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<p><a href="../index.html"><img src="title-21.png" width="253" height="39" alt="C++ Portable Types Library (PTypes) Version 2.1" border="0"></a>
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<p class="hpath"><a href="index.html">Top</a>: <a href="inet.html">Networking</a>:
ipstream</p>
<blockquote>
<pre class="lang">#include <pinet.h>
class ipstream: instm, outstm {
ipstream();
ipstream(ipaddress ip, int port);
ipstream(string host, int port);
~ipstream();
void open();
void close();
void cancel();
bool waitfor(int milliseconds);
ipaddress get/set_ip();
string get/set_host();
int get/set_port();
ipaddress get_myip();
int get_myport();
virtual void sockopt(int socket);
}</pre>
</blockquote>
<p>The <span class="lang">ipstream</span> class implements full-duplex streaming
communication between IP hosts. <span class="lang">Ipstream</span> incorporates
<a href="streams.iobase.html">iobase</a>, <a href="streams.instm.html">instm</a>
and <a href="streams.outstm.html">outstm</a> interfaces and adds two more properties:
peer IP address and peer port number. This means, you can work with <span class="lang">ipstream</span>
the same way you work with <span class="lang">infile</span> and <span class="lang">outfile</span>,
except that you specify the target IP address or the symbolic hostname along with
the port number instead of the filename when constructing an object. Besides,
the rules of object-oriented inheritance allow you to manipulate <span class="lang">ipstream</span>
objects in those parts of your code which are only 'familiar' with the basic <span class="lang">instm</span>
and <span class="lang">outstm</span> interfaces.</p>
<p>In order to open a connection and exchange data you need to set target (peer
host) address and the port number. The peer address can be either a symbolic DNS
name or a numeric IPv4 address. Regardless of which one of these two properties
you set first, the <span class="lang">ipstream</span> object can perform DNS resolving
as necessary and return both properties on your request.</p>
<p><span class="lang">Ipstream</span> adds the following status codes: IO_RESOLVING,
IO_RESOLVED, IO_CONNECTING, IO_CONNECTED (see also <a href="streams.iobase.html">iobase</a>
for the status codes common to all streams).</p>
<p>On UNIX the library startup code blocks <span class="lang">SIGPIPE</span>,
so that all error conditions on sockets always raise exceptions of type <span class="lang">(estream*)</span>.</p>
<p><span class="def">ipstream::ipstream()</span> is the default constructor.</p>
<p><span class="def">ipstream::ipstream(ipaddress ip, int port)</span> constructs
an <span class="lang">ipstream</span> object and assigns the peer <span class="lang">ip</span>/<span class="lang">port</span>
values.</p>
<p><span class="def">ipstream::ipstream(string host, int port)</span> constructs
an <span class="lang">ipstream</span> object and assigns the peer host name and
port values. Before actually opening the stream <span class="lang">ipstream</span>
resolves the host name to a numeric IP address. <span class="lang">Host</span>
can be either a symbolic DNS name or even a numeric address in a string form (e.g.
"somehost.com" or "192.168.1.1").</p>
<p><span class="def">ipstream::~ipstream()</span> cancels the connection immediately
and destroys the object. To shut down the connection 'gracefully' you should call
<span class="lang">close()</span> before destroying the object or before the program
goes beyond the scope of a static/local <span class="lang">ipstream</span> object.</p>
<p><span class="def">void ipstream::open()</span> opens a connection with the
peer. <span class="lang">host</span> or <span class="lang">ip</span> along with
<span class="lang">port</span> properties must be set before opening the stream.</p>
<p><span class="def">void ipstream::close()</span> closes the stream 'gracefully',
and in some situations may be time-consuming. Although all stream objects in PTypes
are closed by the destructors automatically, it is recommended to explicitly
call <span class="lang">close()</span> for socket objects.</p>
<p><span class="def">void ipstream::cancel()</span> closes the stream immediately.
If the connection was successful, calling <span class="lang">cancel()</span> may
leave the peer host in a waiting state for a long time.</p>
<p><span class="def">bool ipstream::waitfor(int milliseconds)</span> waits on
the socket until either data is available for reading (returns <span class="lang">true</span>)
or the time specified in the parameter has elapsed, in which case it returns <span class="lang">false</span>.</p>
<p><span class="def">ipaddress ipstream::get/set_ip()</span> sets/retrieves the
peer address in a numerical form. If the object was constructed using a symbolic
name, <span class="lang">get_ip()</span> may perform a DNS lookup (only once).</p>
<p><span class="def">string ipstream::get/set_host()</span> sets/retrieves the
peer address in a symbolic form. If the object was constructed using a numeric
IP address, <span class="lang">get_host()</span> may perform a reverse DNS lookup.</p>
<p><span class="def">int ipstream::get/set_port()</span> sets/retrieves the peer
port number.</p>
<p><span class="def">ipaddress ipstream::get_myip()</span> returns the local address
associated with the socket.</p>
<p><span class="def">int ipstream::get_myport()</span> returns the local port
number associated with the socket.</p>
<p><span class="def">virtual void ipstream::sockopt(int socket)</span> - override this method in a descendant class if you want to set up additional socket options (normally, by calling <span class="lang">setsockopt()</span>).</p>
<p class="seealso">See also: <a href="streams.iobase.html">iobase</a>, <a href="streams.instm.html">instm</a>,
<a href="streams.outstm.html">outstm</a>, <a href="inet.ipstmserver.html">ipstmserver</a>,
<a href="inet.utils.html">Utilities</a>, <a href="inet.examples.html">Examples</a></p>
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