1
2.. _dns:
3
4DNS utility functions
5=====================
6
7libuv provides asynchronous variants of `getaddrinfo` and `getnameinfo`.
8
9
10Data types
11----------
12
13.. c:type:: uv_getaddrinfo_t
14
15    `getaddrinfo` request type.
16
17.. c:type:: void (*uv_getaddrinfo_cb)(uv_getaddrinfo_t* req, int status, struct addrinfo* res)
18
19    Callback which will be called with the getaddrinfo request result once
20    complete. In case it was cancelled, `status` will have a value of
21    ``UV_ECANCELED``.
22
23.. c:type:: uv_getnameinfo_t
24
25    `getnameinfo` request type.
26
27.. c:type:: void (*uv_getnameinfo_cb)(uv_getnameinfo_t* req, int status, const char* hostname, const char* service)
28
29    Callback which will be called with the getnameinfo request result once
30    complete. In case it was cancelled, `status` will have a value of
31    ``UV_ECANCELED``.
32
33
34Public members
35^^^^^^^^^^^^^^
36
37.. c:member:: uv_loop_t* uv_getaddrinfo_t.loop
38
39    Loop that started this getaddrinfo request and where completion will be
40    reported. Readonly.
41
42.. c:member:: struct addrinfo* uv_getaddrinfo_t.addrinfo
43
44    Pointer to a `struct addrinfo` containing the result. Must be freed by the user
45    with :c:func:`uv_freeaddrinfo`.
46
47    .. versionchanged:: 1.3.0 the field is declared as public.
48
49.. c:member:: uv_loop_t* uv_getnameinfo_t.loop
50
51    Loop that started this getnameinfo request and where completion will be
52    reported. Readonly.
53
54.. c:member:: char[NI_MAXHOST] uv_getnameinfo_t.host
55
56    Char array containing the resulting host. It's null terminated.
57
58    .. versionchanged:: 1.3.0 the field is declared as public.
59
60.. c:member:: char[NI_MAXSERV] uv_getnameinfo_t.service
61
62    Char array containing the resulting service. It's null terminated.
63
64    .. versionchanged:: 1.3.0 the field is declared as public.
65
66.. seealso:: The :c:type:`uv_req_t` members also apply.
67
68
69API
70---
71
72.. c:function:: int uv_getaddrinfo(uv_loop_t* loop, uv_getaddrinfo_t* req, uv_getaddrinfo_cb getaddrinfo_cb, const char* node, const char* service, const struct addrinfo* hints)
73
74    Asynchronous :man:`getaddrinfo(3)`.
75
76    Either node or service may be NULL but not both.
77
78    `hints` is a pointer to a struct addrinfo with additional address type
79    constraints, or NULL. Consult `man -s 3 getaddrinfo` for more details.
80
81    Returns 0 on success or an error code < 0 on failure. If successful, the
82    callback will get called sometime in the future with the lookup result,
83    which is either:
84
85    * status == 0, the res argument points to a valid `struct addrinfo`, or
86    * status < 0, the res argument is NULL. See the UV_EAI_* constants.
87
88    Call :c:func:`uv_freeaddrinfo` to free the addrinfo structure.
89
90    .. versionchanged:: 1.3.0 the callback parameter is now allowed to be NULL,
91                        in which case the request will run **synchronously**.
92
93.. c:function:: void uv_freeaddrinfo(struct addrinfo* ai)
94
95    Free the struct addrinfo. Passing NULL is allowed and is a no-op.
96
97.. c:function:: int uv_getnameinfo(uv_loop_t* loop, uv_getnameinfo_t* req, uv_getnameinfo_cb getnameinfo_cb, const struct sockaddr* addr, int flags)
98
99    Asynchronous :man:`getnameinfo(3)`.
100
101    Returns 0 on success or an error code < 0 on failure. If successful, the
102    callback will get called sometime in the future with the lookup result.
103    Consult `man -s 3 getnameinfo` for more details.
104
105    .. versionchanged:: 1.3.0 the callback parameter is now allowed to be NULL,
106                        in which case the request will run **synchronously**.
107
108.. seealso:: The :c:type:`uv_req_t` API functions also apply.
109