The. h header file cannot be introduced to the IOS Prefix. pch file.

We know that you can use the Prefix. pch file in the IOS project to perform some pre-compilation operations, such as introducing global header files and defining constants. I encountered an incredible problem when I was preparing to write a Demo today. No matter how I did it, introducing the header file in the pch file would result in an error, saying that the file could not be found, however, why can't I find all the file names I typed out using the auto-HELP function. After a detailed analysis, I found that the problem was that I used brackets ...... The normal method for introducing files is import "xxx. h "www.2cto.com, And when I import files, the default system package is imported before copying: import <xxx. h> This is the blood caused by Angle brackets. Angle brackets indicate that the system package is referenced, and double quotation marks indicate that the content in the project folder is introduced. Therefore, an error will be reported during compilation.