PCH File Settings

PCH file is a globally visible file in iOS development, which generally writes the global variables required in the program to the PCH file as a macro definition, such as a screen fit, and how to add a PCH file after X-code6:

First Command+n, open the new File window: ios->other->pch file, create a PCH files add header filename

Then, modify the project configuration file, add the path to the PCH file you just created to the Precomplie header option in building setting, and note that the debug and release two columns are added:

You're done, you can add a macro definition to the PCH file!!!

PCH File Settings