gtype.sgml

GLib是GTK+和GNOME工程的基础底层核心程序库

  if (!object_p)
    return g_strdup_printf ("object location passed as NULL");
  if (!value->data[0].v_pointer)
    *object_p = NULL;
  else if (collect_flags & G_VALUE_NOCOPY_CONTENTS) /* always honour */
    *object_p = value->data[0].v_pointer;
  else
    *object_p = g_object_ref (value->data[0].v_pointer);
  return NULL;
}
</programlisting></msgtext>

</entry>
</row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-FROM-INSTANCE-CAPS">G_TYPE_FROM_INSTANCE()</title>
<programlisting>#define G_TYPE_FROM_INSTANCE(instance)                          (G_TYPE_FROM_CLASS (((GTypeInstance*) (instance))-&gt;g_class))
</programlisting>
<para>
Returns the type identifier from a given <parameter>instance</parameter> structure.
</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>instance</parameter>&nbsp;:</entry>
<entry>Location of a valid <link linkend="GTypeInstance">GTypeInstance</link> structure.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-FROM-CLASS-CAPS">G_TYPE_FROM_CLASS()</title>
<programlisting>#define G_TYPE_FROM_CLASS(g_class)                              (((GTypeClass*) (g_class))-&gt;g_type)
</programlisting>
<para>
Returns the type identifier from a given <parameter>class</parameter> structure.
</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>g_class</parameter>&nbsp;:</entry>
<entry>Location of a valid <link linkend="GTypeClass">GTypeClass</link> structure.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-FROM-INTERFACE-CAPS">G_TYPE_FROM_INTERFACE()</title>
<programlisting>#define G_TYPE_FROM_INTERFACE(g_iface)                          (((GTypeInterface*) (g_iface))-&gt;g_type)
</programlisting>
<para>
Returns the type identifier from a given <parameter>interface</parameter> structure.
</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>g_iface</parameter>&nbsp;:</entry>
<entry>Location of a valid <link linkend="GTypeInterface">GTypeInterface</link> structure.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-INSTANCE-GET-CLASS-CAPS">G_TYPE_INSTANCE_GET_CLASS()</title>
<programlisting>#define G_TYPE_INSTANCE_GET_CLASS(instance, g_type, c_type)     (_G_TYPE_IGC ((instance), (g_type), c_type))
</programlisting>
<para>
Returns the class structure of a given <parameter>instance</parameter>, casted
to a specified anchestor type <parameter>g_type</parameter> of the instance.
</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>instance</parameter>&nbsp;:</entry>
<entry>	Location of the <link linkend="GTypeInstance">GTypeInstance</link> structure.
</entry></row>
<row><entry align="right"><parameter>g_type</parameter>&nbsp;:</entry>
<entry>	The anchestor type of the class to be returned.
</entry></row>
<row><entry align="right"><parameter>c_type</parameter>&nbsp;:</entry>
<entry>	The corresponding C type of <parameter>g_Type</parameter>.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-INSTANCE-GET-INTERFACE-CAPS">G_TYPE_INSTANCE_GET_INTERFACE()</title>
<programlisting>#define G_TYPE_INSTANCE_GET_INTERFACE(instance, g_type, c_type) (_G_TYPE_IGI ((instance), (g_type), c_type))
</programlisting>
<para>

</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>instance</parameter>&nbsp;:</entry>
<entry>
</entry></row>
<row><entry align="right"><parameter>g_type</parameter>&nbsp;:</entry>
<entry>
</entry></row>
<row><entry align="right"><parameter>c_type</parameter>&nbsp;:</entry>
<entry>


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-CHECK-INSTANCE-CAPS">G_TYPE_CHECK_INSTANCE()</title>
<programlisting>#define G_TYPE_CHECK_INSTANCE(instance)				(_G_TYPE_CHI ((GTypeInstance*) (instance)))
</programlisting>
<para>

</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>instance</parameter>&nbsp;:</entry>
<entry>


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-CHECK-INSTANCE-CAST-CAPS">G_TYPE_CHECK_INSTANCE_CAST()</title>
<programlisting>#define G_TYPE_CHECK_INSTANCE_CAST(instance, g_type, c_type)    (_G_TYPE_CIC ((instance), (g_type), c_type))
</programlisting>
<para>

</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>instance</parameter>&nbsp;:</entry>
<entry>
</entry></row>
<row><entry align="right"><parameter>g_type</parameter>&nbsp;:</entry>
<entry>
</entry></row>
<row><entry align="right"><parameter>c_type</parameter>&nbsp;:</entry>
<entry>


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-CHECK-INSTANCE-TYPE-CAPS">G_TYPE_CHECK_INSTANCE_TYPE()</title>
<programlisting>#define G_TYPE_CHECK_INSTANCE_TYPE(instance, g_type)            (_G_TYPE_CIT ((instance), (g_type)))
</programlisting>
<para>

</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>instance</parameter>&nbsp;:</entry>
<entry>
</entry></row>
<row><entry align="right"><parameter>g_type</parameter>&nbsp;:</entry>
<entry>


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-CHECK-CLASS-CAST-CAPS">G_TYPE_CHECK_CLASS_CAST()</title>
<programlisting>#define G_TYPE_CHECK_CLASS_CAST(g_class, g_type, c_type)        (_G_TYPE_CCC ((g_class), (g_type), c_type))
</programlisting>
<para>

</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>g_class</parameter>&nbsp;:</entry>
<entry>
</entry></row>
<row><entry align="right"><parameter>g_type</parameter>&nbsp;:</entry>
<entry>
</entry></row>
<row><entry align="right"><parameter>c_type</parameter>&nbsp;:</entry>
<entry>


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-CHECK-CLASS-TYPE-CAPS">G_TYPE_CHECK_CLASS_TYPE()</title>
<programlisting>#define G_TYPE_CHECK_CLASS_TYPE(g_class, g_type)                (_G_TYPE_CCT ((g_class), (g_type)))
</programlisting>
<para>

</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>g_class</parameter>&nbsp;:</entry>
<entry>
</entry></row>
<row><entry align="right"><parameter>g_type</parameter>&nbsp;:</entry>
<entry>


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-CHECK-VALUE-CAPS">G_TYPE_CHECK_VALUE()</title>
<programlisting>#define G_TYPE_CHECK_VALUE(value)				(_G_TYPE_CHV ((value)))
</programlisting>
<para>

</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>value</parameter>&nbsp;:</entry>
<entry>


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-CHECK-VALUE-TYPE-CAPS">G_TYPE_CHECK_VALUE_TYPE()</title>
<programlisting>#define G_TYPE_CHECK_VALUE_TYPE(value, g_type)			(_G_TYPE_CVH ((value), (g_type)))
</programlisting>
<para>

</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>value</parameter>&nbsp;:</entry>
<entry>
</entry></row>
<row><entry align="right"><parameter>g_type</parameter>&nbsp;:</entry>
<entry>


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-TYPE-FLAG-RESERVED-ID-BIT-CAPS">G_TYPE_FLAG_RESERVED_ID_BIT</title>
<programlisting>#define	G_TYPE_FLAG_RESERVED_ID_BIT	((GType) (1 &lt;&lt; 0))
</programlisting>
<para>

</para></refsect2>
<refsect2>
<title><anchor id="g-type-init">g_type_init ()</title>
<programlisting>void        g_type_init                     (void);</programlisting>
<para>
Prior to any use of the type system, <link linkend="g-type-init">g_type_init</link>() has to be called to initialize
the type system and assorted other code portions (such as the various fundamental
type implementations or the signal system).
</para></refsect2>
<refsect2>
<title><anchor id="GTypeDebugFlags">enum GTypeDebugFlags</title>
<programlisting>typedef enum	/*&lt; skip &gt;*/
{
  G_TYPE_DEBUG_NONE	= 0,
  G_TYPE_DEBUG_OBJECTS	= 1 &lt;&lt; 0,
  G_TYPE_DEBUG_SIGNALS	= 1 &lt;&lt; 1,
  G_TYPE_DEBUG_MASK	= 0x03
} GTypeDebugFlags;
</programlisting>