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Quick int pointer allocation question
Sep 14, 2012
monarch_dodra
Sep 14, 2012
monarch_dodra
Sep 14, 2012
monarch_dodra
Sep 14, 2012
David
Sep 14, 2012
monarch_dodra
Sep 14, 2012
Jacob Carlborg
Sep 14, 2012
monarch_dodra
Sep 14, 2012
Simen Kjaeraas
Sep 14, 2012
bearophile
Sep 14, 2012
Chris Cain
Sep 14, 2012
monarch_dodra
Sep 14, 2012
Jonathan M Davis
Sep 14, 2012
monarch_dodra
Sep 14, 2012
bearophile
Sep 14, 2012
bearophile
Sep 14, 2012
Maxim Fomin
```This is going to be quick: Is it possible to allocate and initialize an int in the same line?

int* p = new int(5);

I haven't found a way to 1 liner it. Is it possible?
Do I have to two liner it?

int* p = new int();
*p = 5;

Thanks.
```
```On Friday, 14 September 2012 at 09:20:03 UTC, monarch_dodra wrote:
> This is going to be quick: Is it possible to allocate and initialize an int in the same line?
>
> int* p = new int(5);
>
> I haven't found a way to 1 liner it. Is it possible?
> Do I have to two liner it?
>
> int* p = new int();
> *p = 5;
>
> Thanks.

Or dup a pointer to an int for that matter:

int* p1 = ... ;
int* p2 = p1.dup;

?
```
```On Friday, 14 September 2012 at 09:22:09 UTC, monarch_dodra wrote:
> On Friday, 14 September 2012 at 09:20:03 UTC, monarch_dodra wrote:
>> This is going to be quick: Is it possible to allocate and initialize an int in the same line?
>>
>> int* p = new int(5);
>>
>> I haven't found a way to 1 liner it. Is it possible?
>> Do I have to two liner it?
>>
>> int* p = new int();
>> *p = 5;
>>
>> Thanks.
>
> Or dup a pointer to an int for that matter:
>
> int* p1 = ... ;
> int* p2 = p1.dup;
>
> ?

Whilst I'm on the subject of questions, how does one allocate, but bypassing the extra memcpy of T.init? Is this possible?
```
```> Whilst I'm on the subject of questions, how does one allocate, but
> bypassing the extra memcpy of T.init? Is this possible?

int x = void;

http://dpaste.dzfl.pl/24c1baa9
```
```On Friday, September 14, 2012 11:20:16 monarch_dodra wrote:
> This is going to be quick: Is it possible to allocate and initialize an int in the same line?
>
> int* p = new int(5);
>
> I haven't found a way to 1 liner it. Is it possible?

Nope. Though I think that it should be.

> Do I have to two liner it?
>
> int* p = new int();
> *p = 5;

Yep. Though I have a pull request which will make it so that you can do

auto p = makeNew!int(5);

https://github.com/D-Programming-Language/phobos/pull/756

- Jonathan M Davis
```
```On Friday, 14 September 2012 at 10:33:47 UTC, David wrote:
>> Whilst I'm on the subject of questions, how does one allocate, but
>> bypassing the extra memcpy of T.init? Is this possible?
>
> int x = void;
>
> http://dpaste.dzfl.pl/24c1baa9

Hum, but that is a stack allocated variable.

What about:

--------
struct S { }
void main()
{
S* ps = new S(void); //? doesn't work
}

On Friday, 14 September 2012 at 10:37:56 UTC, Jonathan M Davis wrote:
> On Friday, September 14, 2012 11:20:16 monarch_dodra wrote:
>> This is going to be quick: Is it possible to allocate and
>> initialize an int in the same line?
>>
>> int* p = new int(5);
>>
>> I haven't found a way to 1 liner it. Is it possible?
>
> Nope. Though I think that it should be.
>
>> Do I have to two liner it?
>>
>> int* p = new int();
>> *p = 5;
>
> Yep. Though I have a pull request which will make it so that you can do
>
> auto p = makeNew!int(5);
>
> https://github.com/D-Programming-Language/phobos/pull/756
>
> - Jonathan M Davis

Thanks. Glad we have a library solution, but that's the kind of thing that should work out of the box I think.
```
```On 2012-09-14 12:52, monarch_dodra wrote:

>> int x = void;
>>
>> http://dpaste.dzfl.pl/24c1baa9
>
> Hum, but that is a stack allocated variable.

Perhaps using GC.malloc?

--
/Jacob Carlborg
```
```On Friday, 14 September 2012 at 11:17:55 UTC, Jacob Carlborg wrote:
> On 2012-09-14 12:52, monarch_dodra wrote:
>
>>> int x = void;
>>>
>>> http://dpaste.dzfl.pl/24c1baa9
>>
>> Hum, but that is a stack allocated variable.
>
> Perhaps using GC.malloc?

Hum, apparently, there is a second (default aka-hidden) argument that is a bitmask applied to the allocated memory. So not much gain there.

I'm allocating an array of 500_000 ulongs, and afterwards, I'm initializing them all "by hand", making the default allocation useless.

I'm not going to lose any sleep over this, but there is no way in D to get (garbage collected) un-initialized memory/allocations?
```
```On Fri, 14 Sep 2012 05:20:16 -0400, monarch_dodra <monarchdodra@gmail.com> wrote:

> This is going to be quick: Is it possible to allocate and initialize an int in the same line?
>
> int* p = new int(5);
>
> I haven't found a way to 1 liner it. Is it possible?
> Do I have to two liner it?
>
> int* p = new int();
> *p = 5;

int *p = [5].ptr;

-Steve
```
```On Friday, 14 September 2012 at 14:33:51 UTC, Steven Schveighoffer wrote:
> On Fri, 14 Sep 2012 05:20:16 -0400, monarch_dodra <monarchdodra@gmail.com> wrote:
>
>> This is going to be quick: Is it possible to allocate and initialize an int in the same line?
>>
>> int* p = new int(5);
>>
>> I haven't found a way to 1 liner it. Is it possible?
>> Do I have to two liner it?
>>
>> int* p = new int();
>> *p = 5;
>
> int *p = [5].ptr;
>
> -Steve

Fancy!

Thankyou.
```
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