main.sgml

GLib是GTK+和GNOME工程的基础底层核心程序库

<literal>g_main_is_running</literal> is deprecated and should not be used in newly-written code.
</para>
</warning>
<para>
Checks if the main loop is running. A compatibility macro, see
<link linkend="g-main-loop-is-running">g_main_loop_is_running</link>().    
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<row><entry align="right"><parameter>loop</parameter>&nbsp;:</entry>
<entry>a <link linkend="GMainLoop">GMainLoop</link>.
</entry></row>
<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry><literal>TRUE</literal> if the main loop is running.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="G-PRIORITY-HIGH-CAPS">G_PRIORITY_HIGH</title>
<programlisting>#define G_PRIORITY_HIGH            -100
</programlisting>
<para>
Use this for high priority event sources.
It is not used within GLib or GTK+.
</para></refsect2>
<refsect2>
<title><anchor id="G-PRIORITY-DEFAULT-CAPS">G_PRIORITY_DEFAULT</title>
<programlisting>#define G_PRIORITY_DEFAULT          0
</programlisting>
<para>
Use this for default priority event sources.
In GLib this priority is used when adding timeout functions with
<link linkend="g-timeout-add">g_timeout_add</link>().
In GDK this priority is used for events from the X server.
</para></refsect2>
<refsect2>
<title><anchor id="G-PRIORITY-HIGH-IDLE-CAPS">G_PRIORITY_HIGH_IDLE</title>
<programlisting>#define G_PRIORITY_HIGH_IDLE        100
</programlisting>
<para>
Use this for high priority idle functions.
GTK+ uses <link linkend="G-PRIORITY-HIGH-IDLE-CAPS">G_PRIORITY_HIGH_IDLE</link> + 10 for resizing operations, and
<link linkend="G-PRIORITY-HIGH-IDLE-CAPS">G_PRIORITY_HIGH_IDLE</link> + 20 for redrawing operations. (This is done to
ensure that any pending resizes are processed before any pending redraws,
so that widgets are not redrawn twice unnecessarily.)
</para></refsect2>
<refsect2>
<title><anchor id="G-PRIORITY-DEFAULT-IDLE-CAPS">G_PRIORITY_DEFAULT_IDLE</title>
<programlisting>#define G_PRIORITY_DEFAULT_IDLE     200
</programlisting>
<para>
Use this for default priority idle functions.
In GLib this priority is used when adding idle functions with <link linkend="g-idle-add">g_idle_add</link>().
</para></refsect2>
<refsect2>
<title><anchor id="G-PRIORITY-LOW-CAPS">G_PRIORITY_LOW</title>
<programlisting>#define G_PRIORITY_LOW	            300
</programlisting>
<para>
Use this for very low priority background tasks.
It is not used within GLib or GTK+.
</para></refsect2>
<refsect2>
<title><anchor id="GMainContext">struct GMainContext</title>
<programlisting>struct GMainContext;</programlisting>
<para>
The <structname>GMainContext</structname> struct is an opaque data type 
representing a set of sources to be handled in a main loop. 
</para></refsect2>
<refsect2>
<title><anchor id="g-main-context-new">g_main_context_new ()</title>
<programlisting><link linkend="GMainContext">GMainContext</link>* g_main_context_new            (void);</programlisting>
<para>
Creates a new <link linkend="GMainContext">GMainContext</link> strcuture</para>
<para>

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<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry> the new <link linkend="GMainContext">GMainContext</link>
</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-main-context-ref">g_main_context_ref ()</title>
<programlisting>void        g_main_context_ref              (<link linkend="GMainContext">GMainContext</link> *context);</programlisting>
<para>
Increases the reference count on a <link linkend="GMainContext">GMainContext</link> object by one.</para>
<para>

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<row><entry align="right"><parameter>context</parameter>&nbsp;:</entry>
<entry> a <link linkend="GMainContext">GMainContext</link>
</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-main-context-unref">g_main_context_unref ()</title>
<programlisting>void        g_main_context_unref            (<link linkend="GMainContext">GMainContext</link> *context);</programlisting>
<para>
Decreases the reference count on a <link linkend="GMainContext">GMainContext</link> object by one. If
the result is zero, free the context and free all associated memory.</para>
<para>

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<row><entry align="right"><parameter>context</parameter>&nbsp;:</entry>
<entry> a <link linkend="GMainContext">GMainContext</link>
</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-main-context-default">g_main_context_default ()</title>
<programlisting><link linkend="GMainContext">GMainContext</link>* g_main_context_default        (void);</programlisting>
<para>
Returns the default main context. This is the main context used
for main loop functions when a main loop is not explicitly
specified.</para>
<para>

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<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry> the default main context.
</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-main-context-iteration">g_main_context_iteration ()</title>
<programlisting><link linkend="gboolean">gboolean</link>    g_main_context_iteration        (<link linkend="GMainContext">GMainContext</link> *context,
                                             <link linkend="gboolean">gboolean</link> may_block);</programlisting>
<para>
Runs a single iteration for the given main loop. This involves
checking to see if any event sources are ready to be processed,
then if no events sources are ready and <parameter>may_block</parameter> is <literal>TRUE</literal>, waiting
for a source to become ready, then dispatching the highest priority
events sources that are ready. Note that even when <parameter>may_block</parameter> is <literal>TRUE</literal>,
it is still possible for <link linkend="g-main-context-iteration">g_main_context_iteration</link>() to return
<literal>FALSE</literal>, since the the wait may be interrupted for other
reasons than an event source becoming ready.</para>
<para>

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<row><entry align="right"><parameter>context</parameter>&nbsp;:</entry>
<entry> a <link linkend="GMainContext">GMainContext</link> (if <literal>NULL</literal>, the default context will be used) 
</entry></row>
<row><entry align="right"><parameter>may_block</parameter>&nbsp;:</entry>
<entry> whether the call may block.
</entry></row>
<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry> <literal>TRUE</literal> if events were dispatched.
</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-main-iteration">g_main_iteration()</title>
<programlisting>#define     g_main_iteration(may_block)</programlisting>
<warning>
<para>
<literal>g_main_iteration</literal> is deprecated and should not be used in newly-written code.
</para>
</warning>
<para>
Runs a single iteration for the default <link linkend="GMainContext">GMainContext</link>.
A compatibility macro, see <link linkend="g-main-context-iteration">g_main_context_iteration</link>().
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<row><entry align="right"><parameter>may_block</parameter>&nbsp;:</entry>
<entry>set to <literal>TRUE</literal> if it should block (i.e. wait) until an event source
becomes ready. It will return after an event source has been processed.
If set to <literal>FALSE</literal> it will return immediately if no event source is ready to be
processed.
</entry></row>
<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry><literal>TRUE</literal> if more events are pending.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-main-context-pending">g_main_context_pending ()</title>
<programlisting><link linkend="gboolean">gboolean</link>    g_main_context_pending          (<link linkend="GMainContext">GMainContext</link> *context);</programlisting>
<para>
Checks if any sources have pending events for the given context.</para>
<para>

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<row><entry align="right"><parameter>context</parameter>&nbsp;:</entry>
<entry> a <link linkend="GMainContext">GMainContext</link> (if <literal>NULL</literal>, the default context will be used)
</entry></row>
<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry> <literal>TRUE</literal> if events are pending.
</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-main-pending">g_main_pending()</title>
<programlisting>#define     g_main_pending()</programlisting>
<warning>
<para>
<literal>g_main_pending</literal> is deprecated and should not be used in newly-written code.
</para>
</warning>
<para>
Checks if any events are pending for the default <link linkend="GMainContext">GMainContext</link>
(i.e. ready to be processed).  A compatibility macro, see
<link linkend="g-main-context-pending">g_main_context_pending</link>().
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<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry><literal>TRUE</literal> if any events are pending.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-main-context-find-source-by-id">g_main_context_find_source_by_id ()</title>
<programlisting><link linkend="GSource">GSource</link>*    g_main_context_find_source_by_id
                                            (<link linkend="GMainContext">GMainContext</link> *context,
                                             <link linkend="guint">guint</link> source_id);</programlisting>
<para>
Finds a <link linkend="GSource">GSource</link> given a pair of context and ID</para>
<para>

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