title: unichar* to NSString, get the length
body: <p>I am trying to create an NSString object from a const unichar buffer where I don't know the length of the buffer.</p>
  
  <p>I want to use the NSString stringWithCharacters: length: method to create the string (this seems to work), but please can you help me find out the length?</p>
  
  <p>I have:</p>
  
  <pre><code>const unichar *c_emAdd = [... returns successfully from a C++ function...]
  
  NSString *emAdd = [NSString stringWithCharacters:c_emAdd length = unicharLen];
  </code></pre>
  
  <p>Can anyone help me find out how to check what unicharLen is? I don't get this length passed back to me by the call to the C++ function, so I presume I'd need to iterate until I find a terminating character? Anyone have a code snippet to help? Thanks!</p>