C/Motif/*nix: how to append text in an output window?

I've created a simple Scrolled Text area for displaying information to the user during runtime of my app.  How can I append text to this text area?  Essentially I want to use it like a scrollable xterm.  In Java, this is two easy steps once the text area is created:
               OutputWindow.append (text);
               OutputWindow.setCaretPosition ();   // to auto scroll down to the bottom

All the examples I've seen for Motif require creating a buffer yourself, appending new text to the buffer (and managing the allocated space), then using XmTextSetString (output_window,buffer);  Is there an easier way, maybe equivalent to how Java does it?