     mainDiv.expandWidth = true
     mainDiv.expandHeight = true
 
-    fn(div: &mainDiv)
+    try fn(div: &mainDiv)
 
     timeout(0)
 

    addArgs(args)
  }

  public mutating func addArgs(args: [Any]) {
    for v in args {
      if v is String {

  var invalidated = false
  var mainDiv = NCDiv()

  public func start(fn: (inout div: NCDiv) throws -> Void) throws {
    Signal.trap(Signal.INT, ncIntSignalHandler)
    Signal.trap(SIGWINCH, ncWinchSignalHandler)

