Synchronize.swift

public func Synchronize(semaphore : AnyObject, @noescape block : Void throws -> Void) rethrows -> Void
{
    objc_sync_enter(semaphore)
    defer { objc_sync_exit(semaphore) }
    
    try block()
}

@warn_unused_result
public func Synchronize<Type>(semaphore : AnyObject, @noescape block : Void throws -> Type) rethrows -> Type
{
    objc_sync_enter(semaphore)
    defer { objc_sync_exit(semaphore) }
    
    return try block()
}

func example()
{
    let semaphore = NSObject()
    
    let value = Synchronize(semaphore) {
        return someFuncThatNeedsLocking()
    }
    
    Synchronize(semaphore) {
        someOtherFuncThatNeedsLocking()
    }
}