• ref2401 (13/13) Dec 05 2015 I want to create a static array large enough to store 1MB of
• Olivier Pisano (6/19) Dec 05 2015 I suppose you overflow the stack.
• John Colvin (19/32) Dec 05 2015 The default stack size is probably 1MB, which means your 1MB
• Steven Schveighoffer (7/40) Dec 05 2015 T[N]* heapStaticArray(T, size_t N)()

ref2401 <refactor24 gmail.com> writes:

I want to create a static array large enough to store 1MB of 
float values.
What am I doing wrong?
Here is a sample code with notes:

void main(string[] args) {
	enum size_t COUNT = 1024 * 512 / float.sizeof; // works OK :)
	//enum size_t COUNT = 1024 * 512 * 2 / float.sizeof; // 
constantly crashes :(
	float[COUNT] arr;
	writeln(arr.length);
}

DMD: 2069.2
OS: Win 8.1 Pro

Olivier Pisano <olivier.pisano laposte.net> writes:

On Saturday, 5 December 2015 at 09:49:06 UTC, ref2401 wrote:
 I want to create a static array large enough to store 1MB of 
 float values.
 What am I doing wrong?
 Here is a sample code with notes:

 void main(string[] args) {
 	enum size_t COUNT = 1024 * 512 / float.sizeof; // works OK :)
 	//enum size_t COUNT = 1024 * 512 * 2 / float.sizeof; // 
 constantly crashes :(
 	float[COUNT] arr;
 	writeln(arr.length);
 }

 DMD: 2069.2
 OS: Win 8.1 Pro

I suppose you overflow the stack.
I am not a Windows dev, but I suppose there is a linker option to 
increase the stack size.
Or you can try to use a global __gshared variable or allocate 
your array on the heap.

John Colvin <john.loughran.colvin gmail.com> writes:

On Saturday, 5 December 2015 at 09:49:06 UTC, ref2401 wrote:
 I want to create a static array large enough to store 1MB of 
 float values.
 What am I doing wrong?
 Here is a sample code with notes:

 void main(string[] args) {
 	enum size_t COUNT = 1024 * 512 / float.sizeof; // works OK :)
 	//enum size_t COUNT = 1024 * 512 * 2 / float.sizeof; // 
 constantly crashes :(
 	float[COUNT] arr;
 	writeln(arr.length);
 }

 DMD: 2069.2
 OS: Win 8.1 Pro

The default stack size is probably 1MB, which means your 1MB 
array plus a few local variables is too much. Arrays that large 
should be allocated on the heap in most circumstances.

Watch out for this:
static assert(is(typeof(new float[3]) == float[]));
because `new T[n]` is a special case in the grammar. If you 
really must have a static array on the heap (as opposed to a 
dynamic array / slice T[]), you can use something like this, but 
i wouldn't recommend it:

T[N]* heapStaticArray(T, size_t N)()
{
     return cast(T[N]*)((new T[N]).ptr);
}

void main()
{
	int[4]* a = heapStaticArray!(int, 4)();
	(*a)[] = 3;
}

Steven Schveighoffer <schveiguy yahoo.com> writes:

On 12/5/15 8:09 AM, John Colvin wrote:
 On Saturday, 5 December 2015 at 09:49:06 UTC, ref2401 wrote:
 I want to create a static array large enough to store 1MB of float
 values.
 What am I doing wrong?
 Here is a sample code with notes:

 void main(string[] args) {
     enum size_t COUNT = 1024 * 512 / float.sizeof; // works OK :)
     //enum size_t COUNT = 1024 * 512 * 2 / float.sizeof; // constantly
 crashes :(
     float[COUNT] arr;
     writeln(arr.length);
 }

 DMD: 2069.2
 OS: Win 8.1 Pro

 The default stack size is probably 1MB, which means your 1MB array plus
 a few local variables is too much. Arrays that large should be allocated
 on the heap in most circumstances.

 Watch out for this:
 static assert(is(typeof(new float[3]) == float[]));
 because `new T[n]` is a special case in the grammar. If you really must
 have a static array on the heap (as opposed to a dynamic array / slice
 T[]), you can use something like this, but i wouldn't recommend it:

 T[N]* heapStaticArray(T, size_t N)()
 {
      return cast(T[N]*)((new T[N]).ptr);
 }

 void main()
 {
      int[4]* a = heapStaticArray!(int, 4)();
      (*a)[] = 3;
 }

T[N]* heapStaticArray(T, size_t N)()
{
    auto arr = new T[N][1];
    return &arr[0];
}

-Steve