Found a way out by importing CoreGraphics / CoreGraphics.h. If you do not import the library, then that's what it says if you uncomment the import of CoreGraphics, then everything becomes normal I apologize if the question is stupid, but when viewing a training video, the author creates a perpend without importing anything else. I would like to correct this moment. same symptoms when calling NSStringFromCGPoint (p) enter image description here if I add UIKit / UIKit.h, then everything becomes normal. Thanks in advance!

  • What is the question? Add the necessary UIKit and CoreGraphics libraries. Most likely, the author of the instructional video has these libraries in the file ... Prefix.pch. - runia

1 answer 1

Most likely, the author of the video uses the Precompiled Header File (.PCH), in which it connects the necessary libraries (UIKit, CoreGraphics, etc.) only once.