从C函数返回NSString [英] Return NSString from a C function

问题描述

在iOS开发中，是否可以使用 NSString 并从函数中将其返回?

In iOS development, is it possible to use NSString and return it from a function?

例如

(NSString * ) foo {
  return @"";

} 

这不是客观的c方法，只是功能

This is not an objective c method, just function

推荐答案

是的，看到Objective-C对象只是指针，您可以创建一个C函数以返回一个:

Yes, seeing as objective-c objects are just pointers, you can create a C function to return one:

NS_RETURNS_RETAINED NSString *myFunction() {
    return [[NSString alloc] init];
}

注意使用 NS_RETURNS_RETAINED .这是对ARC和静态分析器的提示，该函数将保留值返回给接收器，并且它们有责任释放该值.

Notice the use of NS_RETURNS_RETAINED. This is a hint to ARC and the static analyzer that this function returns a retained value to the receiver, and that it's their responsibility to release it.

如果返回的是自动释放的值，请尝试使用 NS_RETURNS_NOT_RETAINED .

If you were returning an autoreleased value, try using NS_RETURNS_NOT_RETAINED instead.

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