ref">local events</span></a> for <em>code</em>
which are set in <em>event_set</em>. Raises a <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> if <em>tool_id</em> is not
in use.</p>
</dd></dl>

</section>
<section id="disabling-events">
<h3>Disabling events<a class="headerlink" href="#disabling-events" title="Link to this heading">¶</a></h3>
<dl class="py data">
<dt class="sig sig-object py" id="sys.monitoring.DISABLE">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.</span></span><span class="sig-name descname"><span class="pre">DISABLE</span></span><a class="headerlink" href="#sys.monitoring.DISABLE" title="Link to this definition">¶</a></dt>
<dd><p>A special value that can be returned from a callback function to disable
events for the current code location.</p>
</dd></dl>

<p><a class="reference internal" href="#monitoring-event-local"><span class="std std-ref">Local events</span></a> can be disabled for a specific code
location by returning <a class="reference internal" href="#sys.monitoring.DISABLE" title="sys.monitoring.DISABLE"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.monitoring.DISABLE</span></code></a> from a callback function.
This does not change which events are set, or any other code locations for the
same event.</p>
<p>Disabling events for specific locations is very important for high
performance monitoring. For example, a program can be run under a
debugger with no overhead if the debugger disables all monitoring
except for a few breakpoints.</p>
<p>If <a class="reference internal" href="#sys.monitoring.DISABLE" title="sys.monitoring.DISABLE"><code class="xref py py-data docutils literal notranslate"><span class="pre">DISABLE</span></code></a> is returned by a callback for a
<a class="reference internal" href="#monitoring-event-global"><span class="std std-ref">global event</span></a>, <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> will be raised
by the interpreter in a non-specific location (that is, no traceback will be
provided).</p>
<dl class="py function">
<dt class="sig sig-object py" id="sys.monitoring.restart_events">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.</span></span><span class="sig-name descname"><span class="pre">restart_events</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">&#x2192;</span> <span class="sig-return-typehint"><a class="reference internal" href="constants.html#None" title="None"><span class="pre">None</span></a></span></span><a class="headerlink" href="#sys.monitoring.restart_events" title="Link to this definition">¶</a></dt>
<dd><p>Enable all the events that were disabled by <a class="reference internal" href="#sys.monitoring.DISABLE" title="sys.monitoring.DISABLE"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.monitoring.DISABLE</span></code></a>
for all tools.</p>
</dd></dl>

</section>
</section>
<section id="registering-callback-functions">
<span id="callbacks"></span><h2>Registering callback functions<a class="headerlink" href="#registering-callback-functions" title="Link to this heading">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="sys.monitoring.register_callback">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.</span></span><span class="sig-name descname"><span class="pre">register_callback</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">tool_id</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">event</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em>, <em class="sig-param"><span class="n"><span class="pre">func</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="collections.abc.html#collections.abc.Callable" title="collections.abc.Callable"><span class="pre">Callable</span></a><span class="w"> </span><span class="p"><span class="pre">|</span></span><span class="w"> </span><a class="reference internal" href="constants.html#None" title="None"><span class="pre">None</span></a></span></em>, <em class="sig-param"><span class="positional-only-separator o"><abbr title="Positional-only parameter separator (PEP 570)"><span class="pre">/</span></abbr></span></em><span class="sig-paren">)</span> <span class="sig-return"><span class="sig-return-icon">&#x2192;</span> <span class="sig-return-typehint"><a class="reference internal" href="collections.abc.html#collections.abc.Callable" title="collections.abc.Callable"><span class="pre">Callable</span></a><span class="w"> </span><span class="p"><span class="pre">|</span></span><span class="w"> </span><a class="reference internal" href="constants.html#None" title="None"><span class="pre">None</span></a></span></span><a class="headerlink" href="#sys.monitoring.register_callback" title="Link to this definition">¶</a></dt>
<dd><p>Registers the callable <em>func</em> for the <em>event</em> with the given <em>tool_id</em></p>
<p>If another callback was registered for the given <em>tool_id</em> and <em>event</em>,
it is unregistered and returned.
Otherwise <code class="xref py py-func docutils literal notranslate"><span class="pre">register_callback()</span></code> returns <code class="docutils literal notranslate"><span class="pre">None</span></code>.</p>
<p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">sys.monitoring.register_callback</span></code> with argument <code class="docutils literal notranslate"><span class="pre">func</span></code>.</p>
</dd></dl>

<p>Functions can be unregistered by calling
<code class="docutils literal notranslate"><span class="pre">sys.monitoring.register_callback(tool_id,</span> <span class="pre">event,</span> <span class="pre">None)</span></code>.</p>
<p>Callback functions can be registered and unregistered at any time.</p>
<p>Callbacks are called only once regardless if the event is turned on both
globally and locally. As such, if an event could be turned on for both global
and local events by your code then the callback needs to be written to handle
either trigger.</p>
<section id="callback-function-arguments">
<h3>Callback function arguments<a class="headerlink" href="#callback-function-arguments" title="Link to this heading">¶</a></h3>
<dl class="py data">
<dt class="sig sig-object py" id="sys.monitoring.MISSING">
<span class="sig-prename descclassname"><span class="pre">sys.monitoring.</span></span><span class="sig-name descname"><span class="pre">MISSING</span></span><a class="headerlink" href="#sys.monitoring.MISSING" title="Link to this definition">¶</a></dt>
<dd><p>A special value that is passed to a callback function to indicate
that there are no arguments to the call.</p>
</dd></dl>

<p>When an active event occurs, the registered callback function is called.
Callback functions returning an object other than <a class="reference internal" href="#sys.monitoring.DISABLE" title="sys.monitoring.DISABLE"><code class="xref py py-data docutils literal notranslate"><span class="pre">DISABLE</span></code></a> will have no effect.
Different events will provide the callback function with different arguments, as follows:</p>
<ul>
<li><p><a class="reference internal" href="#monitoring-event-PY_START"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_START</span></code></a> and <a class="reference internal" href="#monitoring-event-PY_RESUME"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_RESUME</span></code></a>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">func</span><span class="p">(</span><span class="n">code</span><span class="p">:</span> <span class="n">CodeType</span><span class="p">,</span> <span class="n">instruction_offset</span><span class="p">:</span> <span class="nb">int</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="nb">object</span>
</pre></div>
</div>
</li>
<li><p><a class="reference internal" href="#monitoring-event-PY_RETURN"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_RETURN</span></code></a> and <a class="reference internal" href="#monitoring-event-PY_YIELD"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_YIELD</span></code></a>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">func</span><span class="p">(</span><span class="n">code</span><span class="p">:</span> <span class="n">CodeType</span><span class="p">,</span> <span class="n">instruction_offset</span><span class="p">:</span> <span class="nb">int</span><span class="p">,</span> <span class="n">retval</span><span class="p">:</span> <span class="nb">object</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="nb">object</span>
</pre></div>
</div>
</li>
<li><p><a class="reference internal" href="#monitoring-event-CALL"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">CALL</span></code></a>, <a class="reference internal" href="#monitoring-event-C_RAISE"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">C_RAISE</span></code></a> and <a class="reference internal" href="#monitoring-event-C_RETURN"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">C_RETURN</span></code></a>
(<em>arg0</em> can be <a class="reference internal" href="#sys.monitoring.MISSING" title="sys.monitoring.MISSING"><code class="xref py py-data docutils literal notranslate"><span class="pre">MISSING</span></code></a> specifically):</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">func</span><span class="p">(</span><span class="n">code</span><span class="p">:</span> <span class="n">CodeType</span><span class="p">,</span> <span class="n">instruction_offset</span><span class="p">:</span> <span class="nb">int</span><span class="p">,</span> <span class="nb">callable</span><span class="p">:</span> <span class="nb">object</span><span class="p">,</span> <span class="n">arg0</span><span class="p">:</span> <span class="nb">object</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="nb">object</span>
</pre></div>
</div>
<p><em>code</em> represents the code object where the call is being made, while
<em>callable</em> is the object that is about to be called (and thus
triggered the event).
If there are no arguments, <em>arg0</em> is set to <a class="reference internal" href="#sys.monitoring.MISSING" title="sys.monitoring.MISSING"><code class="xref py py-data docutils literal notranslate"><span class="pre">sys.monitoring.MISSING</span></code></a>.</p>
<p>For instance methods, <em>callable</em> will be the function object as found on the
class with <em>arg0</em> set to the instance (i.e. the <code class="docutils literal notranslate"><span class="pre">self</span></code> argument to the
method).</p>
</li>
<li><p><a class="reference internal" href="#monitoring-event-RAISE"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">RAISE</span></code></a>, <a class="reference internal" href="#monitoring-event-RERAISE"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">RERAISE</span></code></a>, <a class="reference internal" href="#monitoring-event-EXCEPTION_HANDLED"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">EXCEPTION_HANDLED</span></code></a>,
<a class="reference internal" href="#monitoring-event-PY_UNWIND"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_UNWIND</span></code></a>, <a class="reference internal" href="#monitoring-event-PY_THROW"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">PY_THROW</span></code></a> and <a class="reference internal" href="#monitoring-event-STOP_ITERATION"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">STOP_ITERATION</span></code></a>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">func</span><span class="p">(</span><span class="n">code</span><span class="p">:</span> <span class="n">CodeType</span><span class="p">,</span> <span class="n">instruction_offset</span><span class="p">:</span> <span class="nb">int</span><span class="p">,</span> <span class="n">exception</span><span class="p">:</span> <span class="ne">BaseException</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="nb">object</span>
</pre></div>
</div>
</li>
<li><p><a class="reference internal" href="#monitoring-event-LINE"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">LINE</span></code></a>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">func</span><span class="p">(</span><span class="n">code</span><span class="p">:</span> <span class="n">CodeType</span><span class="p">,</span> <span class="n">line_number</span><span class="p">:</span> <span class="nb">int</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="nb">object</span>
</pre></div>
</div>
</li>
<li><p><a class="reference internal" href="#monitoring-event-BRANCH_LEFT"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">BRANCH_LEFT</span></code></a>, <a class="reference internal" href="#monitoring-event-BRANCH_RIGHT"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">BRANCH_RIGHT</span></code></a> and <a class="reference internal" href="#monitoring-event-JUMP"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">JUMP</span></code></a>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">func</span><span class="p">(</span><span class="n">code</span><span class="p">:</span> <span class="n">CodeType</span><span class="p">,</span> <span class="n">instruction_offset</span><span class="p">:</span> <span class="nb">int</span><span class="p">,</span> <span class="n">destination_offset</span><span class="p">:</span> <span class="nb">int</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="nb">object</span>
</pre></div>
</div>
<p>Note that the <em>destination_offset</em> is where the code will next execute.</p>
</li>
<li><p><a class="reference internal" href="#monitoring-event-INSTRUCTION"><code class="xref std std-monitoring-event docutils literal notranslate"><span class="pre">INSTRUCTION</span></code></a>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">func</span><span class="p">(</span><span class="n">code</span><span class="p">:</span> <span class="n">CodeType</span><span class="p">,</span> <span class="n">instruction_offset</span><span class="p">:</span> <span class="nb">int</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="nb">object</span>
</pre></div>
</div>
</li>
</ul>
</section>
</section>
</section>


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    <ul>
<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">sys.monitoring</span></code> — Execution event monitoring</a><ul>
<li><a class="reference internal" href="#tool-identifiers">Tool identifiers</a><ul>
<li><a class="reference internal" href="#registering-and-using-tools">Registering and using tools</a></li>
</ul>
</li>
<li><a class="reference internal" href="#events">Events</a><ul>
<li><a class="reference internal" href="#local-events">Local events</a></li>
<li><a class="reference internal" href="#deprecated-event">Deprecated event</a></li>
<li><a class="reference internal" href="#ancillary-events">Ancillary events</a></li>
<li><a class="reference internal" href="#other-events">Other events</a></li>
<li><a class="reference internal" href="#the-stop-iteration-event">The STOP_ITERATION event</a></li>
</ul>
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<li><a class="reference internal" href="#turning-events-on-and-off">Turning events on and off</a><ul>
<li><a class="reference internal" href="#setting-events-globally">Setting events globally</a></li>
<li><a class="reference internal" href="#per-code-object-events">Per code object events</a></li>
<li><a class="reference internal" href="#disabling-events">Disabling events</a></li>
</ul>
</li>
<li><a class="reference internal" href="#registering-callback-functions">Registering callback functions</a><ul>
<li><a class="reference internal" href="#callback-function-arguments">Callback function arguments</a></li>
</ul>
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