[swift-users] NSMutableData's init?(length length: Int) initializer

[Dmitri Gribenko]

On Fri, Apr 15, 2016 at 10:34 AM, Chris Lattner <clattner at apple.com> wrote:
>
>> On Apr 14, 2016, at 11:22 PM, Dmitri Gribenko <gribozavr at gmail.com> wrote:
>>
>> On Thu, Apr 14, 2016 at 11:16 PM, Chris Lattner via swift-users
>> <swift-users at swift.org> wrote:
>>>
>>>> On Apr 14, 2016, at 10:45 AM, soyer via swift-users <swift-users at swift.org> wrote:
>>>>
>>>> Hello Guys, Girls,
>>>>
>>>> Do you know why is the init?(length length: Int) NSMutableData's initializer failable?
>>>> The memory allocation can fail, but I think Swift doesn't handle that cases. (it is not a real issue in a modern OS)
>>>> The code on github calls a non failable initializer.
>>>> https://github.com/apple/swift-corelibs-foundation/blob/master/Foundation/NSData.swift#L904
>>>
>>> Swift’s policy on memory allocation failure is that fixed-size object allocation is considered to be a runtime failure if it cannot be handled.  OTOH, APIs that can take a variable and arbitrarily large amount to allocate should be failable.  NSData falls into the later category.
>>
>> Does this principle apply to Array(repeating:count:)?
>> Array.append(contentsOf:)?
>
> As you know well enough, “no”. :-)

Why?  These APIs also "take a variable and arbitrarily large amount to
allocate".

Dmitri

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