glib-threads.html

glid编写实例

This function can also be used, if <a href="glib-Threads.html#g-thread-init"><code class="function">g_thread_init()</code></a> has not yet been
called and will do nothing then.
</p>
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<td>
<span class="term"><em class="parameter"><code>mutex</code></em>&#160;:</span></td>
<td>a <a href="glib-Threads.html#GMutex"><span class="type">GMutex</span></a>.


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<div class="refsect2" lang="en">
<a name="id2873490"></a><h3>
<a name="g-mutex-free"></a>g_mutex_free ()</h3>
<a class="indexterm" name="id2873501"></a><pre class="programlisting">void        g_mutex_free                    (<a href="glib-Threads.html#GMutex">GMutex</a> *mutex);</pre>
<p>
Destroys <em class="parameter"><code>mutex</code></em>.
</p>
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<td>
<span class="term"><em class="parameter"><code>mutex</code></em>&#160;:</span></td>
<td>a <a href="glib-Threads.html#GMutex"><span class="type">GMutex</span></a>.


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<div class="refsect2" lang="en">
<a name="id2873561"></a><h3>
<a name="GStaticMutex"></a>GStaticMutex</h3>
<a class="indexterm" name="id2873571"></a><pre class="programlisting">typedef struct _GStaticMutex GStaticMutex;</pre>
<p>
A <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a> works like a <a href="glib-Threads.html#GMutex"><span class="type">GMutex</span></a>, but it has one significant
advantage. It doesn't need to be created at run-time like a <a href="glib-Threads.html#GMutex"><span class="type">GMutex</span></a>,
but can be defined at compile-time. Here is a shorter, easier and
safer version of our <code class="function"><code class="function">give_me_next_number()</code></code> example:
</p>
<p>
</p>
<div class="example">
<a name="id2873632"></a><p class="title"><b>Example&#160;6.&#160;Using <span class="structname">GStaticMutex</span> to simplify thread-safe programming</b></p>
<pre class="programlisting">
  int give_me_next_number ()
  {
    static int current_number = 0;
    int ret_val;
    static GStaticMutex mutex = G_STATIC_MUTEX_INIT;

    g_static_mutex_lock (&amp;mutex);
    ret_val = current_number = calc_next_number (current_number); 
    g_static_mutex_unlock (&amp;mutex);
    return ret_val;
  }
</pre>
</div>
<p>
</p>
<p>
Sometimes you would like to dynamically create a mutex. If you don't
want to require prior calling to <a href="glib-Threads.html#g-thread-init"><code class="function">g_thread_init()</code></a>, because your code
should also be usable in non-threaded programs, you are not able to
use <a href="glib-Threads.html#g-mutex-new"><code class="function">g_mutex_new()</code></a> and thus <a href="glib-Threads.html#GMutex"><span class="type">GMutex</span></a>, as that requires a prior call to
<a href="glib-Threads.html#g-thread-init"><code class="function">g_thread_init()</code></a>. In theses cases you can also use a <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a>. It
must be initialized with <a href="glib-Threads.html#g-static-mutex-init"><code class="function">g_static_mutex_init()</code></a> before using it and
freed with with <a href="glib-Threads.html#g-static-mutex-free"><code class="function">g_static_mutex_free()</code></a> when not needed anymore to free
up any allocated resources.
</p>
<p>
Even though <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a> is not opaque, it should only be used with
the following functions, as it is defined differently on different
platforms.
</p>
<p>
All of the <code class="function">g_static_mutex_*</code> functions can also be 
used, if <a href="glib-Threads.html#g-thread-init"><code class="function">g_thread_init()</code></a> has not yet been called.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>
<p>
All of the <code class="function">g_static_mutex_*</code> functions are actually 
macros. Apart from taking their addresses, you can however use them 
as if they were functions.
</p>
</div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2873786"></a><h3>
<a name="G-STATIC-MUTEX-INIT:CAPS"></a>G_STATIC_MUTEX_INIT</h3>
<a class="indexterm" name="id2873798"></a><pre class="programlisting">#define G_STATIC_MUTEX_INIT
</pre>
<p>
A <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a> must be initialized with this macro, before it can be
used. This macro can used be to initialize a variable, but it cannot
be assigned to a variable. In that case you have to use
<a href="glib-Threads.html#g-static-mutex-init"><code class="function">g_static_mutex_init()</code></a>.
</p>
<p>
</p>
<div class="informalexample"><pre class="programlisting">
GStaticMutex my_mutex = G_STATIC_MUTEX_INIT;
</pre></div>
<p>
</p>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2873847"></a><h3>
<a name="g-static-mutex-init"></a>g_static_mutex_init ()</h3>
<a class="indexterm" name="id2873858"></a><pre class="programlisting">void        g_static_mutex_init             (<a href="glib-Threads.html#GStaticMutex">GStaticMutex</a> *mutex);</pre>
<p>
Initializes <em class="parameter"><code>mutex</code></em>. Alternatively you can initialize it with
<a href="glib-Threads.html#G-STATIC-MUTEX-INIT:CAPS"><span class="type">G_STATIC_MUTEX_INIT</span></a>.
</p>
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<td>
<span class="term"><em class="parameter"><code>mutex</code></em>&#160;:</span></td>
<td>a <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a> to be initialized.


</td>
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</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2873928"></a><h3>
<a name="g-static-mutex-lock"></a>g_static_mutex_lock ()</h3>
<a class="indexterm" name="id2873939"></a><pre class="programlisting">void        g_static_mutex_lock             (<a href="glib-Threads.html#GStaticMutex">GStaticMutex</a> *mutex);</pre>
<p>
Works like <a href="glib-Threads.html#g-mutex-lock"><code class="function">g_mutex_lock()</code></a>, but for a <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a>.
</p>
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<td>
<span class="term"><em class="parameter"><code>mutex</code></em>&#160;:</span></td>
<td>a <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a>.


</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2874013"></a><h3>
<a name="g-static-mutex-trylock"></a>g_static_mutex_trylock ()</h3>
<a class="indexterm" name="id2874024"></a><pre class="programlisting"><a href="glib-Basic-Types.html#gboolean">gboolean</a>    g_static_mutex_trylock          (<a href="glib-Threads.html#GStaticMutex">GStaticMutex</a> *mutex);</pre>
<p>
Works like <a href="glib-Threads.html#g-mutex-trylock"><code class="function">g_mutex_trylock()</code></a>, but for a <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a>.
</p>
<div class="variablelist"><table border="0">
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<td>
<span class="term"><em class="parameter"><code>mutex</code></em>&#160;:</span></td>
<td>a <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a>.
</td>
</tr>
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<td>
<span class="term"><span class="emphasis"><em>Returns</em></span>&#160;:</span></td>
<td>
<code class="literal">TRUE</code>, if the <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a> could be locked.


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<hr>
<div class="refsect2" lang="en">
<a name="id2874121"></a><h3>
<a name="g-static-mutex-unlock"></a>g_static_mutex_unlock ()</h3>
<a class="indexterm" name="id2874132"></a><pre class="programlisting">void        g_static_mutex_unlock           (<a href="glib-Threads.html#GStaticMutex">GStaticMutex</a> *mutex);</pre>
<p>
Works like <a href="glib-Threads.html#g-mutex-unlock"><code class="function">g_mutex_unlock()</code></a>, but for a <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td>
<span class="term"><em class="parameter"><code>mutex</code></em>&#160;:</span></td>
<td>a <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a>.


</td>
</tr></tbody>
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<hr>
<div class="refsect2" lang="en">
<a name="id2874206"></a><h3>
<a name="g-static-mutex-get-mutex"></a>g_static_mutex_get_mutex ()</h3>
<a class="indexterm" name="id2874217"></a><pre class="programlisting"><a href="glib-Threads.html#GMutex">GMutex</a>*     g_static_mutex_get_mutex        (<a href="glib-Threads.html#GStaticMutex">GStaticMutex</a> *mutex);</pre>
<p>
For some operations (like <a href="glib-Threads.html#g-cond-wait"><code class="function">g_cond_wait()</code></a>) you must have a <a href="glib-Threads.html#GMutex"><span class="type">GMutex</span></a>
instead of a <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a>. This function will return the
corresponding <a href="glib-Threads.html#GMutex"><span class="type">GMutex</span></a> for <em class="parameter"><code>mutex</code></em>.
</p>
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<td>
<span class="term"><em class="parameter"><code>mutex</code></em>&#160;:</span></td>
<td>a <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a>.
</td>
</tr>
<tr>
<td>
<span class="term"><span class="emphasis"><em>Returns</em></span>&#160;:</span></td>
<td>the <a href="glib-Threads.html#GMutex"><span class="type">GMutex</span></a> corresponding to <em class="parameter"><code>mutex</code></em>.


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<hr>
<div class="refsect2" lang="en">
<a name="id2874338"></a><h3>
<a name="g-static-mutex-free"></a>g_static_mutex_free ()</h3>
<a class="indexterm" name="id2874349"></a><pre class="programlisting">void        g_static_mutex_free             (<a href="glib-Threads.html#GStaticMutex">GStaticMutex</a> *mutex);</pre>
<p>
Releases all resources allocated to <em class="parameter"><code>mutex</code></em>. 
</p>
<p>
You don't have to call this functions for a <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a> with an
unbounded lifetime, i.e. objects declared 'static', but if you have a
<a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a> as a member of a structure and the structure is freed,
you should also free the <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td>
<span class="term"><em class="parameter"><code>mutex</code></em>&#160;:</span></td>
<td>a <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a> to be freed.


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</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2874442"></a><h3>
<a name="G-LOCK-DEFINE:CAPS"></a>G_LOCK_DEFINE()</h3>
<a class="indexterm" name="id2874452"></a><pre class="programlisting">#define     G_LOCK_DEFINE(name)</pre>
<p>
The <code class="literal">G_LOCK_</code>* macros provide a convenient interface to <a href="glib-Threads.html#GStaticMutex"><span class="type">GStaticMutex</span></a>
with t