Re: SEEK_HOLE Support in Cygwin?

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Aug 25 13:09, Roland Mainz wrote:
> On Fri, Aug 25, 2023 at 11:05 AM Corinna Vinschen
> <corinna-cygwin@cygwin.com> wrote:
> >
> > On Aug 24 14:03, Roland Mainz wrote:
> > > Question for Corinna:
> >
> > Everybody involved in the project could answer this question, but...
> >
> > > Does Cygwin support allocation/deallocation of filesystem blocks via
> > > Linux's |fallocate()|-API ?
> >
> > ...just try this:
> >
> > $ cat > a.c <<EOF
> > extern void fallocate();
> > extern void posix_fallocate();
> >
> > int main()
> > {
> >   fallocate();
> >   posix_fallocate();
> > }
> > EOF
> > $ gcc -o a a.c
> 
> Thanks...
> ... I saw that the functions are there,

So you didn't actually run the test?

> but my question was more like
> "supports"=="calls native Windows API".
> 
> |fallocate()| support seems to be in
> ./newlib-cygwin/winsup/cygwin/fhandler/disk_file.cc, and supports the
> allocation of blocks - but I couldn't find support for
> |FALLOC_FL_PUNCH_HOLE|, e.g. deallocation of blocks (to "punch" a hole
> into the file).
> Is this an oversight, or does Window's native API not support that ?

If you found fallocate() in fhandler/disk_file.cc, I need new glasses.


Corinna