如何知道 Xcode 中的 Objective-C 语言版本

Question

有什么方法可以检查我在我的应用程序中使用的 Objective-C 版本

Answer 1

Objective-C 级别的语言支持由用于编译代码的 Clang 版本定义，它本身与 Xcode 的版本非常接近。

#if __clang_major__ >= 11
    NSLog(@"My Objective-C language support is what Apple Clang/Xcode 11.x can support.");
    // This language version supports the additional features/fixes written under "Apple Clang Compiler"
    // https://developer.apple.com/documentation/xcode_release_notes/xcode_11_release_notes
    // Notably this version adds Objective-C support to:
    // - `[[clang::no_destroy]]` and `[[clang::always_destroy]]`

#elif __clang_major__ >= 10
    NSLog(@"My Objective-C language support is what Apple Clang/Xcode 10.x can support.");
    // This language version supports the additional features/fixes written under "Apple Clang Compiler"
    // https://developer.apple.com/documentation/xcode_release_notes/xcode_10_release_notes
    // Notably this version adds macro support to:
    // - detect most builtin pseudo-functions with `__has_builtin`

#elif __clang_major__ >= 9
    NSLog(@"My Objective-C language support is what Apple Clang/Xcode 9.x can support.");
    // This language version supports the additional features/fixes written under "Apple LLVM Compiler and Low-Level Tools"
    // https://developer.apple.com/library/archive/releasenotes/DeveloperTools/RN-Xcode/Chapters/Introduction.html#//apple_ref/doc/uid/TP40001051-CH1-SW878
    // Notably this version adds Objective-C support for:
    // - the `@available` language feature

#elif __clang_major__ >= 8
    NSLog(@"My Objective-C language support is what Apple Clang/Xcode 8.x can support.");
    // This language version supports the additional features/fixes written under "Objective-C and C++"
    // https://developer.apple.com/library/archive/releasenotes/DeveloperTools/RN-Xcode/Chapters/Introduction.html#//apple_ref/doc/uid/TP40001051-CH1-SW78
    // Notably this version adds Objective-C support for:
    // - the `@property (class)` language feature

#elif __clang_major__ >= 7
    NSLog(@"My Objective-C language support is what Apple Clang/Xcode 7.x can support.");
    // This language version supports the additional features/fixes written under "Objective-C"
    // https://developer.apple.com/library/archive/releasenotes/DeveloperTools/RN-Xcode/Chapters/Introduction.html#//apple_ref/doc/uid/TP40001051-CH1-SW326
    // Notably this version adds Objective-C support for:
    // - `CF_RETURNS_NOT_RETAINED` and `CF_RETURNS_RETAINED`
    // - `__kindof`
    // - `_Nullable`, `_Nonnull`, and `_Null_unspecified`
    // - Lightweight generics like `NSArray<UIImage *> *` and `NSDictionary<NSString *, NSURL *>`

#elif __clang_major__ >= 6
    NSLog(@"My Objective-C language support is what Apple Clang/Xcode 6.x can support.");
    // This language version supports the additional features/fixes written at:
    // https://developer.apple.com/library/archive/releasenotes/DeveloperTools/RN-Xcode/Chapters/Introduction.html#//apple_ref/doc/uid/TP40001051-CH1-SW453

#else
    NSLog(@"My Objective-C language support is so old that I won't even be allowed to publish this on any App Store nowadays.");

#endif

如果您需要更精确的版本，您也可以使用__clang_minor__。

建议尽可能使用__has_builtin 来检查Objective-C 语言功能的可用性，而不是__clang_major__ 和__clang_minor__。

其他一些值得注意的较旧的历史语言功能，您甚至不应该再费心测试可用性：

• NS_ENUM 和 NS_OPTIONS 在 Xcode 4.5 中添加
• Xcode 4.4 / 4.5 中添加了NSDictionary 和NSArray 下标
• 在 Xcode 4.4 / 4.5 中添加了 @YES 和 @NO 文字
• Xcode 4.4 中添加了NSNumber、NSDictionary 和 NSArray 文字
• Xcode 4.2 中添加了@autoreleasepool 块
• “Objective-C 2.0”是非常古老的东西（Xcode 2.x）

最后，“Modern Objective-C”只是指任何当前可用的 Xcode 对 Objective-C 的支持。

相关：

• How can I reliably detect the version of clang at preprocessing time?

Answer 2

Objective-C 运行时有两个版本——“现代”和“传统”。 OS X v10.5 及更高版本上的 iPhone 应用程序和 64 位程序使用现代版本的 runtime.check here

objective-c中引入的所有主要特性，可以查看here