inet(3N)           UNIX System V(User Environment Utilities)           inet(3N)


NAME
      inet: inetaddr, inetnetwork, inetmakeaddr, inetlnaof, inetnetof,
      inetntoa - Internet address manipulation

SYNOPSIS
      #include <sys/types.h>
      #include <sys/socket.h>
      #include <netinet/in.h>
      #include <arpa/inet.h>
      unsigned long inetaddr(char *cp);
      unsigned long inetnetwork(char *cp);
      struct inaddr inetmakeaddr(int net, int lna);
      int inetlnaof(struct inaddr in);
      int inetnetof(struct inaddr in);
      char *inetntoa(struct inaddr in);

DESCRIPTION
      The routines inetaddr and inetnetwork each interpret character strings
      representing numbers expressed in the Internet standard `.'  notation,
      returning numbers suitable for use as Internet addresses and Internet
      network numbers, respectively.  The routine inetmakeaddr takes an
      Internet network number and a local network address and constructs an
      Internet address from it.  The routines inetnetof and inetlnaof break
      apart Internet host addresses, returning the network number and local
      network address part, respectively.

      The routine inetntoa returns a pointer to a string in the base 256
      notation d.d.d.d described below.

      All Internet addresses are returned in network order (bytes ordered from
      left to right).  All network numbers and local address parts are returned
      as machine format integer values.

INTERNET ADDRESSES
      Values specified using the `.'  notation take one of the following forms:


            a.b.c.d
            a.b.c
            a.b
            a

      When four parts are specified, each is interpreted as a byte of data and
      assigned, from left to right, to the four bytes of an Internet address.

      When a three part address is specified, the last part is interpreted as a
      16-bit quantity and placed in the right most two bytes of the network
      address.  This makes the three part address format convenient for
      specifying Class B network addresses as 128.net.host.





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inet(3N)           UNIX System V(User Environment Utilities)           inet(3N)


      When a two part address is supplied, the last part is interpreted as a
      24-bit quantity and placed in the right most three bytes of the network
      address.  This makes the two part address format convenient for
      specifying Class A network addresses as net.host.

      When only one part is given, the value is stored directly in the network
      address without any byte rearrangement.

      All numbers supplied as parts in a `.'  notation may be decimal, octal,
      or hexadecimal, as specified in the C language (that is, a leading 0x or
      0X implies hexadecimal; otherwise, a leading 0 implies octal; otherwise,
      the number is interpreted as decimal).

SEE ALSO
      gethostent(3N), getnetent(3N), hosts(4), networks(4)

DIAGNOSTICS
      The value -1 is returned by inetaddr and inetnetwork for malformed
      requests.

NOTES
      The problem of host byte ordering versus network byte ordering is
      confusing.  A simple way to specify Class C network addresses in a manner
      similar to that for Class B and Class A is needed.

      The return value from inetntoa points to static information which is
      overwritten in each call.



























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