overlay(3NCURSES) Library calls overlay(3NCURSES)
NAME
overlay, overwrite, copywin - overlay curses windows and manipulate them
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
overlay, overwrite
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 destruc-
tive.
copywin
The copywin routine provides a finer granularity of control over the
overlay and overwrite routines. As in the prefresh routine, a rectangle
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
These functions return OK on success and ERR on failure.
In ncurses, they return ERR if
• either of the window pointers are null, or
• any part of the window would be placed off-screen.
NOTES
overlay and overwrite may be implemented as macros.
PORTABILITY
X/Open Curses Issue 4 describes these functions. It specifies no error
conditions for them. It adds const qualifiers to the arguments. It
further specifies their behavior in the presence of characters with
multibyte renditions (not yet supported in this implementation).
SVr4 describes a successful return value only as “an integer value other
than ERR”.
SEE ALSO
ncurses(3NCURSES), pad(3NCURSES), refresh(3NCURSES)
ncurses 6.5 2025-01-18 overlay(3NCURSES)
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