mirror of https://gitee.com/openkylin/nodejs.git
123 lines
3.4 KiB
Groff
123 lines
3.4 KiB
Groff
.\"
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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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.\" SPDX-License-Identifier: MIT
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.\"
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.TH ARES_PARSE_TXT_REPLY 3 "27 October 2009"
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.SH NAME
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ares_parse_txt_reply \- Parse a reply to a DNS query of type TXT
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.SH SYNOPSIS
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.nf
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#include <ares.h>
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int ares_parse_txt_reply(const unsigned char* \fIabuf\fP, int \fIalen\fP,
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struct ares_txt_reply **\fItxt_out\fP);
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int ares_parse_txt_reply_ext(const unsigned char* \fIabuf\fP, int \fIalen\fP,
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struct ares_txt_ext **\fItxt_out\fP);
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.fi
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.SH DESCRIPTION
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The
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.BR "ares_parse_txt_reply" " (" "ares_parse_txt_reply_ext" ")"
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function parses the response to a query of type TXT into a
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linked list (one element per sub-string) of
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.IR "struct ares_txt_reply" " (" "struct ares_txt_ext" ")"
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The parameters
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.I abuf
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and
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.I alen
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give the contents of the response. The result is stored in allocated
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memory and a pointer to it stored into the variable pointed to by
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.IR txt_out .
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It is the caller's responsibility to free the resulting
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.IR txt_out
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structure when it is no longer needed using the function
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.B ares_free_data
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.PP
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The structure
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.I ares_txt_reply
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contains the following fields:
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.sp
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.in +4n
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.nf
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struct ares_txt_reply {
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struct ares_txt_reply *next;
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unsigned int length;
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unsigned char *txt;
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};
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.fi
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.in
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.PP
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The structure
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.I ares_txt_ext
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contains the following fields:
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.sp
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.in +4n
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.nf
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struct ares_txt_ext {
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struct ares_txt_ext *next;
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unsigned int length;
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unsigned char *txt;
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unsigned char record_start;
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};
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.fi
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.in
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.PP
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The
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.I record_start
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field in
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.I struct ares_txt_ext
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is 1 if this structure is a start of a TXT record, and 0 if the structure is a
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continuation of a previous record. The linked list of the
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.I struct ares_txt_ext
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will have at least one item with
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.I record_start
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equal to 1, and may have some items with
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.I record_start
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equal to 0 between them.
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.PP
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These sequences of
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.I struct ares_txt_ext
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(starting from the item with
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.I record_start
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equal to 1, and ending right before the record start item) may be treated as
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either components of a single TXT record or as a multi-parted TXT record,
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depending on particular use case.
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.PP
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.SH RETURN VALUES
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.BR "ares_parse_txt_reply" " (" "ares_parse_txt_reply_ext" ")"
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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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The response was successfully parsed.
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.TP 15
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.B ARES_EBADRESP
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The response was malformatted.
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.TP 15
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.B ARES_ENODATA
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The response did not contain an answer to the query.
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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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This function was first introduced in c-ares version 1.7.0.
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.SH SEE ALSO
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.BR ares_query (3)
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.BR ares_free_data (3)
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.SH AUTHOR
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Written by Jakub Hrozek <jhrozek@redhat.com>, on behalf of Red Hat, Inc http://www.redhat.com
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.PP
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Amended by Fedor Indutny <fedor@indutny.com>, on behalf of PayPal, Inc https://www.paypal.com
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