From: Peter Wood <peter@...>
Date: 2005-04-06T23:33:24+09:00
Subject: Re: extconf.rb and dyld problem

>hello people!
>
>just trying to use extconf.rb script using mkmf to compile a bundle 
>for osx (some c++ libraries)
>
>compilation is going ok and linking (even libstdc++) seems ok, but 
>invoking the shared bundle in IRB gives me:
>
>dyld: ruby Undefined symbols:
><snip>
>(long list of symbols)
>
>could someone point at the most common reason this happens?
>
>sorry for such n00b question, but just can't figure it out, tried 
>several different LDFLAGS options after googling, and currently have 
>the following options set:
>
>if RUBY_PLATFORM =~ /darwin/
>     $CPPFLAGS += " -DUNIX"
>     $LDFLAGS += " -lstdc++ -L/usr/local/lib"
>     dir_config("fmod","/usr/local/include","/usr/local/lib")
>end
>
>if have_header("fmod.h")
>     if RUBY_PLATFORM =~ /darwin/
>         CONFIG["CC"] = "c++"
>         CONFIG["LDSHARED"].gsub!("cc","g++") #make sure you're using 
>g++ so it links libstdc++
>         CONFIG['LDSHARED'].gsub!('gcc','g++')
>         $create = true if have_library("fmod")
>     elsif have_library("fmod") #more than likely a linux box
>         CONFIG['LDSHARED'].gsub!('gcc','g++') #make sure c++ gets 
>linked properly
>         $create = true
>     end
>end
>
>any advice?
>
>thanks!
>
>david casal

 From your mail it looks as if you doing your best to use the C++ 
compiler rather than the standard C compiler. Won't you then be 
subject to name mangling? Ruby is expecting certain elements under 
standard names. If those names have been mangled by the C++ compiler 
it won't find them.