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

  Curses Screen Management function that draws a box around the
  window using the character vert as the character for drawing the
  vertical lines of the rectangle, and hor for drawing the horizontal
  lines of the rectangle.

  Syntax:

       #include <curses.h>

       int box(WINDOW *win, char vert, char hor);