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 span.virtual_style 22 { 23 font-size : 8pt; 24 color : white; 25 font-weight : bold; 26 background : #0a0; 27 border-left : solid 1px #0f0; 28 border-top : solid 1px #0f0; 29 border-right : solid 1px #060; 30 border-bottom : solid 1px #060; 31 padding-left : 2px; 32 padding-right : 2px; 33 } 34 span.protected_style 35 { 36 font-size : 8pt; 37 color : white; 38 font-weight : bold; 39 background : #444; 40 border-left : solid 1px #ccc; 41 border-top : solid 1px #ccc; 42 border-right : solid 1px #222; 43 border-bottom : solid 1px #222; 44 padding-left : 2px; 45 padding-right : 2px; 46 } 47 --></style> 48<title>nn::os::Semaphore</title> 49 </head> 50 <body> 51<h1><CODE><a href="../../../nn/Overview.html">nn</a>::<a href="../../../nn/os/Overview.html">os</a>::Semaphore</CODE> Class</h1> 52 <div class="section"> 53<b>Header file: </b>nn/os.h</div> 54<h2>Syntax</h2> 55 <div class="section"> 56<pre class="definition">class Semaphore : public <a href="../../../nn/os/InterruptEvent/Overview.html">nn::os::InterruptEvent</a></pre> 57 </div> 58<h2>Description</h2> 59 <div class="section"> 60<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> 61 <a name="function" id="function"> 62<h2>Member Functions</h2> 63 <div class="section"> 64 <table class="members"> 65 <tr> 66 <td width="100"> </td> 67 <th> 68<a href="../../../nn/os/Semaphore/Semaphore.html"><CODE>Semaphore</CODE></a> 69 </th> 70<td>Constructs and initializes a semaphore.</td> 71 </tr> 72 <tr> 73 <td width="100"> </td> 74 <th> 75<a href="../../../nn/os/Semaphore/Initialize.html"><CODE>Initialize</CODE></a> 76 </th> 77<td>Initializes a semaphore that has already been constructed.</td> 78 </tr> 79 <tr> 80 <td width="100"> </td> 81 <th> 82<a href="../../../nn/os/Semaphore/TryInitialize.html"><CODE>TryInitialize</CODE></a> 83 </th> 84<td>Tries to initialize a semaphore that has already been constructed.</td> 85 </tr> 86 <tr> 87 <td width="100"> </td> 88 <th> 89<a href="../../../nn/os/Semaphore/Finalize.html"><CODE>Finalize</CODE></a> 90 </th> 91<td>Destroys a semaphore.</td> 92 </tr> 93 <tr> 94 <td width="100"> </td> 95 <th> 96<a href="../../../nn/os/Semaphore/~Semaphore.html"><CODE>~Semaphore</CODE></a> 97 </th> 98<td>Destructor.</td> 99 </tr> 100 <tr> 101 <td width="100"> </td> 102 <th> 103<a href="../../../nn/os/Semaphore/Release.html"><CODE>Release</CODE></a> 104 </th> 105<td>Releases a semaphore (performs a "V operation") and increases the counter value.</td> 106 </tr> 107 <tr> 108 <td width="100"> </td> 109 <th> 110<a href="../../../nn/os/Semaphore/Acquire.html"><CODE>Acquire</CODE></a> 111 </th> 112<td>Acquires a semaphore (performs a "P operation") and decrements the counter value.</td> 113 </tr> 114 <tr> 115 <td width="100"> </td> 116 <th> 117<a href="../../../nn/os/Semaphore/TryAcquire.html"><CODE>TryAcquire</CODE></a> 118 </th> 119<td>Tries to acquire a semaphore (perform a "P operation").</td> 120 </tr> </table> 121 </div> 122 </a> 123<h2>Class Hierarchy</h2> 124 <div class="section"> 125<p class="hierarchy"><span>ADLFireWall::NonCopyable</span><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 /> <a href="../../../nn/os/InterruptEvent/Overview.html">nn::os::InterruptEvent</a><br /> <b>nn::os::Semaphore</b> 126 </p> 127 </div> 128<h2>Revision History</h2> 129 <div class="section"> 130 <dl class="history"> 131 <dt>2010/01/07</dt> 132<dd>Initial version.<br /> 133 </dd> 134 </dl> 135 </div> 136 <hr><p>CONFIDENTIAL</p></body> 137</html> 138