Cygwin api to punch a hole into a file?

[Cedric Blancher]

Linux has fallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, ...)
to punch a hole into a file, i.e. deallocate the blocks given and make
the file a "sparse file".

But how can I do that with the Cygwin API? Does anyone have an example
for Cygwin, which is the Win equivalent to Linux fallocate(fd,
FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, 1048576, 2097152);?

I tried with Cygwin 3.5, but the file was not sparse after that.

Ced
-- 
Cedric Blancher <cedric.blancher@gmail.com>
[https://plus.google.com/u/0/+CedricBlancher/]
Institute Pasteur