This is mostly for my own reference, but also because I couldn’t find any great help while googling the problem.

I’m working on switching from memcache-client to Evan Weaver’s libmemcached gem, and it’s gone well, except for one nagging error:

libmemcached.so.2: cannot open shared object file: No such file or directory - /opt/ruby-enterprise-1.8.6-20081215/lib/ruby/gems/1.8/gems/memcached-0.13/lib/rlibmemcached.so

libmemcached.so.2 was absolutely there, in my /usr/local/lib path. However, ldd was showing that rlibmemcached.so wasn’t properly linked to that library. The solution was the following:

[root@polaris libmemcached-0.25.14]# ./configure --prefix=/usr
[root@polaris libmemcached-0.25.14]# make && make install

ldd now shows the proper reference, and everything works. All better!