One of the two will be used. Which one is undefined

objc[37995]: Class PLBuildVersion is implemented in both /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/System/Library/PrivateFrameworks/AssetsLibraryServices.framework/AssetsLibraryServices (0x11450e998) and /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/System/Library/PrivateFrameworks/PhotoLibraryServices.framework/PhotoLibraryServices (0x114333d38). One of the two will be used. Which one is undefined.app

意思是ui

类PLBuildVersion在/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/System/Library/PrivateFrameworks/AssetsLibraryServices.framework/AssetsLibraryServices(0x11450e998)和/ Applications / Xcode中实现 .app / Contents / Developer / Platforms / iPhoneSimulator.platform / Developer / SDKs / iPhoneSimulator.sdk / System / Library / PrivateFrameworks / PhotoLibraryServices.framework / PhotoLibraryServices(0x114333d38) 将使用二者之一。哪个是不肯定的。
类PLBuildVersion在二者中实现。
spa

在模拟器中、发现“One of the two will be used. Which one is undefined.”日志3d

  查找资料发现缘由:objc runtime 对所用app使用同一个命名空间(flat namespace),运行机制以下:
  1. 首先二进制映像被加载,检查程序依赖关系
  2. 每个二进制映像被加载的同时,程序的objc classes在objc runtime命名空间中注册
  3. 若是具备相同名称的类被再次加载,objc runtime的行为是不可预知的。一种可能的状况是任意一个程序的该类会被加载(这应该也是默认动做)