From: "Iñaki Baz Castillo" <ibc@...>
Date: 2012-03-07T01:01:21+09:00
Subject: [C extension] How to detect Linux Kernel and glibc version?

Hi, for a Ruby C extension I need to check in extconf.rb the Linux
kernel and glibc version in which the extension is being compiled (so
when running "gem install xxxx"). I need to know this information in
order to use the accept4 system call which exists from kernel 2.6.28
and from glibc 2.10 (both conditions must be satisfied).

So I expect something like the following in my extconf.rb:

----------------------------------
case RUBY_PLATFORM
when /linux/
  if KERNEL_VERSION >= "2.6.28" and GLIBC_VERSION >= "2.10"
    add_define 'HAVE_ACCEPT4'
  end
----------------------------------


Well, I could run "uname -r" but that is dangerous, example:

  "2.6.3" >= "2.6.28"
  => true    OPSSSSS !!!

And unfortunatelly I cannot add more gems (i.e. versionomy) as depencency.

Also, no idea to get the current "glibc" version.


Thanks for any tip.



-- 
Iñaki Baz Castillo
<ibc@aliax.net>