
INET(3)                    UNIX Programmer's Manual                    INET(3)

NNAAMMEE
     iinneett__aattoonn, iinneett__aaddddrr, iinneett__nneettwwoorrkk, iinneett__nnttooaa, iinneett__mmaakkeeaaddddrr, iinneett__llnnaaooff,
     iinneett__nneettooff - Internet address manipulation routines

SSYYNNOOPPSSIISS
     ##iinncclluuddee <<ssyyss//ssoocckkeett..hh>>
     ##iinncclluuddee <<nneettiinneett//iinn..hh>>
     ##iinncclluuddee <<aarrppaa//iinneett..hh>>

     _i_n_t
     iinneett__aattoonn(_c_h_a_r _*_c_p, _s_t_r_u_c_t _i_n___a_d_d_r _*_p_i_n)

     _u_n_s_i_g_n_e_d _l_o_n_g
     iinneett__aaddddrr(_c_h_a_r _*_c_p)

     _u_n_s_i_g_n_e_d _l_o_n_g
     iinneett__nneettwwoorrkk(_c_h_a_r _*_c_p)

     _c_h_a_r _*
     iinneett__nnttooaa(_s_t_r_u_c_t _i_n___a_d_d_r _i_n)

     _s_t_r_u_c_t _i_n___a_d_d_r
     iinneett__mmaakkeeaaddddrr(_i_n_t _n_e_t, _i_n_t _l_n_a)

     _u_n_s_i_g_n_e_d _l_o_n_g
     iinneett__llnnaaooff(_s_t_r_u_c_t _i_n___a_d_d_r _i_n)

     _u_n_s_i_g_n_e_d _l_o_n_g
     iinneett__nneettooff(_s_t_r_u_c_t _i_n___a_d_d_r _i_n)

DDEESSCCRRIIPPTTIIOONN
     The routines iinneett__aattoonn(), iinneett__aaddddrr() and iinneett__nneettwwoorrkk() interpret char-
     acter strings representing numbers expressed in the Internet standard `.'
     notation.  The iinneett__aattoonn() routine interprets the specified character
     string as an Internet address, placing the address into the structure
     provided.  It returns 1 if the string was successfully interpreted, or 0
     if the string is invalid.  The iinneett__aaddddrr() and iinneett__nneettwwoorrkk() functions
     return numbers suitable for use as Internet addresses and Internet net-
     work numbers, respectively.  The routine iinneett__nnttooaa() takes an Internet
     address and returns an ASCII string representing the address in `.' nota-
     tion.  The routine iinneett__mmaakkeeaaddddrr() takes an Internet network number and a
     local network address and constructs an Internet address from it.  The
     routines iinneett__nneettooff() and iinneett__llnnaaooff() break apart Internet host address-
     es, returning the network number and local network address part, respec-
     tively.

     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.

IINNTTEERRNNEETT AADDDDRREESSSSEESS
     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.
     Note that when an Internet address is viewed as a 32-bit integer quantity
     on the VAX the bytes referred to above appear as ``d.c.b.a''. That is,
     VAX bytes are ordered from right to left.

     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 ad-
     dress.  This makes the three part address format convenient for specify-
     ing Class B network addresses as ``128.net.host''.

     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 specify-
     ing 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, oc-
     tal, or hexadecimal, as specified in the C language (i.e., a leading 0x
     or 0X implies hexadecimal; otherwise, a leading 0 implies octal; other-
     wise, the number is interpreted as decimal).

DDIIAAGGNNOOSSTTIICCSS
     The constant INADDR_NONE is returned by iinneett__aaddddrr() and iinneett__nneettwwoorrkk()
     for malformed requests.

SSEEEE AALLSSOO
     gethostbyname(3),  getnetent(3),  hosts(5),  networks(5),

HHIISSTTOORRYY
     These functions appeared in 4.2BSD.

BBUUGGSS
     The value INADDR_NONE (0xffffffff) is a valid broadcast address, but
     iinneett__aaddddrr() cannot return that value without indicating failure.  The
     newer iinneett__aattoonn() function does not share this problem.  The problem of
     host byte ordering versus network byte ordering is confusing.  The string
     returned by iinneett__nnttooaa() resides in a static memory area.

     Inet_addr should return a _s_t_r_u_c_t _i_n___a_d_d_r.

 MiNT-Net                       April 19, 1991                               2



























