How to delete dynamic array ?

jmh530 john.michael.hall at gmail.com
Wed Mar 17 10:54:10 UTC 2021


On Tuesday, 16 March 2021 at 23:49:00 UTC, H. S. Teoh wrote:
> [snip]
>
> Note that T[] is just a slice, not the dynamic array itself. 
> The dynamic array is allocated and managed by the GC when you 
> append stuff to it, or when you create a new array with `new` 
> or an array literal.
>
> None of the latter, however, precludes you from using T[] for 
> memory that you manage yourself. For example, you could do this:
>
> 	double[] data;
> 	data = cast(double[]) malloc(n * double.sizeof)[0 .. n];
>
> Now you have a slice to memory you allocated yourself, and you 
> have to manage its lifetime manually.  When you're done with it:
>
> 	free(data.ptr);
> 	data = []; // null out dangling pointer, just in case
>
> The GC does not get involved unless you actually allocate from 
> it. As long as .ptr does not point to GC-managed memory, the GC 
> will not care about it. (Be aware, though, that the ~ and ~= 
> operators may allocate from the GC, so you will have to refrain 
> from using them. @nogc may help in this regard.)
>
>
> T

This is one of those things that is not explained well enough.


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