overlay(), overwrite(), copywin() - overlay and manipulate overlapped curses windows
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);
The overlay(3) and overwrite(3) routines overlay srcwin on top of dstwin. srcwin and dstwinarenot to be the same size; only text where the two windows overlap is copied. The difference is that overlay(3) is non-destructive (blanks are not copied) whereas overwrite(3) is destructive.
The copywin(3) routine provides a finer granularity of control over the overlay and overwrite(3) routines. Like in the prefresh(3) routine, a rectangle is specified in the destination window, (dminrow dmincol) and (maxrow 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(3).
Routines that return an integer return ERR upon failure, and OK (SVr4 only specifies "an integer value other than ERR") upon successful completion.
overlay(3) and overwrite(3) may be macros.
The XSI Curses standard, Issue 4 describes these functions (adding the const qualifiers). It further specifies their behavior in the presence of characters with multi-byte renditions (not yet supported in this implementation).