如何确定 ruby 是否可以在不过度使用正则表达式的情况下进行分叉？

发布于 2024-08-30 00:26:31 字数 881 浏览 3 评论 0原文

是否可以确定您正在运行的 ruby 实现是否能够支持 fork，而无需针对 RUBY_PLATFORM 运行正则表达式，该正则表达式将扩展直到召唤克苏鲁？

编辑：我尝试了马克-安德烈的建议。它不适用于默认禁用 fork 的 jruby：

192-168-1-7:~ agrimm$ jruby --1.9 -S jirb 
irb(main):001:0> RUBY_VERSION
=> "1.9.2dev"
irb(main):002:0> Process.respond_to?(:fork)
=> true
irb(main):003:0> Process.fork
NotImplementedError: fork is unsafe and disabled by default on JRuby

更新：从 Marc-Andre 的链接来看，从创建 ruby 实现的角度来看，它似乎比我更明智地解决了这个问题，但失败了。

从编写 ruby 库的人的角度来看，除了运行 fork 并查看它是否引发异常之外，最全面的咒语是什么？

原文

Is it possible to determine whether the implementation of ruby you're running on is capable of supporting fork, without running a regex against RUBY_PLATFORM that'll expand until it summons Cthulhu?

Edit: I tried Marc-Andre's suggestion. It doesn't work for jruby with fork disabled by default:

192-168-1-7:~ agrimm$ jruby --1.9 -S jirb 
irb(main):001:0> RUBY_VERSION
=> "1.9.2dev"
irb(main):002:0> Process.respond_to?(:fork)
=> true
irb(main):003:0> Process.fork
NotImplementedError: fork is unsafe and disabled by default on JRuby

Update: From Marc-Andre's link, it seems wiser heads than I have grappled with this problem from the perspective of creating ruby implementations, and failed.

From the perspective of someone who's writing a ruby library, what would be the most comprehensive incantation, short of running fork and seeing if it raises an exception?

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皇甫轩 2024-09-06 00:26:31

在 Ruby 1.9 中：

Process.respond_to?(:fork)  # => true if fork is supported, false otherwise

对于 Ruby 1.8 或 JRuby（当前未实现此功能），您必须实际测试它。

另请参阅关于 ruby-core 的长篇讨论。

In Ruby 1.9:

Process.respond_to?(:fork)  # => true if fork is supported, false otherwise

For Ruby 1.8, or JRuby (which doesn't implement this currently) you'll have to actually test it.

See also this long discussion on ruby-core.

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别靠近我心 2024-09-06 00:26:31

您可以测试 fork 本身，而不是针对 RUBY_PLATFORM 或其他内容进行容易出错的测试：

def can_fork?
  pid = fork
  exit unless pid # exit the child immediately
  true
rescue NotImplementedError
  false
end

一个缺点是，如果以某种方式模拟 fork ，这可能会使此检查变得昂贵。

Instead of error-prone testing against RUBY_PLATFORM or other things you could test fork itself:

def can_fork?
  pid = fork
  exit unless pid # exit the child immediately
  true
rescue NotImplementedError
  false
end

One downside would be if fork is somehow emulated which could make this check expensive.

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楠木可依 2024-09-06 00:26:31

最近对 Rails 的提交用于

Config::CONFIG['host_os'] !~ /mswin|mingw/)

测试它是否不在 Windows 上，

RUBY_PLATFORM !~ /java/

并测试它是否不在 JRuby 上。但是，我知道可以启用 fork 作为命令行开关。我必须研究是否有任何方法可以判断它是否已启用。

我怀疑 macruby 不支持或强烈反对分叉，并且从 Marc-Andre 提到的线程中，您可以使用

 RUBY_ENGINE != "macruby"

Now 对所有其他平台进行测试...（正在进行中，标记为社区 wiki ，请随意编辑）

A recent commit to rails uses

Config::CONFIG['host_os'] !~ /mswin|mingw/)

to test whether it's not on Windows, and

RUBY_PLATFORM !~ /java/

to test whether it's not on JRuby. However, I know it's possible to enable fork as a command-line switch. I'd have to look into whether there's any way of telling whether it's been enabled.

I suspect macruby doesn't support, or strongly discourages, forking, and from the thread Marc-Andre refers to, you can test for it with