Re: Does a null pointer always raise Constraint_Error?

[Wayne Magor <none@nowhere.com>]

Mike Silva wrote:

> How does one choose the null value?  I understand that the null value
> need not be zero, but I always thought it was fixed in a given
> compiler, or perhaps CPU architecture.

I remember with one Ada compiler I wanted to make null to be a pointer to a
zero-length segment so
the null check would be unnecessary (the hardware would do it for you).  I
seem to remember there was
a problem with this.  Either the hardware guys never considered that you
might want a zero-length segment
or we wanted to be compatible with the null from C (I think it was the h/w
problem).

In any case, for those h/w types that might read this...  please allow for
zero-length segments!  I believe this
is the "best" implementation for null.

Wayne.