mirror of https://github.com/getdnsapi/getdns.git
96 lines
3.1 KiB
Groff
96 lines
3.1 KiB
Groff
.\" The "BSD-New" License
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.\"
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.\" Copyright (c) 2013, NLNet Labs, Verisign, Inc.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions are met:
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.\" * Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" * Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" * Neither the names of the copyright holders nor the
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.\" names of its contributors may be used to endorse or promote products
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.\" derived from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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.\" DISCLAIMED. IN NO EVENT SHALL Verisign, Inc. BE LIABLE FOR ANY
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.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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.\" ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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.\" SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.TH getdns_cancel_callback 3 "@date@" "getdns @version@" getdns
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.SH NAME
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.B getdns_cancel_callback
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.SH LIBRARY
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DNS Resolver library (libgetdns, -lgetdns)
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.SH SYNOPSIS
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#include <getdns.h>
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getdns_return_t
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.br
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.B getdns_cancel_callback
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(getdns_context_t context,
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.RS 3
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.br
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getdns_transaction_t *transaction_id)
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.RE
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.SH DESCRIPTION
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.LP
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To cancel an outstanding callback, use getdns_cancel_callback. This causes the
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API to call the callback with a callback_type of GETDNS_CALLBACK_CANCEL if the
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callback for this transaction_id has not already been called. The callback code
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for cancellation should clean up any memory related to the identified call,
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such as to deallocate the memory for the userarg. getdns_cancel_callback() may
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return immediately, even before the callback finishes its work and returns.
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.HP 3
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.I context
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.RP
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see getdns_context (3)
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.HP 3
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.I transaction_id
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.RP
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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
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.HP
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.SH "RETURN VALUES"
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Upon successful completion the functions return
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.B GETDNS_RETURN_GOOD
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, otherwise the following error values are returned:
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.LP
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.B GETDNS_RETURN_UNKNOWN_TRANSACTION
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when calling getdns_cancel_callback() with a transaction_id of a callback that has already been called or an unknown transaction_id
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.SH EXAMPLES
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TBD
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.SH FILES
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.br
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/etc/hosts
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.br
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/etc/resolv.conf
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.SH SEE ALSO
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.BR libgetdns (3),
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.BR getdns_context (3),
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.BR getdns_general (3),
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.BR getdns_hostname (3),
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.BR getdns_service (3),
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