smart-green-house/rtt-uart-nb/rt-thread/components/net/uip/doc/html/a00156.html

238 lines
13 KiB
HTML
Raw Permalink Normal View History

2023-10-28 18:00:47 +08:00
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1">
<title>uIP 1.0: Timer library</title>
<link href="doxygen.css" rel="stylesheet" type="text/css">
<link href="tabs.css" rel="stylesheet" type="text/css">
</head><body>
<!-- Generated by Doxygen 1.4.6 -->
<div class="tabs">
<ul>
<li><a href="main.html"><span>Main&nbsp;Page</span></a></li>
<li><a href="modules.html"><span>Modules</span></a></li>
<li><a href="classes.html"><span>Data&nbsp;Structures</span></a></li>
<li><a href="files.html"><span>Files</span></a></li>
<li><a href="examples.html"><span>Examples</span></a></li>
</ul></div>
<h1>Timer library</h1><hr><a name="_details"></a><h2>Detailed Description</h2>
The timer library provides functions for setting, resetting and restarting timers, and for checking if a timer has expired.
<p>
An application must "manually" check if its timers have expired; this is not done automatically.<p>
A timer is declared as a <code>struct</code> <code>timer</code> and all access to the timer is made by a pointer to the declared timer.<p>
<dl compact><dt><b>Note:</b></dt><dd>The timer library uses the <a class="el" href="a00157.html">Clock library</a> to measure time. Intervals should be specified in the format used by the clock library. </dd></dl>
<p>
<table border="0" cellpadding="0" cellspacing="0">
<tr><td></td></tr>
<tr><td colspan="2"><br><h2>Files</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">file &nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="a00130.html">timer.h</a></td></tr>
<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Timer library header file. <br></td></tr>
<p>
<tr><td class="memItemLeft" nowrap align="right" valign="top">file &nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="a00129.html">timer.c</a></td></tr>
<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Timer library implementation. <br></td></tr>
<p>
<tr><td colspan="2"><br><h2>Data Structures</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">struct &nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="a00087.html">timer</a></td></tr>
<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">A timer. <a href="a00087.html#_details">More...</a><br></td></tr>
<tr><td colspan="2"><br><h2>Functions</h2></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="a00156.html#g6614d96fdfcd95c95ec6e6f63071ff51">timer_set</a> (struct <a class="el" href="a00087.html">timer</a> *t, clock_time_t interval)</td></tr>
<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Set a timer. <a href="#g6614d96fdfcd95c95ec6e6f63071ff51"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="a00156.html#gedaf3e48c2b04229b85455fb948468d6">timer_reset</a> (struct <a class="el" href="a00087.html">timer</a> *t)</td></tr>
<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Reset the timer with the same interval. <a href="#gedaf3e48c2b04229b85455fb948468d6"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">void&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="a00156.html#gcb807bd57e5489b386b876af5c1f163a">timer_restart</a> (struct <a class="el" href="a00087.html">timer</a> *t)</td></tr>
<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Restart the timer from the current point in time. <a href="#gcb807bd57e5489b386b876af5c1f163a"></a><br></td></tr>
<tr><td class="memItemLeft" nowrap align="right" valign="top">int&nbsp;</td><td class="memItemRight" valign="bottom"><a class="el" href="a00156.html#g6d71dececfce707c668e6257aad5906e">timer_expired</a> (struct <a class="el" href="a00087.html">timer</a> *t)</td></tr>
<tr><td class="mdescLeft">&nbsp;</td><td class="mdescRight">Check if a timer has expired. <a href="#g6d71dececfce707c668e6257aad5906e"></a><br></td></tr>
</table>
<hr><h2>Function Documentation</h2>
<a class="anchor" name="g6d71dececfce707c668e6257aad5906e"></a><!-- doxytag: member="timer.h::timer_expired" ref="g6d71dececfce707c668e6257aad5906e" args="(struct timer *t)" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top">int timer_expired </td>
<td class="md" valign="top">(&nbsp;</td>
<td class="md" nowrap valign="top">struct <a class="el" href="a00087.html">timer</a> *&nbsp;</td>
<td class="mdname1" valign="top" nowrap> <em>t</em> </td>
<td class="md" valign="top">&nbsp;)&nbsp;</td>
<td class="md" nowrap></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
&nbsp;
</td>
<td>
<p>
Check if a timer has expired.
<p>
This function tests if a timer has expired and returns true or false depending on its status.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>t</em>&nbsp;</td><td>A pointer to the timer</td></tr>
</table>
</dl>
<dl compact><dt><b>Returns:</b></dt><dd>Non-zero if the timer has expired, zero otherwise. </dd></dl>
<dl compact><dt><b>Examples: </b></dt><dd>
<a class="el" href="a00048.html#a26">dhcpc.c</a>, <a class="el" href="a00042.html#a77">example-mainloop-with-arp.c</a>, and <a class="el" href="a00043.html#a94">example-mainloop-without-arp.c</a>.</dl>
<p>
Definition at line <a class="el" href="a00195.html#l00121">121</a> of file <a class="el" href="a00195.html">timer.c</a>.
<p>
References <a class="el" href="a00157.html#ge5b7160f2e653725ba5e2024c3cb7bff">clock_time()</a>, <a class="el" href="a00196.html#l00076">interval</a>, and <a class="el" href="a00196.html#l00075">start</a>. </td>
</tr>
</table>
<a class="anchor" name="gedaf3e48c2b04229b85455fb948468d6"></a><!-- doxytag: member="timer.h::timer_reset" ref="gedaf3e48c2b04229b85455fb948468d6" args="(struct timer *t)" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top">void timer_reset </td>
<td class="md" valign="top">(&nbsp;</td>
<td class="md" nowrap valign="top">struct <a class="el" href="a00087.html">timer</a> *&nbsp;</td>
<td class="mdname1" valign="top" nowrap> <em>t</em> </td>
<td class="md" valign="top">&nbsp;)&nbsp;</td>
<td class="md" nowrap></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
&nbsp;
</td>
<td>
<p>
Reset the timer with the same interval.
<p>
This function resets the timer with the same interval that was given to the <a class="el" href="a00156.html#g6614d96fdfcd95c95ec6e6f63071ff51">timer_set()</a> function. The start point of the interval is the exact time that the timer last expired. Therefore, this function will cause the timer to be stable over time, unlike the timer_rester() function.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>t</em>&nbsp;</td><td>A pointer to the timer.</td></tr>
</table>
</dl>
<dl compact><dt><b>See also:</b></dt><dd><a class="el" href="a00156.html#gcb807bd57e5489b386b876af5c1f163a">timer_restart()</a> </dd></dl>
<dl compact><dt><b>Examples: </b></dt><dd>
<a class="el" href="a00042.html#a78">example-mainloop-with-arp.c</a>, and <a class="el" href="a00043.html#a95">example-mainloop-without-arp.c</a>.</dl>
<p>
Definition at line <a class="el" href="a00195.html#l00084">84</a> of file <a class="el" href="a00195.html">timer.c</a>.
<p>
References <a class="el" href="a00196.html#l00076">interval</a>, and <a class="el" href="a00196.html#l00075">start</a>. </td>
</tr>
</table>
<a class="anchor" name="gcb807bd57e5489b386b876af5c1f163a"></a><!-- doxytag: member="timer.h::timer_restart" ref="gcb807bd57e5489b386b876af5c1f163a" args="(struct timer *t)" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top">void timer_restart </td>
<td class="md" valign="top">(&nbsp;</td>
<td class="md" nowrap valign="top">struct <a class="el" href="a00087.html">timer</a> *&nbsp;</td>
<td class="mdname1" valign="top" nowrap> <em>t</em> </td>
<td class="md" valign="top">&nbsp;)&nbsp;</td>
<td class="md" nowrap></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
&nbsp;
</td>
<td>
<p>
Restart the timer from the current point in time.
<p>
This function restarts a timer with the same interval that was given to the <a class="el" href="a00156.html#g6614d96fdfcd95c95ec6e6f63071ff51">timer_set()</a> function. The timer will start at the current time.<p>
<dl compact><dt><b>Note:</b></dt><dd>A periodic timer will drift if this function is used to reset it. For preioric timers, use the <a class="el" href="a00156.html#gedaf3e48c2b04229b85455fb948468d6">timer_reset()</a> function instead.</dd></dl>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>t</em>&nbsp;</td><td>A pointer to the timer.</td></tr>
</table>
</dl>
<dl compact><dt><b>See also:</b></dt><dd><a class="el" href="a00156.html#gedaf3e48c2b04229b85455fb948468d6">timer_reset()</a> </dd></dl>
<p>
Definition at line <a class="el" href="a00195.html#l00104">104</a> of file <a class="el" href="a00195.html">timer.c</a>.
<p>
References <a class="el" href="a00157.html#ge5b7160f2e653725ba5e2024c3cb7bff">clock_time()</a>, and <a class="el" href="a00196.html#l00075">start</a>. </td>
</tr>
</table>
<a class="anchor" name="g6614d96fdfcd95c95ec6e6f63071ff51"></a><!-- doxytag: member="timer.h::timer_set" ref="g6614d96fdfcd95c95ec6e6f63071ff51" args="(struct timer *t, clock_time_t interval)" --><p>
<table class="mdTable" cellpadding="2" cellspacing="0">
<tr>
<td class="mdRow">
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td class="md" nowrap valign="top">void timer_set </td>
<td class="md" valign="top">(&nbsp;</td>
<td class="md" nowrap valign="top">struct <a class="el" href="a00087.html">timer</a> *&nbsp;</td>
<td class="mdname" nowrap> <em>t</em>, </td>
</tr>
<tr>
<td class="md" nowrap align="right"></td>
<td class="md"></td>
<td class="md" nowrap>clock_time_t&nbsp;</td>
<td class="mdname" nowrap> <em>interval</em></td>
</tr>
<tr>
<td class="md"></td>
<td class="md">)&nbsp;</td>
<td class="md" colspan="2"></td>
</tr>
</table>
</td>
</tr>
</table>
<table cellspacing="5" cellpadding="0" border="0">
<tr>
<td>
&nbsp;
</td>
<td>
<p>
Set a timer.
<p>
This function is used to set a timer for a time sometime in the future. The function <a class="el" href="a00156.html#g6d71dececfce707c668e6257aad5906e">timer_expired()</a> will evaluate to true after the timer has expired.<p>
<dl compact><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>t</em>&nbsp;</td><td>A pointer to the timer </td></tr>
<tr><td valign="top"></td><td valign="top"><em>interval</em>&nbsp;</td><td>The interval before the timer expires. </td></tr>
</table>
</dl>
<dl compact><dt><b>Examples: </b></dt><dd>
<a class="el" href="a00048.html#a22">dhcpc.c</a>, <a class="el" href="a00042.html#a62">example-mainloop-with-arp.c</a>, and <a class="el" href="a00043.html#a86">example-mainloop-without-arp.c</a>.</dl>
<p>
Definition at line <a class="el" href="a00195.html#l00064">64</a> of file <a class="el" href="a00195.html">timer.c</a>.
<p>
References <a class="el" href="a00157.html#ge5b7160f2e653725ba5e2024c3cb7bff">clock_time()</a>, <a class="el" href="a00196.html#l00076">interval</a>, and <a class="el" href="a00196.html#l00075">start</a>. </td>
</tr>
</table>
<hr size="1"><address style="align: right;"><small>Generated on Mon Jun 12 10:23:02 2006 for uIP 1.0 by&nbsp;
<a href="http://www.doxygen.org/index.html">
<img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.4.6 </small></address>
</body>
</html>