Comtrol eCos - Manual (Page 535)

Chapter 38. TCP/IP Library Reference
and inet_network() functions return numbers suitable for use as Internet
addresses and Internet network numbers, respectively.
The function inet_ntop() converts an address from network format (usually
a struct in_addr or some other binary form, in network byte order) to
presentation format (suitable for external display purposes). It returns
NULL if a system error occurs (in which case, errno will have been set),
or it returns a pointer to the destination string. The routine
inet_ntoa() takes an Internet address and returns an ASCII string repre-
senting the address in ‘.’ notation. The routine inet_makeaddr() takes
an Internet network number and a local network address and constructs an
Internet address from it. The routines inet_netof() and inet_lnaof()
break apart Internet host addresses, returning the network number and
local network address part, respectively.
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 (IP VERSION 4)
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 a system that uses little-endian byte order (such as the Intel 386,
486 and Pentium processors) the bytes referred to above appear as
“d.c.b.a”. That is, little-endian 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 rightmost two bytes of the network
address. This makes the three part address format convenient for speci-
fying 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 rightmost 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,
octal, 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).
INTERNET ADDRESSES (IP VERSION 6)
In order to support scoped IPv6 addresses, getaddrinfo(3) and
431