Thank you for your reply, Eskimo! I. can understand more of how Xcode compiler work right now. But it looks like the issue still exist. Here were attempts I made: I tried include the header as system header, so I added the "Include" file in System Header Search Path, and included <GLFW/glfw3.h> and <glfw3.h> separately, both compiled an error. I tried include the header as my own header, so I did the same thing but put the "Include" file in Header Search Path, and included "GLFW/glfw3.h" and "glfw3.h" separately, it still generates the same error. I did not make other changes, the linking binary with library has libglfw3.a file, library search path has "lib-arm64" which contains ".a" file in it. Probably I am missing some steps. The template code I downloaded from OpenGL website: https://www.glfw.org/documentation.html The package as well from their resources: https://www.glfw.org/download.html Once again, thank you so much for your reply, if you find other portion is missing, feel free to leave another comment. I will work on my end as well to indicate where the error comes from :)

Please ignore anything down the separated line, I created a new post for that question :)