Semantic Issue: Implicit declaration of function 'SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO' is invali

最新推荐文章于 2023-11-11 10:48:25 发布

转载最新推荐文章于 2023-11-11 10:48:25 发布 · 3.8k 阅读

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本文介绍了如何解决Objective-C代码中遇到的C99标准下函数隐式声明错误的问题，并提供了相关的宏定义解决方案。通过在预处理器中添加必要的宏定义，可以避免编译器找不到函数的错误。

Problems:

Semantic Issue: Implicit declaration of function 'SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO' is invalid in C99

Semantic Issue: Implicit declaration of function 'SYSTEM_VERSION_LESS_THAN' is invalid in C99

The relevant lines of code are in the Appirater.m file:

    if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0") && SYSTEM_VERSION_LESS_THAN(@"7.1")) {
        reviewURL = [templateReviewURLiOS7 stringByReplacingOccurrencesOfString:@"APP_ID" withString:[NSString stringWithFormat:@"%@", _appId]];
    }

Answers:

Add these lines from your link to your .pch file. Clean and build. It should go away.

#define SYSTEM_VERSION_EQUAL_TO(v)                  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedSame)
#define SYSTEM_VERSION_GREATER_THAN(v)              ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedDescending)
#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v)  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)
#define SYSTEM_VERSION_LESS_THAN(v)                 ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedAscending)
#define SYSTEM_VERSION_LESS_THAN_OR_EQUAL_TO(v)     ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedDescending)

More info: since the preprocessor cannot find them to do a find and replace for these macros, they pass through to the compiler where they look like C functions. The compiler cannot find them and gives you an error.

参考：http://stackoverflow.com/questions/23818606/semantic-issue-implicit-declaration-of-function