How to create a protocol at runtime in Objective-C?

Question

Hi, First of all, I want to be clear that I'm not talking about defining a protocol, and that I understand the concept of

@protocol someprotocol
- (void)method;
@end

I know that the Obj-C runtime allows creation of classes at RUNTIME, as well as its ivars and methods. Also available for creation are SEL-s. I think I'm just missing something, but does anyone know what function to call to create a protocol at runtime? The main reason for this is for conformsToProtocol: to work, so just adding the appropriate methods doesn't really cut it.

Answer 1

the following sort of works, but a proper way of doing this would be much appreciated:

Protocol *proto = [Protocol alloc];
object_setInstanceVariable(proto, "protocol_name", &"mySuperDuperProtocol");
void *nada = NULL;
object_setInstanceVariable(proto, "protocol_list", &nada);
object_setInstanceVariable(proto, "class_methods", &nada);

struct objc_method_description_list *methods;
methods = malloc(sizeof(int) + sizeof(struct objc_method_description) * 1);
methods->count = 1;
methods->list[0].name = @selector(foobar:);
methods->list[0].types = "v:@";
object_setInstanceVariable(proto, "instance_methods", &methods);

class_addProtocol([self class], proto);
NSLog(@"%d %s", [self conformsToProtocol:proto], protocol_getName(objc_getProtocol("mySuperDuperProtocol")));

The first NSLog parameter is 1, and isn't when the line adding the protocol to the class is commented out, meaning the protocol is somehow registered with the class. On the other hand, it does not get returned by objc_getProtocol (the second thing logged is nil).