Don't use 'libc' as the library, use FFI::Library::LIBC

On linux, /usr/lib/libc.so is a linker script, not a library.  (you
have to use libc.so.6, which is what FFI::Library::LIBC will be on
linux)

If thats in an example on the wiki, please correct it, or if its in
the source tree, report and issue with a patch for it.


On 27 May 2010 09:09, bwv549 <jtprince@gmail.com> wrote:

> ---
> require 'ffi'
>
> LIBC = 'libc'
> module Hello
>  extend FFI::Library
>  ffi_lib LIBC
>  attach_function 'puts', [ :string ], :int
> end
>
> Hello.puts("Hello, World")
> ---
>
> Gives me:
> /home/jtprince/.gem/ruby/1.9.1/gems/ffi-0.6.3/lib/ffi/library.rb:61:in
> `block in ffi_lib': Could not open library 'libc': libc: cannot open
> shared object file: No such file or directory. Could not open library
> 'libc.so': /usr/lib/libc.so: invalid ELF header (LoadError)
>        from /home/jtprince/.gem/ruby/1.9.1/gems/ffi-0.6.3/lib/ffi/library.rb:
> 43:in `map'
>        from /home/jtprince/.gem/ruby/1.9.1/gems/ffi-0.6.3/lib/ffi/library.rb:
> 43:in `ffi_lib'
>        from hello.rb:7:in `<module:Hello>'
>        from hello.rb:5:in `<main>'
>
> Seems like it can see libc but says "invalid ELF header".  How do I
> get hello world to run on linux?
>