NSString实例报告其类为NSCFString [英] NSString instance reports its class as NSCFString

问题描述

我的目标很简单 - 我试图为一些测试数据设置一个 NSString ，然后返回类，它应该是 NSString 。这里是我的代码：

My objective here is really simple -- I'm trying to set an NSString to some test data, then return the class, which should be NSString. Here's my code:

NSString* stringer = [NSString stringWithFormat: @"Test"];
NSLog(@"%@", [stringer class]);

日志表示类 NSCFString ，而不是 NSString 。这里发生了什么？

The log says that the class is NSCFString, not NSString. What's going on here?

推荐答案

NSString真的是一个容器类，用于不同类型的字符串对象。一般来说，NSString构造函数返回一个实际上是NSCFString类型的对象，这是一个围绕着Core Foundation CFString结构的薄包装。

NSString is really a container class for different types of string objects. Generally an NSString constructor does return an object that is actually of type NSCFString, which is a thin wrapper around the Core Foundation CFString struct.

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