Allocating a wstring on the stack (no GC)?

[bearophile via Digitalmars-d]

Maxime Chevalier-Boisvert:

> I do need it to be dynamically sized.

But often you can determine statically a maximum length of the 
string, so you can use a fixed size stack buffer and slice it 
with a dynamic length. If this is not acceptable, then use alloca.


> Basically, I just want to create a wstring "view" on an 
> existing "raw" buffer that exists in memory somewhere, based on 
> a pointer to this buffer and its length.

This is named slicing. You can also slice a 
global/static/__gshared buffer.


> Side note: wouldn't alloca just produce a wchar*, not an array 
> (wouldn't have length information)?

alloca returns a void*, then you can cast it to the pointer type 
you want, and then you slice the pointer:

auto ptr = cast(wchar*)alloca(wchar.sizeof * len);
if (ptr == null) throw new Error("...");
auto mySlice = ptr[0 .. len];

Bye,
bearophile