860 lines
25 KiB
HTML
860 lines
25 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<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>sendmsg()--Send a Message Over a Socket</title>
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<!-- Begin Header Records ========================================== -->
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<!-- Unix8 SCRIPT J converted by B2H R4.1 (346) (CMS) by V2KEA304 -->
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<!-- at RCHVMW2 on 17 Feb 1999 at 11:05:09 -->
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<!-- End Header Records -->
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<!-- Edited by Kersten Feb 02 -->
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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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<!-- Java sync-link -->
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<script type="text/javascript" language="Javascript" src="../rzahg/synch.js">
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</script>
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<h2>sendmsg()--Send a Message Over a Socket</h2>
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<div class="box" style="width: 60%;">
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<br>
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BSD 4.3 Syntax<br>
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<pre>
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#include <sys/types.h>
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#include <sys/socket.h>
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int sendmsg(int <em>socket_descriptor</em>,
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struct msghdr *<em>message_structure</em>,
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int <em>flags</em>)
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</pre>
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<br>
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Service Program Name: QSOSRV1<br>
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<!-- iddvc RMBR -->
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<br>
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Default Public Authority: *USE<br>
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<!-- iddvc RMBR -->
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<br>
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Threadsafe: Yes<br>
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<!-- iddvc RMBR -->
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<br>
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</div>
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<br>
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<div class="box" style="width: 60%;">
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<br>
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<a href="_xopen_source.htm">UNIX 98 Compatible Syntax</a><br>
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<pre>
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#define _XOPEN_SOURCE 520
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#include <sys/socket.h>
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ssize_t sendmsg(int <em>socket_descriptor</em>,
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const struct msghdr *<em>message_structure</em>,
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int <em>flags</em>)
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</pre>
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<br>
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Service Program Name: QSOSRV1<br>
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<!-- iddvc RMBR -->
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<br>
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Default Public Authority: *USE<br>
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<!-- iddvc RMBR -->
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<br>
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Threadsafe: Yes<br>
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<!-- iddvc RMBR -->
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<br>
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</div>
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<p>The <em>sendmsg()</em> function is used to send data or descriptors or
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ancillary data or a combination of these through a connected or unconnected socket.</p>
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<p>There are two versions of
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the API, as shown above. The base i5/OS API uses BSD 4.3 structures and
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syntax. The other uses syntax and structures compatible with the UNIX 98
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programming interface specifications. You can select the UNIX 98 compatible
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interface with the <a href="_xopen_source.htm">_XOPEN_SOURCE</a> macro.</p>
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<br>
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<h3>Parameters</h3>
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<dl>
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<dt><strong>socket_descriptor</strong></dt>
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<dd>(Input) The socket descriptor that is to be written to.<br>
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<br>
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</dd>
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<dt><strong>message_structure</strong></dt>
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<dd>(I/O) The pointer to the message structure that contains the following:
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<ul>
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<li>The address to which the message is to be sent<br>
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<br>
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</li>
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<li>The vector array in which the data to be sent is stored<br>
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<br>
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</li>
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<li>The ancillary data; or an access
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rights list in which the descriptors to be sent are stored.</li>
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</ul>
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The structure pointed to by the <em>message_structure</em> parameter is defined
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in <strong><sys/socket.h></strong>.
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<p>The BSD 4.3 structure is:</p>
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<pre>
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struct msghdr {
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caddr_t msg_name;
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int msg_namelen;
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struct iovec *msg_iov;
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int msg_iovlen;
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caddr_t msg_accrights;
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int msg_accrightslen;
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};
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</pre>
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<p>The BSD 4.4/UNIX 98 compatible structure is:</p>
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<pre>
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struct msghdr {
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void *msg_name;
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socklen_t msg_namelen;
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struct iovec *msg_iov;
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int msg_iovlen;
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void *msg_control; /* Set to NULL if not needed */
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socklen_t msg_controllen; /* Set to 0 if not needed */
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int msg_flags;
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};
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</pre>
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<p>The <em>msg_name</em> and <em>msg_namelen</em> fields contain the address
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and address length to which the message is sent. For further information on the
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structure of socket addresses, see
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<a href="../rzab6/rzab6soxoverview.htm">Sockets Programming</a> in the iSeries
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Information Center. If the <em>msg_name</em> field is set to a NULL pointer,
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the address information is not returned.</p>
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<p>The <em>msg_iov</em> and <em>msg_iovlen</em> fields are for scatter/gather
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I/O.</p>
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<p>The BSD 4.3 structure uses
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the <em>msg_accrights</em> and <em>msg_accrightslen</em> fields to pass
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descriptors. The <em>msg_accrights</em> field is a list of zero or more
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descriptors, and <em>msg_accrightslen</em> is the total length (in bytes) of
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the descriptor list.</p>
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<p>The BSD 4.4/UNIX 98 compatible structure uses the <em>msg_control</em> and
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<em>msg_controllen</em> fields to pass ancillary data. The <em>msg_control</em>
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field is a pointer to ancillary data (of length <em>msg_controllen</em>) with
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the form:</p>
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<pre>
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struct cmsghdr {
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socklen_t cmsg_len; /* # bytes, including this header */
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int cmsg_level; /* originating protocol */
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int cmsg_type; /* protocol-specific type */
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/* followed by unsigned char cmsg_data[]; */
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};
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</pre>
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<p>The <em>cmsg_len</em> field is the total length including this header.
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<em>cmsg_level</em> is the originating protocol. <em>cmsg_type</em> is the
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protocol-specific type. If ancillary data is not being passed,
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the <em>msg_control</em> field must be initalized to NULL and the
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<em>msg_controllen</em> field must be initialized to 0.
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The following tables list the supported ancillary data types when
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using the BSD 4.4/UNIX 98 compatible structures.</p>
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<p><strong><a name="Table_1-1">Ancillary Data Types That Apply to the Socket Layer
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(where <em>cmsg_level</em> is <samp>SOL_SOCKET</samp> ):</a></strong></p>
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<table border cellpadding="5">
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<!-- cols="15 85" -->
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<tr>
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<th align="left" valign="top">cmsg_type</th>
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<th align="left" valign="top">cmsg_data</th>
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</tr>
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<tr>
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<td align="left" valign="top"><samp>SCM_RIGHTS</samp> </td>
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<td align="left" valign="top">The rest of the buffer is a
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list of zero or more descriptors to be sent.
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<p>This ancillary data type is only supported for sockets with an
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address family of AF_UNIX or AF_UNIX_CCSID.</p>
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</td>
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</tr>
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</table>
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<p><strong><a name="Table_1-2">Ancillary Data Types That Apply to the IP Layer
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(where <em>cmsg_level</em> is <samp>IPPROTO_IP</samp>):</a></strong></p>
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<table border cellpadding="5">
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<!-- cols="25 75" -->
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<tr>
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<th align="left" valign="top">cmsg_type</th>
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<th align="left" valign="top">cmsg_data</th>
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</tr>
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<tr>
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<td align="left" valign="top"><samp>IP_QOS_CLASSIFICATION_DATA</samp> </td>
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<td align="left" valign="top">The rest of the buffer is an
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<em>ip_qos_classification_data</em> structure.
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This structure is defined in <strong><netinet/ip.h></strong>.
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For further information on the how this structure should be initialized,
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see <a href="../rzak8/rzak8kickoff.htm">Quality of Service</a> in the
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iSeries Information Center.
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<p>This ancillary data type is only supported for sockets with an
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address family of AF_INET and a type of SOCK_STREAM.</p>
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</td>
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</table>
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<p>Macros are provided for navigating these structures.</p>
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<ul>
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<li><em><samp>CMSG_DATA(cmsg)</samp></em> If the argument is a pointer to a
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<em>cmsghdr</em> structure, this macro returns an unsigned character pointer to
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the data array associated with the <em>cmsghdr</em> structure.</li>
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<li><em><samp>CMSG_NXTHDR(mhdr,cmsg)</samp></em> If the first argument is a
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pointer to a <em>msghdr</em> structure and the second argument is a pointer to
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a <em>cmsghdr</em> structure in the ancillary data, pointed to by the
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msg_control field of that msghdr structure, this macro returns a pointer to the
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next <em>cmsghdr</em> structure, or a null pointer if this structure is the
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last <em>cmsghdr</em> in the ancillary data.</li>
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<li><em><samp>CMSG_FIRSTHDR(mhdr)</samp></em> If the argument is a pointer to a
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<em>msghdr</em> structure, this macro returns a pointer to the first
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<em>cmsghdr</em> structure in the ancillary data associated with this
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<em>msghdr</em> structure, or a null pointer if there is no ancillary data
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associated with the <em>msghdr</em> structure.</li>
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</ul>
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<p>The BSD 4.4/UNIX 98 <em>msg_flags</em> field is ignored for sendmsg().</p>
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</dd>
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<dt><strong>flags</strong></dt>
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<dd>(Input) A flag value that controls the transmission of the data. The
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<em>flags</em> value is either zero, or is obtained by performing an OR
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operation on one or more of the following constants:
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<table cellpadding="5">
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<!-- cols="15 85" -->
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<tr>
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<td align="left" valign="top"><em><samp>MSG_EOR</samp></em></td>
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<td align="left" valign="top">Terminate a record, if supported by the
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protocol.<br>
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<br>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em><samp>MSG_OOB</samp></em></td>
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<td align="left" valign="top">Send data as out-of-band data. Valid only for
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sockets with an address family of <samp>AF_INET</samp> or <samp>AF_INET6</samp>
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and type <samp>SOCK_STREAM</samp>.<br>
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<br>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em><samp>MSG_DONTROUTE</samp></em></td>
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<td align="left" valign="top">Bypass routing. Valid only for sockets with
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address family of <samp>AF_INET</samp>. It is ignored for other address
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families.</td>
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</tr>
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</table>
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</dd>
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</dl>
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<br>
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<h3>Authorities</h3>
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<p>When the address family of the socket identified by the
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<strong><em>socket_descriptor</em></strong> is AF_INET and is running IP over
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SNA, the thread must have retrieve, insert, delete, and update authority to the
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APPC device. When the thread does not have this level of authority, an
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<em>errno</em> of EACCES is returned.</p>
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<br>
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<h3>Return Value</h3>
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<p><em>sendmsg()</em> returns an integer. Possible values are:</p>
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<ul>
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<li>-1 (unsuccessful)<br>
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<br>
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</li>
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<li>n (successful), where n is the number of bytes sent.</li>
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</ul>
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<br>
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<h3>Error Conditions</h3>
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<p>When <em>sendmsg()</em> fails, <em>errno</em> can be set to one of the
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following:</p>
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<table cellpadding="5">
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<!-- cols="20 80" -->
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<tr>
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<td align="left" valign="top"><em>[EACCES]</em></td>
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<td align="left" valign="top">Permission denied.
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<p>The process does not have the appropriate privileges to the destination
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address.</p>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[EADDRNOTAVAIL]</em></td>
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<td align="left" valign="top">Address not available.
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<p>A socket with an address family of <samp>AF_INET</samp> or
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<samp>AF_INET6</samp> is using a connectionless transport
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service, the socket was not bound. The system tried to bind the socket but
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could not because a port was not available.</p>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[EBADF]</em></td>
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<td align="left" valign="top">Descriptor not valid.<br>
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<br>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[ECONNREFUSED]</em></td>
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<td align="left" valign="top">The destination socket refused an attempted
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connect operation.
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<p>This error code can only be returned on sockets that use a connectionless
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transport service.</p>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[EDESTADDRREQ]</em></td>
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<td align="left" valign="top">Operation requires destination address.
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<p>A destination address has not been associated with the socket pointed to by
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the <em>socket_descriptor</em> parameter and a destination address was not set
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in the <em>msghdr</em> structure (pointed to by the <em>message_structure</em>
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parameter). This error code can only be returned on sockets that use a
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connectionless transport service.</p>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[EFAULT]</em></td>
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<td align="left" valign="top">Bad address.
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<p>The system detected an address which was not valid while attempting to
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access the <em>message_structure</em> parameter or a field within the structure
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pointed to by the <em>message_structure</em> parameter.</p>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[EHOSTDOWN]</em></td>
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<td align="left" valign="top">A remote host is not available.
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<p>This error code can only be returned on sockets that use a connectionless
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transport service.</p>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[EHOSTUNREACH]</em></td>
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<td align="left" valign="top">A route to the remote host is not available.
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<p>This error code can only be returned on sockets that use a connectionless
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transport service.</p>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[EINTR]</em></td>
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<td align="left" valign="top">Interrupted function call.<br>
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<br>
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</td>
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</tr>
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<tr>
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<td align="left" valign="top"><em>[EINVAL]</em></td>
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<td align="left" valign="top">Parameter not valid.
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<p>This error code indicates one of the following:</p>
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<ul>
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<li>The <em>msg_iovlen</em> field or the <strong>iov_len</strong> field in a
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<strong>iovec</strong> structure specifies a negative value. The fields are
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contained in the <em>msghdr</em> structure (pointed to by the
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<em>message_structure</em> parameter).<br>
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<br>
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</li>
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<li>The <em>msg_namelen</em> field in the <em>msghdr</em> structure (pointed to
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by the <em>message_structure</em> parameter) specifies a length that is not
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valid for the address family.<br>
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<br>
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</li>
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<li>The <em>msg_accrightslen</em> field in the <em>msghdr</em> structure
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specifies a negative value or is not large enough when <em>msg_accrights</em>
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was specified. <br>
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<br>
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</li>
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<li>The <em>msg_controllen</em> field in the <em>msghdr</em> structure
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specifies a negative value or is not large enough when <em>msg_control</em>
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was specified. <br>
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<br>
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</li>
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<li>The <em>socket_descriptor</em> points to a socket with an address family of
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<samp>AF_UNIX_CCSID</samp>, and the CCSID specified in <em>sunc_qlg</em> in the
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<strong>sockaddr_unc</strong> structure (pointed to by <em>local_address</em>)
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cannot be converted to the current default CCSID for integrated file system
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path names.<br>
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<br>
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</li>
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<li>The <em>socket_descriptor</em> points to a socket with an address family of
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<samp>AF_UNIX_CCSID</samp>, and there was an incomplete character or shift
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state sequence at the end of <em>sunc_path</em> in the
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<strong>sockaddr_unc</strong> structure (pointed to by
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<em>local_address</em>).<br>
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<br>
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</li>
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<li>The <em>socket_descriptor</em> points to a socket with an address family of
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<samp>AF_UNIX_CCSID</samp>, and the <strong>sockaddr_unc</strong> structure
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(pointed to by <em>local_address</em>) was not valid:
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<ul>
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<li>The sunc_format was not set to SO_UNC_DEFAULT or SO_UNC_USE_QLG.<br>
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<br>
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</li>
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<li>The sunc_zero was not initialized to zeros.<br>
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<br>
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</li>
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<li>The sunc_format field was set to SO_UNC_USE_QLG and the sunc_qlg structure
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was not valid:
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<ul>
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<li>The path type was less than 0 or greater than 3.<br>
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<br>
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</li>
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<li>The path length was less than 0 or out of bounds. For example, a
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single-byte path name was greater than 126 bytes or a double-byte path name was
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greater than 252 bytes.<br>
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<br>
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</li>
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<li>A reserved field was not initialized to zeros.</li>
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</ul>
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</li>
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</ul>
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</li>
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</ul>
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<br>
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</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[EIO]</em></td>
|
|
<td align="left" valign="top">Input/output error.<br>
|
|
<br>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[EISCONN]</em></td>
|
|
<td align="left" valign="top">A connection has already been established.
|
|
|
|
<p>A destination address was set, but the socket pointed to by the
|
|
<em>socket_descriptor</em> parameter already has a destination address
|
|
associated with it.</p>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[ELOOP]</em></td>
|
|
<td align="left" valign="top">A loop exists in symbolic links encountered
|
|
during pathname resolution.
|
|
|
|
<p>This error code refers to the destination address, and can only be returned
|
|
by sockets that use the <samp>AF_UNIX</samp> or <samp>AF_UNIX_CCSID</samp>
|
|
address family.</p>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[EMSGSIZE]</em></td>
|
|
<td align="left" valign="top">Message size out of range.
|
|
|
|
<p>This error code indicates one of the following:</p>
|
|
|
|
<ul>
|
|
<li>The data to be sent could not be sent atomically because the total size of
|
|
the data to be sent is too large.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>The <em>msg_iovlen</em> field in the <em>msghdr</em> structure (pointed to
|
|
by the <em>message_structure</em> parameter) specifies a value that is greater
|
|
than [MSG_MAXIOVLEN] (defined in <strong><sys/socket.h></strong>).</li>
|
|
</ul>
|
|
|
|
<br>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[ENAMETOOLONG]</em></td>
|
|
<td align="left" valign="top">File name too long.
|
|
|
|
<p>This error code refers to the destination address, and can only be returned
|
|
by sockets that use the <samp>AF_UNIX</samp> or <samp>AF_UNIX_CCSID</samp>
|
|
address family.</p>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[ENETDOWN]</em></td>
|
|
<td align="left" valign="top">The network is not currently available.
|
|
|
|
<p>This error code can only be returned on sockets that use a connectionless
|
|
transport service.</p>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[ENETUNREACH]</em></td>
|
|
<td align="left" valign="top">Cannot reach the destination network.
|
|
|
|
<p>This error code can only be returned on sockets that use a connectionless
|
|
transport service.</p>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[ENOBUFS]</em></td>
|
|
<td align="left" valign="top">There is not enough buffer space for the
|
|
requested operation.</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[ENOENT]</em></td>
|
|
<td align="left" valign="top">No such file or directory.
|
|
|
|
<p>This error code refers to the destination address, and can only be returned
|
|
by sockets that use the <samp>AF_UNIX</samp> or <samp>AF_UNIX_CCSID</samp>
|
|
address family.</p>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[ENOSYS]</em></td>
|
|
<td align="left" valign="top">Function not implemented.
|
|
|
|
<p>This error code refers to the destination address, and can only be returned
|
|
by sockets that use the <samp>AF_UNIX</samp> or <samp>AF_UNIX_CCSID</samp>
|
|
address family.</p>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[ENOTCONN]</em></td>
|
|
<td align="left" valign="top">Requested operation requires a connection.
|
|
|
|
<p>This error code can only be returned on sockets that use a
|
|
connection-oriented transport service.</p>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[ENOTDIR]</em></td>
|
|
<td align="left" valign="top">Not a directory.
|
|
|
|
<p>This error code refers to the destination address, and can only be returned
|
|
by sockets that use the <samp>AF_UNIX</samp> or <samp>AF_UNIX_CCSID</samp>
|
|
address family.</p>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[ENOTSOCK]</em></td>
|
|
<td align="left" valign="top">The specified descriptor does not reference a
|
|
socket.<br>
|
|
<br>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[EOPNOTSUPP]</em></td>
|
|
<td align="left" valign="top">Operation not supported.
|
|
|
|
<p>This error code indicates one of the following:</p>
|
|
|
|
<ul>
|
|
<li>The <em>flags</em> parameter specifies a value that includes the
|
|
<samp>MSG_OOB</samp> flag, but the <em>socket_descriptor</em> parameter points
|
|
to a connectionless socket.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>The <em>flags</em> parameter specifies a value that includes the
|
|
<samp>MSG_OOB</samp> flag, but the <em>socket_descriptor</em> parameter points
|
|
to a socket that does not have an address family of <samp>AF_INET</samp> or
|
|
<samp>AF_INET6</samp>.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>The <em>msg_accrights</em> and <em>msg_accrightslen</em> (or the
|
|
BSD 4.4/UNIX 98 compatible fields <em>msg_control</em> and
|
|
<em>msg_controllen</em>) were specified and the underlying
|
|
instance represented by the descriptor does not support the passing of access
|
|
rights.</li>
|
|
</ul>
|
|
|
|
<br>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[EPIPE]</em></td>
|
|
<td align="left" valign="top">Broken pipe.<br>
|
|
<br>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[EUNATCH]</em></td>
|
|
<td align="left" valign="top">The protocol required to support the specified
|
|
address family is not available at this time.<br>
|
|
<br>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[EUNKNOWN]</em></td>
|
|
<td align="left" valign="top">Unknown system state.<br>
|
|
<br>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top"><em>[EWOULDBLOCK]</em></td>
|
|
<td align="left" valign="top">Operation would have caused the thread to be
|
|
suspended.</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<br>
|
|
<br>
|
|
<h3>Error Messages</h3>
|
|
|
|
<table width="100%" cellpadding="5">
|
|
<!-- cols="15 85" -->
|
|
<tr>
|
|
<th align="left" valign="top">Message ID</th>
|
|
<th align="left" valign="top">Error Message Text</th>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td width="15%" valign="top">CPE3418 E</td>
|
|
<td width="85%" valign="top">Possible APAR condition or hardware failure.</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">CPF9872 E</td>
|
|
<td align="left" valign="top">Program or service program &1 in library
|
|
&2 ended. Reason code &3.</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td align="left" valign="top">CPFA081 E</td>
|
|
<td align="left" valign="top">Unable to set return value or error code.</td>
|
|
</tr>
|
|
</table>
|
|
|
|
<br>
|
|
<br>
|
|
|
|
|
|
<h3>Usage Notes</h3>
|
|
|
|
<ol>
|
|
<li>The passing of descriptors is only supported over sockets that have an
|
|
address family of <samp>AF_UNIX</samp> or <samp>AF_UNIX_CCSID</samp>. The
|
|
<em>msg_accrightslen</em> and the <em>msg_accrights</em> fields (or the
|
|
BSD 4.4/UNIX 98 compatible fields <em>msg_control</em> and
|
|
<em>msg_controllen</em>) are ignored if the socket has any other
|
|
address family. When you use <em>sendmsg()</em> and <em>recvmsg()</em> to pass
|
|
descriptors, the target job must be running with either of the following:
|
|
|
|
<ul>
|
|
<li>The same user profile as the source job (in essence, passing the descriptor
|
|
to yourself)</li>
|
|
|
|
<li>*ALLOBJ special authority</li>
|
|
</ul>
|
|
|
|
If the target job closes the receiving end of the UNIX domain socket while a
|
|
descriptor is in transit, the descriptor is reclaimed by the system, and the
|
|
resource that it represented is closed. For files and directories, the ability
|
|
to pass descriptors using <em>sendmsg()</em> and <em>recvmsg()</em> is only
|
|
supported for objects in
|
|
Root, QOpenSys, User-defined file systems (UDFS), and Network File System (NFS).
|
|
<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><em>sendmsg()</em> is an atomic operation in that it produces one packet of
|
|
data each time the call is issued on a connectionless socket. For example, a
|
|
<em>sendmsg()</em> to a datagram socket will result in a single datagram.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>A destination address cannot be specified if the socket pointed to by the
|
|
<em>socket_descriptor</em> parameter already has a destination address
|
|
associated with it. To <strong>not</strong> specify an address, users must set
|
|
the <em>msg_name</em> field to NULL or set the <em>msg_namelen</em> field to
|
|
zero. (Not specifying an address by setting the <em>msg_namelen</em> field to
|
|
zero is an IBM extension.)
|
|
|
|
<p><strong>Note:</strong> The <em>msg_name</em> and <em>msg_namelen</em> fields
|
|
are ignored if the socket is using a connection-oriented transport service.</p>
|
|
</li>
|
|
|
|
<li>If the socket is using a connectionless transport device, the socket is not
|
|
bound to an address, and the socket type is <samp>SOCK_DGRAM</samp>, the system
|
|
automatically selects an address (INADDR_ANY or in6addr_any and an available
|
|
port number) and binds it to the socket before sending the data.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>To broadcast on an <samp>AF_INET</samp> socket, the socket option
|
|
<samp>SO_BROADCAST</samp> must be set (with a <em>setsockopt()</em>).<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>When using a connection-oriented transport service, all errors except
|
|
<samp>[EUNATCH]</samp> and <samp>[EUNKNOWN]</samp> are mapped to
|
|
<samp>[EPIPE]</samp> on an output operation when either of the following
|
|
occurs:
|
|
|
|
<ul>
|
|
<li>A connection that is in progress is unsuccessful.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>An established connection is broken.</li>
|
|
</ul>
|
|
|
|
To get the actual error, use <em>getsockopt()</em> with the
|
|
<samp>SO_ERROR</samp> option, or perform an input operation (for example,
|
|
<em>read()</em>).<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>If the socket is using an address family of <samp>AF_UNIX</samp>, the
|
|
destination address (which is a path name) is assumed to be in the default
|
|
coded character set identifier (CCSID) currently in effect for the job. For
|
|
<samp>AF_UNIX_CCSID</samp>, the destination address is assumed to be in the
|
|
format and coded character set identifier (CCSID) specified in the
|
|
<strong>sockaddr_unc</strong>.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li>For <samp>AF_INET</samp> sockets over SNA, type <samp>SOCK_DGRAM</samp>, if
|
|
a datagram can not be delivered, no errors are returned. (As an example, a
|
|
datagram might not be delivered if there is no datagram application at the
|
|
remote host listening at the requested port.)</li>
|
|
|
|
<li>When you develop in C-based
|
|
languages and an application is compiled with the _XOPEN_SOURCE macro defined
|
|
to the value 520 or greater, the <em>sendmsg()</em> API is mapped to
|
|
<em>qso_sendmsg98()</em>.</li>
|
|
</ol>
|
|
|
|
<br>
|
|
<h3>Related Information</h3>
|
|
|
|
<ul>
|
|
<li>For additional information and sample programs on how to use sendmsg() and
|
|
recvmsg() to pass descriptors between iSeries jobs, see <a href=
|
|
"../rzab6/rzab6soxoverview.htm">Socket Programming</a> in the iSeries
|
|
Information Center.<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="_xopen_source.htm">_XOPEN_SOURCE</a>--Using _XOPEN_SOURCE for the
|
|
UNIX 98 compatible interface<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="fcntl.htm">fcntl()</a>--Perform File Control Command<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="ioctl.htm">ioctl()</a>--Perform I/O Control Request<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="gvsoc.htm">givedescriptor()</a>--Pass Descriptor Access to Another
|
|
Job<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="send.htm">send()</a>--Send Data<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="sendto.htm">sendto()</a>--Send Data<br>
|
|
<br>
|
|
</li>
|
|
|
|
<li><a href="tksoc.htm">takedescriptor()</a>--Receive Socket Access from Another
|
|
Job</li>
|
|
</ul>
|
|
|
|
<br>
|
|
|
|
|
|
<hr>
|
|
API introduced: V3R1
|
|
|
|
<hr>
|
|
<center>
|
|
<table cellpadding="2" cellspacing="2">
|
|
<tr align="center">
|
|
<td valign="middle" align="center"><a href="#Top_Of_Page">Top</a> |
|
|
<a href="unix.htm">UNIX-Type APIs</a> |
|
|
<a href="aplist.htm">APIs by category</a> </td>
|
|
</tr>
|
|
</table>
|
|
</center>
|
|
</body>
|
|
</html>
|
|
|