How do you use C level factory methods in Swift?

Let's try using a factory such as NewMusicSequence().

OSStatus status
var sequence:MusicSequence
status=NewMusicSequence(&sequence)

This errors out with "error: variable 'sequence' passed by reference before being initialized". Set sequence to nil, and you get EXC_BAD_INSTRUCTION.

You can try being explicit like this:

var sp:CMutablePointer<MusicSequence>=nil
status=NewMusicSequence(sp)

But then you get a bad access exception when you set sp to nil. If you don't set sp, you get an "error: variable 'sp' used before being initialized"

Here's the reference.