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8<TITLE>OSSendMessage</TITLE>
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11<H1>OSSendMessage</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>BOOL OSSendMessage(
18OSMessageQueue*   mq,
19OSMessage         msg,
20s32             flags);</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><CODE><EM><CODE>msg</CODE></EM></CODE></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><STRONG><EM><CODE>flags</CODE></EM></STRONG></CODE></B></I></TD>
35<TD width="520">When <code>OS_MESSAGE_BLOCK</code> is set and the queue is full, the <code>OSSendMessage</code> function blocks. When <code>OS_MESSAGE_NOBLOCK</code> is set, the <code>OSSendMessage</code> function immediately returns  whether or not the queue is full.</TD>
36    </TR>
37  </TBODY>
38</TABLE>
39<H2>Return Values</H2>
40<P>Returns <code>TRUE</code> if the message is successfully sent.</P>
41<P>Returns <code>FALSE</code> if <code>OS_MESSAGE_NOBLOCK</code> is specified and the queue is full.</P>
42<H2>Description</H2>
43<P>This function inserts a message at the end of the specified message queue. This function allows threads waiting in the message queue to execute. The receiving threads execute in order of priority.</P>
44<P>If <i><b><code>flags</code></b></i> is set to <code>OS_MESSAGE_BLOCK</code> and the queue is full, the calling thread will be paused.&nbsp;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 temporarily pause again until the receiving thread makes an opening in the message queue.</P>
45<P>If <em><strong><code>flags</code></strong></em> is set to <code>OS_MESSAGE_NOBLOCK</code>, it returns to the calling thread immediately. When the queue isn't full, <code>TRUE</code> is returned. If the queue is full, <CODE>FALSE</CODE> is returned.</P>
46
47<H2>See Also</H2>
48<P><a href="../list.html#Thread" target="contents">Thread Functions</a>, <a href="../list.html#ThreadSynchronization" target="contents">Thread Synchronization Functions</a>, <a href="OSInitMessageQueue.html"><code>OSInitMessageQueue</code></a>, <a href="OSJamMessage.html"><code>OSJamMessage</code></a>, <a href="OSReceiveMessage.html"><code>OSReceiveMessage</code></a></P>
49<H2>Revision History</H2>
50<P>03/01/2006 Initial version.</p>
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