Returns the resource values for the properties identified by specified array of keys.
- iOS 4.0+
- macOS 10.6+
- tvOS 9.0+
- watchOS 2.0+
An array of property keys for the desired resource properties.
The error that occurred if one or more resource values could not be retrieved. This parameter is optional. If you are not interested in receiving error information, you can pass
A dictionary of resource values indexed by key.
This method first checks if the URL object already caches the specified resource values. If so, it returns the cached resource values to the caller. If not, then this method synchronously obtains the resource values from the backing store, adds the resource values to the URL object's cache, and returns the resource values to the caller.
The type of the returned resource value varies by resource property; for details, see the documentation for the key you want to access.
If the result dictionary does not contain a resource value for one or more of the requested resource keys, it means those resource properties are not available for the URL, and no errors occurred when determining those resource properties were not available.
If an error occurs, this method returns
nil and populates the object pointer referenced by
error with additional information.