#import <objc/objc.h>
#import <objc/Object.h>

@interface TestObj : Object
{
    int num;
}
- (void)foo;
@end

@implementation TestObj

- (void)foo {
     printf("foo\n");
}

int main()
{
    id obj = [[TestObj alloc] init];
    [obj foo];
    return 0;
}
@end