title: How to use #ifdef _DEBUG on Linux?
body: <p>I have a problem with _DEBUG macro on Linux C++.
  I tried to use something like this:</p>
  
  <pre><code>#ifdef _DEBUG
  cout &lt;&lt; "Debug!" &lt;&lt; endl;
  #endif
  </code></pre>
  
  <p>But it doesn't work when I select Debug in IDE. However it worked on Windows.
  I use Eclipse IDE for C++ coding on Linux.</p>