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| <title>Debugging with GDB: Xmethod API</title> |
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| <a name="Xmethod-API"></a> |
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| Next: <a href="Writing-an-Xmethod.html#Writing-an-Xmethod" accesskey="n" rel="next">Writing an Xmethod</a>, Previous: <a href="Xmethods-In-Python.html#Xmethods-In-Python" accesskey="p" rel="prev">Xmethods 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> |
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| <hr> |
| <a name="Xmethod-API-1"></a> |
| <h4 class="subsubsection">23.2.2.14 Xmethod API</h4> |
| <a name="index-xmethod-API"></a> |
| |
| <p>The <small>GDB</small> Python API provides classes, interfaces and functions |
| to implement, register and manipulate xmethods. |
| See <a href="Xmethods-In-Python.html#Xmethods-In-Python">Xmethods In Python</a>. |
| </p> |
| <p>An xmethod matcher should be an instance of a class derived from |
| <code>XMethodMatcher</code> defined in the module <code>gdb.xmethod</code>, or an |
| object with similar interface and attributes. An instance of |
| <code>XMethodMatcher</code> has the following attributes: |
| </p> |
| <dl> |
| <dt><a name="index-name"></a>Variable: <strong>name</strong></dt> |
| <dd><p>The name of the matcher. |
| </p></dd></dl> |
| |
| <dl> |
| <dt><a name="index-enabled"></a>Variable: <strong>enabled</strong></dt> |
| <dd><p>A boolean value indicating whether the matcher is enabled or disabled. |
| </p></dd></dl> |
| |
| <dl> |
| <dt><a name="index-methods"></a>Variable: <strong>methods</strong></dt> |
| <dd><p>A list of named methods managed by the matcher. Each object in the list |
| is an instance of the class <code>XMethod</code> defined in the module |
| <code>gdb.xmethod</code>, or any object with the following attributes: |
| </p> |
| <dl compact="compact"> |
| <dt><code>name</code></dt> |
| <dd><p>Name of the xmethod which should be unique for each xmethod |
| managed by the matcher. |
| </p> |
| </dd> |
| <dt><code>enabled</code></dt> |
| <dd><p>A boolean value indicating whether the xmethod is enabled or |
| disabled. |
| </p> |
| </dd> |
| </dl> |
| |
| <p>The class <code>XMethod</code> is a convenience class with same |
| attributes as above along with the following constructor: |
| </p> |
| <dl> |
| <dt><a name="index-XMethod_002e_005f_005finit_005f_005f"></a>Function: <strong>XMethod.__init__</strong> <em>(self, name)</em></dt> |
| <dd><p>Constructs an enabled xmethod with name <var>name</var>. |
| </p></dd></dl> |
| </dd></dl> |
| |
| <p>The <code>XMethodMatcher</code> class has the following methods: |
| </p> |
| <dl> |
| <dt><a name="index-XMethodMatcher_002e_005f_005finit_005f_005f"></a>Function: <strong>XMethodMatcher.__init__</strong> <em>(self, name)</em></dt> |
| <dd><p>Constructs an enabled xmethod matcher with name <var>name</var>. The |
| <code>methods</code> attribute is initialized to <code>None</code>. |
| </p></dd></dl> |
| |
| <dl> |
| <dt><a name="index-XMethodMatcher_002ematch"></a>Function: <strong>XMethodMatcher.match</strong> <em>(self, class_type, method_name)</em></dt> |
| <dd><p>Derived classes should override this method. It should return a |
| xmethod worker object (or a sequence of xmethod worker |
| objects) matching the <var>class_type</var> and <var>method_name</var>. |
| <var>class_type</var> is a <code>gdb.Type</code> object, and <var>method_name</var> |
| is a string value. If the matcher manages named methods as listed in |
| its <code>methods</code> attribute, then only those worker objects whose |
| corresponding entries in the <code>methods</code> list are enabled should be |
| returned. |
| </p></dd></dl> |
| |
| <p>An xmethod worker should be an instance of a class derived from |
| <code>XMethodWorker</code> defined in the module <code>gdb.xmethod</code>, |
| or support the following interface: |
| </p> |
| <dl> |
| <dt><a name="index-XMethodWorker_002eget_005farg_005ftypes"></a>Function: <strong>XMethodWorker.get_arg_types</strong> <em>(self)</em></dt> |
| <dd><p>This method returns a sequence of <code>gdb.Type</code> objects corresponding |
| to the arguments that the xmethod takes. It can return an empty |
| sequence or <code>None</code> if the xmethod does not take any arguments. |
| If the xmethod takes a single argument, then a single |
| <code>gdb.Type</code> object corresponding to it can be returned. |
| </p></dd></dl> |
| |
| <dl> |
| <dt><a name="index-XMethodWorker_002eget_005fresult_005ftype"></a>Function: <strong>XMethodWorker.get_result_type</strong> <em>(self, *args)</em></dt> |
| <dd><p>This method returns a <code>gdb.Type</code> object representing the type |
| of the result of invoking this xmethod. |
| The <var>args</var> argument is the same tuple of arguments that would be |
| passed to the <code>__call__</code> method of this worker. |
| </p></dd></dl> |
| |
| <dl> |
| <dt><a name="index-XMethodWorker_002e_005f_005fcall_005f_005f"></a>Function: <strong>XMethodWorker.__call__</strong> <em>(self, *args)</em></dt> |
| <dd><p>This is the method which does the <em>work</em> of the xmethod. The |
| <var>args</var> arguments is the tuple of arguments to the xmethod. Each |
| element in this tuple is a gdb.Value object. The first element is |
| always the <code>this</code> pointer value. |
| </p></dd></dl> |
| |
| <p>For <small>GDB</small> to lookup xmethods, the xmethod matchers |
| should be registered using the following function defined in the module |
| <code>gdb.xmethod</code>: |
| </p> |
| <dl> |
| <dt><a name="index-register_005fxmethod_005fmatcher"></a>Function: <strong>register_xmethod_matcher</strong> <em>(locus, matcher, replace=False)</em></dt> |
| <dd><p>The <code>matcher</code> is registered with <code>locus</code>, replacing an |
| existing matcher with the same name as <code>matcher</code> if |
| <code>replace</code> is <code>True</code>. <code>locus</code> can be a |
| <code>gdb.Objfile</code> object (see <a href="Objfiles-In-Python.html#Objfiles-In-Python">Objfiles In Python</a>), or a |
| <code>gdb.Progspace</code> object (see <a href="Progspaces-In-Python.html#Progspaces-In-Python">Progspaces In Python</a>), or |
| <code>None</code>. If it is <code>None</code>, then <code>matcher</code> is registered |
| globally. |
| </p></dd></dl> |
| |
| <hr> |
| <div class="header"> |
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| Next: <a href="Writing-an-Xmethod.html#Writing-an-Xmethod" accesskey="n" rel="next">Writing an Xmethod</a>, Previous: <a href="Xmethods-In-Python.html#Xmethods-In-Python" accesskey="p" rel="prev">Xmethods 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> |
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