Documentation question for UnsafeMutablePointer

Kyle-Ye · October 19, 2023, 5:22am

Why do we declare in the document comments of the initialization method of the UnsafeMutablePointer type that it "Create an immutable typed pointer"?

I am a little confused by the doc statement here.

Could you help check with it and maybe give some explanation here? Thanks @Alex_Martini

github.com

apple/swift/blob/6d246def5e6c9e7a9ca323945c355debd5579346/stdlib/public/core/UnsafePointer.swift#L615-L633


      
          /// Creates an immutable typed pointer referencing the same memory as the
          /// given mutable pointer.
          ///
          /// - Parameter other: The pointer to convert.
          @_transparent
          public init(@_nonEphemeral _ other: UnsafeMutablePointer<Pointee>) {
           self._rawValue = other._rawValue
          }
          
          /// Creates an immutable typed pointer referencing the same memory as the
          /// given mutable pointer.
          ///
          /// - Parameter other: The pointer to convert. If `other` is `nil`, the
          ///   result is `nil`.
          @_transparent
          public init?(@_nonEphemeral _ other: UnsafeMutablePointer<Pointee>?) {
           guard let unwrapped = other else { return nil }
           self.init(unwrapped)
          }

Alex_Martini · October 19, 2023, 9:22pm

I'm not sure — the work I've done on "unsafe' docs was cleaning up some trailing whitespace and other minor wording fixes. It's possible this is just a copy/paste error from UnsafePointer to UnsafeMutablePointer.

Looking at Git blame, maybe @nnnnnnnn or @hamishknight can help with this? But it's probably not in anybody's recent memory, since changes to these docs and APIs are from 4 and 7 years ago.

scanon · October 19, 2023, 9:47pm

Yeah, I'm pretty sure this is just an error.

Alex_Martini · October 24, 2023, 4:52am

For folks following along, Kyle Ye's PR that fixes this copy/paste error was merged:

https://github.com/apple/swift/pull/69297

Thanks!

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Usage of `UnsafeMutablePointer.init(mutating)` Using Swift	10	1779	May 18, 2020
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Proposal: Extend the &x -> UnsafePointer behavior to work with immutable values Discussion	12	567	December 17, 2015
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Documentation question for UnsafeMutablePointer

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