objc_msgSend 调用时报错Implicitly declaring library function ‘objc_msgSend‘ with type ‘id (id, SEL, ...)‘

1、需引入objc头文件

#import <objc/message.h>

2、mark一下有返回值的写法

id (*Fun)(id, SEL, NSString *, NSURL *, NSString *) = (id (*)(id, SEL, NSString *,NSURL *,NSString *))objc_msgSend;

id ret = Fun(obj, @selector(_cookieForSetCookieString:forURL:partition:), @"a=b", [NSURL URLWithString:@"https://www.baidu.com"], nil);