#import <Foundation/Foundation.h>

// gcc -g -Wall -framework Foundation -o sel sel.m

@interface ObjectCallback : NSObject
- (void)callback;
@end

@implementation ObjectCallback

- (int) groovyness {
    return 23;
}

- (void)callback {
    NSLog(@"My spoon is too big %d", [self groovyness]);
}
@end

typedef void (*C_callback)(void);

int main (void) {
    ObjectCallback *cb = [[ObjectCallback alloc] init];
    [cb callback];

    IMP method = [cb methodForSelector:@selector(callback)];

    // This is what the C library would be doing.
    C_callback c_function = (C_callback)method;
    c_function();
    
    return (0);
} // main