Question

Create default iPad split view based apps from template from xcode 4, then we have codes like

@synthesize popoverController=_myPopoverController;

in file DetailViewController.m

My question is

what is “_myPopoverController” ? We do not declare such attribute in the interface, why introduce this magically ?

Answer 1

The Objective-C Programming Language Guide says this:

For the modern runtimes (see “Runtime
Versions and Platforms” in Objective-C
Runtime Programming Guide), instance
variables are synthesized as needed.
If an instance variable of the same
name already exists, it is used.

That means the instance variable _myPopoverController (or whatever name you put here) will be considered as if you would declare it in the @interface section.