我是 Objective C 的新手,并试图弄清楚 ^ 运算符的作用是什么?在探索一些源代码时,我看到了下一个构造:
dispatch_once(&onceToken, ^{
UIGraphicsBeginImageContextWithOptions(CGSizeMake(20.f, 13.f), NO, 0.0f);
[[UIColor blackColor] setFill];
[[UIBezierPath bezierPathWithRect:CGRectMake(0, 0, 20, 1)] fill];
[[UIBezierPath bezierPathWithRect:CGRectMake(0, 5, 20, 1)] fill];
[[UIBezierPath bezierPathWithRect:CGRectMake(0, 10, 20, 1)] fill];
[[UIColor whiteColor] setFill];
[[UIBezierPath bezierPathWithRect:CGRectMake(0, 1, 20, 2)] fill];
[[UIBezierPath bezierPathWithRect:CGRectMake(0, 6, 20, 2)] fill];
[[UIBezierPath bezierPathWithRect:CGRectMake(0, 11, 20, 2)] fill];
defaultImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
});
我想知道^是什么?