If the result of init(contents, compile, execute, or execute, signals failure (nil, false, nil, or nil, respectively), a pointer to an autoreleased dictionary is put at the location pointed to by the error parameter. The error info dictionary may contain entries that use any combination of the following keys, including no entries at all.
Framework
class let errorAn NSString that supplies a detailed description of the error condition.
class let errorAn NSNumber that specifies the error number.
class let errorAn NSString that specifies the name of the application that generated the error.
class let errorAn NSString that provides a brief description of the error.
class let errorAn NSValue that specifies a range.