NAME¶
FBB::LocalServerSocket - Unix Domain Server socket accepting connection requests
SYNOPSIS¶
#include <bobcat/localserversocket>
Linking option:
-lbobcat
DESCRIPTION¶
An
FBB::LocalServerSocket 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
blocking or
non-blocking 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
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::IFdStream,
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.
NAMESPACE¶
FBB
All constructors, members, operators and manipulators, mentioned in this
man-page, are defined in the namespace
FBB.
INHERITS FROM¶
FBB::LocalSocketBase
ENUMERATION¶
The following enumeration is defined in th class
FBB::LocalServerSocket:
enum Socket
This enumeration holds two values:
- o
- KEEP:
When this value is specified at construction time, the file representing the
Unix Domain Socket will not be removed when the LocalServerSocket
is destroyed. This is the default value used with the
LocalServerSocket constructor.
- o
- UNLINK:
When this value is specified at construction time, the file representing the
Unix Domain Socket will be removed when the LocalServerSocket is
destroyed.
CONSTRUCTOR¶
- o
- LocalServerSocket():
This constructor creates an empty (non-functioning)
FBB::LocalServerSocket object. Before it can be used, the
open() member must be called (see below).
- o
- LocalServerSocket(string const &name, Socket action
= KEEP) throw (Errno):
This constructor initializes an FBB::LocalServerSocket object, which
will listen for connection requests using the named Unix Domain socket. An
FBB::Errno is thrown if the socket could not be constructed. If the
constructor is given a second argument
FBB::LocalServerSocket::UNLINK, the constructed socket will be
unlinked when the FBB::LocalServerSocket object is destroyed. The
construction of the socket does not mean that the
FBB::LocalServerSocket object is actually listening for
connections. To start listening, the member listen() should be
called. The copy constructor is not available.
MEMBER FUNCTIONS¶
- o
- size_t accept():
The accept() member returns an size_t 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
FBB::Fork, handling the communication with the child as a separate
(child) process.
- o
- void listen(size_t backlog = 5, bool blocking =
true):
The listen() member defines the way the FBB::LocalServerSocket
will listen for clients requesting a connection. It can be used only once
with a FBB::LocalServerSocket. An FBB::Errno object is
thrown if listening fails.
- The listen() member’s backlog parameter
defines the size of the FBB::LocalServerSocket’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 lost.
- 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
intervals. Otherwise, in more complex programs, an FBB::Selector
object can be used to sense input on the server socket and/or on various
client sockets.
- o
- void open(string const &name, Socket action =
KEEP):
This member prepares a FBB::LocalServerSocket object for use. It
should only be used in combination with the default constructor. Following
open() the FBB:::LocalServerSocket object will be able to
listen for connection requests using the named Unix Domain socket. An
FBB::Errno is thrown if the socket could not be constructed. If the
a second argument FBB::LocalServerSocket::UNLINK, is provided the
constructed socket will be unlinked when the FBB::LocalServerSocket
object is destroyed. The construction of the socket does not mean that the
FBB::LocalServerSocket object is actually listening for
connections. To start listening, the member listen() should be
called next.
EXAMPLE¶
See also the
localclientsocket(3bobcat) example.
#include <iostream>
#include <bobcat/localserversocket>
#include <bobcat/ifdstream>
#include <bobcat/ofdstream>
using namespace std;
using namespace FBB;
int main(int argc, char **argv)
try
{
if (argc == 1)
{
cerr << "Provide local filename, e.g., /tmp/uds\n";
return 1;
}
LocalServerSocket server(argv[1]);
cerr << "server using `" << argv[1] << "’" << endl;
cout <<
"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" << endl;
server.listen(); // listen in blocking mode
while (true)
{
int fd = server.accept();
cerr << "Client FD = " << fd << ", " << endl;
IFdStream in(fd); // stream to read from client
OFdStream out(fd); // stream to write to client
string cmd;
while (getline(in, cmd))
{
cout << "Got: " << cmd << endl;
out << "Got: " << cmd << "\r" << endl;
if (cmd[0] == ’q’)
return 0;
}
cout << "Ready for another connection\n";
}
}
catch (Errno const &err)
{
cerr <<
err.what() << endl <<
"Server socket on port " << argv[1] <<
" can’t be opened" << endl;
return -1;
}
FILES¶
bobcat/serversocket - defines the class interface
SEE ALSO¶
bobcat(7),
localclientsocket(3bobcat),
fork(3bobcat),
ifdstream(3bobcat),
ifdstreambuf(3bobcat),
localsocketbase(3bobcat),
ofdstream(3bobcat),
ofdstream(3bobcat),
select(2),
selector(3bobcat),
serversocket(3bobcat)
BUGS¶
None Reported.
DISTRIBUTION FILES¶
- 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¶
Bobcat is an acronym of `Brokken’s Own Base Classes And Templates’.
COPYRIGHT¶
This is free software, distributed under the terms of the GNU General Public
License (GPL).
AUTHOR¶
Frank B. Brokken (
f.b.brokken@rug.nl).