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84 lines
2.9 KiB
84 lines
2.9 KiB
4 years ago
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.\"
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.\" Copyright 1998 by the Massachusetts Institute of Technology.
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.\"
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.\" Permission to use, copy, modify, and distribute this
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.\" software and its documentation for any purpose and without
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.\" fee is hereby granted, provided that the above copyright
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.\" notice appear in all copies and that both that copyright
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.\" notice and this permission notice appear in supporting
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.\" documentation, and that the name of M.I.T. not be used in
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.\" advertising or publicity pertaining to distribution of the
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.\" software without specific, written prior permission.
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.\" M.I.T. makes no representations about the suitability of
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.\" this software for any purpose. It is provided "as is"
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.\" without express or implied warranty.
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.\"
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.TH ARES_CREATE_QUERY 3 "17 Aug 2012"
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.SH NAME
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ares_create_query \- Compose a single-question DNS query buffer
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.SH SYNOPSIS
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.nf
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#include <ares.h>
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int ares_create_query(const char *\fIname\fP,
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int \fIdnsclass\fP,
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int \fItype\fP,
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unsigned short \fIid\fP,
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int \fIrd\fP,
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unsigned char **\fIbuf\fP,
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int *\fIbuflen\fP,
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int \fImax_udp_size\fP)
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.fi
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.SH DESCRIPTION
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The \fIares_create_query(3)\fP function composes a DNS query with a single
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question. The parameter \fIname\fP gives the query name as a NUL-terminated C
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string of period-separated labels optionally ending with a period; periods and
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backslashes within a label must be escaped with a backlash.
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The parameters \fIdnsclass\fP and \fItype\fP give the class and type of the
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query using the values defined in \fB<arpa/nameser.h>\fP.
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The parameter \fIid\fP gives a 16-bit identifier for the query.
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The parameter \fIrd\fP should be nonzero if recursion is desired, zero if not.
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The query will be placed in an allocated buffer, a pointer to which will be
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stored in the variable pointed to by \fIbuf\fP, and the length of which will
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be stored in the variable pointed to by \fIbuflen\fP.
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It is the caller's responsibility to free this buffer using
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\fIares_free_string(3)\fP when it is no longer needed. The parameter
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\fImax_udp_size\fP should be nonzero to activate EDNS. Usage of
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\fIares_create_query(3)\fP\ with \fImax_udp_size\fP set to zero is equivalent
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to using \fIares_mkquery(3)\fP.
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.SH RETURN VALUES
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.B ares_create_query
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can return any of the following values:
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.TP 15
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.B ARES_SUCCESS
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Construction of the DNS query succeeded.
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.TP 15
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.B ARES_ENOTFOUND
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The query name
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.I name
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refers to a
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.I .onion
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domain name. See RFC 7686.
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.TP 15
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.B ARES_EBADNAME
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The query name
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.I name
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could not be encoded as a domain name, either because it contained a
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zero-length label or because it contained a label of more than 63
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characters.
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.TP 15
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.B ARES_ENOMEM
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Memory was exhausted.
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.SH AVAILABILITY
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Added in c-ares 1.10.0
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.SH SEE ALSO
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.BR ares_expand_name (3),
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.BR ares_free_string (3),
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.BR ares_mkquery (3)
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.SH AUTHOR
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