What is Prefix.pch file in Xcode?

Question

So many developers are adding various convenience macros to the Prefix.pch. But my question is what is that Prefix.pch file.

• If i

Answer 1

Prefix headers are compiled and stored in a cache, and then automatically included in every file during compilation. This can speed up compilation, and lets you include a file without adding an import statement to every file using it. They are not required, and actually slow compilation whenever you change them.

Generally .pch file naming formation is yourProjectName-Prefix.pch