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24 .TH "LWRES_GETADDRINFO" "3" "Jun 30, 2000" "BIND9" "BIND9"
25 .\" disable hyphenation
27 .\" disable justification (adjust text to left margin only)
30 lwres_getaddrinfo, lwres_freeaddrinfo \- socket address structure to host and service name
33 #include <lwres/netdb.h>
36 \fBint\ \fBlwres_getaddrinfo\fR\fR\fB(\fR\fBconst\ char\ *hostname\fR\fB, \fR\fBconst\ char\ *servname\fR\fB, \fR\fBconst\ struct\ addrinfo\ *hints\fR\fB, \fR\fBstruct\ addrinfo\ **res\fR\fB);\fR
38 \fBvoid\ \fBlwres_freeaddrinfo\fR\fR\fB(\fR\fBstruct\ addrinfo\ *ai\fR\fB);\fR
40 If the operating system does not provide a
41 \fBstruct addrinfo\fR, the following structure is used:
45 int ai_flags; /* AI_PASSIVE, AI_CANONNAME */
46 int ai_family; /* PF_xxx */
47 int ai_socktype; /* SOCK_xxx */
48 int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
49 size_t ai_addrlen; /* length of ai_addr */
50 char *ai_canonname; /* canonical name for hostname */
51 struct sockaddr *ai_addr; /* binary address */
52 struct addrinfo *ai_next; /* next structure in linked list */
58 \fBlwres_getaddrinfo()\fR
59 is used to get a list of IP addresses and port numbers for host
62 \fIservname\fR. The function is the lightweight resolver's implementation of
64 as defined in RFC2133.
68 are pointers to null\-terminated strings or
71 is either a host name or a numeric host address string: a dotted decimal IPv4 address or an IPv6 address.
73 is either a decimal port number or a service name as listed in
77 is an optional pointer to a
78 \fBstruct addrinfo\fR. This structure can be used to provide hints concerning the type of socket that the caller supports or wishes to use. The caller can supply the following structure elements in
82 The protocol family that should be used. When
85 \fBPF_UNSPEC\fR, it means the caller will accept any protocol family supported by the operating system.
88 denotes the type of socket \(em
93 \(em that is wanted. When
95 is zero the caller will accept any socket type.
98 indicates which transport protocol is wanted: IPPROTO_UDP or IPPROTO_TCP. If
100 is zero the caller will accept any protocol.
105 bit is set, a successful call to
106 \fBlwres_getaddrinfo()\fR
107 will return a null\-terminated string containing the canonical name of the specified hostname in
111 structure returned. Setting the
113 bit indicates that the returned socket address structure is intended for used in a call to
114 \fBbind\fR(2). In this case, if the hostname argument is a
116 pointer, then the IP address portion of the socket address structure will be set to
118 for an IPv4 address or
119 \fBIN6ADDR_ANY_INIT\fR
126 bit, the returned socket address structure will be ready for use in a call to
128 for a connection\-oriented protocol or
132 if a connectionless protocol was chosen. The IP address portion of the socket address structure will be set to the loopback address if
147 should be treated as a numeric string defining an IPv4 or IPv6 address and no name resolution should be attempted.
149 All other elements of the
150 \fBstruct addrinfo\fR
159 is treated as if the caller provided a
160 \fBstruct addrinfo\fR
161 initialized to zero with
162 \fBai_family\fRset to
165 After a successful call to
166 \fBlwres_getaddrinfo()\fR,
168 is a pointer to a linked list of one or more
171 \fBstruct addrinfo\fR
172 in this list cn be processed by following the
176 pointer is encountered. The three members
178 \fBai_socktype\fR, and
182 structure contain the corresponding arguments for a call to
183 \fBsocket\fR(2). For each
185 structure in the list, the
187 member points to a filled\-in socket address structure of length
190 All of the information returned by
191 \fBlwres_getaddrinfo()\fR
192 is dynamically allocated: the addrinfo structures, and the socket address structures and canonical host name strings pointed to by the
193 \fBaddrinfo\fRstructures. Memory allocated for the dynamically allocated structures created by a successful call to
194 \fBlwres_getaddrinfo()\fR
196 \fBlwres_freeaddrinfo()\fR.
199 \fBstruct addrinfo\fR
201 \fBlwres_getaddrinfo()\fR.
204 \fBlwres_getaddrinfo()\fR
205 returns zero on success or one of the error codes listed in
206 \fBgai_strerror\fR(3 )
207 if an error occurs. If both
212 \fBNULL\fR\fBlwres_getaddrinfo()\fR
218 \fBlwres_getaddrinfo\fR(3),
219 \fBlwres_freeaddrinfo\fR(3),
220 \fBlwres_gai_strerror\fR(3),
222 \fBgetservbyname\fR(3),