如何生成唯一标识符？ [英] How to generate a unique identifier?

问题描述

我需要生成一些永远不会重复的int值（至少在理论上）。我知道有arc4random（）fnc，但我不知道如何使用它与当前日期或smth :(

I need to generate some int value that would never repeat (at least theoretically). I know there is arc4random() fnc but I'm not sure how to use it with some current date or smth :(

推荐答案

这将返回一个与MySQL中生成的UUID非常相似的唯一键。

This returns a unique key very similar to UUID generated in MySQL.

+ (NSString *)uuid
{
    CFUUIDRef uuidRef = CFUUIDCreate(NULL);
    CFStringRef uuidStringRef = CFUUIDCreateString(NULL, uuidRef);
    CFRelease(uuidRef);
    return [(NSString *)uuidStringRef autorelease];
}

ARC版本：

+ (NSString *)uuid
{
    CFUUIDRef uuidRef = CFUUIDCreate(NULL);
    CFStringRef uuidStringRef = CFUUIDCreateString(NULL, uuidRef);
    CFRelease(uuidRef);
    return (__bridge_transfer NSString *)uuidStringRef;
}

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