Problem with Cygwin's fdopen and Windows handles

Christopher Faylor
Mon May 30 18:48:00 GMT 2011

On Mon, May 30, 2011 at 11:39:13AM -0700, Daniel Colascione wrote:
>On 5/30/11 10:46 AM, Christopher Faylor wrote:
>> On Mon, May 30, 2011 at 07:34:27AM +0000, Juanjo wrote:
>>> Christopher Faylor writes:
>>>> Unfortunately, cygwin_attach_handle_to_fd doesn't really work.  Cygwin
>>>> needs to know the type of handle it is attaching in order to set up the
>>>> correct type of file handler.  Since it doesn't do that the handle is
>>>> of limited utility.
>>> If this was true, the function should have then been removed from the
>>> manual or marked as not working.  But I believe this is not right, for
>>> read() and file handlers work perfectly and the problem only arises
>>> with fread() !!!
>> Please calm down.
>> I guess I shouldn't have said the "doesn't really work" and stuck with
>> "of limited utility".  fds attached with cygwin_attach_handle_to_fd are
>> not fully functional.
>If cygwin_attach_handle_to_fd is ever deprecated or replaced entirely,
>could we replace it with opening /proc/self/fd/handle:XXXX, where XXXX
>is the decimal encoding of the handle value?  It'd eliminate a Cygwin
>API call and allow easier interaction with handles inherited from
>non-Cygwin programs, and if the code exists to automatically detect the
>proper fhandler type for a given HANDLE, the loss in API richness
>shouldn't matter.

Getting rid of cygwin_attach_handle_to_fd would break backwards
compatibility.  It's not going anywhere.

Your scheme sounds like a whole lot of extra work that SHTDI.


Problem reports:
Unsubscribe info:

More information about the Cygwin mailing list