#import #if __has_include() #import #define XXView NSView #else #import #define XXView UIView #endif int main() { XXView *view = [[XXView alloc] init]; dispatch_group_t g = dispatch_group_create(); dispatch_group_enter(g); [NSThread detachNewThreadWithBlock:^{ @autoreleasepool { [view superview]; } dispatch_group_leave(g); }]; dispatch_group_wait(g, DISPATCH_TIME_FOREVER); }