SWIG Ruby Examples

The following examples illustrate the use of SWIG with Ruby.

• simple. A minimal example showing how SWIG can be used to wrap a C function, a global variable, and a constant.
• constants. This shows how preprocessor macros and certain C declarations are turned into constants.
• variables. An example showing how to access C global variables from Ruby.
• value. How to pass and return structures by value.
• class. Wrapping a simple C++ class.
• reference. C++ references.
• pointer. Simple pointer handling.
• funcptr. Pointers to functions.
• enum. Enumeration.

Compilation Issues

• To create a Ruby extension, SWIG is run with the following options:

  % swig -ruby interface.i
  

• Please see the Windows page in the main manual for information on using the examples on Windows.

• On Unix the compilation of examples is done using the file Example/Makefile. This makefile performs a manual module compilation which is platform specific. Typically, the steps look like this (Linux):

  % swig -ruby interface.i
  % gcc -fpic -c interface_wrap.c -I/usr/local/lib/ruby/1.4/i686-linux
  % gcc -shared interface_wrap.o $(OBJS) -o interface.so 
  % ruby
  require 'interface'
  Interface.blah(...)
  ...
  

• The politically "correct" way to compile a Ruby extension is to follow the steps described README.EXT in Ruby distribution:
  1. Create a file called extconf.rb that looks like the following:

     require 'mkmf'
     create_makefile('interface')
     

  2. Type the following to build the extension:

     % ruby extconf.rb
     % make
     

Compatibility

• Linux