关于runtime的一点理解代码

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

@interface MyClass : NSObject

@end

@implementation MyClass

@end

void myMethodIMP(id self,SEL _cmd){
NSLog(@"runtime hello");
}

int main(int argc, const char * argv[]) {
@autoreleasepool {
// insert code here...
NSLog(@"Hello, World!");

NSLog(@"%s",@selector(test));
NSLog(@"%lu",strlen(@selector(test)));

char *s = calloc(100, sizeof(char));
strcat(s,@selector(test));
strcat(s,@selector(test));
NSLog(@"%s",s);
free(s);

class_addMethod([MyClass class], @selector(myMethod), (IMP)myMethodIMP, "v@:");
MyClass *myObject = [[MyClass alloc] init];

[myObject performSelector:@selector(myMethod)];

}
return 0;
}

运行结果

2016-03-14 15:25:44.207 KKBOX[5786:187150] Hello, World!
2016-03-14 15:25:44.208 KKBOX[5786:187150] test
2016-03-14 15:25:44.208 KKBOX[5786:187150] 4
2016-03-14 15:25:44.208 KKBOX[5786:187150] testtest
2016-03-14 15:25:44.209 KKBOX[5786:187150] runtime hello
Program ended with exit code: 0