MirOS Manual: Socket(3p)


Socket(3p)      Perl Programmers Reference Guide       Socket(3p)

NAME

     Socket, sockaddr_in, sockaddr_un, inet_aton, inet_ntoa -
     load the C socket.h defines and structure manipulators

SYNOPSIS

         use Socket;

         $proto = getprotobyname('udp');
         socket(Socket_Handle, PF_INET, SOCK_DGRAM, $proto);
         $iaddr = gethostbyname('hishost.com');
         $port = getservbyname('time', 'udp');
         $sin = sockaddr_in($port, $iaddr);
         send(Socket_Handle, 0, 0, $sin);

         $proto = getprotobyname('tcp');
         socket(Socket_Handle, PF_INET, SOCK_STREAM, $proto);
         $port = getservbyname('smtp', 'tcp');
         $sin = sockaddr_in($port,inet_aton("127.1"));
         $sin = sockaddr_in(7,inet_aton("localhost"));
         $sin = sockaddr_in(7,INADDR_LOOPBACK);
         connect(Socket_Handle,$sin);

         ($port, $iaddr) = sockaddr_in(getpeername(Socket_Handle));
         $peer_host = gethostbyaddr($iaddr, AF_INET);
         $peer_addr = inet_ntoa($iaddr);

         $proto = getprotobyname('tcp');
         socket(Socket_Handle, PF_UNIX, SOCK_STREAM, $proto);
         unlink('/var/run/usock');
         $sun = sockaddr_un('/var/run/usock');
         connect(Socket_Handle,$sun);

DESCRIPTION

     This module is just a translation of the C socket.h file.
     Unlike the old mechanism of requiring a translated socket.ph
     file, this uses the h2xs program (see the Perl source dis-
     tribution) and your native C compiler.  This means that it
     has a far more likely chance of getting the numbers right.
     This includes all of the commonly used pound-defines like
     AF_INET, SOCK_STREAM, etc.

     Also, some common socket "newline" constants are provided:
     the constants "CR", "LF", and "CRLF", as well as $CR, $LF,
     and $CRLF, which map to "\015", "\012", and "\015\012".  If
     you do not want to use the literal characters in your pro-
     grams, then use the constants provided here.  They are not
     exported by default, but can be imported individually, and
     with the ":crlf" export tag:

         use Socket qw(:DEFAULT :crlf);

perl v5.8.8                2005-02-05                           1

Socket(3p)      Perl Programmers Reference Guide       Socket(3p)

     In addition, some structure manipulation functions are
     available:

     inet_aton HOSTNAME
         Takes a string giving the name of a host, and translates
         that to an opaque string (if programming in C, struct
         in_addr). Takes arguments of both the 'rtfm.mit.edu'
         type and '18.181.0.24'. If the host name cannot be
         resolved, returns undef.  For multi-homed hosts (hosts
         with more than one address), the first address found is
         returned.

         For portability do not assume that the result of
         inet_aton() is 32 bits wide, in other words, that it
         would contain only the IPv4 address in network order.

     inet_ntoa IP_ADDRESS
         Takes a string (an opaque string as returned by
         inet_aton(), or a v-string representing the four octets
         of the IPv4 address in network order) and translates it
         into a string of the form 'd.d.d.d' where the 'd's are
         numbers less than 256 (the normal human-readable four
         dotted number notation for Internet addresses).

     INADDR_ANY
         Note: does not return a number, but a packed string.

         Returns the 4-byte wildcard ip address which specifies
         any of the hosts ip addresses.  (A particular machine
         can have more than one ip address, each address
         corresponding to a particular network interface. This
         wildcard address allows you to bind to all of them
         simultaneously.) Normally equivalent to
         inet_aton('0.0.0.0').

     INADDR_BROADCAST
         Note: does not return a number, but a packed string.

         Returns the 4-byte 'this-lan' ip broadcast address. This
         can be useful for some protocols to solicit information
         from all servers on the same LAN cable. Normally
         equivalent to inet_aton('255.255.255.255').

     INADDR_LOOPBACK
         Note - does not return a number.

         Returns the 4-byte loopback address.  Normally
         equivalent to inet_aton('localhost').

     INADDR_NONE
         Note - does not return a number.

perl v5.8.8                2005-02-05                           2

Socket(3p)      Perl Programmers Reference Guide       Socket(3p)

         Returns the 4-byte 'invalid' ip address.  Normally
         equivalent to inet_aton('255.255.255.255').

     sockaddr_family SOCKADDR
         Takes a sockaddr structure (as returned by
         pack_sockaddr_in(), pack_sockaddr_un() or the perl buil-
         tin functions getsockname() and getpeername()) and
         returns the address family tag.  It will match the con-
         stant AF_INET for a sockaddr_in and AF_UNIX for a
         sockaddr_un.  It can be used to figure out what unpacker
         to use for a sockaddr of unknown type.

     sockaddr_in PORT, ADDRESS
     sockaddr_in SOCKADDR_IN
         In a list context, unpacks its SOCKADDR_IN argument and
         returns an array consisting of (PORT, ADDRESS).  In a
         scalar context, packs its (PORT, ADDRESS) arguments as a
         SOCKADDR_IN and returns it.  If this is confusing, use
         pack_sockaddr_in() and unpack_sockaddr_in() explicitly.

     pack_sockaddr_in PORT, IP_ADDRESS
         Takes two arguments, a port number and an opaque string,
         IP_ADDRESS (as returned by inet_aton(), or a v-string).
         Returns the sockaddr_in structure with those arguments
         packed in with AF_INET filled in.  For Internet domain
         sockets, this structure is normally what you need for
         the arguments in bind(), connect(), and send(), and is
         also returned by getpeername(), getsockname() and
         recv().

     unpack_sockaddr_in SOCKADDR_IN
         Takes a sockaddr_in structure (as returned by
         pack_sockaddr_in()) and returns an array of two ele-
         ments: the port and an opaque string representing the IP
         address (you can use inet_ntoa() to convert the address
         to the four-dotted numeric format).  Will croak if the
         structure does not have AF_INET in the right place.

     sockaddr_un PATHNAME
     sockaddr_un SOCKADDR_UN
         In a list context, unpacks its SOCKADDR_UN argument and
         returns an array consisting of (PATHNAME).  In a scalar
         context, packs its PATHNAME arguments as a SOCKADDR_UN
         and returns it.  If this is confusing, use
         pack_sockaddr_un() and unpack_sockaddr_un() explicitly.
         These are only supported if your system has <sys/un.h>.

     pack_sockaddr_un PATH
         Takes one argument, a pathname. Returns the sockaddr_un
         structure with that path packed in with AF_UNIX filled
         in. For unix domain sockets, this structure is normally
         what you need for the arguments in bind(), connect(),

perl v5.8.8                2005-02-05                           3

Socket(3p)      Perl Programmers Reference Guide       Socket(3p)

         and send(), and is also returned by getpeername(), get-
         sockname() and recv().

     unpack_sockaddr_un SOCKADDR_UN
         Takes a sockaddr_un structure (as returned by
         pack_sockaddr_un()) and returns the pathname.  Will
         croak if the structure does not have AF_UNIX in the
         right place.

perl v5.8.8                2005-02-05                           4

Generated on 2014-07-04 21:17:45 by $MirOS: src/scripts/roff2htm,v 1.79 2014/02/10 00:36:11 tg Exp $

These manual pages and other documentation are copyrighted by their respective writers; their source is available at our CVSweb, AnonCVS, and other mirrors. The rest is Copyright © 2002‒2014 The MirOS Project, Germany.
This product includes material provided by Thorsten Glaser.

This manual page’s HTML representation is supposed to be valid XHTML/1.1; if not, please send a bug report – diffs preferred.