curs_printw.3x man page
printw, wprintw, mvprintw, mvwprintw, vwprintw, vw_printw — print formatted output in curses windows
int printw(const char *fmt, ...);
int wprintw(WINDOW *win, const char *fmt, ...);
int mvprintw(int y, int x, const char *fmt, ...);
int mvwprintw(WINDOW *win, int y, int x, const char *fmt, ...);
int vwprintw(WINDOW *win, const char *fmt, va_list varglist);
int vw_printw(WINDOW *win, const char *fmt, va_list varglist);
The printw, wprintw, mvprintw and mvwprintw routines are analogous to printf [see printf(3)]. In effect, the string that would be output by printf is output instead as though waddstr were used on the given window.
The vwprintw and wv_printw routines are analogous to vprintf [see printf(3)] and perform a wprintw using a variable argument list. The third argument is a va_list, a pointer to a list of arguments, as defined in <stdarg.h>.
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, an error may be returned if it cannot allocate enough memory for the buffer used to format the results. It will return an error if the window pointer is null.
Functions with a "mv" prefix first perform a cursor movement using wmove, and return an error if the position is outside the window, or if the window pointer is null.
The XSI Curses standard, Issue 4 describes these functions. The function vwprintw is marked TO BE WITHDRAWN, and is to be replaced by a function vw_printw using the <stdarg.h> interface. The Single Unix Specification, Version 2 states that vw_printw is preferred to vwprintw since the latter requires including <varargs.h>, which cannot be used in the same file as <stdarg.h>. This implementation uses <stdarg.h> for both, because that header is included in <curses.h>.
curses(3X), printf(3), vprintf(3).