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<th width="100%" align="center">GLib Reference Manual</th>
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<td><a accesskey="n" href="glib-Keyed-Data-Lists.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td>
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<tr><td colspan="5" class="shortcuts"><nobr><a href="#id3137609" class="shortcut">Top</a>
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<a href="#id3137766" class="shortcut">Description</a></nobr></td></tr>
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<div class="refentry" lang="en">
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<a name="glib-Quarks"></a><div class="titlepage"></div>
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<div class="refnamediv"><table width="100%"><tr>
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<a name="id3137609"></a><span class="refentrytitle">Quarks</span>
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<p>Quarks — a 2-way association between a string and a unique integer identifier.</p>
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<td valign="top" align="right"></td>
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<div class="refsynopsisdiv">
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<pre class="synopsis">
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#include <glib.h>
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typedef <a href="glib-Quarks.html#GQuark">GQuark</a>;
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<a href="glib-Quarks.html#GQuark">GQuark</a> <a href="glib-Quarks.html#g-quark-from-string">g_quark_from_string</a> (const <a href="glib-Basic-Types.html#gchar">gchar</a> *string);
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<a href="glib-Quarks.html#GQuark">GQuark</a> <a href="glib-Quarks.html#g-quark-from-static-string">g_quark_from_static_string</a> (const <a href="glib-Basic-Types.html#gchar">gchar</a> *string);
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const <a href="glib-Basic-Types.html#gchar">gchar</a>* <a href="glib-Quarks.html#g-quark-to-string">g_quark_to_string</a> (<a href="glib-Quarks.html#GQuark">GQuark</a> quark);
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<a href="glib-Quarks.html#GQuark">GQuark</a> <a href="glib-Quarks.html#g-quark-try-string">g_quark_try_string</a> (const <a href="glib-Basic-Types.html#gchar">gchar</a> *string);
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const <a href="glib-Basic-Types.html#gchar">gchar</a>* <a href="glib-Quarks.html#g-intern-string">g_intern_string</a> (const <a href="glib-Basic-Types.html#gchar">gchar</a> *string);
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const <a href="glib-Basic-Types.html#gchar">gchar</a>* <a href="glib-Quarks.html#g-intern-static-string">g_intern_static_string</a> (const <a href="glib-Basic-Types.html#gchar">gchar</a> *string);
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<div class="refsect1" lang="en">
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<a name="id3137766"></a><h2>Description</h2>
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Quarks are associations between strings and integer identifiers.
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Given either the string or the <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a> identifier it is possible to
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Quarks are used for both
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To create a new quark from a string, use <a href="glib-Quarks.html#g-quark-from-string"><code class="function">g_quark_from_string()</code></a> or
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<a href="glib-Quarks.html#g-quark-from-static-string"><code class="function">g_quark_from_static_string()</code></a>.
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To find the string corresponding to a given <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a>, use <a href="glib-Quarks.html#g-quark-to-string"><code class="function">g_quark_to_string()</code></a>.
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To find the <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a> corresponding to a given string, use <a href="glib-Quarks.html#g-quark-try-string"><code class="function">g_quark_try_string()</code></a>.
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Another use for the string pool maintained for the quark functions is string
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interning, using <a href="glib-Quarks.html#g-intern-string"><code class="function">g_intern_string()</code></a> or <a href="glib-Quarks.html#g-intern-static-string"><code class="function">g_intern_static_string()</code></a>. An interned string
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is a canonical representation for a string. One important advantage of interned strings
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is that they can be compared for equality by a simple pointer comparision, rather than
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using <code class="function">strcmp()</code>.
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<div class="refsect1" lang="en">
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<a name="id3137922"></a><h2>Details</h2>
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<div class="refsect2" lang="en">
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<a name="id3137932"></a><h3>
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<a name="GQuark"></a>GQuark</h3>
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<a class="indexterm" name="id3137944"></a><pre class="programlisting">typedef guint32 GQuark;
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A GQuark is an integer which uniquely identifies a particular string.
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<div class="refsect2" lang="en">
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<a name="id3137961"></a><h3>
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<a name="g-quark-from-string"></a>g_quark_from_string ()</h3>
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<a class="indexterm" name="id3137974"></a><pre class="programlisting"><a href="glib-Quarks.html#GQuark">GQuark</a> g_quark_from_string (const <a href="glib-Basic-Types.html#gchar">gchar</a> *string);</pre>
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Gets the <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a> identifying the given string.
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If the string does not currently have an associated <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a>, a new
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<a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a> is created, using a copy of the string.
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<div class="variablelist"><table border="0">
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<col align="left" valign="top">
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<td><span class="term"><em class="parameter"><code>string</code></em> :</span></td>
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<td><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></td>
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<td>the <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a> identifying the string.
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<div class="refsect2" lang="en">
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<a name="id3138064"></a><h3>
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<a name="g-quark-from-static-string"></a>g_quark_from_static_string ()</h3>
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<a class="indexterm" name="id3138078"></a><pre class="programlisting"><a href="glib-Quarks.html#GQuark">GQuark</a> g_quark_from_static_string (const <a href="glib-Basic-Types.html#gchar">gchar</a> *string);</pre>
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Gets the <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a> identifying the given (static) string.
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If the string does not currently have an associated <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a>, a new
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<a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a> is created, linked to the given string.
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Note that this function is identical to <a href="glib-Quarks.html#g-quark-from-string"><code class="function">g_quark_from_string()</code></a> except
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that if a new <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a> is created the string itself is used rather than
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a copy. This saves memory, but can only be used if the string will
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<span class="emphasis"><em>always</em></span> exist. It can be used with statically
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allocated strings in the main program, but not with statically
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allocated memory in dynamically loaded modules, if you expect to
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ever unload the module again (e.g. do not use this function in
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<div class="variablelist"><table border="0">
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<col align="left" valign="top">
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<td><span class="term"><em class="parameter"><code>string</code></em> :</span></td>
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<td><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></td>
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<td>the <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a> identifying the string.
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<div class="refsect2" lang="en">
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<a name="id3138202"></a><h3>
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<a name="g-quark-to-string"></a>g_quark_to_string ()</h3>
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<a class="indexterm" name="id3138214"></a><pre class="programlisting">const <a href="glib-Basic-Types.html#gchar">gchar</a>* g_quark_to_string (<a href="glib-Quarks.html#GQuark">GQuark</a> quark);</pre>
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Gets the string associated with the given <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a>.
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<div class="variablelist"><table border="0">
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<col align="left" valign="top">
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<td><span class="term"><em class="parameter"><code>quark</code></em> :</span></td>
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<td>a <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a>.
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<td><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></td>
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<td>the string associated with the <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a>.
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<div class="refsect2" lang="en">
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<a name="id3138296"></a><h3>
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<a name="g-quark-try-string"></a>g_quark_try_string ()</h3>
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<a class="indexterm" name="id3138310"></a><pre class="programlisting"><a href="glib-Quarks.html#GQuark">GQuark</a> g_quark_try_string (const <a href="glib-Basic-Types.html#gchar">gchar</a> *string);</pre>
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Gets the <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a> associated with the given string, or 0 if the string has
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no associated <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a>.
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If you want the GQuark to be created if it doesn't already exist, use
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<a href="glib-Quarks.html#g-quark-from-string"><code class="function">g_quark_from_string()</code></a> or <a href="glib-Quarks.html#g-quark-from-static-string"><code class="function">g_quark_from_static_string()</code></a>.
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<div class="variablelist"><table border="0">
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<col align="left" valign="top">
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<td><span class="term"><em class="parameter"><code>string</code></em> :</span></td>
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<td><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></td>
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<td>the <a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a> associated with the string, or 0 if there is no
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<a href="glib-Quarks.html#GQuark"><span class="type">GQuark</span></a> associated with the string.
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<div class="refsect2" lang="en">
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<a name="id3138427"></a><h3>
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<a name="g-intern-string"></a>g_intern_string ()</h3>
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<a class="indexterm" name="id3138442"></a><pre class="programlisting">const <a href="glib-Basic-Types.html#gchar">gchar</a>* g_intern_string (const <a href="glib-Basic-Types.html#gchar">gchar</a> *string);</pre>
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Returns a canonical representation for <em class="parameter"><code>string</code></em>. Interned strings can
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be compared for equality by comparing the pointers, instead of using <code class="function">strcmp()</code>.</p>
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<div class="variablelist"><table border="0">
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<col align="left" valign="top">
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<td><span class="term"><em class="parameter"><code>string</code></em> :</span></td>
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<td><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></td>
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<td> a canonical representation for the string
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<p class="since">Since 2.10
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<div class="refsect2" lang="en">
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<a name="id3138529"></a><h3>
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<a name="g-intern-static-string"></a>g_intern_static_string ()</h3>
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<a class="indexterm" name="id3138545"></a><pre class="programlisting">const <a href="glib-Basic-Types.html#gchar">gchar</a>* g_intern_static_string (const <a href="glib-Basic-Types.html#gchar">gchar</a> *string);</pre>
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Returns a canonical representation for <em class="parameter"><code>string</code></em>. Interned strings can
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be compared for equality by comparing the pointers, instead of using <code class="function">strcmp()</code>.
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<a href="glib-Quarks.html#g-intern-static-string"><code class="function">g_intern_static_string()</code></a> does not copy the string, therefore <em class="parameter"><code>string</code></em> must
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not be freed or modified.</p>
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<div class="variablelist"><table border="0">
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<col align="left" valign="top">
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<td><span class="term"><em class="parameter"><code>string</code></em> :</span></td>
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<td><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></td>
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<td> a canonical representation for the string
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<p class="since">Since 2.10
added
removed
docs/reference/glib/html/glib-Quarks.html
