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| <h4 class="subsection">16.6.1 Internet Socket Address Formats</h4> |
| |
| <p>In the Internet namespace, for both IPv4 (<code>AF_INET</code>) and IPv6 |
| (<code>AF_INET6</code>), a socket address consists of a host address |
| and a port on that host. In addition, the protocol you choose serves |
| effectively as a part of the address because local port numbers are |
| meaningful only within a particular protocol. |
| |
| <p>The data types for representing socket addresses in the Internet namespace |
| are defined in the header file <samp><span class="file">netinet/in.h</span></samp>. |
| <a name="index-netinet_002fin_002eh-1684"></a> |
| <!-- netinet/in.h --> |
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| <div class="defun"> |
| — Data Type: <b>struct sockaddr_in</b><var><a name="index-struct-sockaddr_005fin-1685"></a></var><br> |
| <blockquote><p>This is the data type used to represent socket addresses in the |
| Internet namespace. It has the following members: |
| |
| <dl> |
| <dt><code>sa_family_t sin_family</code><dd>This identifies the address family or format of the socket address. |
| You should store the value <code>AF_INET</code> in this member. |
| See <a href="Socket-Addresses.html#Socket-Addresses">Socket Addresses</a>. |
| |
| <br><dt><code>struct in_addr sin_addr</code><dd>This is the Internet address of the host machine. See <a href="Host-Addresses.html#Host-Addresses">Host Addresses</a>, and <a href="Host-Names.html#Host-Names">Host Names</a>, for how to get a value to store |
| here. |
| |
| <br><dt><code>unsigned short int sin_port</code><dd>This is the port number. See <a href="Ports.html#Ports">Ports</a>. |
| </dl> |
| </p></blockquote></div> |
| |
| <p>When you call <code>bind</code> or <code>getsockname</code>, you should specify |
| <code>sizeof (struct sockaddr_in)</code> as the <var>length</var> parameter if |
| you are using an IPv4 Internet namespace socket address. |
| |
| <div class="defun"> |
| — Data Type: <b>struct sockaddr_in6</b><var><a name="index-struct-sockaddr_005fin6-1686"></a></var><br> |
| <blockquote><p>This is the data type used to represent socket addresses in the IPv6 |
| namespace. It has the following members: |
| |
| <dl> |
| <dt><code>sa_family_t sin6_family</code><dd>This identifies the address family or format of the socket address. |
| You should store the value of <code>AF_INET6</code> in this member. |
| See <a href="Socket-Addresses.html#Socket-Addresses">Socket Addresses</a>. |
| |
| <br><dt><code>struct in6_addr sin6_addr</code><dd>This is the IPv6 address of the host machine. See <a href="Host-Addresses.html#Host-Addresses">Host Addresses</a>, and <a href="Host-Names.html#Host-Names">Host Names</a>, for how to get a value to store |
| here. |
| |
| <br><dt><code>uint32_t sin6_flowinfo</code><dd>This is a currently unimplemented field. |
| |
| <br><dt><code>uint16_t sin6_port</code><dd>This is the port number. See <a href="Ports.html#Ports">Ports</a>. |
| |
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