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  54 <a href="#gobject-Varargs-Value-Collection.synopsis" class="shortcut">Top</a>
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  59 <div class="refentry" title="Varargs Value Collection">
  60 <a name="gobject-Varargs-Value-Collection"></a><div class="titlepage"></div>
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  62 <td valign="top">
  63 <h2><span class="refentrytitle"><a name="gobject-Varargs-Value-Collection.top_of_page"></a>Varargs Value Collection</span></h2>
  64 <p>Varargs Value Collection — Converting varargs to generic values</p>
  65 </td>
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  68 <div class="refsynopsisdiv" title="Synopsis">
  69 <a name="gobject-Varargs-Value-Collection.synopsis"></a><h2>Synopsis</h2>
  70 <pre class="synopsis">
  71 #include &lt;glib-object.h&gt;
  72 #include &lt;gobject/gvaluecollector.h&gt;
  73
  74 union               <a class="link" href="gobject-Varargs-Value-Collection.html#GTypeCValue" title="union GTypeCValue">GTypeCValue</a>;
  75 #define             <a class="link" href="gobject-Varargs-Value-Collection.html#G-VALUE-COLLECT:CAPS" title="G_VALUE_COLLECT()">G_VALUE_COLLECT</a>                     (value, var_args, flags, __error)
  76 #define             <a class="link" href="gobject-Varargs-Value-Collection.html#G-VALUE-LCOPY:CAPS" title="G_VALUE_LCOPY()">G_VALUE_LCOPY</a>                       (value, var_args, flags, __error)
  77 #define             <a class="link" href="gobject-Varargs-Value-Collection.html#G-VALUE-COLLECT-FORMAT-MAX-LENGTH:CAPS" title="G_VALUE_COLLECT_FORMAT_MAX_LENGTH">G_VALUE_COLLECT_FORMAT_MAX_LENGTH</a>
  78 </pre>
  79 </div>
  80 <div class="refsect1" title="Description">
  81 <a name="gobject-Varargs-Value-Collection.description"></a><h2>Description</h2>
  82 <p>
  83 The macros in this section provide the varargs parsing support needed
  84 in variadic GObject functions such as <a class="link" href="gobject-The-Base-Object-Type.html#g-object-new" title="g_object_new ()"><code class="function">g_object_new()</code></a> or <a class="link" href="gobject-The-Base-Object-Type.html#g-object-set" title="g_object_set ()"><code class="function">g_object_set()</code></a>.
  85 They currently support the collection of integral types, floating point
  86 types and pointers.</p>
  87 </div>
  88 <div class="refsect1" title="Details">
  89 <a name="gobject-Varargs-Value-Collection.details"></a><h2>Details</h2>
  90 <div class="refsect2" title="union GTypeCValue">
  91 <a name="GTypeCValue"></a><h3>union GTypeCValue</h3>
  92 <pre class="programlisting">union GTypeCValue
  93 {
  94   gint     v_int;
  95   glong    v_long;
  96   gint64   v_int64;
  97   gdouble  v_double;
  98   gpointer v_pointer;
  99 };
 100 </pre>
 101 <p>
 102 A union holding one collected value.</p>
 103 </div>
 104 <hr>
 105 <div class="refsect2" title="G_VALUE_COLLECT()">
 106 <a name="G-VALUE-COLLECT:CAPS"></a><h3>G_VALUE_COLLECT()</h3>
 107 <pre class="programlisting">#define             G_VALUE_COLLECT(value, var_args, flags, __error)</pre>
 108 <p>
 109 Collects a variable argument value from a va_list. We have to
 110 implement the varargs collection as a macro, because on some systems
 111 va_list variables cannot be passed by reference.
 112 </p>
 113 <p>
 114 Note: If you are creating the <em class="parameter"><code>value</code></em> argument just before calling this macro,
 115 you should use the <span class="type">G_VALUE_COLLECT_INIT</span> variant and pass the unitialized
 116 <a class="link" href="gobject-Generic-values.html#GValue" title="GValue"><span class="type">GValue</span></a>. That variant is faster than <a class="link" href="gobject-Varargs-Value-Collection.html#G-VALUE-COLLECT:CAPS" title="G_VALUE_COLLECT()"><span class="type">G_VALUE_COLLECT</span></a>.</p>
 117 <div class="variablelist"><table border="0">
 118 <col align="left" valign="top">
 119 <tbody>
 120 <tr>
 121 <td><p><span class="term"><em class="parameter"><code>value</code></em> :</span></p></td>
 122 <td> a <a class="link" href="gobject-Generic-values.html#GValue" title="GValue"><span class="type">GValue</span></a> return location. <em class="parameter"><code>value</code></em> is supposed to be initialized
 123  according to the value type to be collected
 124 </td>
 125 </tr>
 126 <tr>
 127 <td><p><span class="term"><em class="parameter"><code>var_args</code></em> :</span></p></td>
 128 <td> the va_list variable; it may be evaluated multiple times
 129 </td>
 130 </tr>
 131 <tr>
 132 <td><p><span class="term"><em class="parameter"><code>flags</code></em> :</span></p></td>
 133 <td> flags which are passed on to the <code class="function">collect_value()</code> function of
 134  the <a class="link" href="gobject-Type-Information.html#GTypeValueTable" title="GTypeValueTable"><span class="type">GTypeValueTable</span></a> of <em class="parameter"><code>value</code></em>.
 135 </td>
 136 </tr>
 137 <tr>
 138 <td><p><span class="term"><em class="parameter"><code>__error</code></em> :</span></p></td>
 139 <td> a <a href="./../glib/glib/glib-Basic-Types.html#gchar"><span class="type">gchar</span></a>** variable that will be modified to hold a <a href="./../glib/glib/glib-Memory-Allocation.html#g-new"><code class="function">g_new()</code></a>
 140  allocated error messages if something fails
 141 </td>
 142 </tr>
 143 </tbody>
 144 </table></div>
 145 </div>
 146 <hr>
 147 <div class="refsect2" title="G_VALUE_LCOPY()">
 148 <a name="G-VALUE-LCOPY:CAPS"></a><h3>G_VALUE_LCOPY()</h3>
 149 <pre class="programlisting">#define             G_VALUE_LCOPY(value, var_args, flags, __error)</pre>
 150 <p>
 151 Collects a value's variable argument locations from a va_list. Usage is
 152 analogous to <a class="link" href="gobject-Varargs-Value-Collection.html#G-VALUE-COLLECT:CAPS" title="G_VALUE_COLLECT()"><code class="function">G_VALUE_COLLECT()</code></a>.</p>
 153 <div class="variablelist"><table border="0">
 154 <col align="left" valign="top">
 155 <tbody>
 156 <tr>
 157 <td><p><span class="term"><em class="parameter"><code>value</code></em> :</span></p></td>
 158 <td> a <a class="link" href="gobject-Generic-values.html#GValue" title="GValue"><span class="type">GValue</span></a> return location. <em class="parameter"><code>value</code></em> is supposed to be initialized
 159  according to the value type to be collected
 160 </td>
 161 </tr>
 162 <tr>
 163 <td><p><span class="term"><em class="parameter"><code>var_args</code></em> :</span></p></td>
 164 <td> the va_list variable; it may be evaluated multiple times
 165 </td>
 166 </tr>
 167 <tr>
 168 <td><p><span class="term"><em class="parameter"><code>flags</code></em> :</span></p></td>
 169 <td> flags which are passed on to the <code class="function">lcopy_value()</code> function of
 170  the <a class="link" href="gobject-Type-Information.html#GTypeValueTable" title="GTypeValueTable"><span class="type">GTypeValueTable</span></a> of <em class="parameter"><code>value</code></em>.
 171 </td>
 172 </tr>
 173 <tr>
 174 <td><p><span class="term"><em class="parameter"><code>__error</code></em> :</span></p></td>
 175 <td> a <a href="./../glib/glib/glib-Basic-Types.html#gchar"><span class="type">gchar</span></a>** variable that will be modified to hold a <a href="./../glib/glib/glib-Memory-Allocation.html#g-new"><code class="function">g_new()</code></a>
 176  allocated error messages if something fails
 177 </td>
 178 </tr>
 179 </tbody>
 180 </table></div>
 181 </div>
 182 <hr>
 183 <div class="refsect2" title="G_VALUE_COLLECT_FORMAT_MAX_LENGTH">
 184 <a name="G-VALUE-COLLECT-FORMAT-MAX-LENGTH:CAPS"></a><h3>G_VALUE_COLLECT_FORMAT_MAX_LENGTH</h3>
 185 <pre class="programlisting">#define G_VALUE_COLLECT_FORMAT_MAX_LENGTH (8)
 186 </pre>
 187 <p>
 188 The maximal number of <a class="link" href="gobject-Varargs-Value-Collection.html#GTypeCValue" title="union GTypeCValue"><span class="type">GTypeCValue</span></a>s which can be collected for a
 189 single <a class="link" href="gobject-Generic-values.html#GValue" title="GValue"><span class="type">GValue</span></a>.</p>
 190 </div>
 191 </div>
 192 <div class="refsect1" title="See Also">
 193 <a name="gobject-Varargs-Value-Collection.see-also"></a><h2>See Also</h2>
 194 <span class="type">GValueTable</span>
 195 </div>
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