/usr/share/doc/libbobcat4-dev/man/serversocket.3.html

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<h1 id="title">FBB::ServerSocket(3bobcat)</h1>
<h2 id="author">Server Socket<br/>(libbobcat-dev_4.08.02-x.tar.gz)</h2>
<h2 id="date">2005-2017</h2>


<p>
<h2 >NAME</h2>FBB::ServerSocket - Server socket accepting Internet connection requests
<p>
<h2 >SYNOPSIS</h2>
    <strong >#include &lt;bobcat/serversocket&gt;</strong><br/>
    Linking option: <em >-lbobcat</em> 
<p>
<h2 >DESCRIPTION</h2>
    An <strong >FBB::ServerSocket</strong> may be constructed to listen for connection
requests from the Internet or from the local host. Connection requests may be
accepted in either <em >blocking</em> or <em >non-blocking</em> modes. When a connection
is accepted a socket is returned which may be used to read information from or
write information to the client that requested the connection. The socket that
is made available is a <em >file descriptor</em> which may be used to initialize a
<strong >std::istream</strong> and/or <strong >std::ostream</strong>. The <strong >std::istream</strong> is used to read
information from the client process; the <strong >std::ostream</strong> is used to send
information to the client process.  Since a socket may be considered a <em >file
descriptor</em> the available <strong >FBB::IFdStream</strong>, <strong >FBB::IFdStreamBuf</strong>,
<strong >FBB::OFdStream</strong>, and <strong >FBB::OFdStreamBuf</strong> classes may be used profitably
here. Note that having available a socket does not mean that this defines the
communication protocol. It is (still) the responsibility of the programmer to
comply with an existing protocol or to implement a tailor-made protocol. The
latter situation implies that the sequence of input- and output operations is
defined by the programmer.
<p>
A Unix Domain server socket can be defined using
<em >FBB::LocalServerSocket</em>. 
<p>
<h2 >NAMESPACE</h2>
    <strong >FBB</strong><br/>
    All constructors, members, operators and manipulators, mentioned in this
man-page, are defined in the namespace <strong >FBB</strong>.
<p>
<h2 >INHERITS FROM</h2>
    <strong >FBB::SocketBase</strong>
<p>
<h2 >CONSTRUCTOR</h2>
    <ul>
    <li> <strong >ServerSocket(size_t  port)</strong>:<br/>
        This constructor initializes an <strong >FBB::ServerSocket</strong> object, which
will listen for connections at the specified port.  The construction of the
socket does not mean that the <strong >FBB::ServerSocket</strong> object is actually
listening for connections. To start listening, the member <strong >listen()</strong> should
be used.
    </ul>
    The copy constructor is not available.
<p>
<h2 >MEMBER FUNCTIONS</h2>
     All members of <strong >FBB::SocketBase</strong> (and thus of <strong >FBB::InetAddress</strong>) are
available, as <strong >FBB::ServerSocket</strong> inherits from <strong >FBB::SocketBase</strong>.
    <ul>
    <li> <strong >void listen(size_t backlog = 5, bool blocking = true)</strong>:<br/>
        The <strong >listen()</strong> member defines the way the <strong >FBB::ServerSocket</strong> will
listen for clients requesting a connection.  It can be used only once with a
<strong >FBB::ServerSocket</strong>. An <strong >FBB::Exception</strong> object is thrown if listening fails,
if the constructor could not create a socket, or if the <strong >SocketBase</strong> base
class could not properly be constructed.
<p>
The <strong >listen()</strong> member's <em >backlog</em> parameter defines the size of the
<strong >FBB::ServerSocket</strong>'s internal queue in which connection requests may be
stored waiting for their turn to be serviced. When <em >backlog</em> requests are
waiting and another request arrives, then that request is lost. 
<p>
The member's second parameter, <em >blocking</em>, is used to control the
blocking mode. By default, blocking is used, and <em >listen()</em> will wait until
a connection is established. This is ok in situations where clients connect
infrquently and for relatively short time intervals. Otherwise, in more
complex programs, an <strong >FBB::Selector</strong> object can be used to sense input on
the server socket and/or on various client sockets.
<p>
<li> <strong >SocketBase accept()</strong>:<br/>
        The <strong >accept()</strong> member returns an <strong >FBB::SocketBase</strong> object
containing information about the client whose connection request was
accepted. The <strong >FBB::SocketBase</strong> object's socket value may be used to
initialize streams that can be used to communicate with the client. In more
complex programs the <strong >FBB::SocketBase</strong> could be passed to a class derived
from <strong >FBB::Fork</strong>, handling the communication with the child as a separate
(child) process. 
    </ul>
<p>
<h2 >EXAMPLE</h2>
    See also the <strong >clientsocket</strong>(3bobcat) example.
        <pre>

    #include &lt;iostream&gt;
    #include &lt;bobcat/serversocket&gt;
    #include &lt;bobcat/ifdstream&gt;
    #include &lt;bobcat/ofdstream&gt;
    
    #include &lt;bobcat/a2x&gt;
    
    using namespace std;
    using namespace FBB;
    
    int main(int argc, char **argv)
    try
    {
        if (argc == 1)
        {
            cerr &lt;&lt; "Provide server port number\n";
            return 1;
        }
    
        size_t portnr = A2x(argv[1]);
    
        ServerSocket server(portnr);
    
        cerr &lt;&lt; "server listens on port " &lt;&lt; argv[1] &lt;&lt; endl;
    
        cerr &lt;&lt; "serversocket returns:\n" &lt;&lt;
            "address = " &lt;&lt; server.dottedDecimalAddress() &lt;&lt; "\n"
            "port    = " &lt;&lt; server.port() &lt;&lt; endl;
    
        int fd = server.socket();       // open the socket's descriptor
    
        cout &lt;&lt; "File descriptor of the socket is " &lt;&lt; fd &lt;&lt; "\n"
            "The server terminates when it receives a "
                                        "single `q' on a line\n"
            "A connection is terminated when no input "
                                        "is received anymore.\n"
            "Then another connection is possible" &lt;&lt; endl;
    
        server.listen();                // listen in blocking mode
    
        while (true)
        {
            SocketBase fdb = server.accept();
            int fd = fdb.socket();
    
            cerr &lt;&lt; "Client FD = " &lt;&lt; fd &lt;&lt; ", " &lt;&lt; endl &lt;&lt;
                    "address = " &lt;&lt; fdb.dottedDecimalAddress() &lt;&lt; ", " &lt;&lt; 
                    endl &lt;&lt;
                    "communication through port " &lt;&lt; fdb.port() &lt;&lt; endl;
    
            IFdStream in(fd);           // stream to read from client
            OFdStream out(fd);          // stream to write to client
            string cmd;
            
            while (getline(in, cmd))
            {
                cout &lt;&lt; "Got: " &lt;&lt; cmd &lt;&lt; endl;
                out &lt;&lt; "Got: " &lt;&lt; cmd &lt;&lt; "\r" &lt;&lt; endl;
    
                if (cmd[0] == 'q')
                    return 0;
            }
            cout &lt;&lt; "Ready for another connection\n";
        }
    }
    catch (Exception const &amp;err)
    {
        cerr &lt;&lt;
            err.what() &lt;&lt; endl &lt;&lt;
            "Server socket on port " &lt;&lt; argv[1] &lt;&lt; 
            " can't be opened" &lt;&lt; endl;
        return -1;
    }        
        
</pre>

<p>
<h2 >FILES</h2>
    <em >bobcat/serversocket</em> - defines the class interface
<p>
<h2 >SEE ALSO</h2>
    <strong >bobcat</strong>(7), <strong >clientsocket</strong>(3bobcat), <strong >fork</strong>(3bobcat),
<strong >ifdstream</strong>(3bobcat), <strong >ifdstreambuf</strong>(3bobcat), <strong >inetaddress</strong>(3bobcat),
<strong >localserversocket</strong>(3bobcat), <strong >ofdstream</strong>(3bobcat),
<strong >ofdstream</strong>(3bobcat), <strong >select</strong>(2), <strong >selector</strong>(3bobcat),
<strong >socketbase</strong>(3bobcat)
<p>
<h2 >BUGS</h2>
    None Reported.
<p>

<h2 >DISTRIBUTION FILES</h2>
    <ul>
    <li> <em >bobcat_4.08.02-x.dsc</em>: detached signature;
    <li> <em >bobcat_4.08.02-x.tar.gz</em>: source archive;
    <li> <em >bobcat_4.08.02-x_i386.changes</em>: change log;
    <li> <em >libbobcat1_4.08.02-x_*.deb</em>: debian package holding the
            libraries;
    <li> <em >libbobcat1-dev_4.08.02-x_*.deb</em>: debian package holding the
            libraries, headers and manual pages;
    <li> <em >http://sourceforge.net/projects/bobcat</em>: public archive location;
    </ul>
<p>
<h2 >BOBCAT</h2>
    Bobcat is an acronym of `Brokken's Own Base Classes And Templates'.
<p>
<h2 >COPYRIGHT</h2>
    This is free software, distributed under the terms of the 
    GNU General Public License (GPL).
<p>
<h2 >AUTHOR</h2>
    Frank B. Brokken (<strong >f.b.brokken@rug.nl</strong>).
<p>
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libbobcat-dev 4.08.02-2build1 / usr / share / doc / libbobcat4-dev / man / serversocket.3.html
