<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <!-- Copyright (C) 1988-2019 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being "Free Software" and "Free Software Needs Free Documentation", with the Front-Cover Texts being "A GNU Manual," and with the Back-Cover Texts as in (a) below. (a) The FSF's Back-Cover Text is: "You are free to copy and modify this GNU Manual. 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The type of the object and its attributes will vary depending on the details of the change. All the existing events are described below. </p> <p>In order to be notified of an event, you must register an event handler with an <em>event registry</em>. An event registry is an object in the <code>gdb.events</code> module which dispatches particular events. A registry provides methods to register and unregister event handlers: </p> <dl> <dt><a name="index-EventRegistry_002econnect"></a>Function: <strong>EventRegistry.connect</strong> <em>(object)</em></dt> <dd><p>Add the given callable <var>object</var> to the registry. This object will be called when an event corresponding to this registry occurs. </p></dd></dl> <dl> <dt><a name="index-EventRegistry_002edisconnect"></a>Function: <strong>EventRegistry.disconnect</strong> <em>(object)</em></dt> <dd><p>Remove the given <var>object</var> from the registry. Once removed, the object will no longer receive notifications of events. </p></dd></dl> <p>Here is an example: </p> <div class="smallexample"> <pre class="smallexample">def exit_handler (event): print "event type: exit" print "exit code: %d" % (event.exit_code) gdb.events.exited.connect (exit_handler) </pre></div> <p>In the above example we connect our handler <code>exit_handler</code> to the registry <code>events.exited</code>. Once connected, <code>exit_handler</code> gets called when the inferior exits. The argument <em>event</em> in this example is of type <code>gdb.ExitedEvent</code>. As you can see in the example the <code>ExitedEvent</code> object has an attribute which indicates the exit code of the inferior. </p> <p>The following is a listing of the event registries that are available and details of the events they emit: </p> <dl compact="compact"> <dt><code>events.cont</code></dt> <dd><p>Emits <code>gdb.ThreadEvent</code>. </p> <p>Some events can be thread specific when <small>GDB</small> is running in non-stop mode. When represented in Python, these events all extend <code>gdb.ThreadEvent</code>. Note, this event is not emitted directly; instead, events which are emitted by this or other modules might extend this event. Examples of these events are <code>gdb.BreakpointEvent</code> and <code>gdb.ContinueEvent</code>. </p> <dl> <dt><a name="index-ThreadEvent_002einferior_005fthread"></a>Variable: <strong>ThreadEvent.inferior_thread</strong></dt> <dd><p>In non-stop mode this attribute will be set to the specific thread which was involved in the emitted event. Otherwise, it will be set to <code>None</code>. </p></dd></dl> <p>Emits <code>gdb.ContinueEvent</code> which extends <code>gdb.ThreadEvent</code>. </p> <p>This event indicates that the inferior has been continued after a stop. For inherited attribute refer to <code>gdb.ThreadEvent</code> above. </p> </dd> <dt><code>events.exited</code></dt> <dd><p>Emits <code>events.ExitedEvent</code> which indicates that the inferior has exited. <code>events.ExitedEvent</code> has two attributes: </p><dl> <dt><a name="index-ExitedEvent_002eexit_005fcode"></a>Variable: <strong>ExitedEvent.exit_code</strong></dt> <dd><p>An integer representing the exit code, if available, which the inferior has returned. (The exit code could be unavailable if, for example, <small>GDB</small> detaches from the inferior.) If the exit code is unavailable, the attribute does not exist. </p></dd></dl> <dl> <dt><a name="index-ExitedEvent_002einferior"></a>Variable: <strong>ExitedEvent.inferior</strong></dt> <dd><p>A reference to the inferior which triggered the <code>exited</code> event. </p></dd></dl> </dd> <dt><code>events.stop</code></dt> <dd><p>Emits <code>gdb.StopEvent</code> which extends <code>gdb.ThreadEvent</code>. </p> <p>Indicates that the inferior has stopped. All events emitted by this registry extend StopEvent. As a child of <code>gdb.ThreadEvent</code>, <code>gdb.StopEvent</code> will indicate the stopped thread when <small>GDB</small> is running in non-stop mode. Refer to <code>gdb.ThreadEvent</code> above for more details. </p> <p>Emits <code>gdb.SignalEvent</code> which extends <code>gdb.StopEvent</code>. </p> <p>This event indicates that the inferior or one of its threads has received as signal. <code>gdb.SignalEvent</code> has the following attributes: </p> <dl> <dt><a name="index-SignalEvent_002estop_005fsignal"></a>Variable: <strong>SignalEvent.stop_signal</strong></dt> <dd><p>A string representing the signal received by the inferior. A list of possible signal values can be obtained by running the command <code>info signals</code> in the <small>GDB</small> command prompt. </p></dd></dl> <p>Also emits <code>gdb.BreakpointEvent</code> which extends <code>gdb.StopEvent</code>. </p> <p><code>gdb.BreakpointEvent</code> event indicates that one or more breakpoints have been hit, and has the following attributes: </p> <dl> <dt><a name="index-BreakpointEvent_002ebreakpoints"></a>Variable: <strong>BreakpointEvent.breakpoints</strong></dt> <dd><p>A sequence containing references to all the breakpoints (type <code>gdb.Breakpoint</code>) that were hit. See <a href="Breakpoints-In-Python.html#Breakpoints-In-Python">Breakpoints In Python</a>, for details of the <code>gdb.Breakpoint</code> object. </p></dd></dl> <dl> <dt><a name="index-BreakpointEvent_002ebreakpoint"></a>Variable: <strong>BreakpointEvent.breakpoint</strong></dt> <dd><p>A reference to the first breakpoint that was hit. This function is maintained for backward compatibility and is now deprecated in favor of the <code>gdb.BreakpointEvent.breakpoints</code> attribute. </p></dd></dl> </dd> <dt><code>events.new_objfile</code></dt> <dd><p>Emits <code>gdb.NewObjFileEvent</code> which indicates that a new object file has been loaded by <small>GDB</small>. <code>gdb.NewObjFileEvent</code> has one attribute: </p> <dl> <dt><a name="index-NewObjFileEvent_002enew_005fobjfile"></a>Variable: <strong>NewObjFileEvent.new_objfile</strong></dt> <dd><p>A reference to the object file (<code>gdb.Objfile</code>) which has been loaded. See <a href="Objfiles-In-Python.html#Objfiles-In-Python">Objfiles In Python</a>, for details of the <code>gdb.Objfile</code> object. </p></dd></dl> </dd> <dt><code>events.clear_objfiles</code></dt> <dd><p>Emits <code>gdb.ClearObjFilesEvent</code> which indicates that the list of object files for a program space has been reset. <code>gdb.ClearObjFilesEvent</code> has one attribute: </p> <dl> <dt><a name="index-ClearObjFilesEvent_002eprogspace"></a>Variable: <strong>ClearObjFilesEvent.progspace</strong></dt> <dd><p>A reference to the program space (<code>gdb.Progspace</code>) whose objfile list has been cleared. See <a href="Progspaces-In-Python.html#Progspaces-In-Python">Progspaces In Python</a>. </p></dd></dl> </dd> <dt><code>events.inferior_call</code></dt> <dd><p>Emits events just before and after a function in the inferior is called by <small>GDB</small>. Before an inferior call, this emits an event of type <code>gdb.InferiorCallPreEvent</code>, and after an inferior call, this emits an event of type <code>gdb.InferiorCallPostEvent</code>. </p> <dl compact="compact"> <dd><a name="index-gdb_002eInferiorCallPreEvent"></a> </dd> <dt><code><code>gdb.InferiorCallPreEvent</code></code></dt> <dd><p>Indicates that a function in the inferior is about to be called. </p> <dl> <dt><a name="index-InferiorCallPreEvent_002eptid"></a>Variable: <strong>InferiorCallPreEvent.ptid</strong></dt> <dd><p>The thread in which the call will be run. </p></dd></dl> <dl> <dt><a name="index-InferiorCallPreEvent_002eaddress"></a>Variable: <strong>InferiorCallPreEvent.address</strong></dt> <dd><p>The location of the function to be called. </p></dd></dl> <a name="index-gdb_002eInferiorCallPostEvent"></a> </dd> <dt><code><code>gdb.InferiorCallPostEvent</code></code></dt> <dd><p>Indicates that a function in the inferior has just been called. </p> <dl> <dt><a name="index-InferiorCallPostEvent_002eptid"></a>Variable: <strong>InferiorCallPostEvent.ptid</strong></dt> <dd><p>The thread in which the call was run. </p></dd></dl> <dl> <dt><a name="index-InferiorCallPostEvent_002eaddress"></a>Variable: <strong>InferiorCallPostEvent.address</strong></dt> <dd><p>The location of the function that was called. </p></dd></dl> </dd> </dl> </dd> <dt><code>events.memory_changed</code></dt> <dd><p>Emits <code>gdb.MemoryChangedEvent</code> which indicates that the memory of the inferior has been modified by the <small>GDB</small> user, for instance via a command like <code>set *addr = value</code><!-- /@w -->. The event has the following attributes: </p> <dl> <dt><a name="index-MemoryChangedEvent_002eaddress"></a>Variable: <strong>MemoryChangedEvent.address</strong></dt> <dd><p>The start address of the changed region. </p></dd></dl> <dl> <dt><a name="index-MemoryChangedEvent_002elength"></a>Variable: <strong>MemoryChangedEvent.length</strong></dt> <dd><p>Length in bytes of the changed region. </p></dd></dl> </dd> <dt><code>events.register_changed</code></dt> <dd><p>Emits <code>gdb.RegisterChangedEvent</code> which indicates that a register in the inferior has been modified by the <small>GDB</small> user. </p> <dl> <dt><a name="index-RegisterChangedEvent_002eframe"></a>Variable: <strong>RegisterChangedEvent.frame</strong></dt> <dd><p>A gdb.Frame object representing the frame in which the register was modified. </p></dd></dl> <dl> <dt><a name="index-RegisterChangedEvent_002eregnum"></a>Variable: <strong>RegisterChangedEvent.regnum</strong></dt> <dd><p>Denotes which register was modified. </p></dd></dl> </dd> <dt><code>events.breakpoint_created</code></dt> <dd><p>This is emitted when a new breakpoint has been created. The argument that is passed is the new <code>gdb.Breakpoint</code> object. </p> </dd> <dt><code>events.breakpoint_modified</code></dt> <dd><p>This is emitted when a breakpoint has been modified in some way. The argument that is passed is the new <code>gdb.Breakpoint</code> object. </p> </dd> <dt><code>events.breakpoint_deleted</code></dt> <dd><p>This is emitted when a breakpoint has been deleted. The argument that is passed is the <code>gdb.Breakpoint</code> object. When this event is emitted, the <code>gdb.Breakpoint</code> object will already be in its invalid state; that is, the <code>is_valid</code> method will return <code>False</code>. </p> </dd> <dt><code>events.before_prompt</code></dt> <dd><p>This event carries no payload. It is emitted each time <small>GDB</small> presents a prompt to the user. </p> </dd> <dt><code>events.new_inferior</code></dt> <dd><p>This is emitted when a new inferior is created. Note that the inferior is not necessarily running; in fact, it may not even have an associated executable. </p> <p>The event is of type <code>gdb.NewInferiorEvent</code>. This has a single attribute: </p> <dl> <dt><a name="index-NewInferiorEvent_002einferior"></a>Variable: <strong>NewInferiorEvent.inferior</strong></dt> <dd><p>The new inferior, a <code>gdb.Inferior</code> object. </p></dd></dl> </dd> <dt><code>events.inferior_deleted</code></dt> <dd><p>This is emitted when an inferior has been deleted. Note that this is not the same as process exit; it is notified when the inferior itself is removed, say via <code>remove-inferiors</code>. </p> <p>The event is of type <code>gdb.InferiorDeletedEvent</code>. This has a single attribute: </p> <dl> <dt><a name="index-NewInferiorEvent_002einferior-1"></a>Variable: <strong>NewInferiorEvent.inferior</strong></dt> <dd><p>The inferior that is being removed, a <code>gdb.Inferior</code> object. </p></dd></dl> </dd> <dt><code>events.new_thread</code></dt> <dd><p>This is emitted when <small>GDB</small> notices a new thread. The event is of type <code>gdb.NewThreadEvent</code>, which extends <code>gdb.ThreadEvent</code>. This has a single attribute: </p> <dl> <dt><a name="index-NewThreadEvent_002einferior_005fthread"></a>Variable: <strong>NewThreadEvent.inferior_thread</strong></dt> <dd><p>The new thread. </p></dd></dl> </dd> </dl> <hr> <div class="header"> <p> Next: <a href="Threads-In-Python.html#Threads-In-Python" accesskey="n" rel="next">Threads In Python</a>, Previous: <a href="Inferiors-In-Python.html#Inferiors-In-Python" accesskey="p" rel="prev">Inferiors In Python</a>, Up: <a href="Python-API.html#Python-API" accesskey="u" rel="up">Python API</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> </div> </body> </html>