From: jim@...
Date: 2004-08-20T02:56:54+09:00
Subject: require and LD_LIBRARY_PATH

Here is a little something interesting that I just stumbled
across:

I have a a library installed in a non-standard location and
hence need to have LD_LIBRARY_PATH set so ld.so knows where
to look when loading the shared library.

Without LD_LIBRARY_PATH NOT set I get the following:

  % ruby -e "require 'ITKDb'"
  % ./ITKDb.so: libstdc++.so.5: cannot open shared object file: No such file or
    directory - ./ITKDb.so (LoadError)
          from -e:1
  %

But, if I set it I get:

  % setenv LD_LIBRARY_PATH /disk2/jfn/usr/local/lib
  % ruby -e "require 'ITKDb'"
  % 

So, I thought, that if I set LD_LIBRARY_PATH before I did a require,
but inside the script, that I could still load the library.
Well, it turns out that this doesn't work.

  % unsetenv LD_LIBRARY_PATH
  % ruby -e 'ENV["LD_LIBRARY_PATH"] = "/disk2/jfn/usr/local/lib"; require "ITKDb"'
  % ./ITKDb.so: libstdc++.so.5: cannot open shared object file: No such file
    or directory - ./ITKDb.so (LoadError)
          from -e:1

So, I assume that 

  ENV['LD_LIBRARY_PATH'] = "/disk2/jfn/user/local/lib"
  
is only setting a shell variable and not exporting it to the
environment.

Is this correct? If so, how do I export this variable?

Thanks
-- 
Jim Freeze