Boost C++ Libraries: Ticket #9597: "boost::iostreams::file_descriptor" doesn't close Windows low-level file descriptors properly when specifying "file_descriptor_flags::close

Boost C++ Libraries: Ticket #9597: "boost::iostreams::file_descriptor" doesn't close Windows low-level file descriptors properly when specifying "file_descriptor_flags::close_handle" https://svn.boost.org/trac10/ticket/9597 When opening a file on Windows using <code>boost::iostreams::file_descriptor</code>, <code>boost::iostreams::file_descriptor_sink</code> or <code>boost::iostreams::file_descriptor_source</code> in combination with a low-level file descriptor and when specifying <code>file_descriptor_flags::close_handle</code>, then the file descriptor isn't closed properly on close/exit. Using one of the mentioned methods, the low-level file descriptor is converted to a Windows handle using the API call <code>_get_osfhandle</code> <a class="new ticket" href="https://svn.boost.org/trac10/ticket/9597#point1" title="#9597: Bugs: "boost::iostreams::file_descriptor" doesn't close Windows low-level ... (new)">(1)</a>: <div class="wiki-code"><div class="code"><pre>void file_descriptor_impl::open(int fd, flags f) { open(reinterpret_cast<file_handle>(_get_osfhandle(fd)), f); } </pre></div></div> When closing, the file handle is closed using <code>CloseHandle</code>: <div class="wiki-code"><div class="code"><pre>void file_descriptor_impl::close_impl(bool close_flag, bool throw_) { if (handle_ != invalid_handle()) { if (close_flag) { bool success = #ifdef BOOST_IOSTREAMS_WINDOWS ::CloseHandle(handle_) == 1; #else BOOST_IOSTREAMS_FD_CLOSE(handle_) != -1; #endif if (!success && throw_) throw_system_failure("failed closing file"); } handle_ = invalid_handle(); flags_ = 0; } } </pre></div></div> According to <a class="new ticket" href="https://svn.boost.org/trac10/ticket/9597#point1" title="#9597: Bugs: "boost::iostreams::file_descriptor" doesn't close Windows low-level ... (new)">(1)</a> the API call <code>_close</code> <a class="new ticket" href="https://svn.boost.org/trac10/ticket/9597#point2" title="#9597: Bugs: "boost::iostreams::file_descriptor" doesn't close Windows low-level ... (new)">(2)</a> shall be used to close a low-level file descriptor. Practical tests shew that every time a file is opened and closed using one of the mentioned methods, Windows (XP) assigns a new file descriptor with an increasing value to it, unless the program runs out of available file handles. Manually closing the file by specifying <code>file_descriptor_flags::close_handle</code> and calling <code>_close</code> solves this issue. (1) <a class="ext-link" href="http://msdn.microsoft.com/en-us/library/ks2530z6.aspx">http://msdn.microsoft.com/en-us/library/ks2530z6.aspx</a> (2) <a class="ext-link" href="http://msdn.microsoft.com/en-us/library/5fzwd5ss.aspx">http://msdn.microsoft.com/en-us/library/5fzwd5ss.aspx</a> en-us Boost C++ Libraries /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/9597 Trac 1.4.3