Hello!
Is it possible to get pointer to a data in std.container.Array like .ptr from an array? I need to pass a pointer to some C function (from DerelictGL3 binding) and avoid GC allocation.
Thank you!

On Friday, 28 August 2015 at 17:45:21 UTC, Oleg wrote:
> Hello!
> Is it possible to get pointer to a data in std.container.Array like .ptr from an array? I need to pass a pointer to some C function (from DerelictGL3 binding) and avoid GC allocation.
> Thank you!

I'm pretty sure you can just take the address of the first element, e.g. &a[0] or &a.front

On Friday, 28 August 2015 at 18:21:04 UTC, John Colvin wrote:
> On Friday, 28 August 2015 at 17:45:21 UTC, Oleg wrote:
>> Hello!
>> Is it possible to get pointer to a data in std.container.Array like .ptr from an array? I need to pass a pointer to some C function (from DerelictGL3 binding) and avoid GC allocation.
>> Thank you!
>
> I'm pretty sure you can just take the address of the first element, e.g. &a[0] or &a.front

I've tried, it throws
core.exception.RangeError@/usr/include/dmd/phobos/std/container/array.d(571): Range violation

If I make an array from the Array container with foreach ad pass it's .ptr - it works

On Friday, 28 August 2015 at 18:31:00 UTC, Oleg wrote:
> On Friday, 28 August 2015 at 18:21:04 UTC, John Colvin wrote:
>> On Friday, 28 August 2015 at 17:45:21 UTC, Oleg wrote:
>>> Hello!
>>> Is it possible to get pointer to a data in std.container.Array like .ptr from an array? I need to pass a pointer to some C function (from DerelictGL3 binding) and avoid GC allocation.
>>> Thank you!
>>
>> I'm pretty sure you can just take the address of the first element, e.g. &a[0] or &a.front
>
> I've tried, it throws
> core.exception.RangeError@/usr/include/dmd/phobos/std/container/array.d(571): Range violation

That's unexpected. Could you provide a full example that does this?

On Friday, 28 August 2015 at 18:40:33 UTC, John Colvin wrote:
> On Friday, 28 August 2015 at 18:31:00 UTC, Oleg wrote:
>> On Friday, 28 August 2015 at 18:21:04 UTC, John Colvin wrote:
>>> On Friday, 28 August 2015 at 17:45:21 UTC, Oleg wrote:
>>>> Hello!
>>>> Is it possible to get pointer to a data in std.container.Array like .ptr from an array? I need to pass a pointer to some C function (from DerelictGL3 binding) and avoid GC allocation.
>>>> Thank you!
>>>
>>> I'm pretty sure you can just take the address of the first element, e.g. &a[0] or &a.front
>>
>> I've tried, it throws
>> core.exception.RangeError@/usr/include/dmd/phobos/std/container/array.d(571): Range violation
>
> That's unexpected. Could you provide a full example that does this?

I found solution. I call length instead of reserve. It calls ensureInitialized and everything works fine. By default, Array won't initialize store.

On Friday, 28 August 2015 at 18:46:23 UTC, Oleg wrote:

> I found solution. I call length instead of reserve. It calls ensureInitialized and everything works fine. By default, Array won't initialize store.

Oh, reserve calls it too. My mistake.
I found the problem, that's because I passed an empty Array (like Array!int.init).