I feel the dynamic array .sizeof property is kind of a bait and switch

[WhatMeWorry via Digitalmars-d-learn]

On Wednesday, 26 July 2017 at 02:32:07 UTC, Adam D. Ruppe wrote:
>
>> I've hand rolled a function which is working for me currently, 
>> but with my coding ability, I'd feel much safer with something 
>> official :)
>
> You could also do (cast(ubyte[]) array).length.
>

This was my (way over complicated) attempt at the same thing. 
I'll blame my verbosity because I was trying to teach myself 
about templates and constraints at the time :)

/+
There is a special type of array which acts as a wildcard that 
can hold arrays of any kind, declared as void[].  The .length of 
a void array is the length of the data in
bytes rather than the number of elements in its original type. "
+/

int arrayByteSize(T)(T someArray) if (isDynamicArray!(T))
{
     ubyte[] arr = cast(ubyte[]) someArray;
     return cast(int) arr.length;
}

>> It just seems like something this basic regarding dynamic 
>> arrays should just be built-in.
>
> What are you using it for?

glBufferData(GL_ARRAY_BUFFER, vertices.arrayByteSize, 
vertices.ptr, GL_STATIC_DRAW);

I find that openGL uses array buffers all over the place.

I just keep going back to the idea that such low level 
functionality should be inherent in either the language or 
Phobos.  If that is even possible.