| .\" $Id$ |
| .\" |
| .\" Copyright 1998 by the Massachusetts Institute of Technology. |
| .\" |
| .\" Permission to use, copy, modify, and distribute this |
| .\" software and its documentation for any purpose and without |
| .\" fee is hereby granted, provided that the above copyright |
| .\" notice appear in all copies and that both that copyright |
| .\" notice and this permission notice appear in supporting |
| .\" documentation, and that the name of M.I.T. not be used in |
| .\" advertising or publicity pertaining to distribution of the |
| .\" software without specific, written prior permission. |
| .\" M.I.T. makes no representations about the suitability of |
| .\" this software for any purpose. It is provided "as is" |
| .\" without express or implied warranty. |
| .\" |
| .TH ARES_SEARCH 3 "24 July 1998" |
| .SH NAME |
| ares_search \- Initiate a DNS query with domain search |
| .SH SYNOPSIS |
| .nf |
| .B #include <ares.h> |
| .PP |
| .B typedef void (*ares_callback)(void *\fIarg\fP, int \fIstatus\fP, |
| .B int \fItimeouts\fP, unsigned char *\fIabuf\fP, int \fIalen\fP) |
| .PP |
| .B void ares_search(ares_channel \fIchannel\fP, const char *\fIname\fP, |
| .B int \fIdnsclass\fP, int \fItype\fP, ares_callback \fIcallback\fP, |
| .B void *\fIarg\fP) |
| .fi |
| .SH DESCRIPTION |
| The |
| .B ares_search |
| function initiates a series of single-question DNS queries on the name |
| service channel identified by |
| .IR channel , |
| using the channel's search domains as well as a host alias file given |
| by the HOSTALIAS environment variable. The parameter |
| .I name |
| gives the alias name or the base of the query name as a NUL-terminated |
| C string of period-separated labels; if it ends with a period, the |
| channel's search domains will not be used. Periods and backslashes |
| within a label must be escaped with a backslash. The parameters |
| .I dnsclass |
| and |
| .I type |
| give the class and type of the query using the values defined in |
| .BR <arpa/nameser.h> . |
| When the query sequence is complete or has failed, the ares library |
| will invoke |
| .IR callback . |
| Completion or failure of the query sequence may happen immediately, or |
| may happen during a later call to |
| .BR ares_process (3) |
| or |
| .BR ares_destroy (3). |
| .PP |
| The callback argument |
| .I arg |
| is copied from the |
| .B ares_search |
| argument |
| .IR arg . |
| The callback argument |
| .I status |
| indicates whether the query sequence ended with a successful query |
| and, if not, how the query sequence failed. It may have any of the |
| following values: |
| .TP 19 |
| .B ARES_SUCCESS |
| A query completed successfully. |
| .TP 19 |
| .B ARES_ENODATA |
| No query completed successfully; when the query was tried without a |
| search domain appended, a response was returned with no answers. |
| .TP 19 |
| .B ARES_EFORMERR |
| A query completed but the server claimed that the query was |
| malformatted. |
| .TP 19 |
| .B ARES_ESERVFAIL |
| No query completed successfully; when the query was tried without a |
| search domain appended, the server claimed to have experienced a |
| failure. (This code can only occur if the |
| .B ARES_FLAG_NOCHECKRESP |
| flag was specified at channel initialization time; otherwise, such |
| responses are ignored at the |
| .BR ares_send (3) |
| level.) |
| .TP 19 |
| .B ARES_ENOTFOUND |
| No query completed successfully; when the query was tried without a |
| search domain appended, the server reported that the queried-for |
| domain name was not found. |
| .TP 19 |
| .B ARES_ENOTIMP |
| A query completed but the server does not implement the operation |
| requested by the query. (This code can only occur if the |
| .B ARES_FLAG_NOCHECKRESP |
| flag was specified at channel initialization time; otherwise, such |
| responses are ignored at the |
| .BR ares_send (3) |
| level.) |
| .TP 19 |
| .B ARES_EREFUSED |
| A query completed but the server refused the query. (This code can |
| only occur returned if the |
| .B ARES_FLAG_NOCHECKRESP |
| flag was specified at channel initialization time; otherwise, such |
| responses are ignored at the |
| .BR ares_send (3) |
| level.) |
| .TP 19 |
| .B ARES_TIMEOUT |
| No name servers responded to a query within the timeout period. |
| .TP 19 |
| .B ARES_ECONNREFUSED |
| No name servers could be contacted. |
| .TP 19 |
| .B ARES_ENOMEM |
| Memory was exhausted. |
| .TP 19 |
| .B ARES_EDESTRUCTION |
| The name service channel |
| .I channel |
| is being destroyed; the query will not be completed. |
| .PP |
| The callback argument |
| .I timeouts |
| reports how many times a query timed out during the execution of the |
| given request. |
| .PP |
| If a query completed successfully, the callback argument |
| .I abuf |
| points to a result buffer of length |
| .IR alen . |
| If the query did not complete successfully, |
| .I abuf |
| will usually be NULL and |
| .I alen |
| will usually be 0, but in some cases an unsuccessful query result may |
| be placed in |
| .IR abuf . |
| .SH SEE ALSO |
| .BR ares_process (3) |
| .SH AUTHOR |
| Greg Hudson, MIT Information Systems |
| .br |
| Copyright 1998 by the Massachusetts Institute of Technology. |