getting error message of Type 'UnsafeMutableRawPointer' has no subscript members'

问题

i just need to alloc memory & set values there.Here is my code.

 let radius:Float = 5.79
 let sigma:Float = radius / 2
 let size:Int = Int((round(radius) * 2) + 1)

 var weights:UnsafeMutableRawPointer = malloc(MemoryLayout<Float>.size * size * size)

 weights[some index] = some vale

but I am getting an error message in swift version 4 saying "UnsafeMutableRawPointer has no subscript members"

How can I fixed this.Any ideas please

回答1:

You should better check the official documentation of UnsafeMutableRawPointer

You can write something like this:

let radius:Float = 5.79
let sigma:Float = radius / 2
let size:Int = Int((round(radius) * 2) + 1)

var weights:UnsafeMutableRawPointer = malloc(MemoryLayout<Float>.size * size * size)

weights.storeBytes(of: some value, toByteOffset: some offset, as: SomeType.self)

Or you should better use UnsafeMutablePointer<Float> instead, if all the elements are Float.

var weights:UnsafeMutablePointer<Float> = UnsafeMutablePointer.allocate(capacity: size * size)

weights[some index] = some vale

来源：https://stackoverflow.com/questions/52733309/getting-error-message-of-type-unsafemutablerawpointer-has-no-subscript-members