XSetClassHint(display, w, class_hints)
      Display *display;
      Window w;
      XClassHint *class_hints;
| display | Specifies the connection to the X server. | 
| w | Specifies the window. | 
| class_hints | Specifies the XClassHint structure that is to be used. | 
XSetClassHint() can generate BadAlloc and BadWindow errors.
| BadAlloc | The server failed to allocate the requested source or server memory. | 
| BadWindow | A value for a Window argument does not name a defined Window. |