NAME

printw, wprintw, mvprintw, mvwprintw, vwprintw, vw_printw - write formatted output to a curses window

SYNOPSIS

#include <curses.h>

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 vw_printw(WINDOW *win, const char *fmt, va_list varglist);

/* obsolete */
int vwprintw(WINDOW *win, const char *fmt, va_list varglist);

DESCRIPTION

printw, wprintw, mvprintw, and mvwprintw are analogous to printf(3). In effect, the string that would be output by printf(3) is instead output as though waddstr(3X) were used with win (or stdscr) as its first argument.

vwprintw and vw_printw are analogous to vprintf(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.

RETURN VALUE

These functions return ERR upon failure and OK upon success.

In ncurses, failure occurs if the library cannot allocate enough memory for the buffer into which the output is formatted, or if the window pointer win is null.

Functions prefixed with “mv” first perform cursor movement and fail if the position (y, x) is outside the window boundaries.

NOTES

No wide character counterpart functions are defined by the “wide” ncurses configuration nor by any standard. To format and write a wide-character string to a curses window, consider using swprintf(3) and waddwstr(3X) or similar.

PORTABILITY

X/Open Curses, Issue 4 describes these functions. It specifies no error conditions for them.

ncurses defines vw_printw and vwprintw identically to support legacy applications. However, the latter is obsolete.

X/Open Curses, Issue 4 Version 2 (1996), marked vwprintw as requiring varargs.h and “TO BE WITHDRAWN”, and specified vw_printw using the stdarg.h interface.
X/Open Curses, Issue 5, Draft 2 (December 2007) marked vwprintw (along with vwscanw and the termcap interface) as withdrawn. After incorporating review comments, this became X/Open Curses, Issue 7 (2009).
ncurses provides vwprintw, but marks it as deprecated.

HISTORY

While printw was implemented in 4BSD (November 1980), it was unused until 4.2BSD (August 1983), which employed it for games. That early version of curses preceded the ANSI C standard of 1989. It did not use varargs.h, though that had been available since Seventh Edition Unix (1979). In 1991 (a couple of years after SVr4 was generally available, and after the C standard was published), other developers updated the library, using stdarg.h internally in 4.4BSD curses. Even with this improvement, BSD curses did not use function prototypes (nor even declare functions) in curses.h until 1992.

SVr2 (1984) documented printw and wprintw tersely as “printf on stdscr” and “printf on win”, respectively.

SVr3 (1987) added mvprintw and mvwprintw, with a three-line summary asserting that they were analogous to printf(3), explaining that the string that printf(3) would write to the standard output stream would instead be output using waddstr to the given window. SVr3 also implemented vwprintw, describing its third parameter as a va_list, defined in varargs.h, and referred the reader to the manual pages for varargs and vprintf for detailed descriptions.

SVr4 (1989) introduced no new variations of printw, but provided for using either varargs.h or stdarg.h to define the va_list type.

X/Open Curses, Issue 4 (1995), defined vw_printw to replace vwprintw, stating that its va_list type is defined in stdarg.h.