Lifetimes on the stack

[lone saddle]

Would this piece of code ever not work? I'm curious to know if I could do this safely without any worries of trash overwriting the array's contents, so far it has never failed but I'm wondering if it ever will.

[cyan spruce]

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[delicate frost]

are the members of vec3 of type float or double?

[urban hedge]

Paste code as text.

[lone saddle]

My bad, will do that instead

[lone saddle]

floats

typedef struct
{
    float x;
    float y;
    float z;
} vec3;

[delicate frost]

the code is fine then

[lone saddle]

This is the struct I'm using rn

Nice, would it not work if it was a double?

[urban hedge]

It doesn't matter here, does it?

[delicate frost]

it would work fine with double

[delicate frost]

if it was int then the format strings would be incorrect

[barren thistle]

Each vec3s will be in different, non-overlapping memory locations if that's what you're asking

[lone saddle]

Gotcha, as long as it's native types it would work I assume?

[delicate frost]

'native type'?

[lone saddle]

My bad, not sure what the correct name is

[urban hedge]

You mentioned float and double though.

[lone saddle]

Basically the types that come out of the box with the language

[barren thistle]

So unless you have another code somewhere that invades another function's stack and overwrites them, your code should be 100% fine

[delicate frost]

yes, because it would be correct if it was one of those types

[urban hedge]

OK I took that as picking one out of those two.

[lone saddle]

Gotcha, it was basically that yeah

[delicate frost]

that doesn't really change anything

you're copying the vec3 into the array

[lone saddle]

Aaaah

Alright, that's what I needed to hear, makes a lot more sense now

So it inserts a copy into the array

Didn't know that, thank you

[delicate frost]

yep = with structures will copy the structures (i.e. it copies all of the members)

[lone saddle]

Gotcha, that answers my question, I was worried it would've copied the reference somehow, which would mess up the code once out of scope

Not the code, the array I mean

[barren thistle]

The compiler is allowed to optimize away that a by just directly writing data into vecs, but in essence you can think of it as a copy

[lone saddle]

That's nice, thank you all :)

[delicate frost]

the compiler can theoretically optimize out the entire array and just do one big printf call

[barren thistle]

There's really no way to tell what the compiler does with your code I think lmao

Just don't do UB and the compiler won't ever break your code

[delicate frost]

yeah, you shouldn't really concern yourself with optimizations when thinking about the semantics of the language; i.e. it does a copy but the way it reaches the result of copying (or the entire program in general) is up to the compiler

[lone saddle]

I think compiler optimizations are beyond my skillset right now 💀💀💀 But I'll have to learn them soon enough considering my 3d engine project

It's running well but I doubt it will with millions of polygons

Either way, thank you so much for the help :)

I really appreciate it