🚀 go-pugleaf

Say I want to attach to a large shared memory segment, and I need it to be
aligned across some arbitrary page boundary (i.e. the starting address needs
to be a multiple of this arbitrary page size, where the page size will always
be a multiple of the OS page size). How would I go about ensuring that the
address I pick will work? I assume that arbitrarily picking an address would
be a bad idea, and may fail depending on what other data is using that address
space.

What problems would I bump into by rounding an OS nominated address up by
(address % MY_PAGE_SIZE) bytes? Is there a chance that that would screw up
something at the end of the shared memory segment (i.e. if the OS placed the
segment of size s at a, and I want it to be at a+x, how do I know whether
someone else already occupies the space at a+x+s)?

Are there any foolproof tricks out there? Am I being paranoid?