mirror of https://gitee.com/bigwinds/arangodb
58 lines
1.6 KiB
Plaintext
58 lines
1.6 KiB
Plaintext
[/
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/ Copyright (c) 2003-2016 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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/
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/ Distributed under the Boost Software License, Version 1.0. (See accompanying
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/ file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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/]
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[section:ResolveHandler Resolve handler requirements]
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A resolve handler must meet the requirements for a [link
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boost_asio.reference.Handler handler]. A value `h` of a resolve handler
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class should work correctly in the expression `h(ec, i)`, where `ec` is an
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lvalue of type `const error_code` and `i` is an lvalue of type `const
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ip::basic_resolver_iterator<InternetProtocol>`. `InternetProtocol` is the
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template parameter of the [link boost_asio.reference.ip__resolver_service
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`resolver_service`] which is used to initiate the asynchronous operation.
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[heading Examples]
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A free function as a resolve handler:
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void resolve_handler(
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const boost::system::error_code& ec,
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boost::asio::ip::tcp::resolver::iterator iterator)
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{
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...
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}
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A resolve handler function object:
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struct resolve_handler
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{
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...
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void operator()(
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const boost::system::error_code& ec,
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boost::asio::ip::tcp::resolver::iterator iterator)
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{
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...
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}
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...
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};
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A non-static class member function adapted to a resolve handler using `bind()`:
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void my_class::resolve_handler(
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const boost::system::error_code& ec,
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boost::asio::ip::tcp::resolver::iterator iterator)
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{
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...
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}
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...
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resolver.async_resolve(...,
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boost::bind(&my_class::resolve_handler,
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this, boost::asio::placeholders::error,
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boost::asio::placeholders::iterator));
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[endsect]
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