• Bastiaan Veelo (8/8) Feb 10 2017 // enum int maxarray = 0;
• Stefan Koch (2/10) Feb 10 2017 Yes.
• Jonathan M Davis via Digitalmars-d-learn (12/20) Feb 10 2017 Module-level and static variables all get put in the executable. So,
• sarn (12/17) Feb 10 2017 An important difference with C/C++ in this case is that D floats
• Bastiaan Veelo (4/6) Feb 11 2017 I was actually wondering whether initialisation would make a
• Bastiaan Veelo (1/1) Feb 11 2017 Thanks for the clarifications.

Bastiaan Veelo <Bastiaan Veelo.net> writes:

// enum int maxarray = 0;
enum int maxarray = 2_000_000;

double[maxarray] a, b, c, d;

void main() {}


Compiled using "dub build --arch=x86_64 --build=release" on 
Windows (DMD32 D Compiler v2.073.0), the exe size is 302_592 
bytes v.s. 64_302_592 bytes, depending on the array length.

Is that normal?

Stefan Koch <uplink.coder googlemail.com> writes:

On Friday, 10 February 2017 at 11:21:48 UTC, Bastiaan Veelo wrote:
 // enum int maxarray = 0;
 enum int maxarray = 2_000_000;

 double[maxarray] a, b, c, d;

 void main() {}


 Compiled using "dub build --arch=x86_64 --build=release" on 
 Windows (DMD32 D Compiler v2.073.0), the exe size is 302_592 
 bytes v.s. 64_302_592 bytes, depending on the array length.

 Is that normal?

Yes.

Jonathan M Davis via Digitalmars-d-learn writes:

On Friday, February 10, 2017 11:21:48 Bastiaan Veelo via Digitalmars-d-learn 
wrote:
 // enum int maxarray = 0;
 enum int maxarray = 2_000_000;

 double[maxarray] a, b, c, d;

 void main() {}


 Compiled using "dub build --arch=x86_64 --build=release" on
 Windows (DMD32 D Compiler v2.073.0), the exe size is 302_592
 bytes v.s. 64_302_592 bytes, depending on the array length.

 Is that normal?

Module-level and static variables all get put in the executable. So,
declaring a static array like that is going to take up space. A dynamic
array would do the same thing if you gave it a value of that size. The same
thing happens with global and static variables in C/C++.

Similarly, even with a local variable that's a static or dynamic array, if
you use a literal to initialize it, that literal has to be put in the
executable, increasing its size. But the nature of module-level or global
variables is such that even if they're not explicitly assigned a value, they
take up space.

- Jonathan M Davis

sarn <sarn theartofmachinery.com> writes:

On Friday, 10 February 2017 at 15:12:28 UTC, Jonathan M Davis 
wrote:
 Module-level and static variables all get put in the 
 executable. So, declaring a static array like that is going to 
 take up space. A dynamic array would do the same thing if you 
 gave it a value of that size. The same thing happens with 
 global and static variables in C/C++.

An important difference with C/C++ in this case is that D floats 
are initialised to NaN, not 0.0.  In binary (assuming IEEE 
floating point), 0.0 has an all-zero representation, but NaNs 
don't.  Therefore, in C/C++ (on most platforms), 
default-initialised floats can be allocated in the BSS segment, 
which doesn't take up executable space, but in D, 
default-initialised floats have to be put into the compiled 
binary.

If you explicitly initialise the array to all 0.0, you should see 
it disappear from the binary.

Bastiaan Veelo <Bastiaan Veelo.net> writes:

On Saturday, 11 February 2017 at 00:16:04 UTC, sarn wrote:
 If you explicitly initialise the array to all 0.0, you should 
 see it disappear from the binary.

I was actually wondering whether initialisation would make a 
difference, so thank you for this.

Bastiaan.

Bastiaan Veelo <Bastiaan Veelo.net> writes:

Thanks for the clarifications.