1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>websocket::seed_prng</title> 5<link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../index.html" title="Chapter 1. Boost.Beast"> 8<link rel="up" href="../ref.html" title="This Page Intentionally Left Blank 2/2"> 9<link rel="prev" href="boost__beast__websocket__is_upgrade.html" title="websocket::is_upgrade"> 10<link rel="next" href="boost__beast__websocket__teardown.html" title="websocket::teardown"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="boost__beast__websocket__is_upgrade.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../ref.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="boost__beast__websocket__teardown.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="beast.ref.boost__beast__websocket__seed_prng"></a><a class="link" href="boost__beast__websocket__seed_prng.html" title="websocket::seed_prng">websocket::seed_prng</a> 28</h4></div></div></div> 29<p> 30 <a class="indexterm" name="idm46057502270144"></a> 31 </p> 32<p> 33 Manually provide a one-time seed to initialize the PRNG. 34 </p> 35<h5> 36<a name="beast.ref.boost__beast__websocket__seed_prng.h0"></a> 37 <span class="phrase"><a name="beast.ref.boost__beast__websocket__seed_prng.synopsis"></a></span><a class="link" href="boost__beast__websocket__seed_prng.html#beast.ref.boost__beast__websocket__seed_prng.synopsis">Synopsis</a> 38 </h5> 39<p> 40 Defined in header <code class="literal"><<a href="../../../../../../boost/beast/websocket/stream.hpp" target="_top">boost/beast/websocket/stream.hpp</a>></code> 41 </p> 42<pre class="programlisting"><span class="keyword">void</span> 43<span class="identifier">seed_prng</span><span class="special">(</span> 44 <span class="identifier">std</span><span class="special">::</span><span class="identifier">seed_seq</span><span class="special">&</span> <span class="identifier">ss</span><span class="special">);</span> 45</pre> 46<h5> 47<a name="beast.ref.boost__beast__websocket__seed_prng.h1"></a> 48 <span class="phrase"><a name="beast.ref.boost__beast__websocket__seed_prng.description"></a></span><a class="link" href="boost__beast__websocket__seed_prng.html#beast.ref.boost__beast__websocket__seed_prng.description">Description</a> 49 </h5> 50<p> 51 This function invokes the specified seed sequence to produce a seed suitable 52 for use with the pseudo-random number generator used to create masks and 53 perform WebSocket protocol handshakes. If a seed is not manually provided, 54 the implementation will perform a one-time seed generation using <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">random_device</span></code>. 55 This function may be used when the application runs in an environment where 56 the random device is unreliable or does not provide sufficient entropy. 57 </p> 58<h5> 59<a name="beast.ref.boost__beast__websocket__seed_prng.h2"></a> 60 <span class="phrase"><a name="beast.ref.boost__beast__websocket__seed_prng.preconditions"></a></span><a class="link" href="boost__beast__websocket__seed_prng.html#beast.ref.boost__beast__websocket__seed_prng.preconditions">Preconditions</a> 61 </h5> 62<p> 63 This function may not be called after any websocket <a class="link" href="boost__beast__websocket__stream.html" title="websocket::stream"><code class="computeroutput"><span class="identifier">stream</span></code></a> objects have been constructed. 64 </p> 65<h5> 66<a name="beast.ref.boost__beast__websocket__seed_prng.h3"></a> 67 <span class="phrase"><a name="beast.ref.boost__beast__websocket__seed_prng.parameters"></a></span><a class="link" href="boost__beast__websocket__seed_prng.html#beast.ref.boost__beast__websocket__seed_prng.parameters">Parameters</a> 68 </h5> 69<div class="informaltable"><table class="table"> 70<colgroup> 71<col> 72<col> 73</colgroup> 74<thead><tr> 75<th> 76 <p> 77 Name 78 </p> 79 </th> 80<th> 81 <p> 82 Description 83 </p> 84 </th> 85</tr></thead> 86<tbody><tr> 87<td> 88 <p> 89 <code class="computeroutput"><span class="identifier">ss</span></code> 90 </p> 91 </td> 92<td> 93 <p> 94 A reference to a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">seed_seq</span></code> 95 which will be used to seed the pseudo-random number generator. 96 The seed sequence should have at least 256 bits of entropy. 97 </p> 98 </td> 99</tr></tbody> 100</table></div> 101<h5> 102<a name="beast.ref.boost__beast__websocket__seed_prng.h4"></a> 103 <span class="phrase"><a name="beast.ref.boost__beast__websocket__seed_prng.see_also"></a></span><a class="link" href="boost__beast__websocket__seed_prng.html#beast.ref.boost__beast__websocket__seed_prng.see_also">See Also</a> 104 </h5> 105<p> 106 <a class="link" href="boost__beast__websocket__stream/secure_prng.html" title="websocket::stream::secure_prng"><code class="computeroutput"><span class="identifier">stream</span><span class="special">::</span><span class="identifier">secure_prng</span></code></a> 107 </p> 108</div> 109<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 110<td align="left"></td> 111<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Vinnie 112 Falco<p> 113 Distributed under the Boost Software License, Version 1.0. (See accompanying 114 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 115 </p> 116</div></td> 117</tr></table> 118<hr> 119<div class="spirit-nav"> 120<a accesskey="p" href="boost__beast__websocket__is_upgrade.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../ref.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="boost__beast__websocket__teardown.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 121</div> 122</body> 123</html> 124
