On Alpha and Integrity server systems, deletes a virtual region
    within the process's address space, including all created virtual
    addresses within the region.

    This service accepts 64-bit addresses.

    Format

      SYS$DELETE_REGION_64  region_id_64 ,acmode ,return_va_64

                            ,return_length_64

    C Prototype

      nt sys$delete_region_64  (struct _generic_64 *region_id_64,

                               unsigned int acmode, void

                               *(*(return_va_64)), unsigned __int64

                               *return_length_64);