CoreFoundationはこんな感じですね。

#if __has_feature(assume_nonnull) #define CF_ASSUME_NONNULL_BEGIN _Pragma("clang assume_nonnull begin") #define CF_ASSUME_NONNULL_END _Pragma("clang assume_nonnull end") #else #define CF_ASSUME_NONNULL_BEGIN #define CF_ASSUME_NONNULL_END #endif