About UIKIT_EXTERN in FBShimmeringLayer.m

[zixun]

I was see such code in FBShimmeringLayer.m

UIKIT_EXTERN float UIAnimationDragCoefficient(void); 

I'm not so clear about the UIKIT_EXTERN.

please give your comments~thx!

[travisjeffery]

#ifdef __cplusplus
#define UIKIT_EXTERN        extern "C" __attribute__((visibility ("default")))
#else
#define UIKIT_EXTERN            extern __attribute__((visibility ("default")))
#endif

Here's how it's defined. If you don't know what extern does, then start here: http://www.geeksforgeeks.org/understanding-extern-keyword-in-c/

[grp]

UIAnimationDragCoefficient is a private function defined in UIKit. It's used in Shimmer to add support for the slow animations feature when debugging in the simulator. By using UIKIT_EXTERN, it tells the compiler that the function is implemented in UIKit rather than in Shimmer itself.

[zzz6519003]

private function? wow so many hacks there!

[grp]

It's only used to help debugging in the simulator. It's not required to use Shimmer and won't affect your apps on the App Store.

[zzz6519003]

🆒