VMS Help CC, Run-time functions, [w]insch  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Curses Screen Management function and macro that insert the
  character ch at the current cursor position in the specified
  window.  The insch macro acts on the stdscr window.

  Syntax:

       #include <curses.h>

       int insch(char ch);
       int winsch(WINDOW *win, char ch);