FBB::ServerSocket(3bobcat) Server Socket FBB::ServerSocket(3bobcat)
FBB::ServerSocket - Server socket accepting Internet connection requests
Linking option: -lbobcat
An FBB::ServerSocket may be constructed to listen for connection requests from the Internet or from the local host. Connection requests may
be accepted in either blocking or non-blocking modes. When a connection is accepted a socket is returned which may be used to read informa-
tion from or write information to the client that requested the connection. The socket that is made available is a file descriptor which
may be used to initialize a std::istream and/or std::ostream. The std::istream is used to read information from the client process; the
std::ostream is used to send information to the client process. Since a socket may be considered a file descriptor the avaiable FBB::IFd-
Stream, FBB::IFdStreamBuf, FBB::OFdStream, and FBB::OFdStreamBuf 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.
All constructors, members, operators and manipulators, mentioned in this man-page, are defined in the namespace FBB.
o ServerSocket(size_t port):
This constructor initializes an FBB::ServerSocket object, which will listen for connections at the specified port. The construction
of the socket does not mean that the FBB::ServerSocket object is actually listening for connections. To start listening, the member
listen() should be used. The copy constructor is not available.
All members of FBB::SocketBase (and thus of FBB::InetAddress) are available, as FBB::ServerSocket inherits from FBB::SocketBase.
o void listen(size_t backlog = 5, bool blocking = true):
The listen() member defines the way the FBB::ServerSocket will listen for clients requesting a connection. It can be used only once
with a FBB::ServerSocket. An FBB::Errno object is thrown if listening fails, if the constructor could not create a socket, or if the
SocketBase base class could not properly be constructed.
The listen() member's backlog parameter defines the size of the FBB::ServerSocket's internal queue in which connection requests may
be stored waiting for their turn to be serviced. When backlog requests are waiting and another request arrives, then that request is
The member's second parameter, blocking, is used to control the blocking mode. By default, blocking is used, and listen() will wait
until a connection is established. This is ok in situations where clients connect infrquently and for relatively short time inter-
vals. Otherwise, in more complex programs, an FBB::Selector object can be used to sense input on the server socket and/or on various
o SocketBase accept():
The accept() member returns an FBB::SocketBase object containing information about the client whose connection request was accepted.
The FBB::SocketBase object's socket value may be used to initialize streams that can be used to communicate with the client. In more
complex programs the FBB::SocketBase could be passed to a class derived from FBB::Fork, handling the communication with the child as
a separate (child) process.
See also the clientsocket(3bobcat) example.
using namespace std;
using namespace FBB;
int main(int argc, char **argv)
if (argc == 1)
cerr << "Provide server port number
size_t portnr = A2x(argv);
cerr << "server listens on port " << argv << endl;
cerr << "serversocket returns:
"address = " << server.dottedDecimalAddress() << "
"port = " << server.port() << endl;
int fd = server.socket(); // open the socket's descriptor
cout << "File descriptor of the socket is " << fd << "
"The server terminates when it receives a "
"single `q' on a line
"A connection is terminated when no input "
"is received anymore.
"Then another connection is possible" << endl;
server.listen(); // listen in blocking mode
SocketBase fdb = server.accept();
int fd = fdb.socket();
cerr << "Client FD = " << fd << ", " << endl <<
"address = " << fdb.dottedDecimalAddress() << ", " <<
"communication through port " << fdb.port() << endl;
IFdStream in(fd); // stream to read from client
OFdStream out(fd); // stream to write to client
while (getline(in, cmd))
cout << "Got: " << cmd << endl;
out << "Got: " << cmd << "
" << endl;
if (cmd == 'q')
cout << "Ready for another connection
catch (Errno const &err)
err.what() << endl <<
"Server socket on port " << argv <<
" can't be opened" << endl;
bobcat/serversocket - defines the class interface
bobcat(7), clientsocket(3bobcat), fork(3bobcat), ifdstream(3bobcat), ifdstreambuf(3bobcat), inetaddress(3bobcat), localserversocket(3bob-
cat), ofdstream(3bobcat), ofdstream(3bobcat), select(2), selector(3bobcat), socketbase(3bobcat)
o bobcat_3.01.00-x.dsc: detached signature;
o bobcat_3.01.00-x.tar.gz: source archive;
o bobcat_3.01.00-x_i386.changes: change log;
o libbobcat1_3.01.00-x_*.deb: debian package holding the libraries;
o libbobcat1-dev_3.01.00-x_*.deb: debian package holding the libraries, headers and manual pages;
o http://sourceforge.net/projects/bobcat: public archive location;
Bobcat is an acronym of `Brokken's Own Base Classes And Templates'.
This is free software, distributed under the terms of the GNU General Public License (GPL).
Frank B. Brokken (firstname.lastname@example.org).
libbobcat1-dev_3.01.00-x.tar.gz 2005-2012 FBB::ServerSocket(3bobcat)