array copy/ref question

[Jarrett Billingsley]

"Brian Sturk" <bsturk at comcast.net> wrote in message 
news:g7qoh0$2vvr$1 at digitalmars.com...
> Lars Ivar Igesund Wrote:
>
>> Brian Sturk wrote:
>>
>> > I'm trying to get a handle on the array assignment, slicing operations 
>> > and
>> > am a little confused.  The last copy gives me an "overlapping array 
>> > copy".
>> >  Both arrays have a length of 4.  Is it that I cannot copy from one
>> > dynamic array to another (even if the same size)?
>>
>> It means you are trying to copy from the same memory you are copying to -
>> your arrays reference the same memory.
>
> Hi there,
>
> Thanks for the clarification, sounds like I need to do a memcpy to do a 
> true copy.

Nope, it's memmove you're looking for.  memcpy over overlapping memory 
regions has undefined behavior.  Incidentally, for the same reasons 
overlapping slice copies are illegal -- to allow for the use of faster 
hardware copies that disallow overlapping regions.