PSPDFViewController.h

// Defines a yet undocumented method to add a warning if super isn't called.
#ifndef NS_REQUIRES_SUPER
#if __has_attribute(objc_requires_super)
#define NS_REQUIRES_SUPER __attribute((objc_requires_super))
#else
#define NS_REQUIRES_SUPER
#endif
#endif

@interface UIViewController (SubclassingWarnings)

// PSPDFKit overrides all kind of event hooks for UIViewController.
// You should always call super on those, even if you're just using UIViewController.
- (void)viewWillAppear:(BOOL)animated NS_REQUIRES_SUPER;
- (void)viewDidAppear:(BOOL)animated NS_REQUIRES_SUPER;
- (void)viewWillDisappear:(BOOL)animated NS_REQUIRES_SUPER;
- (void)viewDidDisappear:(BOOL)animated NS_REQUIRES_SUPER;
- (void)viewWillLayoutSubviews NS_REQUIRES_SUPER;
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration NS_REQUIRES_SUPER;
- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration NS_REQUIRES_SUPER;
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation NS_REQUIRES_SUPER;
- (void)didReceiveMemoryWarning NS_REQUIRES_SUPER;

@end