Ffi library refuses to load

Ruby
1

I’m trying to run a sample program from rubygame, but it claims a
library file from ffi is missing. From my terminal:

luther@hrimfaxi:/usr/local/lib/ruby/gems/1.9.1/gems$
./rubygame-2.6.4/samples/demo_rubygame.rb
internal:lib/rubygems/custom_require:29:in require': libffi.so.4: cannot open shared object file: No such file or directory - /usr/local/lib/ruby/gems/1.9.1/gems/ffi-1.0.0/lib/ffi_c.so (LoadError) from <internal:lib/rubygems/custom_require>:29:inrequire’
from /usr/local/lib/ruby/gems/1.9.1/gems/ffi-1.0.0/lib/ffi.rb:8:in
rescue in <top (required)>' from /usr/local/lib/ruby/gems/1.9.1/gems/ffi-1.0.0/lib/ffi.rb:1:in<top (required)>’
from internal:lib/rubygems/custom_require:29:in require' from <internal:lib/rubygems/custom_require>:29:inrequire’
from
/usr/local/lib/ruby/gems/1.9.1/gems/nice-ffi-0.4/lib/nice-ffi.rb:31:in
<top (required)>' from <internal:lib/rubygems/custom_require>:29:inrequire’
from internal:lib/rubygems/custom_require:29:in require' from /usr/local/lib/ruby/gems/1.9.1/gems/ruby-sdl-ffi-0.3/lib/ruby-sdl-ffi/sdl.rb:31:in<top (required)>’
from internal:lib/rubygems/custom_require:29:in require' from <internal:lib/rubygems/custom_require>:29:inrequire’
from
/usr/local/lib/ruby/gems/1.9.1/gems/rubygame-2.6.4/lib/rubygame/main.rb:22:in
<top (required)>' from <internal:lib/rubygems/custom_require>:29:inrequire’
from internal:lib/rubygems/custom_require:29:in require' from /usr/local/lib/ruby/gems/1.9.1/gems/rubygame-2.6.4/lib/rubygame.rb:44:inblock in <top (required)>’
from
/usr/local/lib/ruby/gems/1.9.1/gems/rubygame-2.6.4/lib/rubygame.rb:29:in
each' from /usr/local/lib/ruby/gems/1.9.1/gems/rubygame-2.6.4/lib/rubygame.rb:29:in<top (required)>’
from internal:lib/rubygems/custom_require:33:in require' from <internal:lib/rubygems/custom_require>:33:inrescue in require’
from internal:lib/rubygems/custom_require:29:in require' from ./rubygame-2.6.4/samples/demo_rubygame.rb:25:in’
luther@hrimfaxi:/usr/local/lib/ruby/gems/1.9.1/gems$ ll
ffi-1.0.0/lib/ffi_c.so
-rwxr-xr-x 1 root root 525k 2010-12-02 Thu 20:39:04
ffi-1.0.0/lib/ffi_c.so

As you can see from the ll command at the bottom, the file is most
definitely there. This is very frustrating. Any ideas?

I’m using ‘ruby 1.9.2p0 (2010-08-18 revision 29036) [x86_64-linux]’,
compiled from source, on Trisquel 4.

2

On Dec 2, 2010, at 21:11 , Luther T. wrote:

internal:lib/rubygems/custom_require:29:in `require’: libffi.so.4:
cannot open shared object file: No such file or directory -
/usr/local/lib/ruby/gems/1.9.1/gems/ffi-1.0.0/lib/ffi_c.so (LoadError)

Just a guess, I think this is saying libffi.so.4 is missing, not
ffi_c.so.

3

Is there any way to confirm that? And if it’s true, how can I fix it?
And why doesn’t ‘gem install’ catch the error?

4

On Fri, Dec 3, 2010 at 5:25 PM, Luther T. [email protected]
wrote:

Is there any way to confirm that? And if it’s true, how can I fix it?

Try:
$ locate libffi

If it’s not found, then either use your system’s package manager to
install it, or grab the source from libffi and
compile/install it yourself.

And why doesn’t ‘gem install’ catch the error?

The gem checks for the library (via pkg-config) and for the required
development header. I’m not familiar with Trisquel, perhaps it uses
different conventions that are not covered/tested by the gem.

HTH,
Ammar

5

It works now. Thanks a lot for the help. Details below.

Ammar A. wrote in post #965991:

Try:
$ locate libffi

That showed me two files which, in my uninformed opinion, should have
been valid:
/usr/lib/libffi.so.5
/usr/local/lib64/libffi.so.4

If it’s not found, then either use your system’s package manager to
install it, or grab the source from libffi and
compile/install it yourself.

In Synaptic, I installed libffi-dev. Then I did ‘sudo gem pristine ffi’.
Running demo_rubygame.rb still gave me the same error.

Then, I installed libffi from source. Still the same error.

Then, I remembered to do ‘sudo gem pristine ffi’, and now it does
work!

And why doesn’t ‘gem install’ catch the error?

The gem checks for the library (via pkg-config) and for the required
development header. I’m not familiar with Trisquel, perhaps it uses
different conventions that are not covered/tested by the gem.

Trisquel is based on Ubuntu. I do have a pkg-config command.

Thanks again…
Luther

6

On Fri, Dec 3, 2010 at 8:57 PM, Luther T. [email protected]
wrote:

Thanks again…

You’re welcome. Trisquel sounds interesting, I’d never heard of it
before.

Regards,
Ammar