Cygwin off_t, dev_t, uid_t and gid_t definitions
Corinna Vinschen
vinschen@redhat.com
Wed Apr 13 09:19:00 GMT 2016
On Apr 13 11:12, Sebastian Huber wrote:
> On 13/04/16 11:07, Corinna Vinschen wrote:
> >Ok, one step back. Right now we have newlib's stdio using _off_t and
> >newlib's stdio64 _off64_t. The assumption is that on 32 bit platforms
> >_off_t is a 32 bit type, thus we need _off64_t and stdio64 to implement
> >64 bit file access.
>
> Ok, the _off_t is 64-bit on the main RTEMS targets. I was not aware that
> there is a stdio64. This explains some of my confusion.
stdio64 allows to define 32 and 64 bit stdio functions on 32 bit
targets. As I said, we're using this in Cygwin just to pamper really
old executables from pre-64bit-off_t times, but that requires to
have two off_t's on 32 bit. I'm not happy either with this complication
and I guess we will drop this compatibility stuff in Cygwin in not
too far a future.
> >If we change the definitions of _off_t and _off64_t we're bound to break
> >newlib and probably not only when being used by Cygwin.
> >
> >I'd like to suggest the following. If that's exactly what you suggested,
> >bear with me, I'just m trying to wrap my head around this in public:)
> >
> >- Keep _off_t and _off64_t definitions intact.
> >
> >- Define __off_t in sys/_types.h as the same type as _off_t, unless
> > we're running on Cygwin. In that case __off_t should be defined
> > as always 64 bit.
>
> Ok, this makes sense.
>
> >This should probably go into Cygwin's not yet
> > existing machine/_types.h.
>
> No, the <machine/_types.h> is responsible to define _off_t.
?!? Where's __off_t defined then?
Corinna
--
Corinna Vinschen
Cygwin Maintainer
Red Hat
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