title: _Bool data type of C99
body: <p>The C99 standard of the C programming language defines the <code>_Bool</code> data type as a macro for another data type (as the language isn't able to deal with a type safe boolean).</p>
  
  <p>Is the <code>_Bool</code> a macro for <code>unsigned char</code>, <code>unsigned int</code> or some other data type?</p>