osx man page for overlay

curs_overlay(3X)														  curs_overlay(3X)

NAME
       overlay, overwrite, copywin - overlay and manipulate overlapped curses windows

SYNOPSIS
       #include <curses.h>

       int overlay(const WINDOW *srcwin, WINDOW *dstwin);
       int overwrite(const WINDOW *srcwin, WINDOW *dstwin);
       int copywin(const WINDOW *srcwin, WINDOW *dstwin, int sminrow,
	     int smincol, int dminrow, int dmincol, int dmaxrow,
	     int dmaxcol, int overlay);

DESCRIPTION
       The  overlay  and  overwrite  routines  overlay srcwin on top of dstwin.  scrwin and dstwin are not required to be the same size; only text
       where the two windows overlap is copied.  The difference is that overlay is non-destructive (blanks are not copied)  whereas  overwrite	is
       destructive.

       The  copywin routine provides a finer granularity of control over the overlay and overwrite routines.  Like in the prefresh routine, a rec-
       tangle is specified in the destination window, (dminrow, dmincol) and (dmaxrow, dmaxcol), and  the  upper-left-corner  coordinates  of  the
       source window, (sminrow, smincol).  If the argument overlay is true, then copying is non-destructive, as in overlay.

RETURN VALUE
       Routines  that  return  an  integer return ERR upon failure, and OK (SVr4 only specifies "an integer value other than ERR") upon successful
       completion.

       X/Open defines no error conditions.  In this implementation, copywin, overlay and overwrite return an error if either of the window  point-
       ers are null, or if some part of the window would be placed off-screen.

NOTES
       Note that overlay and overwrite may be macros.

PORTABILITY
       The XSI Curses standard, Issue 4 describes these functions (adding the const qualifiers).  It further specifies their behavior in the pres-
       ence of characters with multibyte renditions (not yet supported in this implementation).

SEE ALSO
       curses(3X), curs_pad(3X), curs_refresh(3X)

																  curs_overlay(3X)