Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
ARES_SET_S...E_CALLBACK(3) Library Functions Manual ARES_SET_S...E_CALLBACK(3)

NAME
       ares_set_server_state_callback  -  Function  for	setting	a server state
       callback

SYNOPSIS
       #include	<ares.h>

       typedef void (*ares_server_state_callback)(const	char *server_string,
						  ares_bool_t success,
						  int flags,
						  void *data);

       void ares_set_server_state_callback(ares_channel_t *channel,
					   ares_server_state_callback callback,
					   void	*user_data);

DESCRIPTION
       The ares_set_server_state_callback(3) function sets a callback function
       callback	in the given ares channel handle channel that is invoked when-
       ever a query on the channel completes. This  includes  both  successful
       and  unsuccessful  queries  (including  hard  errors and	timeouts). The
       callback	function is invoked with a number of parameters	describing the
       query, as follows.

       The server_string parameter indicates the DNS server that was used  for
       the  query,  given  as  a  string  with	the  same  format  returned by
       ares_get_servers_csv(3).

       The success parameter indicates whether the query succeeded or not.  It
       is set to ARES_TRUE on success and ARES_FALSE on	failure.

       The flags parameter is a	bitmask	of flags describing various aspects of
       the  query  (for	 example whether the query used	UDP or TCP). These are
       described below.

       The data	parameter is a reference to the	 custom	 user  data  user_data
       that  was  passed to ares_set_server_state_callback(3) when setting the
       server state callback.

       The server state	callback can be	used by	applications  to  monitor  the
       state  of  the DNS servers used by an ares channel. For example,	it can
       be used to track	metrics	about the numbers and types of queries sent to
       each server or to detect	when a server is uncontactable or unhealthy.

FLAGS
       ARES_SERV_STATE_UDP
	    Indicates that the query was tried over UDP.

       ARES_SERV_STATE_TCP
	    Indicates that the query was tried over TCP.

AVAILABILITY
       This function was first introduced in c-ares version 1.29.0.

SEE ALSO
       ares_get_servers_csv(3)

				  26 Apr 2024	    ARES_SET_S...E_CALLBACK(3)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=ares_set_server_state_callback&sektion=3&manpath=FreeBSD+Ports+14.3.quarterly>

home | help