[PATCH] Cygwin: mmap: allow remapping part of an existing anonymous, mapping

[Corinna Vinschen]

On Jan  7 21:27, Ken Brown wrote:
> On 1/7/2025 3:18 PM, Corinna Vinschen wrote:
> > - mmap_record::prot flag, should be an array of protection bits per page
> >    (POSIX page i e., 64K, not Windows page).
> 
> Question: Since it only takes 3 bits to store all possible protections, do
> you think it's worth the trouble to pack the protections, so that each byte
> stores the protection bits for 2 pages?  Or should I just use an array of
> unsigned char, with 1 byte for each page?  Or did you have something else in
> mind?

I hadn't thought deeply about this.  I had a vague notion of a ULONG
array to match windows protection bits, but, as you note above, we
really only need 3 bits.

I don't think we have to define this as a bit field array, given this
isn't readily available in C and you would have to add bitfield
arithmetic by yourself.  So, yeah, a char or maybe better uint8_t
might be the best matching type here.


Thanks,
Corinna