1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>sockfd_lookup</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="Linux Networking and Network Devices APIs"><link rel="up" href="ch01s02.html" title="Socket Buffer Functions"><link rel="prev" href="API-sk-eat-skb.html" title="sk_eat_skb"><link rel="next" href="API-sock-release.html" title="sock_release"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span class="phrase">sockfd_lookup</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-sk-eat-skb.html">Prev</a>&#160;</td><th width="60%" align="center">Socket Buffer Functions</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-sock-release.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-sockfd-lookup"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sockfd_lookup &#8212; 
2  Go from a file number to its socket slot
3 </p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">struct socket * <b class="fsfunc">sockfd_lookup </b>(</code></td><td>int <var class="pdparam">fd</var>, </td></tr><tr><td>&#160;</td><td>int * <var class="pdparam">err</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1095949684"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>fd</code></em></span></dt><dd><p>
4     file handle
5    </p></dd><dt><span class="term"><em class="parameter"><code>err</code></em></span></dt><dd><p>
6     pointer to an error code return
7    </p></dd></dl></div></div><div class="refsect1"><a name="idp1095952212"></a><h2>Description</h2><p>
8   The file handle passed in is locked and the socket it is bound
9   too is returned. If an error occurs the err pointer is overwritten
10   with a negative errno code and NULL is returned. The function checks
11   for both invalid handles and passing a handle which is not a socket.
12   </p><p>
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14   On a success the socket object pointer is returned.
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