144 lines
4.9 KiB
HTML
144 lines
4.9 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html><head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<meta name="Copyright" content="Copyright (c) 2006 by IBM Corporation">
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<title>if_indextoname--Map an Interface index to its Corresponding Name API</title>
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- Change History: -->
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<!-- YYMMDD USERID Change description -->
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<!-- Created for V5R4 by Tim Mullenbach -->
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<link rel="stylesheet" type="text/css" href="../rzahg/ic.css">
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</head>
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<body>
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<a name="Top_Of_Page"></a>
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<h2><img src="delta.gif" ALT="Start of change">if_indextoname()--Map an Interface index to its Corresponding Name</h2>
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<div class="box" style="width: 80%;">
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<br>
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<br>
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Syntax
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<pre>
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#include <net/if.h>
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char *if_indextoname(unsigned int ifindex, char *ifname);
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</pre>
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Service Program Name: QSOSRV2
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<br>
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Default Public Authority: *USE
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<br>
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Threadsafe: Yes<br><br>
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</div>
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<p>The <strong><em>if_indextoname()</em></strong> function
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places the name of the interface with index <em>ifindex</em> into the buffer
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pointed at by <em>ifname</em>. When this function is called, <em>ifname</em>
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must point to a buffer of at least IFNAMSIZ bytes.</p>
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<br>
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<h3><a name="Header_2">Parameters</a></h3>
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<dl>
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<dt><strong><em>ifindex</em></strong> (Input) </dt>
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<dd>Interface index.<br><br></dd>
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<dt><strong><em>ifname</em></strong> (Output) </dt>
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<dd>Pointer to a null terminated string containing the interface (line
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description) name returned.<br><br></dd>
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</dl>
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<br>
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<h3><a name="Header_3">Authorities</a></h3>
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<p>
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No authorization is required.</p>
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<br>
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<h3><a name="Header_4">Return Value</a></h3>
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<p><em>if_indextoname()</em> returns a pointer to a null terminated string containing the
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interface (line description) name. Possible values are:</p>
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<ul>
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<li>The value supplied in <em>ifname</em>. (successful)</li>
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<li>NULL (unsuccessful)</li>
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</ul>
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<br>
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<h3><a name="Header_5">Error Conditions</a></h3>
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<p>When <em>if_indextoname()</em> fails, <em>errno</em> can be set to one of the following:</p>
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<dl compact>
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<dt><em>[ENXIO]</em></dt>
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<dd>The specified interface index does not exist.</dd>
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<dt><em>[EFAULT]</em></dt>
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<dd>The buffer pointed to by <em>ifname</em> can not be accessed.</dd>
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</dl>
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<br>
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<h3>Usage Notes</h3>
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<ol>
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<li>
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<p>The interface (line description) name stored at <em>ifname</em> will be returned in
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the default coded character set identifier (CCSID) currently in effect for the
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job. If this is not a single byte CCSID, then storage greater than IFNAMSIZ (16) bytes
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may be needed. 22 bytes is large enough for all CCSIDs.</p></li>
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<li><p>It is important to note that the term "Interface" refers to the name on a line
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description (i.e. a physical interface) for this API. Other parts of the
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operating system, when refering to "Interface," mean an IP address.
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</p></li>
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</ol>
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<br>
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<h3><a name="Header_8">Related Information</a></h3>
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<ul>
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<li><a href="gsocko.htm">getsockopt()</a>--Retrieve Information about Socket Options</li>
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<li><a href="if_freenameindex.htm">if_freenameindex()</a>--Free Memory Allocated by
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if_nameindex()</li>
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<li><a href="if_nameindex.htm">if_nameindex()</a>--Return All Interface Names and Indexes</li>
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<li><a href="if_nametoindex.htm">if_nametoindex()</a>--Map an Interface Name to its
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Corresponding Index</li>
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<li><a href="ssocko.htm">setsockopt()</a>--Set Socket Options</li>
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</ul>
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<br>
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<h3><a name="Header_9">Example</a></h3>
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<p>See <a href="../apiref/aboutapis.htm#codedisclaimer">Code disclaimer information</a>
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for information pertaining to code examples.</p>
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<p>The following example shows how <strong>if_indextoname()</strong> is used:</p>
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<pre>
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#include <net/if.h>
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#include <sys/types.h>
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#include <errno.h>
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ref
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void main()
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{
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char interfaceName[IFNAMSIZ];
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<strong>char *interface = if_indextoname(1, &interfaceName); /* retrieve the name of interface 1 */</strong>
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if (interface == NULL)
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{
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printf("if_indextoname() failed with errno = %d %s \n",
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errno,strerror(errno));
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return;
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}
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...
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}</pre>
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<img src="deltaend.gif" ALT="End of change">
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<br>
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<hr>
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API introduced: V5R4
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<hr>
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