1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 2<html xml:lang="en-US" lang="en-US" xmlns="http://www.w3.org/1999/xhtml"> 3 <head> 4 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 5 <meta http-equiv="Content-Style-Type" content="text/css" /> 6 <link rel="stylesheet" href="../../../css/manpage.css" type="text/css" /> 7 <style type="text/css"><!-- 8 span.static_style 9 { 10 font-size : 8pt; 11 color : white; 12 font-weight : bold; 13 background : #44f; 14 border-left : solid 1px #aaf; 15 border-top : solid 1px #aaf; 16 border-right : solid 1px #00c; 17 border-bottom : solid 1px #00c; 18 padding-left : 2px; 19 padding-right : 2px; 20 } 21 22 span.virtual_style 23 { 24 font-size : 8pt; 25 color : white; 26 font-weight : bold; 27 background : #0a0; 28 border-left : solid 1px #0f0; 29 border-top : solid 1px #0f0; 30 border-right : solid 1px #060; 31 border-bottom : solid 1px #060; 32 padding-left : 2px; 33 padding-right : 2px; 34 } 35 36 span.protected_style 37 { 38 font-size : 8pt; 39 color : white; 40 font-weight : bold; 41 background : #444; 42 border-left : solid 1px #ccc; 43 border-top : solid 1px #ccc; 44 border-right : solid 1px #222; 45 border-bottom : solid 1px #222; 46 padding-left : 2px; 47 padding-right : 2px; 48 } 49 --></style> 50<title>nn::os::Semaphore</title> 51 </head> 52 <body> 53<h1><CODE><a href="../../../nn/Overview.html">nn</a>::<a href="../../../nn/os/Overview.html">os</a>::Semaphore</CODE> Class</h1> 54 <div class="section"> 55<b>Header file: </b>nn/os.h</div> 56<h2>Syntax</h2> 57 <div class="section"> 58 <pre class="definition">class Semaphore : public nn::os::InterruptEvent</pre> 59 </div> 60<h2>Description</h2> 61 <div class="section"> 62<p>Class for handling semaphores. Semaphores are synchronization objects that have counters.</p><p>Generally, use the <CODE><a href="../../../nn/os/LightSemaphore/Overview.html">nn::os::LightSemaphore</a></CODE> class instead of <CODE><a href="../../../nn/os/Semaphore/Overview.html">nn::os::Semaphore</a></CODE>. The <CODE><a href="../../../nn/os/LightSemaphore/Overview.html">nn::os::LightSemaphore</a></CODE> class is better than the <CODE><a href="../../../nn/os/Semaphore/Overview.html">nn::os::Semaphore</a></CODE> class in most respects, except that it cannot wait for multiple synchronization objects.</p><p>The semaphore <CODE>Wait</CODE> operation first waits for the semaphore counter to become greater than zero, then increments the semaphore counter by one. <CODE>Wait</CODE> operations are not released while the semaphore counter is zero.</p><p>Call <a href="../../../nn/os/Semaphore/Release.html"><CODE>Release</CODE></a> in order to increment a semaphore's counter.</p><p>See the reference for the <a href="../../../nn/os/Event/Overview.html"><CODE>nn::os::Event</CODE></a> class for more information about synchronization objects.</p><p>You can create up to 8 <a href="../../../nn/os/Semaphore/Overview.html"><CODE>Semaphore</CODE></a> objects. Note also that different functions might use up resources that count against this limit.</p><!-- write here --></div> 63 <a name="function" id="function"> 64<h2>Member Functions</h2> 65 <div class="section"> 66 <table class="members"> 67 <tr> 68 <td width="100"> </td> 69 <th> 70<a href="../../../nn/os/Semaphore/Semaphore.html"><CODE>Semaphore</CODE></a> 71 </th> 72<td>Constructs and initializes a semaphore.</td> 73 </tr> 74 <tr> 75 <td width="100"> </td> 76 <th> 77<a href="../../../nn/os/Semaphore/Initialize.html"><CODE>Initialize</CODE></a> 78 </th> 79<td>Initializes a semaphore that has already been constructed.</td> 80 </tr> 81 <tr> 82 <td width="100"> </td> 83 <th> 84<a href="../../../nn/os/Semaphore/TryInitialize.html"><CODE>TryInitialize</CODE></a> 85 </th> 86<td>Tries to initialize a semaphore that has already been constructed.</td> 87 </tr> 88 <tr> 89 <td width="100"> </td> 90 <th> 91<a href="../../../nn/os/Semaphore/Finalize.html"><CODE>Finalize</CODE></a> 92 </th> 93<td>Destroys a semaphore.</td> 94 </tr> 95 <tr> 96 <td width="100"> </td> 97 <th> 98<a href="../../../nn/os/Semaphore/~Semaphore.html"><CODE>~Semaphore</CODE></a> 99 </th> 100<td>Destructor.</td> 101 </tr> 102 <tr> 103 <td width="100"> </td> 104 <th> 105<a href="../../../nn/os/Semaphore/Release.html"><CODE>Release</CODE></a> 106 </th> 107<td>Releases a semaphore (performs a "V operation") and increases the counter value.</td> 108 </tr> 109 <tr> 110 <td width="100"> </td> 111 <th> 112<a href="../../../nn/os/Semaphore/Acquire.html"><CODE>Acquire</CODE></a> 113 </th> 114<td>Acquires a semaphore (performs a "P operation") and decrements the counter value.</td> 115 </tr> 116 <tr> 117 <td width="100"> </td> 118 <th> 119<a href="../../../nn/os/Semaphore/TryAcquire.html"><CODE>TryAcquire</CODE></a> 120 </th> 121<td>Tries to acquire a semaphore (perform a "P operation").</td> 122 </tr> 123 <tr> 124 <td width="100"> 125<span class="static_style" title="static">S</span> </td> 126 <th> 127<a href="../../../nn/os/Semaphore/GetCurrentCount.html"><CODE>GetCurrentCount</CODE></a> 128 </th> 129<td>Gets the number of <CODE><a href="../../../nn/os/Semaphore/Overview.html">Semaphore</a></CODE> objects that are currently being used.</td> 130 </tr> 131 <tr> 132 <td width="100"> 133<span class="static_style" title="static">S</span> </td> 134 <th> 135<a href="../../../nn/os/Semaphore/GetMaxCount.html"><CODE>GetMaxCount</CODE></a> 136 </th> 137<td>Gets the maximum number of <CODE><a href="../../../nn/os/Semaphore/Overview.html">Semaphore</a></CODE> objects that can be used simultaneously.</td> 138 </tr> </table> 139 </div> 140 </a> 141<h2>Class Hierarchy</h2> 142 <div class="section"> 143<p class="hierarchy"><a href="../../../nn/util/NonCopyable/Overview.html">nn::util::NonCopyable</a><br /> <a href="../../../nn/os/HandleObject/Overview.html">nn::os::HandleObject</a><br /> <a href="../../../nn/os/WaitObject/Overview.html">nn::os::WaitObject</a><br /> <span>nn::os::InterruptEvent</span><br /> <b>nn::os::Semaphore</b> 144 </p> 145 </div> 146<h2>Revision History</h2> 147 <div class="section"> 148 <dl class="history"> 149 <dt>2010/01/07</dt> 150<dd>Initial version.<br /> 151 </dd> 152 </dl> 153 </div> 154 <hr><p>CONFIDENTIAL</p></body> 155</html>