title: How do I turn on RTTI with Cygwin?
body: <p>When my Android NDK C++ native code is compiled, the following error appears:</p>
  
  <blockquote>
    <p>error: 'dynamic_cast' not permitted with -fno-rtti</p>
  </blockquote>
  
  <p>Someone told me to turn on RTTI, but I didn't know how to do. Do I need to modify <code>Application.mk</code> or what?</p>
  
  <p>my <code>Application.mk</code>:</p>
  
  <pre><code># it is needed for ndk-r5
  
  APP_STL := stlport_static
  
  APP_ABI := armeabi armeabi-v7a
  
  APP_MODULES := cocos2d cocosdenshion chipmunk box2d tempestkeep
  </code></pre>
  
  <p>When I add <code>APP_CPPFLAGS += -frtti</code>  in some .o file appears another error:</p>
  
  <blockquote>
    <p>undefined reference to `typeinfo for std::ios_base'</p>
  </blockquote>