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<title>Debugging with GDB: Lazy Strings In Guile</title>
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<a name="Lazy-Strings-In-Guile"></a>
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<div class="header">
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<p>
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Next: <a href="Architectures-In-Guile.html#Architectures-In-Guile" accesskey="n" rel="next">Architectures In Guile</a>, Previous: <a href="Breakpoints-In-Guile.html#Breakpoints-In-Guile" accesskey="p" rel="previous">Breakpoints In Guile</a>, Up: <a href="Guile-API.html#Guile-API" accesskey="u" rel="up">Guile 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>
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<a name="Guile-representation-of-lazy-strings_002e"></a>
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<h4 class="subsubsection">23.3.3.20 Guile representation of lazy strings.</h4>
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<a name="index-lazy-strings-in-guile"></a>
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<a name="index-_003cgdb_003alazy_002dstring_003e"></a>
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<p>A <em>lazy string</em> is a string whose contents is not retrieved or
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encoded until it is needed.
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</p>
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<p>A <code><gdb:lazy-string></code> is represented in <small>GDB</small> as an
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<code>address</code> that points to a region of memory, an <code>encoding</code>
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that will be used to encode that region of memory, and a <code>length</code>
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to delimit the region of memory that represents the string. The
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difference between a <code><gdb:lazy-string></code> and a string wrapped within
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a <code><gdb:value></code> is that a <code><gdb:lazy-string></code> will be treated
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differently by <small>GDB</small> when printing. A <code><gdb:lazy-string></code> is
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retrieved and encoded during printing, while a <code><gdb:value></code>
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wrapping a string is immediately retrieved and encoded on creation.
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</p>
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<p>The following lazy-string-related procedures are provided by the
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<code>(gdb)</code> module:
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</p>
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<dl>
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<dt><a name="index-lazy_002dstring_003f"></a>Scheme Procedure: <strong>lazy-string?</strong> <em>object</em></dt>
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<dd><p>Return <code>#t</code> if <var>object</var> is an object of type <code><gdb:lazy-string></code>.
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Otherwise return <code>#f</code>.
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</p></dd></dl>
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<dl>
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<dt><a name="index-lazy_002dstring_002daddress"></a>Scheme Procedure: <strong>lazy-string-address</strong> <em>lazy-sring</em></dt>
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<dd><p>Return the address of <var>lazy-string</var>.
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</p></dd></dl>
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<dl>
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<dt><a name="index-lazy_002dstring_002dlength"></a>Scheme Procedure: <strong>lazy-string-length</strong> <em>lazy-string</em></dt>
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<dd><p>Return the length of <var>lazy-string</var> in characters. If the
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length is -1, then the string will be fetched and encoded up to the
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first null of appropriate width.
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</p></dd></dl>
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<dl>
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<dt><a name="index-lazy_002dstring_002dencoding"></a>Scheme Procedure: <strong>lazy-string-encoding</strong> <em>lazy-string</em></dt>
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<dd><p>Return the encoding that will be applied to <var>lazy-string</var>
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when the string is printed by <small>GDB</small>. If the encoding is not
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set, or contains an empty string, then <small>GDB</small> will select the
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most appropriate encoding when the string is printed.
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</p></dd></dl>
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<dl>
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<dt><a name="index-lazy_002dstring_002dtype"></a>Scheme Procedure: <strong>lazy-string-type</strong> <em>lazy-string</em></dt>
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<dd><p>Return the type that is represented by <var>lazy-string</var>’s type.
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For a lazy string this is a pointer or array type. To
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resolve this to the lazy string’s character type, use <code>type-target-type</code>.
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See <a href="Types-In-Guile.html#Types-In-Guile">Types In Guile</a>.
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</p></dd></dl>
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<dl>
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<dt><a name="index-lazy_002dstring_002d_003evalue"></a>Scheme Procedure: <strong>lazy-string->value</strong> <em>lazy-string</em></dt>
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<dd><p>Convert the <code><gdb:lazy-string></code> to a <code><gdb:value></code>. This value
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will point to the string in memory, but will lose all the delayed
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retrieval, encoding and handling that <small>GDB</small> applies to a
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<code><gdb:lazy-string></code>.
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</p></dd></dl>
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<hr>
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<div class="header">
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<p>
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Next: <a href="Architectures-In-Guile.html#Architectures-In-Guile" accesskey="n" rel="next">Architectures In Guile</a>, Previous: <a href="Breakpoints-In-Guile.html#Breakpoints-In-Guile" accesskey="p" rel="previous">Breakpoints In Guile</a>, Up: <a href="Guile-API.html#Guile-API" accesskey="u" rel="up">Guile 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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