Both the fish and the bear's paw!

Source: Internet
Author: User

Preface: This part of this paper takes pictures on the internet.

Apple has canceled PCH since Xcode six. Reduce compilation time and increase performance

Before Xcode6, create a new project Xcode automatically creates a "project name-prefix.pch" file under the supporting Files folder, which is also a header file, and the contents of the PCH header file can be shared and accessed by all other source files in the project. is a precompiled file.

First, let's talk about the role of PCH:

1. Store some global macros (macros that are used throughout the project)

2. Used to include all header files (header files that are used throughout the project)

3. Can automatically turn on or off the log output function


Although it took a long time to Xcode6 but the project was created before XCODE5, the PCH file was not found to be missing from the beginning. Why should Apple do this, perhaps because people put a lot of header files and macro definitions into the PCH, resulting in a long compilation time. Apple to get rid of him may be to speed up the compilation time to increase the user experience. Although the convenience of programming has been lost. Have to admire Apple's user-centric approach to thinking. A more detailed discussion can go up to StackOverflow and see http://stackoverflow.com/questions/24158648/. Why-isnt-projectname-prefix-pch-created-automatically-in-xcode-6.

How to add a PCH file in Xcode:

Command+n, open the new File window: ios->other->pch file, create a PCH


2, in the project targets inside building setting search Prefix header, and then the Precompile Prefix header to the right of no change to Yes:



3. Then Double-click on the right side of the Prefix header below the Precompile Prefix header to add the project path to the PCH file you just created , adding the format: "$ (srcroot)/project name/ PCH filename ",$ (srcroot) means the project root directory. If you're not sure, you can right-click the PCH file and show in Finder:



The yellow circle comes out of $ (srcroot), which is the project root directory, and then there is a Pchtext and PCH two folders, so the path to the complete PCH file is:$ (srcroot)/pchtext/pch


Once added, he will automatically help you become the path where your project is located:


Yes, compile the program, if you have an error check the path you added is correct.

4, Precompile Prefix header is yes, pre-compiled PCH file will be cached, can improve the speed of compilation

Good

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

Both the fish and the bear's paw!

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.