objc_msgSend 如何正确传递整数以及文本信息？

#import "ViewController.h"
#import
#import

@interface ViewController ()

@end

@implementation ViewController

• (void)viewDidLoad {
  [super viewDidLoad];

  int ar = 235;

  int add = (int)objc_msgSend(self, NSSelectorFromString(@"addValue:"), (int)&ar);

  NSLog(@"add = %d", add);

  // Do any additional setup after loading the view, typically from a nib.
  }

• (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }

• (int)addValue:(int)a{
  int c = a;
  return a;
  }

@end

打印出来的a = 9，而不是235.
求答案，为什么？

看看函数传值行不行