/usr/bin/ld: ./libudns.a(udns_resolver.o): relocation R_X86_64_32 against `dns_defctx' can not be used when making a shared object; recompile with -fPIC

[Iñaki Baz Castillo]

Hi, I've finished my Ruby C extension for udns, and it works really well !!
I want to thank Michael Tokarev for all your help (and patience).

I just have a problem due to the fact that libudns is no longer part
of Linux distros (they have old 0.0.9 version). I know your reasons,
however it would be great if you would package it again :)

Well, using Debian libudns0 and libudns-dev packages I can compile my
Ruby C extension perfectly (just need to include "-ludns" when
generating my .so). But this is not longer an option for the future so
I must include the sources of udns within my Ruby gem, so when
somebody runs "gem install em-udns" it downloads my gem and the Ruby
Gem mechanism would compile udns, generate a libudns.a, and my Ruby C
extension would compile against it to create a final em-udns.so which
can be loaded in a Ruby program at runtime.

Other option would be compile udns dynamically and generate a
libudns.so, but this would require it to be installed under usual
/usr/lib/ or /usr/local/lib/ and that's not cool for the instalation
of a Ruby gem (Ruby gems can also be installed in user home with no
root permissions).

So let's go with the libudns.a option:

- I compile (make) udns, generate libudns.a and copy it to my Ruby C
folder along with udns.h.
- Then I generate the ruby C extension Makefile.
- And run make. Note that my system is 64 bits. I get this error:

gcc -I. -I/usr/include/ruby-1.9.1/x86_64-linux
-I/usr/include/ruby-1.9.1/ruby/backward -I/usr/include/ruby-1.9.1 -I.
 -fPIC -fno-strict-aliasing -g -g -O2 -fPIC  -o em-udns.o -c em-udns.c
gcc -shared -o em_udns_ext.so em-udns.o -L. -L/usr/lib -L.  -rdynamic
-Wl,-export-dynamic   -lruby-1.9.1 -ludns  -lpthread -lrt -ldl -lcrypt
-lm   -lc
/usr/bin/ld: ./libudns.a(udns_resolver.o): relocation R_X86_64_32
against `dns_defctx' can not be used when making a shared object;
recompile with -fPIC
./libudns.a: could not read symbols: Bad value
collect2: ld returned 1 exit status
make: *** [em_udns_ext.so] Error 1


I'm not an expert in this stuff (not at all), but AFAIK the above
error occurs in 64 bits systems.

Could you please help me with this? what is the best choice? how to
avoid the above error?

Really thanks a lot (again and again). When I've this solved I'll
publish the code and the Ruby gem so hopefully other projects using
Ruby EventMachine reactor will use it (EventMachine needs an async DNS
resolver) :)

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