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| <a href="#GAsyncResult.synopsis" class="shortcut">Top</a> |
| | |
| <a href="#GAsyncResult.description" class="shortcut">Description</a> |
| | |
| <a href="#GAsyncResult.object-hierarchy" class="shortcut">Object Hierarchy</a> |
| | |
| <a href="#GAsyncResult.prerequisites" class="shortcut">Prerequisites</a> |
| | |
| <a href="#GAsyncResult.implementations" class="shortcut">Known Implementations</a> |
| </td></tr> |
| </table> |
| <div class="refentry" title="GAsyncResult"> |
| <a name="GAsyncResult"></a><div class="titlepage"></div> |
| <div class="refnamediv"><table width="100%"><tr> |
| <td valign="top"> |
| <h2><span class="refentrytitle"><a name="GAsyncResult.top_of_page"></a>GAsyncResult</span></h2> |
| <p>GAsyncResult — Asynchronous Function Results</p> |
| </td> |
| <td valign="top" align="right"></td> |
| </tr></table></div> |
| <div class="refsynopsisdiv" title="Synopsis"> |
| <a name="GAsyncResult.synopsis"></a><h2>Synopsis</h2> |
| <pre class="synopsis"> |
| #include <gio/gio.h> |
| |
| <a class="link" href="GAsyncResult.html#GAsyncResult-struct" title="GAsyncResult">GAsyncResult</a>; |
| <a class="link" href="GAsyncResult.html#GAsyncResultIface" title="GAsyncResultIface">GAsyncResultIface</a>; |
| <span class="returnvalue">void</span> (<a class="link" href="GAsyncResult.html#GAsyncReadyCallback" title="GAsyncReadyCallback ()">*GAsyncReadyCallback</a>) (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject"><span class="type">GObject</span></a> *source_object</code></em>, |
| <em class="parameter"><code><a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a> *res</code></em>, |
| <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data</code></em>); |
| <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gpointer"><span class="returnvalue">gpointer</span></a> <a class="link" href="GAsyncResult.html#g-async-result-get-user-data" title="g_async_result_get_user_data ()">g_async_result_get_user_data</a> (<em class="parameter"><code><a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a> *res</code></em>); |
| <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject"><span class="returnvalue">GObject</span></a> * <a class="link" href="GAsyncResult.html#g-async-result-get-source-object" title="g_async_result_get_source_object ()">g_async_result_get_source_object</a> (<em class="parameter"><code><a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a> *res</code></em>); |
| </pre> |
| </div> |
| <div class="refsect1" title="Object Hierarchy"> |
| <a name="GAsyncResult.object-hierarchy"></a><h2>Object Hierarchy</h2> |
| <pre class="synopsis"> |
| GInterface |
| +----GAsyncResult |
| </pre> |
| </div> |
| <div class="refsect1" title="Prerequisites"> |
| <a name="GAsyncResult.prerequisites"></a><h2>Prerequisites</h2> |
| <p> |
| GAsyncResult requires |
| <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject">GObject</a>.</p> |
| </div> |
| <div class="refsect1" title="Known Implementations"> |
| <a name="GAsyncResult.implementations"></a><h2>Known Implementations</h2> |
| <p> |
| GAsyncResult is implemented by |
| <a class="link" href="GSimpleAsyncResult.html" title="GSimpleAsyncResult">GSimpleAsyncResult</a>.</p> |
| </div> |
| <div class="refsect1" title="Description"> |
| <a name="GAsyncResult.description"></a><h2>Description</h2> |
| <p> |
| Provides a base class for implementing asynchronous function results. |
| </p> |
| <p> |
| Asynchronous operations are broken up into two separate operations |
| which are chained together by a <a class="link" href="GAsyncResult.html#GAsyncReadyCallback" title="GAsyncReadyCallback ()"><span class="type">GAsyncReadyCallback</span></a>. To begin |
| an asynchronous operation, provide a <a class="link" href="GAsyncResult.html#GAsyncReadyCallback" title="GAsyncReadyCallback ()"><span class="type">GAsyncReadyCallback</span></a> to the |
| asynchronous function. This callback will be triggered when the |
| operation has completed, and will be passed a <a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a> instance |
| filled with the details of the operation's success or failure, the |
| object the asynchronous function was started for and any error codes |
| returned. The asynchronous callback function is then expected to call |
| the corresponding "<code class="function">_finish()</code>" function, passing the object the |
| function was called for, the <a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a> instance, and (optionally) |
| an <em class="parameter"><code>error</code></em> to grab any error conditions that may have occurred. |
| </p> |
| <p> |
| The "<code class="function">_finish()</code>" function for an operation takes the generic result |
| (of type <a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a>) and returns the specific result that the |
| operation in question yields (e.g. a <a class="link" href="GFileEnumerator.html" title="GFileEnumerator"><span class="type">GFileEnumerator</span></a> for a |
| "enumerate children" operation). If the result or error status of the |
| operation is not needed, there is no need to call the "<code class="function">_finish()</code>" |
| function; GIO will take care of cleaning up the result and error |
| information after the <a class="link" href="GAsyncResult.html#GAsyncReadyCallback" title="GAsyncReadyCallback ()"><span class="type">GAsyncReadyCallback</span></a> returns. Applications may |
| also take a reference to the <a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a> and call "<code class="function">_finish()</code>" |
| later; however, the "<code class="function">_finish()</code>" function may be called at most once. |
| </p> |
| <p> |
| Example of a typical asynchronous operation flow: |
| </p> |
| <div class="informalexample"> |
| <table class="listing_frame" border="0" cellpadding="0" cellspacing="0"> |
| <tbody> |
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| <td class="listing_lines" align="right"><pre>1 |
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| 38</pre></td> |
| <td class="listing_code"><pre class="programlisting"><span class="type">void</span><span class="normal"> </span><span class="function">_theoretical_frobnitz_async</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">Theoretical </span><span class="symbol">*</span><span class="normal">t</span><span class="symbol">,</span> |
| <span class="normal"> <a href="GCancellable.html">GCancellable</a> </span><span class="symbol">*</span><span class="normal">c</span><span class="symbol">,</span> |
| <span class="normal"> <a href="GAsyncResult.html#GAsyncReadyCallback">GAsyncReadyCallback</a> </span><span class="symbol">*</span><span class="normal">cb</span><span class="symbol">,</span> |
| <span class="normal"> <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gpointer">gpointer</a> u</span><span class="symbol">);</span> |
| |
| <span class="normal"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean">gboolean</a> </span><span class="function">_theoretical_frobnitz_finish</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">Theoretical </span><span class="symbol">*</span><span class="normal">t</span><span class="symbol">,</span> |
| <span class="normal"> <a href="GAsyncResult.html">GAsyncResult</a> </span><span class="symbol">*</span><span class="normal">res</span><span class="symbol">,</span> |
| <span class="normal"> <a href="/usr/share/gtk-doc/html/glib/glib-Error-Reporting.html#GError">GError</a> </span><span class="symbol">**</span><span class="normal">e</span><span class="symbol">);</span> |
| |
| <span class="keyword">static</span><span class="normal"> </span><span class="type">void</span> |
| <span class="function">frobnitz_result_func</span><span class="normal"> </span><span class="symbol">(</span><span class="normal"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject">GObject</a> </span><span class="symbol">*</span><span class="normal">source_object</span><span class="symbol">,</span> |
| <span class="normal"> <a href="GAsyncResult.html">GAsyncResult</a> </span><span class="symbol">*</span><span class="normal">res</span><span class="symbol">,</span> |
| <span class="normal"> <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gpointer">gpointer</a> user_data</span><span class="symbol">)</span> |
| <span class="cbracket">{</span> |
| <span class="normal"> <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean">gboolean</a> success </span><span class="symbol">=</span><span class="normal"> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#FALSE:CAPS">FALSE</a></span><span class="symbol">;</span> |
| |
| <span class="normal"> success </span><span class="symbol">=</span><span class="normal"> </span><span class="function">_theoretical_frobnitz_finish</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">source_object</span><span class="symbol">,</span><span class="normal"> res</span><span class="symbol">,</span><span class="normal"> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">);</span> |
| |
| <span class="normal"> </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">success</span><span class="symbol">)</span> |
| <span class="normal"> </span><span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-String-Utility-Functions.html#g-printf">g_printf</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"Hurray!</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">);</span> |
| <span class="normal"> </span><span class="keyword">else</span> |
| <span class="normal"> </span><span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-String-Utility-Functions.html#g-printf">g_printf</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"Uh oh!</span><span class="specialchar">\n</span><span class="string">"</span><span class="symbol">);</span> |
| |
| <span class="normal"> </span><span class="comment">/* ... */</span> |
| |
| <span class="cbracket">}</span> |
| |
| <span class="type">int</span><span class="normal"> </span><span class="function">main</span><span class="normal"> </span><span class="symbol">(</span><span class="type">int</span><span class="normal"> argc</span><span class="symbol">,</span><span class="normal"> </span><span class="type">void</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">argv</span><span class="symbol">[])</span> |
| <span class="cbracket">{</span> |
| <span class="normal"> </span><span class="comment">/* ... */</span> |
| |
| <span class="normal"> </span><span class="function">_theoretical_frobnitz_async</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">theoretical_data</span><span class="symbol">,</span> |
| <span class="normal"> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">,</span> |
| <span class="normal"> frobnitz_result_func</span><span class="symbol">,</span> |
| <span class="normal"> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">);</span> |
| |
| <span class="normal"> </span><span class="comment">/* ... */</span> |
| <span class="cbracket">}</span></pre></td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| |
| <p> |
| </p> |
| <p> |
| The callback for an asynchronous operation is called only once, and is |
| always called, even in the case of a cancelled operation. On cancellation |
| the result is a <a class="link" href="gio-GIOError.html#G-IO-ERROR-CANCELLED:CAPS"><code class="literal">G_IO_ERROR_CANCELLED</code></a> error. |
| </p> |
| <p> |
| Some asynchronous operations are implemented using synchronous calls. |
| These are run in a separate thread, if <a href="/usr/share/gtk-doc/html/glib/glib-Threads.html#GThread"><span class="type">GThread</span></a> has been initialized, but |
| otherwise they are sent to the Main Event Loop and processed in an idle |
| function. So, if you truly need asynchronous operations, make sure to |
| initialize <a href="/usr/share/gtk-doc/html/glib/glib-Threads.html#GThread"><span class="type">GThread</span></a>. |
| </p> |
| </div> |
| <div class="refsect1" title="Details"> |
| <a name="GAsyncResult.details"></a><h2>Details</h2> |
| <div class="refsect2" title="GAsyncResult"> |
| <a name="GAsyncResult-struct"></a><h3>GAsyncResult</h3> |
| <pre class="programlisting">typedef struct _GAsyncResult GAsyncResult;</pre> |
| <p> |
| Holds results information for an asynchronous operation, |
| usually passed directly to a asynchronous <code class="function">_finish()</code> operation. |
| </p> |
| </div> |
| <hr> |
| <div class="refsect2" title="GAsyncResultIface"> |
| <a name="GAsyncResultIface"></a><h3>GAsyncResultIface</h3> |
| <pre class="programlisting">typedef struct { |
| GTypeInterface g_iface; |
| |
| /* Virtual Table */ |
| |
| gpointer (* get_user_data) (GAsyncResult *async_result); |
| GObject * (* get_source_object) (GAsyncResult *async_result); |
| } GAsyncResultIface; |
| </pre> |
| <p> |
| Interface definition for <a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><a href="/usr/share/gtk-doc/html/gobject/gobject-Type-Information.html#GTypeInterface"><span class="type">GTypeInterface</span></a> <em class="structfield"><code><a name="GAsyncResultIface.g-iface"></a>g_iface</code></em>;</span></p></td> |
| <td>The parent interface. |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="structfield"><code><a name="GAsyncResultIface.get-user-data"></a>get_user_data</code></em> ()</span></p></td> |
| <td>Gets the user data passed to the callback. |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="structfield"><code><a name="GAsyncResultIface.get-source-object"></a>get_source_object</code></em> ()</span></p></td> |
| <td>Gets the source object that issued the asynchronous operation. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2" title="GAsyncReadyCallback ()"> |
| <a name="GAsyncReadyCallback"></a><h3>GAsyncReadyCallback ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> (*GAsyncReadyCallback) (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject"><span class="type">GObject</span></a> *source_object</code></em>, |
| <em class="parameter"><code><a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a> *res</code></em>, |
| <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data</code></em>);</pre> |
| <p> |
| Type definition for a function that will be called back when an asynchronous |
| operation within GIO has been completed. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>source_object</code></em> :</span></p></td> |
| <td>the object the asynchronous operation was started with. |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>res</code></em> :</span></p></td> |
| <td>a <a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a>. |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>user_data</code></em> :</span></p></td> |
| <td>user data passed to the callback. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2" title="g_async_result_get_user_data ()"> |
| <a name="g-async-result-get-user-data"></a><h3>g_async_result_get_user_data ()</h3> |
| <pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gpointer"><span class="returnvalue">gpointer</span></a> g_async_result_get_user_data (<em class="parameter"><code><a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a> *res</code></em>);</pre> |
| <p> |
| Gets the user data from a <a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>res</code></em> :</span></p></td> |
| <td>a <a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a>. |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td> the user data for <em class="parameter"><code>res</code></em>. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <hr> |
| <div class="refsect2" title="g_async_result_get_source_object ()"> |
| <a name="g-async-result-get-source-object"></a><h3>g_async_result_get_source_object ()</h3> |
| <pre class="programlisting"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject"><span class="returnvalue">GObject</span></a> * g_async_result_get_source_object (<em class="parameter"><code><a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a> *res</code></em>);</pre> |
| <p> |
| Gets the source object from a <a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a>. |
| </p> |
| <div class="variablelist"><table border="0"> |
| <col align="left" valign="top"> |
| <tbody> |
| <tr> |
| <td><p><span class="term"><em class="parameter"><code>res</code></em> :</span></p></td> |
| <td>a <a class="link" href="GAsyncResult.html" title="GAsyncResult"><span class="type">GAsyncResult</span></a> |
| </td> |
| </tr> |
| <tr> |
| <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> |
| <td> a new reference to the source object for the <em class="parameter"><code>res</code></em>, |
| or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if there is none. |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| </div> |
| <div class="refsect1" title="See Also"> |
| <a name="GAsyncResult.see-also"></a><h2>See Also</h2> |
| <a class="link" href="GSimpleAsyncResult.html" title="GSimpleAsyncResult"><span class="type">GSimpleAsyncResult</span></a> |
| </div> |
| </div> |
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