Subject: Re: [boost] possible problem with boost::iostreams::file_descriptor
From: Eric MALENFANT (Eric.Malenfant_at_[hidden])
Date: 2009-06-11 09:22:55
Zachary Turner wrote:
> nested file_descriptor implementation class is defined as follows:
[snip]
> In the second constructor in particular we have this:
>
> impl(handle_type fd, bool close_on_exit)
> : handle_(fd), flags_(0)
> { if (close_on_exit) flags_ |= impl::close_on_exit; }
>
> I think this should be changed. Just because close_on_exit
> is specified to
> false does not mean a file is not open. It just means don't close it
> if it is. I think flags enumeration should be changed to:
>
> enum flags {
> close_on_exit = 1,
> good = 2,
> append = 4
> };
>
> and constructors / code should be changed accordingly.
> Otherwise following
> code (Windows) asserts, even though I don't think it should:
>
> bool is_open(HANDLE h) { return h && h!=INVALID_HANDLE_VALUE;}
>
> HANDLE h = ::CreateFile("C:\\autoexec.bat", GENERIC_READ,
> FILE_SHARE_READ|FILE_SHARE_WRITE,NULL,OPEN_EXISTING,FILE_ATTRI
> BUTE_NORMAL,NULL);
>
> boost::iostreams::file_descriptor fd(h, false);
>
> BOOST_ASSERT(fd.is_open() == is_open(h));
>
>
> Thoughts?
Wouldn't changing:
bool is_open() const { return pimpl_->flags_ != 0; }
to:
bool is_open() const { return pimpl_->handle_ != -1; }
be a better and/or simpler fix?