overlay, overwrite - copy overlapped windows
#include <curses.h> int overlay(const WINDOW *srcwin, WINDOW *dstwin); int overwrite(const WINDOW *srcwin, WINDOW *dstwin);
The overlay() and overwrite() functions overlay srcwin on top of dstwin. The scrwin and dstwin arguments need not be the same size; only text where the two windows overlap is copied.
The overwrite() function copies characters as though a sequence of win_wch() and wadd_wch() were performed with the destination window's attributes and background attributes cleared.
The overlay() function does the same thing, except that, whenever a character to be copied is the background character of the source window, overlay() does not copy the character but merely moves the destination cursor the width of the source background character.
If any portion of the overlaying window border is not the first column of a multi-column character then all the column positions will be replaced with the background character and rendition before the overlay is done. If the default background character is a multi-column character when this occurs, then these functions fail.
Upon successful completion, these functions return OK. Otherwise, they return ERR.
No errors are defined.