ares_parse_txt_reply(3) Library Functions Manual ares_parse_txt_reply(3)
NAME
ares_parse_txt_reply - Parse a reply to a DNS query of type TXT
SYNOPSIS
#include <ares.h>
int ares_parse_txt_reply(const unsigned char* abuf, int alen,
struct ares_txt_reply **txt_out);
int ares_parse_txt_reply_ext(const unsigned char* abuf, int alen,
struct ares_txt_ext **txt_out);
DESCRIPTION
The ares_parse_txt_reply(3) and ares_parse_txt_reply_ext(3) functions
parse the response to a query of type TXT into a linked list (one
element per sub-string) of struct ares_txt_reply (struct ares_txt_ext)
The parameters abuf and alen give the contents of the response. The
result is stored in allocated memory and a pointer to it stored into
the variable pointed to by txt_out. It is the caller's responsibility
to free the resulting txt_out structure when it is no longer needed
using the function ares_free_data(3).
The structure ares_txt_reply contains the following fields:
struct ares_txt_reply {
struct ares_txt_reply *next;
unsigned int length;
unsigned char *txt;
};
The structure ares_txt_ext contains the following fields:
struct ares_txt_ext {
struct ares_txt_ext *next;
unsigned int length;
unsigned char *txt;
unsigned char record_start;
};
The record_start field in struct ares_txt_ext is 1 if this structure is
a start of a TXT record, and 0 if the structure is a continuation of a
previous record. The linked list of the struct ares_txt_ext will have
at least one item with record_start equal to 1, and may have some items
with record_start equal to 0 between them.
These sequences of struct ares_txt_ext (starting from the item with
record_start equal to 1, and ending right before the record start item)
may be treated as either components of a single TXT record or as a
multi-parted TXT record, depending on particular use case.
RETURN VALUES
ares_parse_txt_reply (ares_parse_txt_reply_ext) can return any of the
following values:
ARES_SUCCESS The response was successfully parsed.
ARES_EBADRESP The response was malformatted.
ARES_ENODATA The response did not contain an answer to the query.
ARES_ENOMEM Memory was exhausted.
AVAILABILITY
This function was first introduced in c-ares version 1.7.0.
SEE ALSO
ares_query(3) ares_free_data(3)
27 October 2009 ares_parse_txt_reply(3)
c-ares 1.30.0 - Generated Thu Jun 13 11:47:46 CDT 2024