title: In a GNU C macro envSet(name), what does (void) "" name mean?
body: <p>I came across this syntax today and couldn't work out what it meant:</p>
  
  <pre><code>// Uses the GNU C statement expression extension
  #define envSet(name) ({ \
  static int initialised; \
  static bool set; \
  (void) "" name; \
  if (!initialised || !g_cacheEnv) { \
      const char *value = getenv(name); \
      set = value != NULL; \
      initialised = true; \
  } \
  set; \
  })
  </code></pre>
  
  <p>The specific line I cannot understand is:</p>
  
  <pre><code>(void) "" name; \
  </code></pre>
  
  <p>Could somebody please shed some light on this?</p>