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28 .\" From: @(#)inet.3 8.1 (Berkeley) 6/4/93
29 .\" $FreeBSD: src/lib/libc/net/inet.3,v 1.36 2007/06/14 07:13:28 delphij Exp $
30 .\" $DragonFly: src/lib/libc/net/inet.3,v 1.2 2003/06/17 04:26:44 dillon Exp $
46 .Nd Internet address manipulation routines
55 .Fn inet_aton "const char *cp" "struct in_addr *pin"
57 .Fn inet_addr "const char *cp"
59 .Fn inet_network "const char *cp"
61 .Fn inet_ntoa "struct in_addr in"
64 .Fa "struct in_addr in"
71 .Fa "const void * restrict src"
72 .Fa "char * restrict dst"
76 .Fn inet_pton "int af" "const char * restrict src" "void * restrict dst"
78 .Fn inet_makeaddr "in_addr_t net" "in_addr_t lna"
80 .Fn inet_lnaof "struct in_addr in"
82 .Fn inet_netof "struct in_addr in"
89 interpret character strings representing
90 numbers expressed in the Internet standard
96 function converts a presentation format address (that is, printable form
97 as held in a character string) to network format (usually a
99 or some other internal binary representation, in network byte order).
100 It returns 1 if the address was valid for the specified address family, or
101 0 if the address was not parseable in the specified address family, or -1
102 if some system error occurred (in which case
105 This function is presently valid for
112 routine interprets the specified character string as an Internet address,
113 placing the address into the structure provided.
114 It returns 1 if the string was successfully interpreted,
115 or 0 if the string is invalid.
120 functions return numbers suitable for use
121 as Internet addresses and Internet network
122 numbers, respectively.
131 or some other binary form, in network byte order) to presentation format
132 (suitable for external display purposes).
135 argument specifies the size, in bytes, of the buffer
140 define the maximum size required to convert an address of the respective
142 It returns NULL if a system error occurs (in which case,
144 will have been set), or it returns a pointer to the destination string.
145 This function is presently valid for
152 takes an Internet address and returns an
154 string representing the address in
159 is the reentrant version of
163 takes an Internet network number and a local
164 network address and constructs an Internet address
170 break apart Internet host addresses, returning
171 the network number and local network address part,
174 All Internet addresses are returned in network
175 order (bytes ordered from left to right).
176 All network numbers and local address parts are
177 returned as machine byte order integer values.
178 .Sh INTERNET ADDRESSES
179 Values specified using the
182 of the following forms:
183 .Bd -literal -offset indent
190 When four parts are specified, each is interpreted
191 as a byte of data and assigned, from left to right,
192 to the four bytes of an Internet address.
194 that when an Internet address is viewed as a 32-bit
195 integer quantity on the
197 the bytes referred to
203 ordered from right to left.
205 When a three part address is specified, the last
206 part is interpreted as a 16-bit quantity and placed
207 in the right-most two bytes of the network address.
208 This makes the three part address format convenient
209 for specifying Class B network addresses as
210 .Dq Li 128.net.host .
212 When a two part address is supplied, the last part
213 is interpreted as a 24-bit quantity and placed in
214 the right most three bytes of the network address.
215 This makes the two part address format convenient
216 for specifying Class A network addresses as
219 When only one part is given, the value is stored
220 directly in the network address without any byte
223 All numbers supplied as
228 may be decimal, octal, or hexadecimal, as specified
229 in the C language (i.e., a leading 0x or 0X implies
230 hexadecimal; otherwise, a leading 0 implies octal;
231 otherwise, the number is interpreted as decimal).
239 for malformed requests.
247 was not large enough to store the presentation form of the address.
248 .It Bq Er EAFNOSUPPORT
259 .Xr gethostbyname 3 ,
269 .%T "IP Version 6 Addressing Architecture"
280 does not accept 1-, 2-, or 3-part dotted addresses; all four parts
281 must be specified and are interpreted only as decimal values.
282 This is a narrower input set than that accepted by
286 functions appeared in
291 (0xffffffff) is a valid broadcast address, but
293 cannot return that value without indicating failure.
296 function does not share this problem.
297 The problem of host byte ordering versus network byte ordering is
299 The string returned by
301 resides in a static memory area.
305 function should return a