title: Regex expression to extract everything inside brackets
body: <p>I need to extract content inside brackets () from the following string in C++;</p>
  
  <p><strong>#82=IFCCLASSIFICATIONREFERENCE($,'E05.11.a','Rectangular',#28);</strong></p>
  
  <p>I tried following regex but it gives an output with brackets intact.</p>
  
  <pre><code>std::regex e2 ("\\((.*?)\\)");
  if (std::regex_search(sLine,m,e2)){
  }
  </code></pre>
  
  <p>Output should be: </p>
  
  <pre><code> $,'E05.11.a','Rectangular',#28
  </code></pre>