<isol>

@ü.li:Listing 1: Beispiel zum Method Swizzling

@li:NSUserDefaults+Timing.h:
#import <Foundation/Foundation.h>
@interface NSUserDefaults(Timing)
@end

NSUserDefaults+Timing.m:
#import "NSUserDefaults+Timing.h"
#import <objc/runtime.h> // Needed for method swizzling

@implementation NSUserDefaults(Timing)

- (BOOL)swizzled_synchronize
{
    NSDate *started;
    BOOL returnValue;
    
    started = [NSDate date];
    returnValue = [self swizzled_synchronize];
    NSLog(@"Writing user defaults took %f seconds.", [[NSDate date] timeIntervalSinceDate:started]);
    
    return returnValue;
}
@end

+ (void)load
{
    Method original, swizzled;
    
    original = class_getInstanceMethod(self, @selector(synchronize));
    swizzled = class_getInstanceMethod(self, @selector(swizzled_synchronize));
    method_exchangeImplementations(original, swizzled);
}

@ü.li:Listing 2: Auszug aus <I>loader.h<I>

@li:#define    LC_LOAD_DYLIB    0xc    /* load a dynamically linked shared library */
...
...
...
/*
 * load a dynamically linked shared library that is allowed to be missing
 * (all symbols are weak imported).
 */
#define    LC_LOAD_WEAK_DYLIB (0x18 | LC_REQ_DYLD)