array !is null fails
Frits van Bommel
fvbommel at REMwOVExCAPSs.nl
Tue Feb 13 09:34:35 PST 2007
> Reply to Jarrett,
>> "BCS" <ao at pathlink.com> wrote in message
>> news:ce0a334373d48c91d12a1b9c0ec at news.digitalmars.com...
>>> What good is the (array !is null) if it doesn't tell you when the
>>> pointer is null?
>> Well if you want to see if the pointer is null then use "if(array.ptr
>> is null)". Though I'll agree with you that the discontinuity between
>> zero-length null pointer arrays and more-than-zero-length null pointer
>> arrays is a bit odd.
> What else could be null? I don't see anything else that it could mean
> other than "is the pointer null".
'null', when interpreted as an array, is an _empty_ array with the
pointer being null.
This allows it to be a reasonable default initializer for dynamic
arrays, and means (arr == null) checks whether the array is empty.
More information about the Digitalmars-d-learn