为什么 LWP::UserAgent 是通过 require LWP::UserAgent 导入的，而不是 use LWP::UserAgent？
我对这种语言还很陌生，但我之前一直使用 use 导入特定模块，
为什么 LWP::UserAgent 使用 require执行来自 perldoc LWP::UserAgent 的工作：
require LWP::UserAgent;
I'm pretty new to this language but I've been using use to import a specific module before,
why LWP::UserAgent uses require to do the job as from perldoc LWP::UserAgent:
require LWP::UserAgent;
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与
如果
require LWP::UserAgent;可接受，则表明import对 LWP::UserAgent 没有任何作用。也许文档使用require的目的是巧妙地暗示这一点？require LWP::UserAgent;和use LWP::UserAgent;之间的唯一区别在于require的执行时间。对于前者，它发生在整个文件编译之后。对于后者，一旦该语句被编译，它就会发生。实际上，面向对象的模块没有太大区别。就我个人而言，我使用
That's the same 与
That way，我保证不会导入任何我不想要的东西，并且我使用我用于其他模块的熟悉的
use。需要使用is the same as
If
require LWP::UserAgent;is acceptable, that goes to show thatimportdoes nothing for LWP::UserAgent. Maybe the point of the documentation's use ofrequireis to subtly imply this?The only difference between
require LWP::UserAgent;anduse LWP::UserAgent;is thus whenrequireis executed. For the former, it happens after the entire file has been compiled. For the latter, it occurs as soon as that statement has been compiled. In practical terms, there's no much difference for object-oriented modules.Personally, I use
That's the same as
That way, I'm guaranteed not to import anything I don't want, and I use the familiar
useI use for other modules.requireuserequire Module::Name与use具有相同的效果，仅在运行时，而不是编译时。当您想有条件地需要一个模块时，这有时是有利的。我认为文档没有任何特殊原因说require而不是use。require Module::Namehas the same effect asuse, only at run-time, not compile-time. This is sometimes advantageous when you want to conditionally require a module. I don't think there's any particular reason for the doc to sayrequireinstead ofuse.对于来自谷歌搜索并寻找此解决方案的人：
对于 Message Error: LWP::UserAgent not found at ./apache_accesses line 86。
解决方案：
apt-get 安装 libwww-perl
For people who come from google search and looking this solutions:
For Message Error: LWP::UserAgent not found at ./apache_accesses line 86.
Solution:
apt-get install libwww-perl