| <html lang="en"> |
| <head> |
| <title>Internet Namespace - The GNU C Library</title> |
| <meta http-equiv="Content-Type" content="text/html"> |
| <meta name="description" content="The GNU C Library"> |
| <meta name="generator" content="makeinfo 4.13"> |
| <link title="Top" rel="start" href="index.html#Top"> |
| <link rel="up" href="Sockets.html#Sockets" title="Sockets"> |
| <link rel="prev" href="Local-Namespace.html#Local-Namespace" title="Local Namespace"> |
| <link rel="next" href="Misc-Namespaces.html#Misc-Namespaces" title="Misc Namespaces"> |
| <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> |
| <!-- |
| This file documents the GNU C library. |
| |
| This is Edition 0.12, last updated 2007-10-27, |
| of `The GNU C Library Reference Manual', for version |
| 2.8 (Sourcery G++ Lite 2011.03-41). |
| |
| Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002, |
| 2003, 2007, 2008, 2010 Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 or |
| any later version published by the Free Software Foundation; with the |
| Invariant Sections being ``Free Software Needs Free Documentation'' |
| and ``GNU Lesser General Public License'', the Front-Cover texts being |
| ``A GNU Manual'', and with the Back-Cover Texts as in (a) below. A |
| copy of the license is included in the section entitled "GNU Free |
| Documentation License". |
| |
| (a) The FSF's Back-Cover Text is: ``You have the freedom to |
| copy and modify this GNU manual. Buying copies from the FSF |
| supports it in developing GNU and promoting software freedom.''--> |
| <meta http-equiv="Content-Style-Type" content="text/css"> |
| <style type="text/css"><!-- |
| pre.display { font-family:inherit } |
| pre.format { font-family:inherit } |
| pre.smalldisplay { font-family:inherit; font-size:smaller } |
| pre.smallformat { font-family:inherit; font-size:smaller } |
| pre.smallexample { font-size:smaller } |
| pre.smalllisp { font-size:smaller } |
| span.sc { font-variant:small-caps } |
| span.roman { font-family:serif; font-weight:normal; } |
| span.sansserif { font-family:sans-serif; font-weight:normal; } |
| --></style> |
| <link rel="stylesheet" type="text/css" href="../cs.css"> |
| </head> |
| <body> |
| <div class="node"> |
| <a name="Internet-Namespace"></a> |
| <p> |
| Next: <a rel="next" accesskey="n" href="Misc-Namespaces.html#Misc-Namespaces">Misc Namespaces</a>, |
| Previous: <a rel="previous" accesskey="p" href="Local-Namespace.html#Local-Namespace">Local Namespace</a>, |
| Up: <a rel="up" accesskey="u" href="Sockets.html#Sockets">Sockets</a> |
| <hr> |
| </div> |
| |
| <h3 class="section">16.6 The Internet Namespace</h3> |
| |
| <p><a name="index-Internet-namespace_002c-for-sockets-1680"></a> |
| This section describes the details of the protocols and socket naming |
| conventions used in the Internet namespace. |
| |
| <p>Originally the Internet namespace used only IP version 4 (IPv4). With |
| the growing number of hosts on the Internet, a new protocol with a |
| larger address space was necessary: IP version 6 (IPv6). IPv6 |
| introduces 128-bit addresses (IPv4 has 32-bit addresses) and other |
| features, and will eventually replace IPv4. |
| |
| <p>To create a socket in the IPv4 Internet namespace, use the symbolic name |
| <code>PF_INET</code> of this namespace as the <var>namespace</var> argument to |
| <code>socket</code> or <code>socketpair</code>. For IPv6 addresses you need the |
| macro <code>PF_INET6</code>. These macros are defined in <samp><span class="file">sys/socket.h</span></samp>. |
| <a name="index-sys_002fsocket_002eh-1681"></a> |
| <!-- sys/socket.h --> |
| <!-- BSD --> |
| |
| <div class="defun"> |
| — Macro: int <b>PF_INET</b><var><a name="index-PF_005fINET-1682"></a></var><br> |
| <blockquote><p>This designates the IPv4 Internet namespace and associated family of |
| protocols. |
| </p></blockquote></div> |
| |
| <!-- sys/socket.h --> |
| <!-- X/Open --> |
| <div class="defun"> |
| — Macro: int <b>PF_INET6</b><var><a name="index-PF_005fINET6-1683"></a></var><br> |
| <blockquote><p>This designates the IPv6 Internet namespace and associated family of |
| protocols. |
| </p></blockquote></div> |
| |
| <p>A socket address for the Internet namespace includes the following components: |
| |
| <ul> |
| <li>The address of the machine you want to connect to. Internet addresses |
| can be specified in several ways; these are discussed in <a href="Internet-Address-Formats.html#Internet-Address-Formats">Internet Address Formats</a>, <a href="Host-Addresses.html#Host-Addresses">Host Addresses</a> and <a href="Host-Names.html#Host-Names">Host Names</a>. |
| |
| <li>A port number for that machine. See <a href="Ports.html#Ports">Ports</a>. |
| </ul> |
| |
| <p>You must ensure that the address and port number are represented in a |
| canonical format called <dfn>network byte order</dfn>. See <a href="Byte-Order.html#Byte-Order">Byte Order</a>, |
| for information about this. |
| |
| <ul class="menu"> |
| <li><a accesskey="1" href="Internet-Address-Formats.html#Internet-Address-Formats">Internet Address Formats</a>: How socket addresses are specified in the |
| Internet namespace. |
| <li><a accesskey="2" href="Host-Addresses.html#Host-Addresses">Host Addresses</a>: All about host addresses of Internet host. |
| <li><a accesskey="3" href="Protocols-Database.html#Protocols-Database">Protocols Database</a>: Referring to protocols by name. |
| <li><a accesskey="4" href="Ports.html#Ports">Ports</a>: Internet port numbers. |
| <li><a accesskey="5" href="Services-Database.html#Services-Database">Services Database</a>: Ports may have symbolic names. |
| <li><a accesskey="6" href="Byte-Order.html#Byte-Order">Byte Order</a>: Different hosts may use different byte |
| ordering conventions; you need to |
| canonicalize host address and port number. |
| <li><a accesskey="7" href="Inet-Example.html#Inet-Example">Inet Example</a>: Putting it all together. |
| </ul> |
| |
| </body></html> |
| |
