id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
9597	"""boost::iostreams::file_descriptor"" doesn't close Windows low-level file descriptors properly when specifying ""file_descriptor_flags::close_handle"""	anonymous	Jonathan Turkanis	"When opening a file on Windows using {{{boost::iostreams::file_descriptor}}}, {{{boost::iostreams::file_descriptor_sink}}} or {{{boost::iostreams::file_descriptor_source}}} in combination with a low-level file descriptor and when specifying {{{file_descriptor_flags::close_handle}}}, 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 {{{_get_osfhandle}}} [#point1 (1)]: 
{{{#!c++
void file_descriptor_impl::open(int fd, flags f)
{ open(reinterpret_cast<file_handle>(_get_osfhandle(fd)), f); }
}}}
When closing, the file handle is closed using {{{CloseHandle}}}:
{{{#!c++
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;
    }
}
}}}

According to [#point1 (1)] the API call {{{_close}}} [#point2 (2)] 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 {{{file_descriptor_flags::close_handle}}} and calling {{{_close}}} solves this issue.

[=#point1 (1)] http://msdn.microsoft.com/en-us/library/ks2530z6.aspx \\
[=#point2 (2)] http://msdn.microsoft.com/en-us/library/5fzwd5ss.aspx"	Bugs	new	To Be Determined	iostreams	Boost 1.55.0	Problem		file_descriptor	m.kosch@…