Rb++ / rbgccxml 0.9.1

Ruby
1

What is rb++ / rbgccxml?

Rb++, rbgccxml, and rice compose a suite of tools that make wrapping
C++
libraries into
Ruby extensions as simple as possible. This is built as a replacement
for
SWIG-Ruby.

What’s New

  • Full 1.9 support through the entire stack!
  • MinGW / MSYS build support on Windows.

rb++:
* Updated to work with the Rice::Director changes
* Fixed a bug where rb++ wasn’t using any superclass on classes with
multiple superclasses
* Generated extension handles exceptions cleaner

* Various other small bug fixes and tweaks

rbgccxml:
* Switched parsing from libxml-ruby to nokogiri
* Fixed crash on encountering , but no real handling of the
type
yet.
* Fixed a bug with older gcc versions on dealing with anonymous
enumerations

Project

Documentation: http://rbplusplus.rubyforge.org

rb++: GitHub - jameskilton/rbplusplus: Account name changed!
rbgccxml: GitHub - jameskilton/rbgccxml: Account name changed!

Installation

This single command will grab the whole stack needed for rb++ to work.

gem install rbplusplus

The stack includes four libraries: rb++, rbgccxml, gccxml_gem, and
rice

rb++

Rb++ makes it almost trivially easy to create Ruby extensions for C++
library.
In the simplest of cases, there is no need to ever touch C++,
everything
is done
in a very simple and clean Ruby API.

rbgccxml

RbGCCXML allows one to easily parse out and query C / C++ code.
This library uses GCC-XML to parse out the C / C++ code into XML, and
then
nokogiri
to parse and query that XML.

gccxml_gem

GCC-XML (www.gccxml.org) is an application that takes takes the parse
tree
of C / C++
and constructs a very parsable and queryable XML file with all related
information.

This gem includes a binary build of GCC-XML for supported platforms,
to make it trivially easy to install. Platforms currently supported
are:

* Linux 32 & 64 bit
* Mac OS X
* Windows via MinGW / MSYS

Rice

The Ruby Interface for C++ Extensions, it provides a C++ API for
working
with ruby. More information
available at its project page:

http://rice.rubyforge.org

Notes

Released under the MIT licence.

For those familiar with py++ / pygccxml, the similarities are in
function
only.
Rb++ / rbgccxml were written from scratch to take advantage of the
Ruby
language to it’s fullest.

Bugs, patches, feature requests, et al should be posted to the
corresponding project’s Issues page on github.

2

Hi,

I seem to have something like a bug in rb++. For the case that I want to
wrap a simple method
the extension doesn’t compile because of multiple definitions. The issue
is somewhat tricky since
when I have a previously compiled extension and merely extend the header
file, it compiles fine.
Here test case:

wrapper.rb
require ‘rubygems’
require ‘rbplusplus’

include RbPlusPlus

Extension.new “test” do |ext|
ext.sources ["/home/thor/rb++/test.hpp"]

ext.module “Test” do |mod|
node = mod.namespace “T”
end
end

test.hpp
#ifndef TEST
#define TEST

#include

namespace T
{

void test()
{
std::cout << “i’m just sitting here” << std::endl;
}

}
#endif

The error is encountered also if I have a class before the function
test.

Thorsten

3

What you’re running into is a general C++ compilation issue when you
have
code in your header files. By default, rb++ writes out code in a
one-file-per-class format, along with another file that’s the ruby
extension
starting point. Your test.hpp file ends up getting included into
multiple
files, and g++ doesn’t like it when it sees a fully defined method
multiple
times.

Two ways to deal with this:

  1. Tell rb++ to write all code to single file:

ext.writer_mode :single

  1. Split your C++ code out:

test.hpp
namespace T { void test(); }

test.cpp
namespace T { void test() { … } }

Jason

4

Sorry, I should have pointed you further towards the right answer. What
you
want is to have hpp + cpp (prototype in the hpp, implementation in the
cpp)
then you need to tell Rb++ to copy over the cpp file in with the
generated
sources so that it’s properly compiled and the linker can find the
implementation of code defined in the hpp:

Extension.new “test” do |e|
e.sources “test.hpp”, :include_source_files => “test.cpp”
end

A more detailed example and definition is found in the tutorial:
http://rbplusplus.rubyforge.org/#source. Also please read the
documentation
on Extension#sources:
http://rbplusplus.rubyforge.org/rbplusplus/classes/RbPlusPlus/Extension.html#M000092

Jason

5

Well, actually it shouldn’t be included more than one time due
to the header guard.
But, you’re correct having method definitions in headers is not
good style, so I decided to go the second route. Now ruby claims
that the symbol test is undefined.
Depending on the sources array, I get:
hpp --> undefined symbol
hpp + cpp --> double definition
cpp --> double definition
I am doing something really stupid here, or is there a way to rb++
to treat hpp + cpp as a package?

Thorsten