From: Dave Harrison <giganews@...>
Date: 2009-01-15T02:39:06+09:00
Subject: Re: Finding ruby.h

John Ky wrote:
> [Note:  parts of this message were removed to make it a legal post.]
> 
> Hi,
> 
> I'm building ruby extensions across many different OSes and architectures.
> 
> Does anyone know an easy way to find ruby.h on any given system?
> 
> I'm told that perl has a "perl -V" or @ENV variable which gives some paths I
> can look through for perl.h.
> 
> Does Ruby have an equivalent?  Is there a better way to find ruby.h?
> 
> Thanks,
> 
> -John
> 

I have used CMake to make a SWIG wrapper with success on Windows and
Linux. The FindRuby.cmake script does all of the hard work at locating
Ruby.h. CMake-2.6.2 (and possibly others) includes FindRuby.cmake and
can be used like so:

(Note: FindRuby.cmake doesn't export RUBY_FOUND, so I create that var
myself)

Main CMakeLists.txt:
...
SET(RUBY_FOUND FALSE)
FIND_PACKAGE( Ruby)
if(RUBY_INCLUDE_PATH AND RUBY_LIBRARY)
SET(RUBY_FOUND TRUE)
endif(RUBY_INCLUDE_PATH AND RUBY_LIBRARY)
...
if(RUBY_FOUND)
INCLUDE_DIRECTORIES( ${RUBY_INCLUDE_PATH})
endif(RUBY_FOUND)
...

CMakeLists.txt for each library in app:
...
if(RUBY_FOUND)
SET_SOURCE_FILES_PROPERTIES(RbDynamic.i PROPERTIES SWIG_FLAGS "-autorename")
SET_SOURCE_FILES_PROPERTIES(RbDynamic.i PROPERTIES CPLUSPLUS ON)
SET_SOURCE_FILES_PROPERTIES(RbDynamic.i PROPERTIES SWIG_FLAGS "-includeall")
SWIG_ADD_MODULE( rbdynamic ruby RbDynamic.i )
SWIG_LINK_LIBRARIES( rbdynamic ${RUBY_LIBRARY}
${MIIND_LIBRARY_PREFIX}dynamic
 )
endif(RUBY_FOUND)
...

CMake is a doddle to use if you don't already know it, and is cross
platform (I've only used Windows and Linux). Check it out at www.cmake.org

Dave H.