If you want to pass a pointer, you can use ```memS...

# kotlin-native

[Dico]

If you want to pass a pointer, you can use

memScope {
    val size = alloc<UIntVar>()
    sysctlbyname(..., ..., size.ptr,)
    size.value
}

[nestserau]

Thank you very much, I will now try this out!

[jonnyzzz]

beware, it will release the memory after the memScope block is completed

[Dico]

Remember to import kotlin.native.cinterop.*

[jonnyzzz]

use Arena or GlobalScope for a loner-living things

[nestserau]

So would this be the correct implementation?

memScoped {
                val size = alloc<ULongVar>()
                sysctlbyname("hw.machine", null, size.ptr, null, 0)
                val machine = allocArray<ByteVar>(size.value.toLong())
                sysctlbyname("hw.machine", machine, size.ptr, null, 0)
                return machine.getPointer(this).toKString()
            }

[Dico]

I don't know what the sys function does. You have to make sure the data in machine is somehow copied to return it

[Dico]

You can replace getPointer(this) with ptr

[nestserau]

This is the corresponding Objective C code that I’m trying to translate:

size_t size;
    sysctlbyname("hw.machine", NULL, &size, NULL, 0);
    char *machine = (char *)malloc(size);
    sysctlbyname("hw.machine", machine, &size, NULL, 0);
    NSString *platform = [NSString stringWithUTF8String:machine];
    free(machine);
    return platform;

[nestserau]

You can replace getPointer(this) with ptr

This doesn’t work for CArrayPointer for some reason.

[Dico]

Well, machine is freed when you leave memScope so you have to use it before that

[nestserau]

Yeah, I make a Kotlin out of it, so should be fine?

[Dico]

Oh yeah, that should be fine

[nestserau]

Cool, thank you very much! Very little documentation, if not this channel I would give up long time ago.

[Dico]

You're welcome