objective c id *

Question

I am using the KVO validations in my cocoa app. I have a method

- (BOOL)validateName:(id *)ioValue error:(NSError **)outError

My controls can now have their bindings validate. How do I invoke that method with a id * NOT id

To use the value that is passed in (a pointer to a string pointer) I call this:

NSString * newName = (NSString *)*ioValue;
if ([newName length] < 4) {

otherwise i get bad exec crashes...

passing in with type casting doesnt work: (id *)myStringVar

passing in with a regular id doesnt work either : (id) myStringVar

Answer 1

NSError *error;
[self validateName:&myStringVar error:&error];

The ampersand means "address of." In this case, it is the address of the pointer, or in other words, a pointer to a pointer (which is what an id* is).