intro(3n)																 intro(3n)

Name
       intro - introduction to network library functions

Description
       This  section describes functions that are available for interprocess communication (IPC).  IPC takes place using sockets.  The system call
       creates a communications channel based on domain, type, and protocol.

       Sockets are created without names.  The system call is used to connect a name to a socket.

       A connection with another process must be made before data can be transferred on a bound socket.  The system call  is  used  to	rendezvous
       with another process.  This process must be listening on a bound socket using the system call.  This listening process can accept a connec-
       tion request using the system call.

       Once two processes have connected and accepted an IPC, data can be transferred with the following system calls: and

       Connectionless sockets are also possible (a socket is bound and data can be transferred).  They use the following system calls to  transfer
       data: and

       IPC operates in three domains:

       UNIX		Local node

       INTERNET 	Local area network (LAN)

       DECNET		DECnet network

       These types of sockets are available for IPC:

       stream		Sequenced, reliable, unduplicated data
			CONNECTED socket
			record boundaries not preserved
			all domains

       datagram 	Not guaranteed to be sequenced, reliable, or
			unduplicated
			user protocol needed to give guarantees
			UNCONNECTED socket
			record boundaries preserved
			UNIX and INTERNET domains

       sequenced packet Like stream socket, except record boundaries preserved
			DECNET domain only

       raw		Access to communications protocols

Internet Addresses Routines
       The inet routines manipulate Internet addresses.

Network Data Base File Routines
       Standard  mapping  routines are used to retrieve entries in network data base files.  Several routines operating on each data base file are
       identified by a group name:

       Retrieves entries from

       Retrieves entries from

       Retrieves entries from

       Retrieves entries from

       Specific routines perform particular operations on each data base file:

       Reads the next line of the file; opens
			the file, if necessary.

       Opens and rewinds the file.

       Closes the file.

       Searches the file sequentially from the beginning
			until a matching name is found, or EOF is encountered.

       Searches the file sequentially from the beginning
			until a matching address is found, or EOF is encountered.

       Searches the file sequentially from the beginning
			until a matching port number is found, or EOF is encountered.

       Searches the file sequentially from the beginning
			until a matching protocol number is found, or EOF is encountered.

       Each network library routine returns a pointer to a structure reflecting individual fields of a line in one of the network data base files.
       The  structure  for each data base file contains some of the fields in the following list, with the prefix x replaced by a different letter
       in each file:

       pointer to a network address,
			returned in network-byte order

       address family of the address being returned

       alternate names

       length of an address, in bytes

       official name

       network number, returned in machine-byte order

       resident port

       protocol number

																	 intro(3n)