📄 int8u osqpostfront.htm
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lang=EN-US> except that the message is inserted at the front of the queue.<span
style="mso-spacerun: yes"> </span>This means that </span><span
class=CodeInText><span lang=EN-US style='font-size:12.0pt;font-family:"Courier New"'>OSQPostFront()</span></span><span
lang=EN-US> makes the message queue behave like a last-in-first-out (LIFO)
queue instead of a first-in-first-out (FIFO) queue.<span style="mso-spacerun:
yes"> </span>A message is a pointer size variable and its use is application
specific.<span style="mso-spacerun: yes"> </span>If the message queue is
full an error code is returned to the caller.<span style="mso-spacerun:
yes"> </span></span><span class=CodeInText><span lang=EN-US
style='font-size:12.0pt;font-family:"Courier New"'>OSQPostFront()</span></span><span
lang=EN-US> will then immediately return to its caller and the message will not
be placed in the queue.<span style="mso-spacerun: yes"> </span>If any
task is waiting for a message at the queue then, the highest priority task will
receive the message.<span style="mso-spacerun: yes"> </span>If the task
waiting for the message has a higher priority than the task sending the message
then, the higher priority task will be resumed and the task sending the message
will be suspended.<span style="mso-spacerun: yes"> </span>In other words,
a context switch will occur.<span style="mso-spacerun: yes"> </span></span></p>
<p class=NewSectionPara><span lang=EN-US><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=NewSectionPara><b><span lang=EN-US>Arguments<o:p></o:p></span></b></p>
<p class=Descript><b><span lang=EN-US style='font-family:"Courier New"'>pevent</span></b><span
lang=EN-US> is a pointer to the queue where the message is to be deposited
into.<span style="mso-spacerun: yes"> </span>This pointer is returned to
your application when the queue is created (see </span><b><span lang=EN-US
style='font-family:"Courier New"'>OSQCreate()</span></b><span lang=EN-US>).</span></p>
<p class=Descript><b><span lang=EN-US style='font-family:"Courier New"'>msg</span></b><span
lang=EN-US> is the actual message sent to the task.<span style="mso-spacerun:
yes"> </span></span><b><span lang=EN-US style='font-family:"Courier New"'>msg</span></b><span
lang=EN-US> is a pointer size variable and is application specific.<span
style="mso-spacerun: yes"> </span>You MUST never post a NULL pointer.</span></p>
<p class=NewSectionPara><span lang=EN-US><span style='mso-tab-count:1'> </span></span></p>
<p class=NewSectionPara><b><span lang=EN-US>Returned Value<o:p></o:p></span></b></p>
<p class=Descript><b><span lang=EN-US style='font-family:"Courier New"'>OSQPostFront()</span></b><span
lang=EN-US> returns one of these two error codes</span></p>
<p class=Descript><span lang=EN-US><span style='mso-tab-count:1'> </span>1)
</span><b><span lang=EN-US style='font-family:"Courier New"'>OS_NO_ERR</span></b><span
lang=EN-US>, if the message was deposited in the queue</span></p>
<p class=Descript><span lang=EN-US><span style='mso-tab-count:1'> </span>2)
</span><b><span lang=EN-US style='font-family:"Courier New"'>OS_Q_FULL</span></b><span
lang=EN-US>, if the queue is already full</span></p>
<p class=NewSectionPara><b><span lang=EN-US><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></b></p>
<p class=NewSectionPara><b><span lang=EN-US>Notes/Warnings<o:p></o:p></span></b></p>
<p class=Descript><span lang=EN-US>Queues must be created before they are used.</span></p>
<p class=NewSectionPara><b><span lang=EN-US><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></b></p>
<p class=NewSectionPara><b><span lang=EN-US>Example<o:p></o:p></span></b></p>
<div style='border:solid #999999 1.5pt;padding:1.0pt 1.0pt 15.0pt 1.0pt;
background:#F2F2F2;mso-shading:windowtext;mso-pattern:gray-5 auto'>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style='mso-tab-count:1'> </span>OS_EVENT *CommQ;</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style='mso-tab-count:1'> </span>INT8U<span style="mso-spacerun:
yes"> </span>CommRxBuf[100];</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style='mso-tab-count:1'> </span>void CommTaskRx(void *pdata)</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style='mso-tab-count:1'> </span>{</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun: yes"> </span>INT8U<span
style="mso-spacerun: yes"> </span>err;</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun: yes"> </span>pdata = pdata;</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun: yes"> </span>for (;;) {</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun: yes">
</span>.</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style='mso-tab-count:3'> </span>.</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style='mso-tab-count:3'> </span>err
= OSQPostFront(CommQ, (void *)&CommRxBuf[0]);</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun: yes">
</span>if (err == OS_NO_ERR) {</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun:
yes">
</span>.<span style="mso-spacerun:
yes">
</span>/* Message was deposited into queue<span style="mso-spacerun:
yes"> </span>*/</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun:
yes">
</span>.</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun: yes">
</span>} else {</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun:
yes">
</span>.<span style="mso-spacerun:
yes">
</span>/* Queue is full<span style="mso-spacerun:
yes">
</span>*/</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun:
yes">
</span>.</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun: yes">
</span>}</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun: yes">
</span>.</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style='mso-tab-count:3'> </span>.</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style="mso-spacerun: yes"> </span>}</span></p>
<p class=CodeSeg style='border:none;mso-border-alt:solid #999999 1.5pt;
padding:0cm;mso-padding-alt:1.0pt 1.0pt 15.0pt 1.0pt'><span lang=EN-US><span
style='mso-tab-count:1'> </span>}</span></p>
</div>
</div>
<span lang=EN-US style='font-size:10.5pt;mso-bidi-font-size:12.0pt;font-family:
"Times New Roman";mso-fareast-font-family:宋体;background:#D9D9D9;mso-shading:
white;mso-pattern:gray-15 auto;mso-font-kerning:1.0pt;mso-ansi-language:EN-US;
mso-fareast-language:ZH-CN;mso-bidi-language:AR-SA'><br clear=all
style='page-break-before:always;mso-break-type:section-break'>
</span>
<div class=Section2 style='layout-grid:15.6pt'>
<p class=MsoNormal><span lang=EN-US><![if !supportEmptyParas]> <![endif]><o:p></o:p></span></p>
</div>
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