x11vnc  0.9.13
About: x11vnc is a VNC (Virtual Network Computing) server for real X displays. The last release by the original author Karl Runge (there are now newer community-based releases on https://github.com/LibVNC/x11vnc available.
  Fossies Dox: x11vnc-0.9.13.tar.gz  ("inofficial" and yet experimental doxygen-generated source code documentation)  

LibVNCClient Documentation

Example Code

See SDLvncviewer.c for a rather complete client example.