An overload of dispatch_sync that throws any error thrown by the closure. (Swift 2)

DispatchSyncThrows.swift

import Foundation

/// Call a throwing block synchronously.
func dispatch_sync(queue: dispatch_queue_t, block: () throws -> ()) throws {
    var error: ErrorType?
    dispatch_sync(queue) {
        do {
            try block()
        } catch let caughtError {
            error = caughtError
        }
    }
    if let error = error {
        throw error
    }
}


// Usage:

enum MyError: ErrorType {
    case OhNo
}

let queue = dispatch_queue_create("test", nil)

do {
    try dispatch_sync(queue) {
        throw MyError.OhNo
    }
} catch let e {
    print("Caught! \(e)")
}