The printw, wprintw, mvprintw and mvwprintw routines are analogous to printf [see printf(3S)]. In effect, the string that would be output by printf is output instead as though waddstr were used on the given window.
The vwprintw routine is analogous to vprintf [see printf(3S)] and performs a wprintw using a variable argument list. The third argument is a va_list, a pointer to a list of arguments, as defined in <varargs.h>.
Routines that return an integer return ERR upon failure and OK (SVr4 only specifies "an integer value other than ERR") upon successful completion.
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 The function vwprintw is marked TO BE WITHDRAWN, and is to be replaced by a function vw_printw using the 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.
curses(3), printf(3S), vprintf(3S)