casting int[] to bool[]

[Jarrett Billingsley]

On Wed, Jan 28, 2009 at 8:25 PM, Bill Baxter <wbaxter at gmail.com> wrote:
> On Thu, Jan 29, 2009 at 10:20 AM, Saaa <empty at needmail.com> wrote:
>>  int[] a = [1,2,3,0];
>>  int[] aa = [0,1,0,1];
>>  bool[] b = cast(bool[])a.dup;
>>  bool[] bb = cast(bool[])aa.dup;
>>  writefln(a,`-->`,b);
>>  writefln(aa,`-->`,bb);
>>
>> --
>>
>> [1 2 3 0]-->[true false false false true false false false true false false
>> false false false false false]
>> [0 1 0 1]-->[false false false false true false false false false false
>> false false true false false false]
>>
>>
>> Why all this disagreeing?
>
> bool is 1 byte under the hood.  Int is 4 bytes.
> So what you are seeing is the 4 bytes of each int being treated as 4
> separate bools in an ordering determined by the endian-ness of your
> platform.
>
> Casting arrays in this way is generally not a good idea.
>
> You need to write a function that makes a fresh bool array out of your
> int array.

Stop beating me to things when I'm in the middle of typing!