According to the SDL documentation:


  Movements to the left generate negative x values and to the right
  generate positive x values. Movements down (scroll backward) generate
  negative y values and up (scroll forward) generate positive y values.


So in your case, you could modify the code as such:

case SDL_MOUSEWHEEL:
    if(evenements.x &lt; 0)
    {
        std::cout &lt;&lt; "MOUSE : WHEEL LEFT" &lt;&lt; std::endl;
    }
    else if(evenements.x &gt; 0)
    {
        std::cout &lt;&lt; "MOUSE : WHEEL RIGHT" &lt;&lt; std::endl;
    }
    if(evenements.y &lt; 0)
    {
        std::cout &lt;&lt; "MOUSE : WHEEL DOWN" &lt;&lt; std::endl;
    }
    else if(evenements.y &gt; 0)
    {
        std::cout &lt;&lt; "MOUSE : WHEEL UP" &lt;&lt; std::endl;
    }
    break;


Events management using SDL 2.0
According to the jekyll site, this is how you make a new website with jekyll: 

~ $ gem install jekyll
~ $ jekyll new myblog
~ $ cd myblog
~/myblog $ jekyll serve


gem install jekyll didn't work, nor did sudo gem install jekyll: 

└─&gt;gem install jekyll
ERROR:  While executing gem ... (Errno::EACCES)
    Permission denied - /var/lib/gems/1.9.1/gems/fast-stemmer-1.0.2/LICENSE
┌─[Sat Jun 08][jon@jon-MacMini:~/Web]
└─&gt;sudo !!
sudo gem install jekyll
Building native extensions.  This could take a while...
ERROR:  Error installing jekyll:
    ERROR: Failed to build gem native extension.

        /usr/bin/ruby1.9.1 extconf.rb
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError)
    from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
    from extconf.rb:1:in `&lt;main&gt;'


Gem files will remain installed in /var/lib/gems/1.9.1/gems/fast-stemmer-1.0.2 for inspection.
Results logged to /var/lib/gems/1.9.1/gems/fast-stemmer-1.0.2/ext/gem_make.out


I also tried following the answer here, but that doesn't help. sudo apt-get install jekyll works. Even then, though, running jekyll new myblog returns this error: 

└─&gt;jekyll new myblog
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': iconv will be deprecated in the future, use String#encode instead.
WARNING: Could not read configuration. Using defaults (and options).
    No such file or directory - new/_config.yml
Building site: new -&gt; myblog
/usr/lib/ruby/vendor_ruby/jekyll/site.rb:126:in `chdir': No such file or directory - /home/jon/Web/new/ (Errno::ENOENT)
    from /usr/lib/ruby/vendor_ruby/jekyll/site.rb:126:in `read_directories'
    from /usr/lib/ruby/vendor_ruby/jekyll/site.rb:98:in `read'
    from /usr/lib/ruby/vendor_ruby/jekyll/site.rb:38:in `process'
    from /usr/bin/jekyll:250:in `&lt;main&gt;'


Anyone know what's causing this? 
