Returns the address of a 64-bit signal array. A 32-bit signal
    array and a mechanism array are passed to a condition handler
    when it is called. $SIGNAL_ARRAY_64 provides the address of the
    64-bit signal array, which might be required for programs that
    use 64-bit address space.

    This service accepts 64-bit addresses.

    Format

      SYS$SIGNAL_ARRAY_64  mcharg, sigarg_64

    C Prototype

      int sys$signal_array_64  (unsigned __int64 mcharg, unsigned

                               __int64 sigarg_64);