In Objective-C, importing same headers in every class make compile time longer?
header, ios, iphone, objective-c
Solution
In general, newly-generated iOS projects come with this functionality, which is called a precompiled header or prefix header, and is a file that has the extension `.pch`.
You can throw all the headers you want in there and Xcode will pre-compile it before it builds anything else, and use it to compile the other compilation units in your project (e.g. `.m` files).
Using a precompiled header may or may not increase compile time; in general, it reduces compile time, as long as you have a lot of common headers and/or a lot of source files.
However, it's not necessarily good practice to treat the pre-compiled header like a big dumping ground, as your compilation units can form implicit dependencies on all sorts of stuff when you may want to enforce loose coupling between components.
Problem
I'm a beginner of Objective-C/iOS programing. I want make a one header file which includes all class headers I use in my project. And import the header in every class header file. Like this question: Including multiple classes in the same header file But does this approach increase compile time? Or are there any other disadvantage? Please tell me the good ways to import headers.