创建一个不可变对象CFArray - 苹果样品不工作 [英] Creating an immutable CFArray object - Apple sample doesn't work

问题描述

有关测试我复制下面的示例code [<一个href=\"https://developer.apple.com/library/ios/documentation/CoreFoundation/Conceptual/CFCollections/Articles/creating.html]\" rel=\"nofollow\">https://developer.apple.com/library/ios/documentation/CoreFoundation/Conceptual/CFCollections/Articles/creating.html]并编译它：

For testing I copied following sample code [https://developer.apple.com/library/ios/documentation/CoreFoundation/Conceptual/CFCollections/Articles/creating.html] and compiled it:

#import <CoreFoundation/CoreFoundation.h>

CFStringRef strs[3];
CFArrayRef anArray;

strs[0] = CFSTR("String One");
strs[1] = CFSTR("String Two");
strs[2] = CFSTR("String Three");

anArray = CFArrayCreate(NULL, (void *)strs, 3, &kCFTypeArrayCallBacks);

现在我得到了以下错误：

Now I got following error: "No matching function for call to CFArrayCreate"

为什么不编译，以及如何实现它，这是编译？

Why it is not compilable and how to implement it that it is compilable?

推荐答案

类型 CFArrayCreate（）是常量无效的第二个参数的* * 。因此，呼叫更改为：

The type of the second parameter of CFArrayCreate() is const void **. So, change the call to:

anArray = CFArrayCreate(NULL, (const void **)strs, 3, &kCFTypeArrayCallBacks);

这是真的只有在C ++中的一个问题，因为它是关于转换和从无效* 更严格了很多。在C，无效* 转换为其他自由指针类型。

This is really only a problem in C++, because it is a lot stricter about converting to and from void*. In C, void* converts to other pointer types freely.

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