| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | .\" |
| 2 | .\" Copyright 1998 by the Massachusetts Institute of Technology. |
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| 16 | .TH ARES_CREATE_QUERY 3 "17 Aug 2012" |
| 17 | .SH NAME |
| 18 | ares_create_query \- Compose a single-question DNS query buffer |
| 19 | .SH SYNOPSIS |
| 20 | .nf |
| 21 | #include <ares.h> |
| 22 | |
| 23 | int ares_create_query(const char *\fIname\fP, |
| 24 | int \fIdnsclass\fP, |
| 25 | int \fItype\fP, |
| 26 | unsigned short \fIid\fP, |
| 27 | int \fIrd\fP, |
| 28 | unsigned char **\fIbuf\fP, |
| 29 | int *\fIbuflen\fP, |
| 30 | int \fImax_udp_size\fP) |
| 31 | .fi |
| 32 | .SH DESCRIPTION |
| 33 | The \fIares_create_query(3)\fP function composes a DNS query with a single |
| 34 | question. The parameter \fIname\fP gives the query name as a NUL-terminated C |
| 35 | string of period-separated labels optionally ending with a period; periods and |
| 36 | backslashes within a label must be escaped with a backlash. |
| 37 | |
| 38 | The parameters \fIdnsclass\fP and \fItype\fP give the class and type of the |
| 39 | query using the values defined in \fB<arpa/nameser.h>\fP. |
| 40 | |
| 41 | The parameter \fIid\fP gives a 16-bit identifier for the query. |
| 42 | |
| 43 | The parameter \fIrd\fP should be nonzero if recursion is desired, zero if not. |
| 44 | |
| 45 | The query will be placed in an allocated buffer, a pointer to which will be |
| 46 | stored in the variable pointed to by \fIbuf\fP, and the length of which will |
| 47 | be stored in the variable pointed to by \fIbuflen\fP. |
| 48 | |
| 49 | It is the caller's responsibility to free this buffer using |
| 50 | \fIares_free_string(3)\fP when it is no longer needed. The parameter |
| 51 | \fImax_udp_size\fP should be nonzero to activate EDNS. Usage of |
| 52 | \fIares_create_query(3)\fP\ with \fImax_udp_size\fP set to zero is equivalent |
| 53 | to using \fIares_mkquery(3)\fP. |
| 54 | .SH RETURN VALUES |
| 55 | .B ares_create_query |
| 56 | can return any of the following values: |
| 57 | .TP 15 |
| 58 | .B ARES_SUCCESS |
| 59 | Construction of the DNS query succeeded. |
| 60 | .TP 15 |
| 61 | .B ARES_EBADNAME |
| 62 | The query name |
| 63 | .I name |
| 64 | could not be encoded as a domain name, either because it contained a |
| 65 | zero-length label or because it contained a label of more than 63 |
| 66 | characters. |
| 67 | .TP 15 |
| 68 | .B ARES_ENOMEM |
| 69 | Memory was exhausted. |
| 70 | .SH AVAILABILITY |
| 71 | Added in c-ares 1.10.0 |
| 72 | .SH SEE ALSO |
| 73 | .BR ares_expand_name (3), |
| 74 | .BR ares_free_string (3), |
| 75 | .BR ares_mkquery (3) |
| 76 | .SH AUTHOR |