blocks|key|654061|text|从Xcode5开始，有一个新特性引入了预编译源数据库。Xcode5基本上只编译一次所有需要的框架，将构建保存在数据库中，并在编译代码时使用已编译的部分。因此，库中的所有内容都会被多次编译。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|654062|所以我的猜测是，在使用Xcode5时，您不必担心。|654063|您可以在https://developer.apple.com/wwdc/videos/上观看WWDC2013视频《Xcode5中的新增功能》介绍此功能|654064|如果我错了，请任何消息灵通的人，请随时纠正我。|654065|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.apple.com/wwdc/videos/^0|J|7|0|0|4|14|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@$9|U|A|V|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|W|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|X|8|@]|D|@$9|Y|A|Z|1|10]]|E|$]]|$1|J|3|K|5|6|7|11|8|@]|D|@]|E|$]]|$1|L|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|M|$N|$5|O|P|Q|E|$R|S]]]]

Since Xcode 5, there is a new feature introducing precompiled sources database. Xcode 5 basically compiles all the required frameworks just once, saves builds in the database and that already compiled pieces uses while compiling your code. So nothing in the library is not compiled multiple times.

So my guess is, while using Xcode 5, you don't need to worry.

You can watch WWDC 2013 video "What’s New in Xcode 5" introducing this feature at <a href="https://developer.apple.com/wwdc/videos/" rel="nofollow">https://developer.apple.com/wwdc/videos/</a>

If I'm wrong, please anyone more informed, feel free to correct me.

blocks|key|654077|text|不是的。它实际上提高了编译速度。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|654078|This+is+a+nice+tutorial实际上消除了使用#import语句和.PCH文件的所有困惑。此外，它还详细介绍了iOS7中引入的称为“模块”的新功能。|offset|length|654079|entityMap|0|LINK|mutability|MUTABLE|url|http://www.raywenderlich.com/49850/whats-new-in-objective-c-and-foundation-in-ios-7^0|0|0|N|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

No. It actually improves the compilation speed. 

<a href="http://www.raywenderlich.com/49850/whats-new-in-objective-c-and-foundation-in-ios-7">This is a nice tutorial</a> that actually clears all the confusion over use of #import statements and .PCH files. Also it tells you in detail about something new known as "modules", introduced in iOS7.

blocks|key|3638281|text|这听起来可能有争议，但与每个人对模块的看法相反，我有过完全相反的经历。我得到了一个你会想到的大型项目(相当大，有各种依赖项和库)。最近，我开始注意到编译时间非常长(在2014+Mac+Pro+12内核和32+GB+RAM上，正常构建时间约为5分钟，归档时间约为15分钟)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3638282|我通过在所有库和项目上自动关闭Enable+Link+Frameworks以及Enable+Modules来运行一个实验。我‘归档’，它花了3分钟归档。|3638283|我打开了“Enable+Modules”，做了同样的事情，像往常一样，花了15分钟。奇怪和奇怪，但我坚持关闭这些选项。|3638284|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

This may sound controversial, but contrary to what everyone is saying about modules, I've had the complete opposite experience. I've got, what you'd consider, a large project (considerably large with various dependencies and libraries). Recently I started noticing that compile times were very very very long (around 5 minutes normal build time and around 15 minutes 'archive' time on a 2014 Mac Pro 12 cores and 32 GB RAM).

I ran an experiment by simply turning off Enable Link Frameworks Automatically on all libraries and projects as well as Enable Modules. I 'archived' and it took 3 minutes archive.

I turned 'Enable Modules' ON and did the same, and it took, as normal, 15 minutes. Strange and weird, but I'm sticking with these options turned off.

I was reading this <a href="http://qualitycoding.org/import-order/" rel="noreferrer">post</a> about imports and I had one question. Does the #import that comes in the prefix.pch file by default slow down the compile time? Should I remove it and import only when necessary?

<pre><code>#ifdef __OBJC__
 #import &lt;UIKit/UIKit.h&gt;
 #import &lt;Foundation/Foundation.h&gt;
#endif
</code></pre>

Does #import <UIKit/UIKit.h> on pch slow down the compile time?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在阅读这篇关于导入的，我有一个问题。默认情况下，prefix.pch文件中的#import会减慢编译时间吗？是否应该将其删除并仅在必要时导入？#ifdef __OBJC__ #import <UIKit/UIKit.h> #import <Foundation/Foundation.h>#endif

问pch上的#import <UIKit/UIKit.h>会减慢编译时间吗？
EN

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问pch上的#import <UIKit/UIKit.h>会减慢编译时间吗？EN