http://digitalmars.com/d/2.0/arrays.html says static arrays are
limited to 16mb, but I can only allocate 1mb.
My fault, or bug?

	enum size = (16 * 1024 * 1024) / int.sizeof;
	//int[size] a;   // Error: index 4194304 overflow for static
array
	enum size2 = (16 * 1000 * 1000) / int.sizeof;
	//int[size2] b; // Stack Overflow
	//int[250_001] c; // Stack Overflow
	int[250_000] d; // ok

This is using dmd 2.052 on windows by the way.

On 2011-04-02 06:21, simendsjo wrote:
> http://digitalmars.com/d/2.0/arrays.html says static arrays are
> limited to 16mb, but I can only allocate 1mb.
> My fault, or bug?
> 
> 	enum size = (16 * 1024 * 1024) / int.sizeof;
> 	//int[size] a;   // Error: index 4194304 overflow for static
> array
> 	enum size2 = (16 * 1000 * 1000) / int.sizeof;
> 	//int[size2] b; // Stack Overflow
> 	//int[250_001] c; // Stack Overflow
> 	int[250_000] d; // ok

Well, 16 * 1024 * 1024 certainly isn't going to work when it's an array ints. An int is 4 bytes. So, the max would be more like 4 * 1024 * 1024, and that's assuming no overhead (which there may or may not be). Now, 4 * 1024 * 1024 is 4_194_304, which is definitely more than 250_000, so if 16mb is indeed the limit, I don't know why you can't create one greater than 250_000, but you're _not_ going to be able to create one of length 16 * 1024 * 10243. That would be 64mb.

- Jonathan M Davis

I think you missed my "/int.sizeof" at the end.

enum size = (16*1024*1024)/int.sizeof;
int[size] a; // "Error index overflow for static" as expected
int[size-1] b; // stack overflow
int[250_001] c; // stack overflow
int[250_000] d; // ok

simendsjo:

> http://digitalmars.com/d/2.0/arrays.html says static arrays are
> limited to 16mb, but I can only allocate 1mb.
> My fault, or bug?

It accepts 4_000_000 ints, but not (16 * 1024 * 1024) / int.sizeof = 4_194_304 ints. I don't know why it's designed this way... I'd like 4_194_304 ints.

Bye,
bearophile

On 02.04.2011 16:45, bearophile wrote:
> simendsjo:
>
>> http://digitalmars.com/d/2.0/arrays.html says static arrays are
>> limited to 16mb, but I can only allocate 1mb.
>> My fault, or bug?
>
> It accepts 4_000_000 ints, but not (16 * 1024 * 1024) / int.sizeof = 4_194_304 ints. I don't know why it's designed this way... I'd like 4_194_304 ints.
>
> Bye,
> bearophile

The main problem is that it gives a Stack Overflow already at 250_001

simendsjo:

> The main problem is that it gives a Stack Overflow already at 250_001

I meant with the array as a global variable.
The stack on Windows can be set very large too, with -L/STACK:10000000

Bye,
bearophile

On Sat, 02 Apr 2011 10:45:51 -0400, bearophile <bearophileHUGS@lycos.com> wrote:

> simendsjo:
>
>> http://digitalmars.com/d/2.0/arrays.html says static arrays are
>> limited to 16mb, but I can only allocate 1mb.
>> My fault, or bug?
>
> It accepts 4_000_000 ints, but not (16 * 1024 * 1024) / int.sizeof = 4_194_304 ints. I don't know why it's designed this way... I'd like 4_194_304 ints.

That would be 16 MiB.

http://en.wikipedia.org/wiki/Mebibyte

-Steve

Steven Schveighoffer:

> That would be 16 MiB.
> 
> http://en.wikipedia.org/wiki/Mebibyte

Then I think 16 MiB are more useful than 16_000_000 bytes.

Bye,
bearophile

On Mon, 04 Apr 2011 12:43:03 -0400, bearophile <bearophileHUGS@lycos.com> wrote:

> Steven Schveighoffer:
>
>> That would be 16 MiB.
>>
>> http://en.wikipedia.org/wiki/Mebibyte
>
> Then I think 16 MiB are more useful than 16_000_000 bytes.

Seems arbitrary to me.  I'm sure some people feel 32MB would be more useful.

-Steve