Provided by: umview_0.6-1_i386 bug

NAME

       msocket  -  create  an  endpoint  for  communication  in  a multi-stack
       environment

SYNOPSIS

       #include <sys/types.h>          /* See NOTES */
       #include <msocket.h>

       int msocket(char * path, int domain, int type, int protocol);

DESCRIPTION

       msocket()  creates  an  endpoint  for  communication  and   returns   a
       descriptor in a multi-stack environment or defines the default stack.

       The  path  parameter selects the stack used for the call. The path must
       refer to a stack special file (S_IFSTACK).   When  path  is  NULL,  the
       default  stack  gets  used. It is possible to specify a default network
       stack for each domain (see SOCK_DEFAULT below).

       The domain parameter specifies a communication domain; this selects the
       protocol  family  which will be used for communication.  These families
       are  defined  in  <sys/socket.h>.   The  currently  understood  formats
       include:

       Name                Purpose                          Man page
       PF_UNIX, PF_LOCAL   Local communication              unix(7)
       PF_INET             IPv4 Internet protocols          ip(7)
       PF_INET6            IPv6 Internet protocols          ipv6(7)
       PF_IPX              IPX - Novell protocols
       PF_NETLINK          Kernel user interface device     netlink(7)
       PF_X25              ITU-T X.25 / ISO-8208 protocol   x25(7)
       PF_AX25             Amateur radio AX.25 protocol
       PF_ATMPVC           Access to raw ATM PVCs
       PF_APPLETALK        Appletalk                        ddp(7)
       PF_PACKET           Low level packet interface       packet(7)

       The  socket  has  the indicated type, which specifies the communication
       semantics  or  SOCK_DEFAULT  to  define  the  standard  stack  for  the
       specified domain(s).  Currently defined types are:

       SOCK_STREAM
              Provides  sequenced,  reliable,  two-way,  connection-based byte
              streams.  An out-of-band  data  transmission  mechanism  may  be
              supported.

       SOCK_DGRAM
              Supports  datagrams  (connectionless,  unreliable  messages of a
              fixed maximum length).

       SOCK_SEQPACKET
              Provides a sequenced, reliable,  two-way  connection-based  data
              transmission  path  for  datagrams  of  fixed  maximum length; a
              consumer is required to read an entire packet  with  each  input
              system call.

       SOCK_RAW
              Provides raw network protocol access.

       SOCK_RDM
              Provides  a  reliable  datagram  layer  that  does not guarantee
              ordering.

       SOCK_PACKET
              Obsolete and should not be used in new programs; see packet(7).

       Some socket types may not be implemented by all protocol families;  for
       example, SOCK_SEQPACKET is not implemented for AF_INET.

       When  type  is  SOCK_DEFAULT  msocket does not define any communication
       endpoint, instead it defines the  stack  that  will  be  used  for  the
       following  msocket  calls with NULL path, or for the following obsolete
       socket(2) calls.  Default stacks get inherited through process creation
       fork(2)  and execution execve(2).  When type is SOCK_DEFAULT and domain
       is PF_UNSPEC the named stack becames the  default  stack  for  all  the
       protocols it supports.

       The  protocol  specifies  a  particular  protocol  to  be used with the
       socket.  Normally only a single protocol exists to support a particular
       socket  type within a given protocol family, in which case protocol can
       be specified as 0.  However, it is possible  that  many  protocols  may
       exist,  in  which  case a particular protocol must be specified in this
       manner.  The protocol number to use is specific to  the  "communication
       domain" in which communication is to take place; see protocols(5).  See
       getprotoent(3) on how to map protocol name strings to protocol numbers.

       Sockets of type SOCK_STREAM are full-duplex byte  streams,  similar  to
       pipes.   They  do not preserve record boundaries.  A stream socket must
       be in a connected state before any data may be sent or received on  it.
       A connection to another socket is created with a connect(2) call.  Once
       connected, data may be transferred using read(2) and write(2) calls  or
       some variant of the send(2) and recv(2) calls.  When a session has been
       completed a close(2) may be performed.  Out-of-band data  may  also  be
       transmitted  as  described  in  send(2)  and  received  as described in
       recv(2).

       The communications protocols which implement a SOCK_STREAM ensure  that
       data  is not lost or duplicated.  If a piece of data for which the peer
       protocol has buffer space cannot be successfully transmitted  within  a
       reasonable  length  of  time,  then  the connection is considered to be
       dead.  When SO_KEEPALIVE is enabled on the socket the  protocol  checks
       in  a  protocol-specific  manner  if  the  other end is still alive.  A
       SIGPIPE signal is raised if a process sends or  receives  on  a  broken
       stream; this causes naive processes, which do not handle the signal, to
       exit.   SOCK_SEQPACKET  sockets  employ  the  same  system   calls   as
       SOCK_STREAM  sockets.   The  only difference is that read(2) calls will
       return only the amount of data requested, and any data remaining in the
       arriving  packet  will  be  discarded.   Also all message boundaries in
       incoming datagrams are preserved.

       SOCK_DGRAM  and  SOCK_RAW  sockets  allow  sending  of   datagrams   to
       correspondents  named  in  sendto(2)  calls.   Datagrams  are generally
       received with recvfrom(2), which returns the next datagram  along  with
       the address of its sender.

       SOCK_PACKET  is an obsolete socket type to receive raw packets directly
       from the device driver.  Use packet(7) instead.

       An fcntl(2) F_SETOWN operation can be used  to  specify  a  process  or
       process  group  to  receive  a  SIGURG signal when the out-of-band data
       arrives  or  SIGPIPE  signal  when  a  SOCK_STREAM  connection   breaks
       unexpectedly.   This  operation  may also be used to set the process or
       process group that receives the I/O and  asynchronous  notification  of
       I/O events via SIGIO.  Using F_SETOWN is equivalent to an ioctl(2) call
       with the FIOSETOWN or SIOCSPGRP argument.

       When the network signals an error  condition  to  the  protocol  module
       (e.g.,  using  a ICMP message for IP) the pending error flag is set for
       the socket.  The next operation on this socket will  return  the  error
       code of the pending error.  For some protocols it is possible to enable
       a per-socket error queue to retrieve  detailed  information  about  the
       error; see IP_RECVERR in ip(7).

       The  operation of sockets is controlled by socket level options.  These
       options are defined in <sys/socket.h>.  The functions setsockopt(2) and
       getsockopt(2) are used to set and get options, respectively.

RETURN VALUE

       On  success,  a  file  descriptor for the new socket is returned except
       when type is SOCK_DEFAULT.  In  this  latter  case  0  is  returned  on
       success.  On error, -1 is returned, and errno is set appropriately.

ERRORS

       EACCES Permission  to  create  a  socket  of  the specified type and/or
              protocol is denied.

       EAFNOSUPPORT
              The  implementation  does  not  support  the  specified  address
              family.

       EINVAL Unknown protocol, or protocol family not available.

       EMFILE Process file table overflow.

       ENFILE The  system  limit  on  the  total number of open files has been
              reached.

       ENOBUFS or ENOMEM
              Insufficient memory is available.  The socket cannot be  created
              until sufficient resources are freed.

       EPROTONOSUPPORT
              The  protocol  type  or  the specified protocol is not supported
              within this domain.

       Other errors may be generated by the underlying protocol modules.

CONFORMING TO

       This is a  system  call  defined  for  View-OS.  It  extends  socket(),
       appeared  in  4.2BSD  and  conforming  to 4.4BSD, POSIX.1-2001.  System
       providing msocket() do  provide  also  a  socket()  call  for  backward
       compatibility.   In fact: socket(domain,type,protocol) is equivalent to
       msocket(NULL,domain,type,protocol)

       In this way it is generally portable to/from non-BSD systems supporting
       clones of the BSD socket layer (including System V variants).

NOTES

       POSIX.1-2001  does not require the inclusion of <sys/types.h>, and this
       header file is not required on Linux.  However, some  historical  (BSD)
       implementations  required  this  header file, and portable applications
       are probably wise to include it.

       The manifest constants used under 4.x BSD  for  protocol  families  are
       PF_UNIX,  PF_INET,  etc.,  while  AF_UNIX  etc.  are  used  for address
       families.  However, already the BSD man page  promises:  "The  protocol
       family  generally  is  the  same as the address family", and subsequent
       standards use AF_* everywhere.

       The header file <sys/types.h> is only required for  libc4  or  earlier.
       Some packages, like util-linux, claim portability to all Linux versions
       and libraries.  They certainly need this header file.

BUGS

       SOCK_UUCP is not implemented yet.

SEE ALSO

       socket(2), accept(2), bind(2),  connect(2),  fcntl(2),  getpeername(2),
       getsockname(2),  getsockopt(2),  ioctl(2), listen(2), read(2), recv(2),
       select(2),    send(2),    shutdown(2),     socketpair(2),     write(2),
       getprotoent(3), ip(7), socket(7), tcp(7), udp(7), unix(7)

COLOPHON

       This  page has been modified from socket(2) page of release 2.79 of the
       Linux. In fact msocket(2) is an  extension  of  this  call.   man-pages
       project.  A description of the project, and information about reporting
       bugs, can be found at http://www.kernel.org/doc/man-pages/.

       View-OS is a project of the Computer Science Department, University  of
       Bologna. Project Leader: Renzo Davoli.
       <http://www.sourceforge.net/projects/view-os>

       Howto's and further information can be found on the project wiki
       <wiki.virtualsquare.org>.