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17<title>Debugging with GDB: Multiple Extension Languages</title>
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64<a name="Multiple-Extension-Languages"></a>
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67Next: <a href="Aliases.html#Aliases" accesskey="n" rel="next">Aliases</a>, Previous: <a href="Auto_002dloading-extensions.html#Auto_002dloading-extensions" accesskey="p" rel="previous">Auto-loading extensions</a>, Up: <a href="Extending-GDB.html#Extending-GDB" accesskey="u" rel="up">Extending GDB</a> &nbsp; [<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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70<a name="Multiple-Extension-Languages-1"></a>
71<h3 class="section">23.5 Multiple Extension Languages</h3>
72
73<p>The Guile and Python extension languages do not share any state,
74and generally do not interfere with each other.
75There are some things to be aware of, however.
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77<a name="Python-Comes-First"></a>
78<h4 class="subsection">23.5.1 Python Comes First</h4>
79
80<p>Python was <small>GDB</small>&rsquo;s first extension language, and to avoid breaking
81existing behaviour Python comes first.  This is generally solved by the
82&ldquo;first one wins&rdquo; principle.  <small>GDB</small> maintains a list of enabled
83extension languages, and when it makes a call to an extension language,
84(say to pretty-print a value), it tries each in turn until an extension
85language indicates it has performed the request (e.g., has returned the
86pretty-printed form of a value).
87This extends to errors while performing such requests: If an error happens
88while, for example, trying to pretty-print an object then the error is
89reported and any following extension languages are not tried.
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