objc-assoc.m

#import <Foundation/Foundation.h>
#import <objc/runtime.h>
#import <objc/objc-auto.h>

/*
cc -Wall -fobjc-gc objc-assoc.m -o objc-assoc -framework Foundation
*/

@interface ExtraData : NSObject
@end
@implementation ExtraData
- (void)dealloc;
{
	fprintf(stderr, "ExtraData %p deallocated\n", self);
	[super dealloc];
}
- (void)finalize;
{
	fprintf(stderr, "ExtraData %p finalized\n", self);
	[super finalize];
}
@end

int main(int argc, char *argv[])
{
	NSObject *owner = [[NSObject alloc] init];
	ExtraData *data = [[ExtraData alloc] init];
	
	static void *ExtraDataKey;
	
	objc_setAssociatedObject(owner, &ExtraDataKey, data, OBJC_ASSOCIATION_RETAIN);
	[data release];
	
	fprintf(stderr, "Releasing owner...\n");
	[owner release];
	
	// In GC-land, make sure we don't have any pointers to the owner
	if ([NSGarbageCollector defaultCollector]) {
		owner = nil;
		data = nil;
		objc_clear_stack(0);
		[[NSGarbageCollector defaultCollector] collectExhaustively];
	}
	
	return 0;
}