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

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


<p>
<h2 >NAME</h2>FBB::LocalServerSocket - Unix Domain Server socket accepting connection requests
<p>
<h2 >SYNOPSIS</h2>
    <strong >#include &lt;bobcat/localserversocket&gt;</strong><br/>
    Linking option: <em >-lbobcat</em> 
<p>
<h2 >DESCRIPTION</h2>
    An <strong >FBB::LocalServerSocket</strong> defines a Unix Domain server socket,
listening for connection requests from the local host using a Unix Domain
socket. 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
requesting 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>
<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::LocalSocketBase</strong>
<p>
<h2 >ENUMERATION</h2>
    The following enumeration is defined in th class
<strong >FBB::LocalServerSocket</strong>:
<p>
<strong >enum Socket</strong><br/>
    This enumeration holds two values:
    <ul>
    <li> <strong >KEEP</strong>:<br/>
        When this value is specified at construction time, the file
representing the Unix Domain Socket is not removed when the
<strong >LocalServerSocket</strong> is destroyed.
    <li> <strong >UNLINK</strong>:<br/>
        When this value is specified at construction time, the file
representing the Unix Domain Socket is removed when the <strong >LocalServerSocket</strong>
is destroyed. As a socket cannot be reused, this is the default value used
with the <strong >LocalServerSocket</strong> constructor.
    </ul>
<p>
<h2 >CONSTRUCTOR</h2>
    <ul>
    <li> <strong >LocalServerSocket()</strong>:<br/> 
        This constructor creates an empty (non-functioning)
<em >FBB::LocalServerSocket</em> object. Before it can be used, the <em >open()</em> member
must be called (see below).
    <li> <strong >LocalServerSocket(string const &amp;name, Socket action = UNLINK) 
        throw (Exception)</strong>:<br/>
        This constructor initializes an <strong >FBB::LocalServerSocket</strong> object,
which will listen for connection requests using the named Unix Domain
socket.  An <strong >FBB::Exception</strong> is thrown if the socket could not be
constructed. If the constructor is given a second argument
<em >FBB::LocalServerSocket::KEEP</em>, the constructed socket is not unlinked
when the <strong >FBB::LocalServerSocket</strong> object is destroyed.  The construction of
the socket does not mean that the <strong >FBB::LocalServerSocket</strong> object is
actually listening for connections. To start listening, the member
<strong >listen()</strong> should be called.
    </ul>
    The copy constructor is not available.
<p>
<h2 >MEMBER FUNCTIONS</h2>
    <ul>
    <li> <strong >size_t accept()</strong>:<br/>
        The <strong >accept()</strong> member returns an <em >size_t</em> which is a file
descriptor (socket) that may be used to communicate with the client requesting
the connection. In more complex programs the returned file descriptor (socket)
could be passed to a class derived from <strong >FBB::Fork</strong>, handling the
communication with the child as a separate (child) process.
<p>
<li> <strong >void listen(size_t backlog = 5, bool blocking = true)</strong>:<br/>
        The <strong >listen()</strong> member defines the way the <strong >FBB::LocalServerSocket</strong>
will listen for clients requesting a connection.  It can be used only once
with a <strong >FBB::LocalServerSocket</strong>. An <strong >FBB::Exception</strong> object is thrown if
listening fails.
<p>
The <strong >listen()</strong> member's <em >backlog</em> parameter defines the size of the
<strong >FBB::LocalServerSocket</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 >void open(string const &amp;name, Socket action = UNLINK)</strong>:<br/>
        This member prepares a <strong >FBB::LocalServerSocket</strong> object for use. It
should only be used in combination with the default constructor. Following
<em >open()</em> the <em >FBB:::LocalServerSocket</em> object will be able to listen for
connection requests using the named Unix Domain socket.  An <strong >FBB::Exception</strong>
is thrown if the socket could not be constructed. If the a second argument
<em >FBB::LocalServerSocket::KEEP</em>, is provided the constructed socket is not
unlinked when the <strong >FBB::LocalServerSocket</strong> object is destroyed.  The
construction of the socket does not mean that the <strong >FBB::LocalServerSocket</strong>
object is actually listening for connections. To start listening, the member
<strong >listen()</strong> should be called next.
    </ul>
<p>
<h2 >EXAMPLE</h2>
    See also the <strong >localclientsocket</strong>(3bobcat) example.
        <pre>

    #include &lt;iostream&gt;
    #include &lt;bobcat/localserversocket&gt;
    #include &lt;bobcat/ifdstream&gt;
    #include &lt;bobcat/ofdstream&gt;
    
    using namespace std;
    using namespace FBB;
    
    int main(int argc, char **argv)
    try
    {
        if (argc == 1)
        {
            cerr &lt;&lt; "Provide local filename, e.g., /tmp/uds\n";
            return 1;
        }
    
        LocalServerSocket server(argv[1]);
    
        cerr &lt;&lt; "server using `" &lt;&lt; argv[1] &lt;&lt; "'" &lt;&lt; endl;
    
        cout &lt;&lt; 
            "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)
        {
            int fd = server.accept();
    
            cerr &lt;&lt; "Client FD = " &lt;&lt; fd &lt;&lt; ", " &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 >localclientsocket</strong>(3bobcat), <strong >fork</strong>(3bobcat),
<strong >ifdstream</strong>(3bobcat), <strong >ifdstreambuf</strong>(3bobcat),
<strong >localsocketbase</strong>(3bobcat), <strong >ofdstream</strong>(3bobcat), <strong >ofdstream</strong>(3bobcat),
<strong >select</strong>(2), <strong >selector</strong>(3bobcat), <strong >serversocket</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 / localserversocket.3.html
