GC handle? - Silk.NET

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TechPizza

T

TechPizza•1/6/23, 9:49 PM

pin only when you need a pointer

Aqua

AAqua GC handle?

TechPizza

T

TechPizza•1/6/23, 9:49 PM

GCHandle

TechPizza

T

TechPizza•1/6/23, 9:49 PM

long-term pinning managed memory is pretty bad though

Aqua

A

AquaOP•1/6/23, 9:50 PM

i don't need it much but its useful in certain situations
the struct needs to be unmanagedunmanaged and so i just store a pointer

Aqua

A

AquaOP•1/6/23, 9:50 PM

gchandle doesn't look unmanagedunmanaged...

TechPizza

T

TechPizza•1/6/23, 9:50 PM

GCHandle can be converted to and from IntPtr

Aqua

A

AquaOP•1/6/23, 9:51 PM

i see

Aqua

A

AquaOP•1/6/23, 9:51 PM

i suppose my question is

Aqua

A

AquaOP•1/6/23, 9:51 PM

what is the correct way to store a pointer as a field
because seemingly my method that has worked fine every single time is not the correct way of doing it

Perksey

P

Perksey•1/6/23, 9:51 PM

@grifon.petre this Silk.NET 3.0 design prototype may interest you

Volte

V

Volte•1/6/23, 9:51 PM

here's a better design with more implicitness https://sharplab.io/#v2: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

Original Message

Quoted by Perksey#6579

Perksey

P

Perksey•1/6/23, 9:53 PM

essentially we store it as a ref (well, actually in a span, as ref fields are impossible atm if you're anyone other than the BCL)

TechPizza

T

TechPizza•1/6/23, 9:54 PM

net7 has ref fields my guy

Perksey

P

Perksey•1/6/23, 9:54 PM

wait

Perksey

P

Perksey•1/6/23, 9:54 PM

what

Aqua

A

AquaOP•1/6/23, 9:54 PM

maybe i am too tired to understand but this just converts a string to span? or something?

Aqua

AAqua maybe i am too tired to understand but this just converts a string to span? or s...

Perksey

P

Perksey•1/6/23, 9:54 PM

no, that's just one of the uses

Aqua

A

AquaOP•1/6/23, 9:54 PM

ah
ok

Perksey

P

Perksey•1/6/23, 9:54 PM

    public static implicit operator PointerLike<T>(T[] a) => new(){Span = a};

    public static implicit operator PointerLike<T>(T[] a) => new(){Span = a};

Perksey

PPerksey _what_

TechPizza

T

TechPizza•1/6/23, 9:54 PM

we got UnscopedRef, Scoped refs, and ref fields, pick your poison

Perksey

P

Perksey•1/6/23, 9:55 PM

i pick rust when

when

Aqua

AAqua hm. been looking and seems like ```cs public class Thing { void* whatever; ...

Aqua

A

AquaOP•1/6/23, 9:55 PM

so my question is
what is the best way to do this
i need to store a pointer to something in a struct like this
currently i used the fixed thing but seemingly that's incorrect
so i have no idea
ive never had any issues with it
but i'd rather there wasn't a chance to have any issues with it

Perksey

P

Perksey•1/6/23, 9:56 PM

...i just gave you an example

Perksey

P

Perksey•1/6/23, 9:56 PM

don't think of it as storing a pointer

Perksey

P

Perksey•1/6/23, 9:56 PM

store a ref

Perksey

P

Perksey•1/6/23, 9:56 PM

a ref can be anything

Perksey

P

Perksey•1/6/23, 9:56 PM

managed, unmanaged

Perksey

P

Perksey•1/6/23, 9:56 PM

the only plus being if it's managed, it'll still be GC tracked

TechPizza

T

TechPizza•1/6/23, 9:56 PM

i bet rollie wants to store it in an ECS .)

Aqua

A

AquaOP•1/6/23, 9:56 PM

no, it's because i use the struct as the input parameter for my texture creation

Perksey

PPerksey store a ref

Aqua

A

AquaOP•1/6/23, 9:57 PM

interesting, although i am not on .net 7 so i can't use ref fields
hm

Perksey

P

Perksey•1/6/23, 9:57 PM

yeah

Perksey

P

Perksey•1/6/23, 9:57 PM

that doesn't use .net 7 ref fields

Perksey

P

Perksey•1/6/23, 9:57 PM

i didn't know they existed until 5 seconds ago

Perksey

P

Perksey•1/6/23, 9:57 PM

so it'd be impressive if i managed to use ref fields before knowing about it!

Aqua

AAqua no, it's because i use the struct as the input parameter for my texture creation

TechPizza

T

TechPizza•1/6/23, 9:58 PM

take a pointer to a ref struct and pass that when

when

Perksey

PPerksey i didn't know they existed until 5 seconds ago

TechPizza

T

TechPizza•1/6/23, 9:58 PM

you can take pointers to object locals now as well

Perksey

P

Perksey•1/6/23, 9:58 PM

is that a GC hole

Aqua

A

AquaOP•1/6/23, 9:58 PM

so basically
if i am understanding this
storing it as a span is the correct way to do it
instead of storing a raw pointer?
i think i have confused myself

Aqua

AAqua so basically if i am understanding this storing it as a span is the correct way ...

Perksey

P

Perksey•1/6/23, 9:58 PM

well storing it as a ref

Perksey

PPerksey is that a GC hole

TechPizza

T

TechPizza•1/6/23, 9:58 PM

nope, pointers to locals with GC refs are now correctly tracked

Perksey

P

Perksey•1/6/23, 9:58 PM

so that could be ref fields, or if you're on anything but .net 7 span is the way to do that

Aqua

A

AquaOP•1/6/23, 9:58 PM

ah
gotcha

TechPizza

T

TechPizza•1/6/23, 9:59 PM

so you can do this:

object local = new();
object* ptr = &local;
PassToNative(ptr);

object local = new();
object* ptr = &local;
PassToNative(ptr);

TechPizza

T

TechPizza•1/6/23, 9:59 PM

it's a bit cursed but super useful

Perksey

P

Perksey•1/6/23, 9:59 PM

TechPizza

T

TechPizza•1/6/23, 10:03 PM

way better than GC handles. i'm already using it in my V8 bindings lol

Aqua

A

AquaOP•1/6/23, 10:03 PM

so i changed the struct from the pointer to the span and it doesn't seem to be complaining so i'm happy with this, thanks!

TechPizza

TTechPizza way better than GC handles. i'm already using it in my V8 bindings lol

TechPizza

T

TechPizza•1/6/23, 10:04 PM

although non-pinning GCHandle is still useful for long-term stuff in native

Aqua

A

AquaOP•1/6/23, 10:06 PM

this also helped me understand my original question of why you need to deallocate the memory with silkmarshal instead of just using fixed on it so that's good too