C++的一个好库。。。现在很流行

				// (C) Copyright Jonathan Turkanis 2004
				// 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.)
				
				// See http://www.boost.org/libs/iostreams for documentation.
				
				#ifndef BOOST_IOSTREAMS_TEST_WRITE_BIDIRECTIONAL_HPP_INCLUDED
				#define BOOST_IOSTREAMS_TEST_WRITE_BIDIRECTIONAL_HPP_INCLUDED
				
				#include 
				#include 
				#include 
				#include 
				#include 
				#include "detail/temp_file.hpp"
				#include "detail/verification.hpp"
				
				void write_bidirectional_test()
				{
				    using namespace std;
				    using namespace boost;
				    using namespace boost::iostreams;
				    using namespace boost::iostreams::test;
				
				    test_file test;
				
				    {
				        temp_file                        dest;
				        temp_file                        src; // Dummy;
				        filtering_stream  out(
				           combine(file_source(src.name()), file_sink(dest.name(), out_mode)), 0
				        );
				        write_data_in_chars(out);
				        out.reset();
				        BOOST_CHECK_MESSAGE(
				            compare_files(dest.name(), test.name()),
				            "failed writing to filtering_stream in chars "
				            "with no buffer"
				        );
				    }
				
				    {
				        temp_file                        dest;
				        temp_file                        src; // Dummy;
				        filtering_stream  out(
				           combine(file_source(src.name()), file_sink(dest.name(), out_mode)), 0
				        );
				        write_data_in_chunks(out);
				        out.reset();
				        BOOST_CHECK_MESSAGE(
				            compare_files(dest.name(), test.name()),
				            "failed writing to filtering_stream in chunks "
				            "with no buffer"
				        );
				    }
				
				    {
				        temp_file                        dest;
				        temp_file                        src; // Dummy;
				        filtering_stream  out(
				           combine(file_source(src.name()), file_sink(dest.name(), out_mode))
				        );
				        write_data_in_chars(out);
				        out.reset();
				        BOOST_CHECK_MESSAGE(
				            compare_files(dest.name(), test.name()),
				            "failed writing to filtering_stream in chars "
				            "with large buffer"
				        );
				    }
				
				    {
				        temp_file                        dest;
				        temp_file                        src; // Dummy;
				        filtering_stream  out(
				           combine(file_source(src.name()), file_sink(dest.name(), out_mode))
				        );
				        write_data_in_chunks(out);
				        out.reset();
				        BOOST_CHECK_MESSAGE(
				            compare_files(dest.name(), test.name()),
				            "failed writing to filtering_stream in chunks "
				            "with large buffer"
				        );
				    }
				}
				
				#endif // #ifndef BOOST_IOSTREAMS_TEST_WRITE_BIDIRECTIONAL_HPP_INCLUDED