On Tuesday, 25 July 2017 at 13:24:36 UTC, Mike Parker wrote:
On Tuesday, 25 July 2017 at 12:40:13 UTC, John Burton wrote:
[...]
This should give you the answer:
writefln("Before: ptr = %s capacity = %s", slice.ptr,
slice.capacity);
slice ~= 1;
writefln("After: ptr = %s capacity = %s", slice.ptr,
slice.capacity);
It shows that before the append, the capacity is 0. That
indicates that any append will cause a new allocation -- from
the GC. The next writefln verifies this by showing a different
value for ptr and a new capacity of 15.
In order for this to work, you'll need to manually manage the
length and track the capacity yourself. If all you want is to
allocate space for 10 ints, but not 10 actual ints, then
something like this:
size_t capacity = 10;
int* ints = cast(int*)malloc(int.sizeof * capacity);
int[] slice = ints[0 .. 10];
slice.length = 0;
slice ~= 1;
--capacity;
Then reallocate the array when capacity reaches 0. Or just use
std.container.array.Array which does all this for you.
Ok so it sounds like this is "safe" in that it will copy my data
into GC memory and all work safely. I'll need to somehow keep
track of my original memory and free it to avoid a memory leak...
(I don't plan to do any of this, but I wanted to understand)(
