什么是NSSearchPathForDirectoriesInDomains? [英] What is NSSearchPathForDirectoriesInDomains?

问题描述

[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject]

我曾经知道向对象发送消息是一种方法的调用.但是，我不知道什么是NSSearchPathForDirectoriesInDomains.是C风格的功能吗?如果是，那为什么在所有message样式调用中我们都有某种功能?

I used to know that sending a message to the object is kind of calling the method. However, I can't recognize what is NSSearchPathForDirectoriesInDomains. Is it C style function? If yes then why among all message style calls we have thing kind of function?

推荐答案

是的，它是一个普通的C函数，用于接收和返回Objective-C对象.

Yes, it's a plain C function taking and returning objective-c objects.

关于原因... Apple可能找不到适合的类.:-)不过，认真的说，它可能是UIApplication或NSApplication或类似方法上的静态方法，但是很难以证明其合理性和特定于系统(您可以在OS X的NSApplication和iOS的UIApplication中使用它.)

As to the why... Apple probably didn't find a nice class to put it in. :-) Seriously though, it could be a static method on UIApplication or NSApplication or similar, but it's hard to justify and quite system-specific (you'd have it in NSApplication on OS X and UIApplication on iOS).

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