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getdns_cancel_callback(3)	    getdns	     getdns_cancel_callback(3)

NAME
       getdns_cancel_callback -- cancel	an outstanding asyn getdns request

LIBRARY
       DNS Resolver library (libgetdns,	-lgetdns)

SYNOPSIS
       #include	<getdns.h>

       getdns_return_t
       getdns_cancel_callback (getdns_context_t	context,
	  getdns_transaction_t *transaction_id)

DESCRIPTION
       To  cancel  an  outstanding  callback, use getdns_cancel_callback. This
       causes  the  API	 to  call  the	callback  with	a   callback_type   of
       GETDNS_CALLBACK_CANCEL  if the callback for this	transaction_id has not
       already been called. The	callback code for cancellation should clean up
       any  memory  related  to	the identified call, such as to	deallocate the
       memory for the userarg.	getdns_cancel_callback()  may  return  immedi-
       ately, even before the callback finishes	its work and returns.

       context see getdns_context (3)

       transaction_id  populated  by the API and used to identify the callback
	  (for example to getdns_cancel_callback), can be NULL,	set  to	 0  if
	  the function fails

RETURN VALUES
       Upon  successful	 completion  the functions return GETDNS_RETURN_GOOD ,
       otherwise the following error values are	returned:

       GETDNS_RETURN_INVALID_PARAMETER if context == NULL

       GETDNS_RETURN_UNKNOWN_TRANSACTION if the	transaction_id that is unknown
       or belongs to a callback	that has already been called

EXAMPLES
       TBD

FILES
       /etc/hosts
       /etc/resolv.conf

SEE ALSO
       libgetdns(3), getdns_context(3),	getdns_general(3), getdns_hostname(3),
       getdns_service(3),

getdns 1.5.2			 December 2015	     getdns_cancel_callback(3)

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | EXAMPLES | FILES | SEE ALSO

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