Clang-ns_consumed属性

测试是否支持：ns_consumed

#if __has_attribute(ns_consumed)
    NSLog(@"ns_consumed");
#else
    NSLog(@"ns_consumed not");
#endif
输出：ns_consumed

测试代码：

- (void)_foo_have_attribute:(id) __attribute((ns_consumed))x {
    NSLog(@"start count in _foo_have_attribute:%zd", [RXMRCUtil objectRetainCount:x]);
    NSLog(@"Do something");
    NSLog(@"end count in _foo_have_attribute:%zd", [RXMRCUtil objectRetainCount:x]);
}

- (void)_foo:(id)x {
    NSLog(@"start count _foo_not_attribute:%zd", [RXMRCUtil objectRetainCount:x]);
    NSLog(@"Do something");
    NSLog(@"end count in _foo_not_attribute:%zd", [RXMRCUtil objectRetainCount:x]);
}

- (void)test {
    RXARCTmpObject *object = [[RXARCTmpObject alloc] init];
    NSLog(@"start count outside method:%zd", [RXMRCUtil objectRetainCount:object]);
    
    [self _foo_have_attribute:object]; // 代码1
//    [self _foo:object]; // 代码2

    NSLog(@"end count outside method:%zd", [RXMRCUtil objectRetainCount:object]);
}

输出结果：

start count outside method:1
start count in _foo_have_attribute:2
Do something
end count in _foo_have_attribute:2
end count outside method:1
RXARCTmpObject dealloc

当注释代码1，打开代码2的时候，输出的数量结果是一样的
也就是说在ARC，是否加__attribute((ns_consumed))都是一样的。