On Alpha and Integrity server systems, gets information about a
    specified virtual region.

    This service accepts 64-bit addresses.

    Format

      SYS$GET_REGION_INFO  function_code ,region_id_64 ,start_va_64

                           ,nullarg ,buffer_length ,buffer_address_64

                           ,return_length_64

    C Prototype

      int sys$get_region_info  (unsigned int function_code, struct

                               _generic_64 *region_id_64, void

                               *start_va_64, void *reserved,

                               unsigned int buffer_length, void

                               *buffer_address_64, unsigned int

                               *return_length_64);