<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://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"/> <title>Mail Queue</title> <title>CMSIS-RTOS: Mail Queue</title> <link href="tabs.css" rel="stylesheet" type="text/css"/> <link href="cmsis.css" rel="stylesheet" type="text/css" /> <script type="text/javascript" src="jquery.js"></script> <script type="text/javascript" src="dynsections.js"></script> <script type="text/javascript" src="printComponentTabs.js"></script> <link href="navtree.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="resize.js"></script> <script type="text/javascript" src="navtree.js"></script> <script type="text/javascript"> $(document).ready(initResizable); $(window).load(resizeHeight); </script> <link href="search/search.css" rel="stylesheet" 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<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"> $(document).ready(function(){initNavTree('group__CMSIS__RTOS__Mail.html','');}); </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)"> <a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(0)"><span class="SelectionMark"> </span>All</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(1)"><span class="SelectionMark"> </span>Data Structures</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(2)"><span class="SelectionMark"> </span>Files</a><a class="SelectItem" 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class="SelectionMark"> </span>Pages</a></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="summary"> <a href="#define-members">Macros</a> | <a href="#func-members">Functions</a> </div> <div class="headertitle"> <div class="title">Mail Queue<div class="ingroups"><a class="el" href="group__CMSIS__RTOS__InterThread.html">Inter-Thread Communication and Resource Sharing</a></div></div> </div> </div><!--header--> <div class="contents"> <p>Exchange data between threads using a queue of memory blocks. <a href="#details">More...</a></p> <table class="memberdecls"> <tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="define-members"></a> Macros</h2></td></tr> <tr class="memitem:gaceb2e0071ce160d153047f2eac1aca8e"><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__Mail.html#gaceb2e0071ce160d153047f2eac1aca8e">osFeature_MailQ</a>   1</td></tr> <tr class="memdesc:gaceb2e0071ce160d153047f2eac1aca8e"><td class="mdescLeft"> </td><td class="mdescRight">Mail Queues: 1=available, 0=not available. <a href="#gaceb2e0071ce160d153047f2eac1aca8e">More...</a><br/></td></tr> <tr class="separator:gaceb2e0071ce160d153047f2eac1aca8e"><td class="memSeparator" colspan="2"> </td></tr> <tr class="memitem:ga58d712b16c0c6668059f509386d1e55b"><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__Mail.html#ga58d712b16c0c6668059f509386d1e55b">osMailQDef</a>(name, queue_sz, type)</td></tr> <tr class="memdesc:ga58d712b16c0c6668059f509386d1e55b"><td class="mdescLeft"> </td><td class="mdescRight">Create a Mail Queue Definition. <a href="#ga58d712b16c0c6668059f509386d1e55b">More...</a><br/></td></tr> <tr class="separator:ga58d712b16c0c6668059f509386d1e55b"><td class="memSeparator" colspan="2"> </td></tr> <tr class="memitem:gad2deeb66d51ade54e63d8f87ff2ec9d2"><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__Mail.html#gad2deeb66d51ade54e63d8f87ff2ec9d2">osMailQ</a>(name)   &os_mailQ_def_##name</td></tr> <tr class="memdesc:gad2deeb66d51ade54e63d8f87ff2ec9d2"><td class="mdescLeft"> </td><td class="mdescRight">Access a Mail Queue Definition. <a href="#gad2deeb66d51ade54e63d8f87ff2ec9d2">More...</a><br/></td></tr> <tr class="separator:gad2deeb66d51ade54e63d8f87ff2ec9d2"><td class="memSeparator" colspan="2"> </td></tr> </table><table class="memberdecls"> <tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="func-members"></a> Functions</h2></td></tr> <tr class="memitem:gaa177e7fe5820dd70d8c9e46ded131174"><td class="memItemLeft" align="right" valign="top"><a class="el" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__Mail.html#gaa177e7fe5820dd70d8c9e46ded131174">osMailCreate</a> (const <a class="el" href="structosMailQDef__t.html">osMailQDef_t</a> *queue_def, <a class="el" href="cmsis__os_8h.html#adfeb153a84a81309e2d958268197617f">osThreadId</a> thread_id)</td></tr> <tr class="memdesc:gaa177e7fe5820dd70d8c9e46ded131174"><td class="mdescLeft"> </td><td class="mdescRight">Create and Initialize mail queue. <a href="#gaa177e7fe5820dd70d8c9e46ded131174">More...</a><br/></td></tr> <tr class="separator:gaa177e7fe5820dd70d8c9e46ded131174"><td class="memSeparator" colspan="2"> </td></tr> <tr class="memitem:gadf5ce811bd6a56e617e902a1db6c2194"><td class="memItemLeft" align="right" valign="top">void * </td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__Mail.html#gadf5ce811bd6a56e617e902a1db6c2194">osMailAlloc</a> (<a class="el" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> queue_id, uint32_t millisec)</td></tr> <tr class="memdesc:gadf5ce811bd6a56e617e902a1db6c2194"><td class="mdescLeft"> </td><td class="mdescRight">Allocate a memory block from a mail. <a href="#gadf5ce811bd6a56e617e902a1db6c2194">More...</a><br/></td></tr> <tr class="separator:gadf5ce811bd6a56e617e902a1db6c2194"><td class="memSeparator" colspan="2"> </td></tr> <tr class="memitem:ga8fde74f6fe5b9e88f75cc5eb8f2124fd"><td class="memItemLeft" align="right" valign="top">void * </td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__Mail.html#ga8fde74f6fe5b9e88f75cc5eb8f2124fd">osMailCAlloc</a> (<a class="el" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> queue_id, uint32_t millisec)</td></tr> <tr class="memdesc:ga8fde74f6fe5b9e88f75cc5eb8f2124fd"><td class="mdescLeft"> </td><td class="mdescRight">Allocate a memory block from a mail and set memory block to zero. <a href="#ga8fde74f6fe5b9e88f75cc5eb8f2124fd">More...</a><br/></td></tr> <tr class="separator:ga8fde74f6fe5b9e88f75cc5eb8f2124fd"><td class="memSeparator" colspan="2"> </td></tr> <tr class="memitem:ga485ef6f81854ebda8ffbce4832181e02"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__CMSIS__RTOS__Status.html#gae2e091fefc4c767117727bd5aba4d99e">osStatus</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__Mail.html#ga485ef6f81854ebda8ffbce4832181e02">osMailPut</a> (<a class="el" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> queue_id, void *mail)</td></tr> <tr class="memdesc:ga485ef6f81854ebda8ffbce4832181e02"><td class="mdescLeft"> </td><td class="mdescRight">Put a mail to a queue. <a href="#ga485ef6f81854ebda8ffbce4832181e02">More...</a><br/></td></tr> <tr class="separator:ga485ef6f81854ebda8ffbce4832181e02"><td class="memSeparator" colspan="2"> </td></tr> <tr class="memitem:gac6ad7e6e7d6c4a80e60da22c57a42ccd"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__CMSIS__RTOS__Definitions.html#structosEvent">osEvent</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__Mail.html#gac6ad7e6e7d6c4a80e60da22c57a42ccd">osMailGet</a> (<a class="el" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> queue_id, uint32_t millisec)</td></tr> <tr class="memdesc:gac6ad7e6e7d6c4a80e60da22c57a42ccd"><td class="mdescLeft"> </td><td class="mdescRight">Get a mail from a queue. <a href="#gac6ad7e6e7d6c4a80e60da22c57a42ccd">More...</a><br/></td></tr> <tr class="separator:gac6ad7e6e7d6c4a80e60da22c57a42ccd"><td class="memSeparator" colspan="2"> </td></tr> <tr class="memitem:ga27c1060cf21393f96b4fd1ed1c0167cc"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__CMSIS__RTOS__Status.html#gae2e091fefc4c767117727bd5aba4d99e">osStatus</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__CMSIS__RTOS__Mail.html#ga27c1060cf21393f96b4fd1ed1c0167cc">osMailFree</a> (<a class="el" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> queue_id, void *mail)</td></tr> <tr class="memdesc:ga27c1060cf21393f96b4fd1ed1c0167cc"><td class="mdescLeft"> </td><td class="mdescRight">Free a memory block from a mail. <a href="#ga27c1060cf21393f96b4fd1ed1c0167cc">More...</a><br/></td></tr> <tr class="separator:ga27c1060cf21393f96b4fd1ed1c0167cc"><td class="memSeparator" colspan="2"> </td></tr> </table> <a name="details" id="details"></a><h2 class="groupheader">Description</h2> <p>A <b>mail</b> <b>queue</b> resembles a <a class="el" href="group__CMSIS__RTOS__Message.html">Message Queue</a>, but the data that is being transferred consists of memory blocks that need to be allocated (before putting data in) and freed (after taking data out). The mail queue uses a <a class="el" href="group__CMSIS__RTOS__PoolMgmt.html">Memory Pool</a> to create formatted memory blocks and passes pointers to these blocks in a message queue. This allows the data to stay in an allocated memory block while only a pointer is moved between the separate threads. This is an advantage over <a class="el" href="group__CMSIS__RTOS__Message.html">messages</a> that can transfer only a 32-bit value or a pointer. Using the mail queue functions, you can control, send, receive, or wait for mail.</p> <div class="image"> <img src="MailQueue.png" alt="MailQueue.png"/> <div class="caption"> CMSIS-RTOS Mail Queue</div></div> <h2>Working with Mail Queues </h2> <p>Follow these steps to create and use a mail queue:</p> <ol type="1"> <li>Declare a data structure that combines a number of elements: <div class="fragment"><div class="line"><span class="keyword">typedef</span> <span class="keyword">struct </span>{</div> <div class="line"> uint32_t length;</div> <div class="line"> uint32_t width;</div> <div class="line"> uint32_t height;</div> <div class="line"> uint32_t weight;</div> <div class="line">} properties_t;</div> </div><!-- fragment --></li> <li>Declare a mail queue made up of these objects: <div class="fragment"><div class="line"><a class="code" href="group__CMSIS__RTOS__Mail.html#ga58d712b16c0c6668059f509386d1e55b">osMailQDef</a> (object_pool_q, 10, properties_t); <span class="comment">// Declare mail queue</span></div> <div class="line"><a class="code" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> (object_pool_q_id); <span class="comment">// Mail queue ID</span></div> </div><!-- fragment --></li> <li>Then, create the mail pool in a thread: <div class="fragment"><div class="line">object_pool_q_id = <a class="code" href="group__CMSIS__RTOS__Mail.html#gaa177e7fe5820dd70d8c9e46ded131174">osMailCreate</a>(<a class="code" href="group__CMSIS__RTOS__Mail.html#gad2deeb66d51ade54e63d8f87ff2ec9d2">osMailQ</a>(object_pool_q), NULL);</div> </div><!-- fragment --></li> <li>Allocate the mail queue within a thread and fill it with data: <div class="fragment"><div class="line">properties_t *object_data;</div> <div class="line"> object_data = (properties_t *) <a class="code" href="group__CMSIS__RTOS__Mail.html#gadf5ce811bd6a56e617e902a1db6c2194">osMailAlloc</a>(object_pool_q_id, <a class="code" href="cmsis__os_8h.html#a9eb9a7a797a42e4b55eb171ecc609ddb">osWaitForever</a>);</div> <div class="line"> </div> <div class="line">object_data->length = 100;</div> <div class="line">object_data->width = 10;</div> <div class="line">object_data->height = 23;</div> <div class="line">object_data->weight = 1000;</div> </div><!-- fragment --></li> <li>Pass the pointer to the mail queue to another thread: <div class="fragment"><div class="line"><a class="code" href="group__CMSIS__RTOS__Mail.html#ga485ef6f81854ebda8ffbce4832181e02">osMailPut</a>(object_pool_q_id, object_data);</div> </div><!-- fragment --></li> <li>Access the data in another thread: <div class="fragment"><div class="line"><a class="code" href="group__CMSIS__RTOS__Definitions.html#structosEvent">osEvent</a> <span class="keyword">event</span> = <a class="code" href="group__CMSIS__RTOS__Mail.html#gac6ad7e6e7d6c4a80e60da22c57a42ccd">osMailGet</a>(properties_q_id, <a class="code" href="cmsis__os_8h.html#a9eb9a7a797a42e4b55eb171ecc609ddb">osWaitForever</a>);</div> <div class="line">properties_t *received = (properties_t *)event.value.p; <span class="comment">// ".p" indicates that the message is a pointer</span></div> <div class="line">my_length(received->length);</div> </div><!-- fragment --></li> <li>Once the data has been used, the memory block must be freed so that the memory pool can be reused <div class="fragment"><div class="line"><a class="code" href="group__CMSIS__RTOS__Mail.html#ga27c1060cf21393f96b4fd1ed1c0167cc">osMailFree</a>(object_pool_q_id, received);</div> </div><!-- fragment --> </li> </ol> <h2 class="groupheader">Macro Definition Documentation</h2> <a class="anchor" id="gaceb2e0071ce160d153047f2eac1aca8e"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">#define osFeature_MailQ   1</td> </tr> </table> </div><div class="memdoc"> <p>A CMSIS-RTOS implementation may support mail queues.</p> <ul> <li>When <a class="el" href="group__CMSIS__RTOS__Mail.html#gaceb2e0071ce160d153047f2eac1aca8e">osFeature_MailQ</a> is 1 mail queues are supported.</li> <li>When <a class="el" href="group__CMSIS__RTOS__Mail.html#gaceb2e0071ce160d153047f2eac1aca8e">osFeature_MailQ</a> is 0 no mail queues are supported.</li> </ul> <p><a class="el" href="rtxImplementation.html">CMSIS-RTOS RTX</a> Setting: <b>osFeature_MailQ</b> is 1 </p> </div> </div> <a class="anchor" id="gad2deeb66d51ade54e63d8f87ff2ec9d2"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">#define osMailQ</td> <td>(</td> <td class="paramtype"> </td> <td class="paramname">name</td><td>)</td> <td>   &os_mailQ_def_##name</td> </tr> </table> </div><div class="memdoc"> <p>Access to the mail queue definition for the function <a class="el" href="group__CMSIS__RTOS__Mail.html#gaa177e7fe5820dd70d8c9e46ded131174">osMailCreate</a>.</p> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramname">name</td><td>name of the queue </td></tr> </table> </dd> </dl> <dl class="section note"><dt>Note</dt><dd>CAN BE CHANGED: The parameter to <b>osMailQ</b> shall be consistent but the macro body is implementation specific in every CMSIS-RTOS. </dd></dl> </div> </div> <a class="anchor" id="ga58d712b16c0c6668059f509386d1e55b"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">#define osMailQDef</td> <td>(</td> <td class="paramtype"> </td> <td class="paramname">name, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"> </td> <td class="paramname">queue_sz, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"> </td> <td class="paramname">type </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div><div class="memdoc"> <p>Define the attributes of a mail queue that can by the function <a class="el" href="group__CMSIS__RTOS__Mail.html#gaa177e7fe5820dd70d8c9e46ded131174">osMailCreate</a> using <a class="el" href="group__CMSIS__RTOS__Mail.html#gad2deeb66d51ade54e63d8f87ff2ec9d2">osMailQ</a>.</p> <dl class="section note"><dt>Note</dt><dd>The parameter <em>thread</em> registers the receiving thread for a mail and is needed for the general <a class="el" href="technicalData.html#osWait">osWait</a> function to deliver the mail.</dd></dl> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramname">name</td><td>name of the queue </td></tr> <tr><td class="paramname">queue_sz</td><td>maximum number of messages in queue </td></tr> <tr><td class="paramname">type</td><td>data type of a single message element </td></tr> </table> </dd> </dl> <dl class="section note"><dt>Note</dt><dd>CAN BE CHANGED: The parameter to <b>osMailQDef</b> shall be consistent but the macro body is implementation specific in every CMSIS-RTOS. </dd></dl> </div> </div> <h2 class="groupheader">Function Documentation</h2> <a class="anchor" id="gadf5ce811bd6a56e617e902a1db6c2194"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">void * osMailAlloc </td> <td>(</td> <td class="paramtype"><a class="el" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> </td> <td class="paramname"><em>queue_id</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">uint32_t </td> <td class="paramname"><em>millisec</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div><div class="memdoc"> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramdir">[in]</td><td class="paramname">queue_id</td><td>mail queue ID obtained with <a class="el" href="group__CMSIS__RTOS__Mail.html#gaa177e7fe5820dd70d8c9e46ded131174">osMailCreate</a>. </td></tr> <tr><td class="paramdir">[in]</td><td class="paramname">millisec</td><td><a class="el" href="functionOverview.html#CMSIS_RTOS_TimeOutValue">Timout Value</a> or 0 in case of no time-out </td></tr> </table> </dd> </dl> <dl class="section return"><dt>Returns</dt><dd>pointer to memory block that can be filled with mail or NULL in case of error. </dd></dl> <dl class="section note"><dt>Note</dt><dd>MUST REMAIN UNCHANGED: <b>osMailAlloc</b> shall be consistent in every CMSIS-RTOS.</dd></dl> <p>Allocate a memory block from the mail queue that is filled with the mail information.</p> <p>The argument <em>queue_id</em> specifies a mail queue identifier that is obtain with <a class="el" href="group__CMSIS__RTOS__Mail.html#gaa177e7fe5820dd70d8c9e46ded131174">osMailCreate</a>.</p> <p>The argument <em>millisec</em> specifies how long the system waits for a mail slot to become available. While the system waits the tread calling this function is put into the state <b>WAITING</b>. The <em>millisec</em> timeout can have the following values:</p> <ul> <li>when <em>millisec</em> is 0, the function returns instantly.</li> <li>when <em>millisec</em> is set to <b>osWaitForever</b> the function will wait for an infinite time until a mail slot can be allocated.</li> <li>all other values specify a time in millisecond for a timeout.</li> </ul> <dl class="section note"><dt>Note</dt><dd>The parameter <em>millisec</em> must be 0 for using this function in an ISR. </dd> <dd> <a class="el" href="functionOverview.html#CMSIS_RTOS_ISR_Calls">Interrupt Service Routines</a> can call this function.</dd></dl> <p>A NULL pointer is returned when no memory slot can be obtained or <em>queue</em> specifies an illegal parameter. </p> </div> </div> <a class="anchor" id="ga8fde74f6fe5b9e88f75cc5eb8f2124fd"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">void * osMailCAlloc </td> <td>(</td> <td class="paramtype"><a class="el" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> </td> <td class="paramname"><em>queue_id</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">uint32_t </td> <td class="paramname"><em>millisec</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div><div class="memdoc"> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramdir">[in]</td><td class="paramname">queue_id</td><td>mail queue ID obtained with <a class="el" href="group__CMSIS__RTOS__Mail.html#gaa177e7fe5820dd70d8c9e46ded131174">osMailCreate</a>. </td></tr> <tr><td class="paramdir">[in]</td><td class="paramname">millisec</td><td><a class="el" href="functionOverview.html#CMSIS_RTOS_TimeOutValue">Timout Value</a> or 0 in case of no time-out </td></tr> </table> </dd> </dl> <dl class="section return"><dt>Returns</dt><dd>pointer to memory block that can be filled with mail or NULL in case of error. </dd></dl> <dl class="section note"><dt>Note</dt><dd>MUST REMAIN UNCHANGED: <b>osMailCAlloc</b> shall be consistent in every CMSIS-RTOS.</dd></dl> <p>Allocate a memory block from the mail queue that is filled with the mail information. The memory block returned is cleared.</p> <p>The argument <em>queue_id</em> specifies a mail queue identifier that is obtain with <a class="el" href="group__CMSIS__RTOS__Mail.html#gaa177e7fe5820dd70d8c9e46ded131174">osMailCreate</a>.</p> <p>The argument <em>millisec</em> specifies how long the system waits for a mail slot to become available. While the system waits the thread that is calling this function is put into the state <b>WAITING</b>. The <em>millisec</em> timeout can have the following values:</p> <ul> <li>when <em>millisec</em> is 0, the function returns instantly.</li> <li>when <em>millisec</em> is set to <b>osWaitForever</b> the function will wait for an infinite time until a mail slot can be allocated.</li> <li>all other values specify a time in millisecond for a timeout.</li> </ul> <dl class="section note"><dt>Note</dt><dd>The parameter <em>millisec</em> must be 0 for using this function in an ISR. </dd> <dd> <a class="el" href="functionOverview.html#CMSIS_RTOS_ISR_Calls">Interrupt Service Routines</a> can call this function.</dd></dl> <p>A NULL pointer is returned when no memory block can be obtained or <em>queue</em> specifies an illegal parameter. </p> </div> </div> <a class="anchor" id="gaa177e7fe5820dd70d8c9e46ded131174"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname"><a class="el" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> osMailCreate </td> <td>(</td> <td class="paramtype">const <a class="el" href="structosMailQDef__t.html">osMailQDef_t</a> * </td> <td class="paramname"><em>queue_def</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype"><a class="el" href="cmsis__os_8h.html#adfeb153a84a81309e2d958268197617f">osThreadId</a> </td> <td class="paramname"><em>thread_id</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div><div class="memdoc"> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramdir">[in]</td><td class="paramname">queue_def</td><td>reference to the mail queue definition obtain with <a class="el" href="group__CMSIS__RTOS__Mail.html#gad2deeb66d51ade54e63d8f87ff2ec9d2">osMailQ</a> </td></tr> <tr><td class="paramdir">[in]</td><td class="paramname">thread_id</td><td>thread ID (obtained by <a class="el" href="group__CMSIS__RTOS__ThreadMgmt.html#gac59b5713cb083702dce759c73fd90dff">osThreadCreate</a> or <a class="el" href="group__CMSIS__RTOS__ThreadMgmt.html#gab1df2a28925862ef8f9cf4e1c995c5a7">osThreadGetId</a>) or NULL. </td></tr> </table> </dd> </dl> <dl class="section return"><dt>Returns</dt><dd>mail queue ID for reference by other functions or NULL in case of error. </dd></dl> <dl class="section note"><dt>Note</dt><dd>MUST REMAIN UNCHANGED: <b>osMailCreate</b> shall be consistent in every CMSIS-RTOS.</dd></dl> <p>Initialize and create a mail queue.</p> <dl class="section note"><dt>Note</dt><dd>Cannot be called from <a class="el" href="functionOverview.html#CMSIS_RTOS_ISR_Calls">Interrupt Service Routines</a>.</dd></dl> <p><b>Code Example</b> </p> <div class="fragment"><div class="line"><span class="preprocessor">#include "<a class="code" href="cmsis__os_8h.html">cmsis_os.h</a>"</span></div> <div class="line"> </div> <div class="line"><a class="code" href="cmsis__os_8h.html#adfeb153a84a81309e2d958268197617f">osThreadId</a> tid_thread1; <span class="comment">// ID for thread 1</span></div> <div class="line"><a class="code" href="cmsis__os_8h.html#adfeb153a84a81309e2d958268197617f">osThreadId</a> tid_thread2; <span class="comment">// ID for thread 2</span></div> <div class="line"> </div> <div class="line"><span class="keyword">typedef</span> <span class="keyword">struct </span>{ <span class="comment">// Mail object structure</span></div> <div class="line"> <span class="keywordtype">float</span> voltage; <span class="comment">// AD result of measured voltage</span></div> <div class="line"> <span class="keywordtype">float</span> current; <span class="comment">// AD result of measured current</span></div> <div class="line"> <span class="keywordtype">int</span> counter; <span class="comment">// A counter value</span></div> <div class="line">} T_MEAS;</div> <div class="line"> </div> <div class="line"><a class="code" href="group__CMSIS__RTOS__Mail.html#ga58d712b16c0c6668059f509386d1e55b">osMailQDef</a>(mail, 16, T_MEAS); <span class="comment">// Define mail queue</span></div> <div class="line"><a class="code" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> mail;</div> <div class="line"> </div> <div class="line"><span class="keywordtype">void</span> send_thread (<span class="keywordtype">void</span> <span class="keyword">const</span> *argument); <span class="comment">// forward reference</span></div> <div class="line"><span class="keywordtype">void</span> recv_thread (<span class="keywordtype">void</span> <span class="keyword">const</span> *argument);</div> <div class="line"> </div> <div class="line"><a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gaee93d929beb350f16e5cc7fa602e229f">osThreadDef</a>(send_thread, <a class="code" href="cmsis__os_8h.html#ga7f2b42f1983b9107775ec2a1c69a849aa45a2895ad30c79fb97de18cac7cc19f1">osPriorityNormal</a>, 1, 0); <span class="comment">// thread definitions</span></div> <div class="line"><a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gaee93d929beb350f16e5cc7fa602e229f">osThreadDef</a>(recv_thread, <a class="code" href="cmsis__os_8h.html#ga7f2b42f1983b9107775ec2a1c69a849aa45a2895ad30c79fb97de18cac7cc19f1">osPriorityNormal</a>, 1, 2000);</div> <div class="line"> </div> <div class="line"><span class="comment">//</span></div> <div class="line"><span class="comment">// Thread 1: Send thread</span></div> <div class="line"><span class="comment">//</span></div> <div class="line"><span class="keywordtype">void</span> send_thread (<span class="keywordtype">void</span> <span class="keyword">const</span> *argument) {</div> <div class="line"> T_MEAS *mptr;</div> <div class="line"> </div> <div class="line"> mptr = <a class="code" href="group__CMSIS__RTOS__Mail.html#gadf5ce811bd6a56e617e902a1db6c2194">osMailAlloc</a>(mail, <a class="code" href="cmsis__os_8h.html#a9eb9a7a797a42e4b55eb171ecc609ddb">osWaitForever</a>); <span class="comment">// Allocate memory</span></div> <div class="line"> mptr->voltage = 223.72; <span class="comment">// Set the mail content</span></div> <div class="line"> mptr->current = 17.54;</div> <div class="line"> mptr->counter = 120786;</div> <div class="line"> <a class="code" href="group__CMSIS__RTOS__Mail.html#ga485ef6f81854ebda8ffbce4832181e02">osMailPut</a>(mail, mptr); <span class="comment">// Send Mail</span></div> <div class="line"> <a class="code" href="group__CMSIS__RTOS__Wait.html#ga02e19d5e723bfb06ba9324d625162255">osDelay</a>(100);</div> <div class="line"> </div> <div class="line"> mptr = <a class="code" href="group__CMSIS__RTOS__Mail.html#gadf5ce811bd6a56e617e902a1db6c2194">osMailAlloc</a>(mail, <a class="code" href="cmsis__os_8h.html#a9eb9a7a797a42e4b55eb171ecc609ddb">osWaitForever</a>); <span class="comment">// Allocate memory</span></div> <div class="line"> mptr->voltage = 227.23; <span class="comment">// Prepare 2nd mail</span></div> <div class="line"> mptr->current = 12.41;</div> <div class="line"> mptr->counter = 170823;</div> <div class="line"> <a class="code" href="group__CMSIS__RTOS__Mail.html#ga485ef6f81854ebda8ffbce4832181e02">osMailPut</a>(mail, mptr); <span class="comment">// Send Mail</span></div> <div class="line"> <a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gaf13a667493c5d629a90c13e113b99233">osThreadYield</a>(); <span class="comment">// Cooperative multitasking</span></div> <div class="line"> <span class="comment">// We are done here, exit this thread</span></div> <div class="line">}</div> <div class="line"> </div> <div class="line"><span class="comment">//</span></div> <div class="line"><span class="comment">// Thread 2: Receive thread</span></div> <div class="line"><span class="comment">//</span></div> <div class="line"><span class="keywordtype">void</span> recv_thread (<span class="keywordtype">void</span> <span class="keyword">const</span> *argument) {</div> <div class="line"> T_MEAS *rptr;</div> <div class="line"> <a class="code" href="group__CMSIS__RTOS__Definitions.html#structosEvent">osEvent</a> evt;</div> <div class="line"> </div> <div class="line"> <span class="keywordflow">for</span> (;;) {</div> <div class="line"> evt = <a class="code" href="group__CMSIS__RTOS__Mail.html#gac6ad7e6e7d6c4a80e60da22c57a42ccd">osMailGet</a>(mail, <a class="code" href="cmsis__os_8h.html#a9eb9a7a797a42e4b55eb171ecc609ddb">osWaitForever</a>); <span class="comment">// wait for mail</span></div> <div class="line"> <span class="keywordflow">if</span> (evt.<a class="code" href="group__CMSIS__RTOS__Definitions.html#ad477a289f1f03ac45407b64268d707d3">status</a> == <a class="code" href="group__CMSIS__RTOS__Status.html#gae2e091fefc4c767117727bd5aba4d99ea15b12e42b42b53f35fb8a2724ad02926">osEventMail</a>) {</div> <div class="line"> rptr = evt.<a class="code" href="group__CMSIS__RTOS__Definitions.html#a0b9f8fd3645f01d8cb09cae82add2d7f">value</a>.<a class="code" href="group__CMSIS__RTOS__Definitions.html#a117104b82864d3b23ec174af6d392709">p</a>;</div> <div class="line"> printf (<span class="stringliteral">"\nVoltage: %.2f V\n"</span>, rptr->voltage);</div> <div class="line"> printf (<span class="stringliteral">"Current: %.2f A\n"</span>, rptr->current);</div> <div class="line"> printf (<span class="stringliteral">"Number of cycles: %d\n"</span>, rptr->counter);</div> <div class="line"> <a class="code" href="group__CMSIS__RTOS__Mail.html#ga27c1060cf21393f96b4fd1ed1c0167cc">osMailFree</a>(mail, rptr); <span class="comment">// free memory allocated for mail</span></div> <div class="line"> }</div> <div class="line"> }</div> <div class="line">}</div> <div class="line"> </div> <div class="line"><span class="keywordtype">void</span> StartApplication (<span class="keywordtype">void</span>) {</div> <div class="line"> mail = <a class="code" href="group__CMSIS__RTOS__Mail.html#gaa177e7fe5820dd70d8c9e46ded131174">osMailCreate</a>(<a class="code" href="group__CMSIS__RTOS__Mail.html#gad2deeb66d51ade54e63d8f87ff2ec9d2">osMailQ</a>(mail), NULL); <span class="comment">// create mail queue</span></div> <div class="line"> </div> <div class="line"> tid_thread1 = <a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gac59b5713cb083702dce759c73fd90dff">osThreadCreate</a>(<a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gaf0c7c6b5e09f8be198312144b5c9e453">osThread</a>(send_thread), NULL);</div> <div class="line"> tid_thread2 = <a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gac59b5713cb083702dce759c73fd90dff">osThreadCreate</a>(<a class="code" href="group__CMSIS__RTOS__ThreadMgmt.html#gaf0c7c6b5e09f8be198312144b5c9e453">osThread</a>(recv_thread), NULL);</div> <div class="line"> :</div> <div class="line">}</div> </div><!-- fragment --> </div> </div> <a class="anchor" id="ga27c1060cf21393f96b4fd1ed1c0167cc"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname"><a class="el" href="group__CMSIS__RTOS__Status.html#gae2e091fefc4c767117727bd5aba4d99e">osStatus</a> osMailFree </td> <td>(</td> <td class="paramtype"><a class="el" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> </td> <td class="paramname"><em>queue_id</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">void * </td> <td class="paramname"><em>mail</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div><div class="memdoc"> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramdir">[in]</td><td class="paramname">queue_id</td><td>mail queue ID obtained with <a class="el" href="group__CMSIS__RTOS__Mail.html#gaa177e7fe5820dd70d8c9e46ded131174">osMailCreate</a>. </td></tr> <tr><td class="paramdir">[in]</td><td class="paramname">mail</td><td>pointer to the memory block that was obtained with <a class="el" href="group__CMSIS__RTOS__Mail.html#gac6ad7e6e7d6c4a80e60da22c57a42ccd">osMailGet</a>. </td></tr> </table> </dd> </dl> <dl class="section return"><dt>Returns</dt><dd>status code that indicates the execution status of the function. </dd></dl> <dl class="section note"><dt>Note</dt><dd>MUST REMAIN UNCHANGED: <b>osMailFree</b> shall be consistent in every CMSIS-RTOS.</dd></dl> <p>Free the memory block specified by <em>mail</em> and return it to the mail queue.</p> <dl class="section note"><dt>Note</dt><dd><a class="el" href="functionOverview.html#CMSIS_RTOS_ISR_Calls">Interrupt Service Routines</a> can call this function.</dd></dl> <p><b><a class="el" href="group__CMSIS__RTOS__Status.html">Status and Error Codes</a></b><br/> </p> <ul> <li><em>osOK:</em> the <em>mail</em> block is released.</li> <li><em>osErrorValue:</em> <em>mail</em> block does not belong to the mail queue pool.</li> <li><em>osErrorParameter:</em> the value to the parameter <em>queue_id</em> is incorrect. </li> </ul> </div> </div> <a class="anchor" id="gac6ad7e6e7d6c4a80e60da22c57a42ccd"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname"><a class="el" href="group__CMSIS__RTOS__Definitions.html#structosEvent">osEvent</a> osMailGet </td> <td>(</td> <td class="paramtype"><a class="el" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> </td> <td class="paramname"><em>queue_id</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">uint32_t </td> <td class="paramname"><em>millisec</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div><div class="memdoc"> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramdir">[in]</td><td class="paramname">queue_id</td><td>mail queue ID obtained with <a class="el" href="group__CMSIS__RTOS__Mail.html#gaa177e7fe5820dd70d8c9e46ded131174">osMailCreate</a>. </td></tr> <tr><td class="paramdir">[in]</td><td class="paramname">millisec</td><td><a class="el" href="functionOverview.html#CMSIS_RTOS_TimeOutValue">Timout Value</a> or 0 in case of no time-out </td></tr> </table> </dd> </dl> <dl class="section return"><dt>Returns</dt><dd>event that contains mail information or error code. </dd></dl> <dl class="section note"><dt>Note</dt><dd>MUST REMAIN UNCHANGED: <b>osMailGet</b> shall be consistent in every CMSIS-RTOS.</dd></dl> <p>Suspend the execution of the current <b>RUNNING</b> thread until a mail arrives. When a mail is already in the queue, the function returns instantly with the mail information.</p> <p>The argument <em>millisec</em> specifies how long the system waits for a mail to arrive. While the system waits the thread that is calling this function is put into the state <b>WAITING</b>. The <em>millisec</em> timeout can have the following values:</p> <ul> <li>when <em>millisec</em> is 0, the function returns instantly.</li> <li>when <em>millisec</em> is set to <b>osWaitForever</b> the function will wait for an infinite time until a mail arrives.</li> <li>all other values specify a time in millisecond for a timeout.</li> </ul> <dl class="section note"><dt>Note</dt><dd>The parameter <em>millisec</em> must be 0 for using this function in an ISR. </dd> <dd> <a class="el" href="functionOverview.html#CMSIS_RTOS_ISR_Calls">Interrupt Service Routines</a> can call this function.</dd></dl> <p><b><a class="el" href="group__CMSIS__RTOS__Status.html">Status and Error Codes</a></b><br/> </p> <ul> <li><em>osOK:</em> no mail is available in the queue and no timeout was specified</li> <li><em>osEventTimeout:</em> no mail has arrived during the given timeout period.</li> <li><em>osEventMail:</em> mail received, <em>value.p</em> contains the pointer to mail content.</li> <li><em>osErrorParameter:</em> a parameter is invalid or outside of a permitted range. </li> </ul> </div> </div> <a class="anchor" id="ga485ef6f81854ebda8ffbce4832181e02"></a> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname"><a class="el" href="group__CMSIS__RTOS__Status.html#gae2e091fefc4c767117727bd5aba4d99e">osStatus</a> osMailPut </td> <td>(</td> <td class="paramtype"><a class="el" href="cmsis__os_8h.html#a1dac049fb7725a8af8b26c71cbb373b5">osMailQId</a> </td> <td class="paramname"><em>queue_id</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">void * </td> <td class="paramname"><em>mail</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div><div class="memdoc"> <dl class="params"><dt>Parameters</dt><dd> <table class="params"> <tr><td class="paramdir">[in]</td><td class="paramname">queue_id</td><td>mail queue ID obtained with <a class="el" href="group__CMSIS__RTOS__Mail.html#gaa177e7fe5820dd70d8c9e46ded131174">osMailCreate</a>. </td></tr> <tr><td class="paramdir">[in]</td><td class="paramname">mail</td><td>memory block previously allocated with <a class="el" href="group__CMSIS__RTOS__Mail.html#gadf5ce811bd6a56e617e902a1db6c2194">osMailAlloc</a> or <a class="el" href="group__CMSIS__RTOS__Mail.html#ga8fde74f6fe5b9e88f75cc5eb8f2124fd">osMailCAlloc</a>. </td></tr> </table> </dd> </dl> <dl class="section return"><dt>Returns</dt><dd>status code that indicates the execution status of the function. </dd></dl> <dl class="section note"><dt>Note</dt><dd>MUST REMAIN UNCHANGED: <b>osMailPut</b> shall be consistent in every CMSIS-RTOS.</dd></dl> <p>Put the memory block specified with <em>mail</em> into the mail queue specified by <em>queue</em>.</p> <p><b><a class="el" href="group__CMSIS__RTOS__Status.html">Status and Error Codes</a></b><br/> </p> <ul> <li><em>osOK:</em> the message is put into the queue.</li> <li><em>osErrorValue:</em> <em>mail</em> was previously not allocated as memory slot.</li> <li><em>osErrorParameter:</em> a parameter is invalid or outside of a permitted range. </li> </ul> </div> </div> </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 on Wed Feb 8 2017 10:21:02 for CMSIS-RTOS by ARM Ltd. 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