Get the next element of the iterator
@param i Pointer to a xcb_glx_drawable_iterator_t
Get the next element in the iterator. The member rem is
decreased by one. The member data points to the next
element. The member index is increased by sizeof(xcb_glx_drawable_t)
Get the next element of the iterator @param i Pointer to a xcb_glx_drawable_iterator_t
Get the next element in the iterator. The member rem is decreased by one. The member data points to the next element. The member index is increased by sizeof(xcb_glx_drawable_t)