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POC++: purpose of for(;;)?
 

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  1. POC++: purpose of for(;;)?
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    <p>I just wanted to know the reasoning for the line <code>for(;;)</code> in the following code.</p> <pre><code>// // blocking_tcp_echo_server.cpp // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2012 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 &lt;cstdlib&gt; #include &lt;iostream&gt; #include &lt;boost/bind.hpp&gt; #include &lt;boost/smart_ptr.hpp&gt; #include &lt;boost/asio.hpp&gt; #include &lt;boost/thread/thread.hpp&gt; using boost::asio::ip::tcp; const int max_length = 1024; typedef boost::shared_ptr&lt;tcp::socket&gt; socket_ptr; void session(socket_ptr sock) { try { for (;;) { char data[max_length]; boost::system::error_code error; size_t length = sock-&gt;read_some(boost::asio::buffer(data), error); if (error == boost::asio::error::eof) break; // Connection closed cleanly by peer. else if (error) throw boost::system::system_error(error); // Some other error. boost::asio::write(*sock, boost::asio::buffer(data, length)); } } catch (std::exception&amp; e) { std::cerr &lt;&lt; "Exception in thread: " &lt;&lt; e.what() &lt;&lt; "\n"; } } void server(boost::asio::io_service&amp; io_service, short port) { tcp::acceptor a(io_service, tcp::endpoint(tcp::v4(), port)); for (;;) { socket_ptr sock(new tcp::socket(io_service)); a.accept(*sock); boost::thread t(boost::bind(session, sock)); } } int main(int argc, char* argv[]) { try { if (argc != 2) { std::cerr &lt;&lt; "Usage: blocking_tcp_echo_server &lt;port&gt;\n"; return 1; } boost::asio::io_service io_service; using namespace std; // For atoi. server(io_service, atoi(argv[1])); } catch (std::exception&amp; e) { std::cerr &lt;&lt; "Exception: " &lt;&lt; e.what() &lt;&lt; "\n"; } return 0; } </code></pre>
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    1. COIt's the for-ever loop.
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    2. COBecause your program wants to continuously and infintely(*unless an error occurs*) accept the requests/connections available on socket and process them. The infinite loop is provided by `for(;;;)` while the condition to break from this loop is if error occurs during socket communication.
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    3. CORelevant question on different ways to express forever loops: http://stackoverflow.com/q/224138/10468
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