CODEWITHSUNDEEP
xcodensstringswiftswift-playground
darrinm
darrinm

Reputation: 9257

Converting NSString to CString in Xcode Playground

When I attempt:

import Cocoa
var ns: NSString = "whatever"
var cs: CString = ns.UTF8String
println(cs)

in an Playground it reports this exception when executing the var cs: CString = ns.UTF8String statement:

fatal error: Can't unwrap Optional.None
Playground execution failed: error: Execution was interrupted, reason: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0).
The process has been left at the point where it was interrupted, use "thread return -x" to return to the state before expression evaluation.
* thread #1: tid = 0xbf05a5, 0x000000010401b02d libswift_stdlib_core.dylib`Swift._StringCore._growBuffer (@inout Swift._StringCore)(Swift.Int, minElementWidth : Swift.Int) -> Swift.COpaquePointer + 813, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
  * frame #0: 0x000000010401b02d libswift_stdlib_core.dylib`Swift._StringCore._growBuffer (@inout Swift._StringCore)(Swift.Int, minElementWidth : Swift.Int) -> Swift.COpaquePointer + 813
    frame #1: 0x000000010401643f libswift_stdlib_core.dylib`Swift._StringCore.append (@inout Swift._StringCore)(Swift._StringCore) -> () + 607
    frame #2: 0x0000000104016fa5 libswift_stdlib_core.dylib`Swift.+ @infix (Swift.String, Swift.String) -> Swift.String + 117
...truncated...

However the same code works as expected when compiled into an app. It looks like a Playground bug but does anyone know a workaround to convert an NSString to Cstring in the Playground?

Upvotes: 1

Views: 1913

Answers (1)

Connor
Connor

Reputation: 64684

I was able to get it to work in the playground by making cs a CString optional. 

import Cocoa
var ns: NSString = "whatever"
println(ns)
var cs: CString? = ns.UTF8String
println(cs)

and if you need to unwrap the optional

if let str = cs{
println(str)
}

Upvotes: 1

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