curs_printw(3X)

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 However, the latter is obsolete. X/Open Curses Issue 4 Version 2 (1996), marked vwprintw as requiring varargs.h and “TO BE WITHDRAWN”, and specified vw_printw using the stdarg.h interface. X/Open Curses Issue 5, Draft 2 (December 2007) marked vwprintw (along with vwscanw and the termcap interface) as withdrawn.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
4BSD (1980) introduced wprintw and its variants. It implemented all as functions, not macros; this initial distribution of curses preceded the ANSI C standard of 1989, prior to which a variadic macro facility was not widely available in the language. printw went unused in Berkeley distributions until 4.1cBSD (1983), which employed it in games. 4BSD's wprintw did not use varargs.h, which 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.

4BSD documented printw and wprintw tersely as “printf on stdscr” and “printf on win”, respectively.

SVr3 summarized the functions in three lines, asserting that they were analogous to printf(3) and 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 added 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.

SEE ALSO
curses(3X), curs_addstr(3X), curs_scanw(3X), printf(3), vprintf(3)