On Alpha and Integrity server systems, unlocks a virtual address
    range that was previously locked in the working set by the Lock
    Pages in Working Set ($LKWSET_64) service.

    This service accepts 64-bit addresses.

    Format

      SYS$ULWSET_64  start_va_64 ,length_64 ,acmode ,return_va_64

                     ,return_length_64

    C Prototype

      int sys$ulwset_64  (void *start_va_64, unsigned __int64

                         length_64, unsigned int acmode, void

                         *(*(return_va_64)), unsigned __int64

                         *return_length_64);