137 lines
6.0 KiB
HTML
137 lines
6.0 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "https://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
|
<html xmlns="http://www.w3.org/1999/xhtml">
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
|
|
<meta http-equiv="X-UA-Compatible" content="IE=9"/>
|
|
<meta name="generator" content="Doxygen 1.8.20"/>
|
|
<meta name="viewport" content="width=device-width, initial-scale=1"/>
|
|
<title>Labor04: xSemaphoreTake</title>
|
|
<link href="tabs.css" rel="stylesheet" type="text/css"/>
|
|
<script type="text/javascript" src="jquery.js"></script>
|
|
<script type="text/javascript" src="dynsections.js"></script>
|
|
<link href="navtree.css" rel="stylesheet" type="text/css"/>
|
|
<script type="text/javascript" src="resize.js"></script>
|
|
<script type="text/javascript" src="navtreedata.js"></script>
|
|
<script type="text/javascript" src="navtree.js"></script>
|
|
<link href="search/search.css" rel="stylesheet" type="text/css"/>
|
|
<script type="text/javascript" src="search/searchdata.js"></script>
|
|
<script type="text/javascript" src="search/search.js"></script>
|
|
<link href="doxygen.css" rel="stylesheet" type="text/css" />
|
|
</head>
|
|
<body>
|
|
<div id="top"><!-- do not remove this div, it is closed by doxygen! -->
|
|
<div id="titlearea">
|
|
<table cellspacing="0" cellpadding="0">
|
|
<tbody>
|
|
<tr style="height: 56px;">
|
|
<td id="projectalign" style="padding-left: 0.5em;">
|
|
<div id="projectname">Labor04
|
|
</div>
|
|
</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
</div>
|
|
<!-- end header part -->
|
|
<!-- Generated by Doxygen 1.8.20 -->
|
|
<script type="text/javascript">
|
|
/* @license magnet:?xt=urn:btih:cf05388f2679ee054f2beb29a391d25f4e673ac3&dn=gpl-2.0.txt GPL-v2 */
|
|
var searchBox = new SearchBox("searchBox", "search",false,'Search');
|
|
/* @license-end */
|
|
</script>
|
|
<script type="text/javascript" src="menudata.js"></script>
|
|
<script type="text/javascript" src="menu.js"></script>
|
|
<script type="text/javascript">
|
|
/* @license magnet:?xt=urn:btih:cf05388f2679ee054f2beb29a391d25f4e673ac3&dn=gpl-2.0.txt GPL-v2 */
|
|
$(function() {
|
|
initMenu('',true,false,'search.php','Search');
|
|
$(document).ready(function() { init_search(); });
|
|
});
|
|
/* @license-end */</script>
|
|
<div id="main-nav"></div>
|
|
</div><!-- top -->
|
|
<div id="side-nav" class="ui-resizable side-nav-resizable">
|
|
<div id="nav-tree">
|
|
<div id="nav-tree-contents">
|
|
<div id="nav-sync" class="sync"></div>
|
|
</div>
|
|
</div>
|
|
<div id="splitbar" style="-moz-user-select:none;"
|
|
class="ui-resizable-handle">
|
|
</div>
|
|
</div>
|
|
<script type="text/javascript">
|
|
/* @license magnet:?xt=urn:btih:cf05388f2679ee054f2beb29a391d25f4e673ac3&dn=gpl-2.0.txt GPL-v2 */
|
|
$(document).ready(function(){initNavTree('group__x_semaphore_take.html',''); initResizable(); });
|
|
/* @license-end */
|
|
</script>
|
|
<div id="doc-content">
|
|
<!-- window showing the filter options -->
|
|
<div id="MSearchSelectWindow"
|
|
onmouseover="return searchBox.OnSearchSelectShow()"
|
|
onmouseout="return searchBox.OnSearchSelectHide()"
|
|
onkeydown="return searchBox.OnSearchSelectKey(event)">
|
|
</div>
|
|
|
|
<!-- iframe showing the search results (closed by default) -->
|
|
<div id="MSearchResultsWindow">
|
|
<iframe src="javascript:void(0)" frameborder="0"
|
|
name="MSearchResults" id="MSearchResults">
|
|
</iframe>
|
|
</div>
|
|
|
|
<div class="header">
|
|
<div class="headertitle">
|
|
<div class="title">xSemaphoreTake</div> </div>
|
|
</div><!--header-->
|
|
<div class="contents">
|
|
<p>semphr. h </p><pre>xSemaphoreTake(
|
|
SemaphoreHandle_t xSemaphore,
|
|
TickType_t xBlockTime
|
|
)</pre><p><em>Macro</em> to obtain a semaphore. The semaphore must have previously been created with a call to xSemaphoreCreateBinary(), xSemaphoreCreateMutex() or xSemaphoreCreateCounting().</p>
|
|
<dl class="params"><dt>Parameters</dt><dd>
|
|
<table class="params">
|
|
<tr><td class="paramname">xSemaphore</td><td>A handle to the semaphore being taken - obtained when the semaphore was created.</td></tr>
|
|
<tr><td class="paramname">xBlockTime</td><td>The time in ticks to wait for the semaphore to become available. The macro portTICK_PERIOD_MS can be used to convert this to a real time. A block time of zero can be used to poll the semaphore. A block time of portMAX_DELAY can be used to block indefinitely (provided INCLUDE_vTaskSuspend is set to 1 in <a class="el" href="_free_r_t_o_s_config_8h.html">FreeRTOSConfig.h</a>).</td></tr>
|
|
</table>
|
|
</dd>
|
|
</dl>
|
|
<dl class="section return"><dt>Returns</dt><dd>pdTRUE if the semaphore was obtained. pdFALSE if xBlockTime expired without the semaphore becoming available.</dd></dl>
|
|
<p>Example usage: </p><pre>
|
|
SemaphoreHandle_t xSemaphore = NULL;</pre><pre>// A task that creates a semaphore.
|
|
void vATask( void * pvParameters )
|
|
{
|
|
// Create the semaphore to guard a shared resource.
|
|
xSemaphore = xSemaphoreCreateBinary();
|
|
}</pre><pre>// A task that uses the semaphore.
|
|
void vAnotherTask( void * pvParameters )
|
|
{
|
|
// ... Do other things.</pre><pre> if( xSemaphore != NULL )
|
|
{
|
|
// See if we can obtain the semaphore. If the semaphore is not available
|
|
// wait 10 ticks to see if it becomes free.
|
|
if( <a class="el" href="semphr_8h.html#af116e436d2a5ae5bd72dbade2b5ea930">xSemaphoreTake( xSemaphore, ( TickType_t ) 10 )</a> == pdTRUE )
|
|
{
|
|
// We were able to obtain the semaphore and can now access the
|
|
// shared resource.</pre><pre> // ...</pre><pre> // We have finished accessing the shared resource. Release the
|
|
// semaphore.
|
|
<a class="el" href="semphr_8h.html#aae55761cabfa9bf85c8f4430f78c0953">xSemaphoreGive( xSemaphore )</a>;
|
|
}
|
|
else
|
|
{
|
|
// We could not obtain the semaphore and can therefore not access
|
|
// the shared resource safely.
|
|
}
|
|
}
|
|
}
|
|
</pre> </div><!-- contents -->
|
|
</div><!-- doc-content -->
|
|
<!-- start footer part -->
|
|
<div id="nav-path" class="navpath"><!-- id is needed for treeview function! -->
|
|
<ul>
|
|
<li class="footer">Generated by <a href="http://www.doxygen.org/index.html"><img class="footer" src="doxygen.svg" width="104" height="31" alt="doxygen"/></a> 1.8.20 </li>
|
|
</ul>
|
|
</div>
|
|
</body>
|
|
</html>
|