socket++.texi

《CODE READING》配套书源代码 《CODE READING》配套书源代码

@item uns = su
@findex sockunixbuf::operator =
@code{sockunixbuf} object @code{uns} closes its current socket if no other
@code{sockbuf} is referring to it and uses the socket that @code{sockbuf}
object @code{su} is using.

@item uns.open(ty, proto)
@findex sockunixbuf::open
create a @code{sockunixbuf} object with @code{ty} as its type and
@code{proto} as its protocol and assign the @code{sockunixbuf} object so
created to @code{*this}. It returns @code{this}. @code{proto} defaults
to 0.

@item uns.bind(path)
@findex sockunixbuf::bind
binds @code{uns} to the @var{unix} pathname @code{path}.
It returns 0 on success and returns the errno on failure.

@item uns.connect(path)
@findex sockunixbuf::connect
connects @code{uns} to the @var{unix} pathname @code{path}.
It returns 0 on success and returns the errno on failure.

@end table

@node Datagram UNIX
@section @var{unix} Datagram Sockets
@cindex datagram unix
@cindex isockunix example
@cindex osockunix example

The following two programs illustrates how to use @code{sockunixbuf} class
for datagram connection in @var{unix} domain. @code{tdunread.cc} also
shows how to use @code{isockunix} class and @code{tdunwrite.cc} shows
how to use @code{osockunix} class.

@subheading tdunread.cc
@example
// reads data sent by tdunwrite.cc
#include <sockunix.h>
#include <unistd.h>
#include <errno.h>

int main(int ac, char** av)
@{
        if (ac != 2) @{
                cerr << "USAGE: " << av[0] << " socket_path_name\n";
                return 1;
        @}
        
        // isockunix builds the sockunixbuf object
        isockunix 	su (sockbuf::sock_dgram);
    
        su->bind(av[1]);

        cout << "Socket name = " << av[1] << endl;

        if (chmod(av[1], 0777) == -1) @{
                perror("chmod");
                return 1;
        @}

        char buf[1024];
        int i;
        su >> i;
        cout << av[0] << ": " << i << " strings: ";
        while (i--) @{
                su >> buf;
                cout  << buf << ' ';
        @}
        cout << endl;
        
        unlink(av[1]);
        return 0;
@}
@end example

@subheading tdunwrite.cc
@example
// sends data to tdunread.cc
#include <sockunix.h>

int main(int ac, char** av)
@{
        if (ac < 2) @{
                cerr << "USAGE: " << av[0]
                     << " socket_path_name data...\n";
                return 1;
        @}

        osockunix	su (sockbuf::sock_dgram);

	su->connect (av[1]);

        su << ac << ' ';
        while (*av) @{ su << av[i] << ' '; av++; @}
        su << endl;

        return 0;
@}
@end example

@node Stream UNIX
@section @var{unix} Stream Sockets
@cindex stream unix
@cindex sockunixbuf example
@cindex iosockunix example

The following two programs illustrates how to use @code{sockunixbuf} class
for stream connection in @var{unix} domain. It also shows how to use
@code{iosockunix} class.

@subheading tsunread.cc
@example
// exchanges char strings with tsunwrite.cc
#include <sockunix.h>
#include <unistd.h>
#include <errno.h>

int main(int ac, char** av)
@{
        if (ac != 2) @{
                cerr << "USAGE: " << av[0] << " socket_path_name\n";
                return 1;
        @}
        
        sockunixbuf  su(sockbuf::sock_stream);
        su.bind(av [1]);

        cout << "Socket name = " << av[1] << endl;

        if (chmod(av[1], 0777) == -1) @{
                perror("chmod");
                return 1;
        @}

        su.listen(3);
        
        iosockunix ioput = su.accept ();
        char       buf[1024];
        
        ioput << av[0] << ' ' << av[1] << endl;
        while ( ioput >> buf ) cout << av[0] << ": " << buf << endl;
        unlink(av[1]);
        return 0;
@}
@end example

@subheading tsunwrite.cc
@example
// exchanges char strings with tsunread.cc
#include <sockunix.h>

int main(int ac, char** av)
@{
        if (ac < 2) @{
                cerr << "USAGE: " << av[0]
                     << " socket_path_name data...\n";
                return 1;
        @}

        iosockunix oput (sockbuf::sock_stream);
        oput->connect (av [1]);

        char buf[128];

        oput >> buf;
        cout << buf << ' ';
        oput >> buf;
        cout << buf << endl;

        while (*av) oput << *av++ << ' ';
        oput << endl;
        
        return 0;
@}
@end example

@node sockunixaddr Class
@chapter sockunixaddr Class
@cindex sockunixaddr class
@cindex unix address class

Class @code{sockunixaddr} is derived from class @code{sockAddr} declared in
@code{<sockstream.h>} and from struct @code{sockaddr_un} declared in
@code{<sys/un.h>}. Always use @code{sockunixaddr} objects for addresses
with @var{unix} domain of sockets. @xref{Connection Establishment}.

In what follows,
@itemize @minus
@item
@code{path} is the @var{unix} path name like "/tmp/unix_socket"
@end itemize

@table @code

@item sockunixaddr suna(path)
@findex sockunixaddr::sockunixaddr
Constructs a @code{sockunixaddr} object @code{suna} with @code{path} as
the @var{unix} path name.

@item void* a = suna
@findex sockunixaddr::operator void*
returns the address of the @code{sockaddr_un} part of
@code{sockunixaddr} object @code{suna} as void*.

@item int sz = suna.size()
@findex sockunixaddr::size
returns the sizeof @code{sockaddr_un} part of @code{sockunixaddr} object
@code{suna}.

@item int af = suna.family()
@findex sockunixaddr::family
returns @code{sockunixbuf::af_unix} if all is well.

@end table

@node sockstream Classes
@chapter sockstream Classes
@cindex sockstream classes
@cindex iosockstream classes

sockstream classes are designed in such a way that they provide the same
interface as their stream counterparts do. We have @code{isockstream}
derived from @code{istream} and @code{osockstream} derived from
@code{ostream}. We also have @code{iosockstream} which is derived from
@code{iostream}.

Each domain also has its own set of @code{stream} classes. For example,
@code{unix} domain has @code{isockunix}, @code{osockunix}, and
@code{iosockunix} derived from @code{isockstream}, @code{osockstream},
and @code{iosockstream} respectively. Similarly, @code{inet} domain has
@code{isockinet}, @code{osockinet}, and @code{iosockinet}.

@menu
* iosockstream::             Generic IOStream classes for sockbuf
                                   buffers.
* iosockinet::               IOStream classes for @var{inet} domain of
                                   sockets.
* iosockunix::               IOStream classes for @var{unix} domain of
                                   sockets.
@end menu

@node iosockstream
@section iosockstreams

@subsection isockstream Class
@cindex isockstream class

Since @code{isockstream} is publicly derived from @code{istream}, most
of the public functions of @code{istream} are also available in
@code{isockstream}. 

@code{isockstream} redefines @code{rdbuf()} defined in its virtual base
class @code{ios}. Since, @code{ios::rdbuf()} is not virtual, care must
be taken to call the correct @code{rdbuf()} through a reference or a
pointer to an object of class @code{isockstream}.

In what follows,
@itemize @minus
@item
@code{sb} is a @code{sockbuf} object
@item
@code{sbp} is a pointer to a @code{sockbuf} object
@end itemize

@table @code

@item isockstream is(sb)
@findex isockstream::isockstream
Constructs an @code{isockstream} object @code{is} with @code{sb} as its
@code{sockbuf}.

@item isockstream is(sbp)
Constructs an @code{isockstream} object @code{is} with @code{*sbp} as its
@code{sockbuf}.

@item sbp = is.rdbuf()
@findex isockstream::rdbuf
returns a pointer to the @code{sockbuf} of the @code{isockstream} object
@code{is}.

@item isockstream::operator -> ()
@findex isockstream::operator->
returns a pointer to the @code{isockstream}'s @code{sockbuf} so that
the user can use @code{isockstream} object as a @code{sockbuf} object.

@example
    is->connect (sa); // same as is.rdbuf()->connect (sa);
@end example

@end table

@subsection osockstream Class
@cindex osockstream class

Since @code{osockstream} is publicly derived from @code{ostream}, most
of the public functions of @code{ostream} are also available in
@code{osockstream}. 

@code{osockstream} redefines @code{rdbuf()} defined in its virtual base
class @code{ios}. Since, @code{ios::rdbuf()} is not virtual, care must
be taken to call the correct @code{rdbuf()} through a reference or a
pointer to an object of class @code{osockstream}.

In what follows,
@itemize @minus
@item
@code{sb} is a @code{sockbuf} object
@item
@code{sbp} is a pointer to a @code{sockbuf} object
@end itemize

@table @code

@item osockstream os(sb)
@findex osockstream::osockstream
Constructs an @code{osockstream} object @code{os} with @code{sb} as its
@code{sockbuf}.

@item osockstream os(sbp)
Constructs an @code{osockstream} object @code{os} with @code{*sbp} as its
@code{sockbuf}.

@item sbp = os.rdbuf()
@findex osockstream::rdbuf
returns a pointer to the @code{sockbuf} of the @code{osockstream} object
@code{os}.

@item osockstream::operator -> ()
@findex osockstream::operator->
returns a pointer to the @code{osockstream}'s @code{sockbuf} so that
the user can use @code{osockstream} object as a @code{sockbuf} object.

@example
    os->connect (sa); // same as os.rdbuf()->connect (sa);
@end example

@end table

@subsection iosockstream Class
@cindex iosockstream class

Since @code{iosockstream} is publicly derived from @code{iostream}, most
of the public functions of @code{iostream} are also available in
@code{iosockstream}. 

@code{iosockstream} redefines @code{rdbuf()} defined in its virtual base
class @code{ios}. Since, @code{ios::rdbuf()} is not virtual, care must
be taken to call the correct @code{rdbuf()} through a reference or a
pointer to an object of class @code{iosockstream}.

In what follows,
@itemize @minus
@item
@code{sb} is a @code{sockbuf} object
@item
@code{sbp} is a pointer to a @code{sockbuf} object
@end itemize

@table @code

@item iosockstream io(sb)
@findex iosockstream::iosockstream
Constructs an @code{iosockstream} object @code{io} with @code{sb} as its
@code{sockbuf}.

@item iosockstream io(sbp)
Constructs an @code{iosockstream} object @code{io} with @code{*sbp} as its
@code{sockbuf}.

@item sbp = io.rdbuf()
@findex iosockstream::rdbuf
returns a pointer to the @code{sockbuf} of the @code{iosockstream} object
@code{io}.

@item iosockstream::operator -> ()
@findex iosockstream::operator->
returns a pointer to the @code{iosockstream}'s @code{sockbuf} so that
the user can use @code{iosockstream} object as a @code{sockbuf} object.

@example
    io->connect (sa); // same as io.rdbuf()->connect (sa);
@end example

@end table

@node iosockinet
@section iosockinet Stream Classes

We discus only @code{isockinet} class here. @code{osockinet} and
@code{iosockinet} are similar and are left out. However, they are
covered in the examples that follow.

@subsection isockinet
@cindex isockinet class
@cindex class isockinet

@code{isockinet} is used to handle interprocess communication in
@var{inet} domain. It is derived from @code{isockstream} class and it
uses a @code{sockinetbuf} as its stream buffer. @xref{iosockstream}, for
more details on @code{isockstream}. @xref{sockinetbuf Class}, for
information on @code{sockinetbuf}.

In what follows,
@itemize @minus
@item
@code{ty} is a @code{sockbuf::type} and must be one of
@code{sockbuf::sock_stream}, @code{sockbuf::sock_dgram},
@code{sockbuf::sock_raw}, @code{sockbuf::sock_rdm}, and
@code{sockbuf::sock_seqpacket}
@item
@code{proto} denotes the protocol number and is of type int