Re: A question about postblit constructor

[Ferhat Kurtulmuş via Digitalmars-d-learn]

On Tuesday, 5 November 2019 at 12:09:15 UTC, Ferhat Kurtulmuş 
wrote:
On Tuesday, 5 November 2019 at 12:06:44 UTC, Ferhat Kurtulmuş 
wrote:
On Tuesday, 5 November 2019 at 11:20:47 UTC, Mike Parker wrote:
On Tuesday, 5 November 2019 at 10:32:03 UTC, Ferhat Kurtulmuş 
wrote:
[...]

I meant the example as an answer to your statement, "I wonder 
how new memory is allocated without an explicit malloc here". 
The postblit was intended as a chance to "fixup" everything 
when you needed a deep copy. The new struct is initialized as 
a shallow copy, so when you enter into the postblit, the 
pointer is already pointing at the original location. Without 
assigning it a new malloc'ed address, your memcpy was 
essentially overwriting the original location with its own 
data.

What I need was a deep copy, and I thought I could have done 
it using postblit constructor. Thanks for clarification.

I think copy constructor is less confusing though.

Oh I see I have to do this to make a deep copy using postblit 
constructor:

    this(this){
        int* _vals = cast(int*)malloc(length * S.sizeof);
        foreach(i; 0..length)
            _vals[i] = vals[i];
        vals = _vals;
        writeln("copied");
    }