How do you deal with scoped allocations?
John Colvin
john.loughran.colvin at gmail.com
Sun Dec 8 01:21:50 PST 2013
On Saturday, 7 December 2013 at 22:32:59 UTC, Namespace wrote:
> Since my last thread doesn't get much attention I like to ask
> here: How did you deal with temporary memory? Let's assume that
> the size is only known at runtime.
> I have this situation e.g. in Dgame in the capture method: I
> get the pixel data from my Window with glReadPixel but it is
> reversed. So I have to reverse it again, but I still need at
> least temporary memory for one pixel-line which stores the
> currently swapped pixels. So how would you solve such a
> situation?
>
> Since D doesn't offer VLA's and alloca is broken (besides the
> ugly syntax),
> I use a scoped wrapper (since scope doesn't do the job):
>
> ----
> struct scoped(A : T[], T) {
> T[] arr;
>
> alias arr this;
>
> this(T[] arr) {
> this.arr = arr;
>
> writefln("Get %d %s's (ptr = %x)", arr.length, T.stringof,
> arr.ptr);
> }
>
> ~this() {
> GC.free(this.arr.ptr);
> this.arr = null;
> GC.minimize();
> }
> }
>
> void main() {
> // need temp memory
> scoped!(int[]) arr = new int[n];
> }
> ----
>
> And what do you use?
From my probably somewhat incomplete understanding of such things:
This is not a good use-case for the gc. Use the c heap or just
let the gc do its job normally.
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