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11<H1>OSJamMessage</H1>
12<H2>C Specification</H2>
13<DL>
14  <DD>
15  <PRE><CODE>#include &lt;revolution/os.h&gt;</CODE></PRE>
16  <DD>
17  <PRE><CODE>BOOL OSJamMessage(
18    OSMessageQueue* mq,
19    OSMessage       msg,
20    s32             flags);</CODE></PRE>
21</DL>
22<H2>Arguments</H2>
23<TABLE border="1" cellpadding="3" cellspacing="0.1">
24  <TBODY>
25    <TR>
26<TD width="120" bgcolor="#ffffe8"><I><B><CODE><STRONG><EM><CODE>mq</CODE></EM></STRONG></CODE></B></I></TD>
27<TD width="520">Pointer to message queue.</TD>
28    </TR>
29    <TR>
30<TD width="120" bgcolor="#ffffe8"><I><B><CODE>msg</CODE></B></I></TD>
31<TD width="520">Message to send.</TD>
32    </TR>
33    <TR>
34<TD width="120" bgcolor="#ffffe8"><I><B><CODE>flags</CODE></B></I></TD>
35<TD width="520">If set to <code>OS_MESSAGE_BLOCK</code>, <code>OSJamMessage()</code> will block on a full queue. If set to <code>OS_MESSAGE_NOBLOCK</code>, <code>OSJamMessage()</code> will return immediately whether the queue is full or not.</TD>
36    </TR>
37  </TBODY>
38</TABLE>
39<H2>Return Values</H2>
40<P><code>TRUE</code> is returned if the message is successfully sent.</P>
41<P><code>FALSE</code> is returned if <code>OS_MESSAGE_NOBLOCK</code> was specified and the queue is full.</P>
42<H2>Description</H2>
43<P><code>OSJamMessage</code> is similar to <code>OSSendMessage</code> except that it inserts a message at the beginning of the specified message queue. Call this function when sending high priority messages.</P>
44<P>If <code>OS_MESSAGE_BLOCK</code> is set in <em><strong><code>flags</code></strong></em> and the queue is full, the thread that called this function is temporarily stopped. You can restart this thread by running a receiving thread and removing messages from the queue. Be aware that sending threads with a higher priority will execute first and may fill up the queue. In this case, this thread will be paused again until the receiving thread makes an opening in the message queue.</P>
45<P>When <code>OS_MESSAGE_NOBLOCK</code> is set in <em><strong><code>flags</code></strong></em>, the called thread is returned immediately. When the queue is not full, <code>TRUE</code> is returned. If the queue is full, <code>FALSE</code> is returned.</P>
46<P>This function may put the current thread to sleep. For precautions when calling similar functions, refer to <A href="../Interrupt/intro.html">Interrupts and Callback Functions</A>.</P>
47
48<H2>See Also</H2>
49<P><A href="../toc.html#Thread" target="contents">Thread Functions</a>, <A href="../toc.html#ThreadSynchronization" target="contents">Thread Synchronization Functions</a>,<BR> <A href="OSInitMessageQueue.html"><CODE>OSInitMessageQueue</CODE></a>, <A href="OSReceiveMessage.html"><CODE>OSReceiveMessage</CODE></a>, <A href="OSSendMessage.html"><CODE>OSSendMessage</CODE></a>, <A href="../Interrupt/intro.html">Interrupts and Callback Functions</A></P>
50<H2>Revision History</H2>
51<p>
522007/09/25 Added information on the sleeping status of threads.<br>2006/03/01 Initial version.<br>
53</p>
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