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Diffstat (limited to 'src/boost/libs/asio/example/cpp03/timeouts/blocking_udp_client.cpp')
-rw-r--r-- | src/boost/libs/asio/example/cpp03/timeouts/blocking_udp_client.cpp | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/src/boost/libs/asio/example/cpp03/timeouts/blocking_udp_client.cpp b/src/boost/libs/asio/example/cpp03/timeouts/blocking_udp_client.cpp new file mode 100644 index 000000000..95c3480c1 --- /dev/null +++ b/src/boost/libs/asio/example/cpp03/timeouts/blocking_udp_client.cpp @@ -0,0 +1,154 @@ +// +// blocking_udp_client.cpp +// ~~~~~~~~~~~~~~~~~~~~~~~ +// +// Copyright (c) 2003-2020 Christopher M. Kohlhoff (chris at kohlhoff dot com) +// +// Distributed under the Boost Software License, Version 1.0. (See accompanying +// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) +// + +#include <boost/asio/buffer.hpp> +#include <boost/asio/io_context.hpp> +#include <boost/asio/ip/udp.hpp> +#include <cstdlib> +#include <boost/bind/bind.hpp> +#include <iostream> + +using boost::asio::ip::udp; + +//---------------------------------------------------------------------- + +// +// This class manages socket timeouts by running the io_context using the timed +// io_context::run_for() member function. Each asynchronous operation is given +// a timeout within which it must complete. The socket operations themselves +// use boost::bind to specify the completion handler: +// +// +---------------+ +// | | +// | receive | +// | | +// +---------------+ +// | +// async_- | +----------------+ +// receive() | | | +// +--->| handle_receive | +// | | +// +----------------+ +// +// For a given socket operation, the client object runs the io_context to block +// thread execution until the operation completes or the timeout is reached. If +// the io_context::run_for() function times out, the socket is closed and the +// outstanding asynchronous operation is cancelled. +// +class client +{ +public: + client(const udp::endpoint& listen_endpoint) + : socket_(io_context_, listen_endpoint) + { + } + + std::size_t receive(const boost::asio::mutable_buffer& buffer, + boost::asio::chrono::steady_clock::duration timeout, + boost::system::error_code& ec) + { + // Start the asynchronous operation. The handle_receive function used as a + // callback will update the ec and length variables. + std::size_t length = 0; + socket_.async_receive(boost::asio::buffer(buffer), + boost::bind(&client::handle_receive, + boost::placeholders::_1, boost::placeholders::_2, &ec, &length)); + + // Run the operation until it completes, or until the timeout. + run(timeout); + + return length; + } + +private: + void run(boost::asio::chrono::steady_clock::duration timeout) + { + // Restart the io_context, as it may have been left in the "stopped" state + // by a previous operation. + io_context_.restart(); + + // Block until the asynchronous operation has completed, or timed out. If + // the pending asynchronous operation is a composed operation, the deadline + // applies to the entire operation, rather than individual operations on + // the socket. + io_context_.run_for(timeout); + + // If the asynchronous operation completed successfully then the io_context + // would have been stopped due to running out of work. If it was not + // stopped, then the io_context::run_for call must have timed out. + if (!io_context_.stopped()) + { + // Cancel the outstanding asynchronous operation. + socket_.cancel(); + + // Run the io_context again until the operation completes. + io_context_.run(); + } + } + + static void handle_receive( + const boost::system::error_code& ec, std::size_t length, + boost::system::error_code* out_ec, std::size_t* out_length) + { + *out_ec = ec; + *out_length = length; + } + +private: + boost::asio::io_context io_context_; + udp::socket socket_; +}; + +//---------------------------------------------------------------------- + +int main(int argc, char* argv[]) +{ + try + { + using namespace std; // For atoi. + + if (argc != 3) + { + std::cerr << "Usage: blocking_udp_client <listen_addr> <listen_port>\n"; + return 1; + } + + udp::endpoint listen_endpoint( + boost::asio::ip::make_address(argv[1]), + std::atoi(argv[2])); + + client c(listen_endpoint); + + for (;;) + { + char data[1024]; + boost::system::error_code ec; + std::size_t n = c.receive(boost::asio::buffer(data), + boost::asio::chrono::seconds(10), ec); + + if (ec) + { + std::cout << "Receive error: " << ec.message() << "\n"; + } + else + { + std::cout << "Received: "; + std::cout.write(data, n); + std::cout << "\n"; + } + } + } + catch (std::exception& e) + { + std::cerr << "Exception: " << e.what() << "\n"; + } + + return 0; +} |