ncurses 6.1 - patch 20190727

[ncurses.git] / man / curs_scanw.3x

diff --git a/man/curs_scanw.3x b/man/curs_scanw.3x
index 85a8ae32be5195e95ff2c32ab538ab1e32e4cb45..905b93ba2f2f24321eca546393d0dd6fe53a056e 100644 (file)
--- a/man/curs_scanw.3x
+++ b/man/curs_scanw.3x
@@ -1,5 +1,5 @@
 .\"***************************************************************************
-.\" Copyright (c) 1998-2010,2017 Free Software Foundation, Inc.              *
+.\" Copyright (c) 1998-2017,2018 Free Software Foundation, Inc.              *
 .\"                                                                          *
 .\" Permission is hereby granted, free of charge, to any person obtaining a  *
 .\" copy of this software and associated documentation files (the            *
@@ -26,8 +26,12 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
-.\" $Id: curs_scanw.3x,v 1.18 2017/04/17 00:07:02 tom Exp $
+.\" $Id: curs_scanw.3x,v 1.24 2018/07/28 21:14:06 tom Exp $
 .TH curs_scanw 3X ""
+.de bP
+.ie n  .IP \(bu 4
+.el    .IP \(bu 2
+..
 .SH NAME
 \fBscanw\fR,
 \fBwscanw\fR,
@@ -37,22 +41,26 @@
 .SH SYNOPSIS
 \fB#include <curses.h>\fR
 .sp
-\fBint scanw(char *fmt, ...);\fR
+\fBint scanw(const char *fmt, ...);\fR
 .br
-\fBint wscanw(WINDOW *win, char *fmt, ...);\fR
+\fBint wscanw(WINDOW *win, const char *fmt, ...);\fR
 .br
-\fBint mvscanw(int y, int x, char *fmt, ...);\fR
+\fBint mvscanw(int y, int x, const char *fmt, ...);\fR
 .br
-\fBint mvwscanw(WINDOW *win, int y, int x, char *fmt, ...);\fR
+\fBint mvwscanw(WINDOW *win, int y, int x, const char *fmt, ...);\fR
 .br
-\fBint vw_scanw(WINDOW *win, char *fmt, va_list varglist);\fR
+\fBint vw_scanw(WINDOW *win, const char *fmt, va_list varglist);\fR
+.sp
+/* obsolete */
 .br
-\fBint vwscanw(WINDOW *win, char *fmt, va_list varglist);\fR
+\fBint vwscanw(WINDOW *win, const char *fmt, va_list varglist);\fR
 .SH DESCRIPTION
 The \fBscanw\fR, \fBwscanw\fR and \fBmvscanw\fR routines are analogous to
-\fBscanf\fR [see \fBscanf\fR(3)].  The effect of these routines is as though
+\fBscanf\fR [see \fBscanf\fR(3)].
+The effect of these routines is as though
 \fBwgetstr\fR were called on the window, and the resulting line used as input
-for \fBsscanf\fR(3).  Fields which do not map to a variable in the \fIfmt\fR
+for \fBsscanf\fR(3).
+Fields which do not map to a variable in the \fIfmt\fR
 field are lost.
 .PP
 The \fBvwscanw\fR and \fBvw_scanw\fR routines are analogous to \fBvscanf\fR(3).
@@ -71,25 +79,48 @@ Functions with a "mv" prefix first perform a cursor movement using
 \fBwmove\fP, and return an error if the position is outside the window,
 or if the window pointer is null.
 .SH PORTABILITY
-The XSI Curses standard, Issue 4 describes these functions.  The function
+In this implementation, \fBvw_scanw\fP and \fBvwscanw\fP are equivalent,
+to support legacy applications.
+However, the latter (\fBvwscanw\fP) is obsolete:
+.bP
+The XSI Curses standard, Issue 4 described these functions,
+noting that the function
 \fBvwscanw\fR is marked TO BE WITHDRAWN, and is to be replaced by a function
 \fBvw_scanw\fR using the \fB<stdarg.h>\fR interface.
+.bP
 The Single Unix Specification, Version 2 states that
 \fBvw_scanw\fR  is preferred to \fBvwscanw\fR since the latter requires
 including \fB<varargs.h>\fR, which
 cannot be used in the same file as \fB<stdarg.h>\fR.
 This implementation uses \fB<stdarg.h>\fR for both, because that header
 is included in \fB<curses.h\fR>.
+.bP
+X/Open Curses, Issue 5 (December 2007) marked \fBvwscanw\fP (along with
+\fBvwprintw\fP and the termcap interface) as withdrawn.
 .LP
 Both XSI and The Single Unix Specification, Version 2 state that these
-functions return ERR or OK.
+functions return \fBERR\fP or \fBOK\fP.
+.bP
 Since the underlying \fBscanf\fR(3) can return the number of items scanned,
 and the SVr4 code was documented to use this feature,
 this is probably an editing error which was introduced in XSI,
 rather than being done intentionally.
-Portable applications should only test if the return value is ERR,
-since the OK value (zero) is likely to be misleading.
+.bP
+This implementation returns the number of items scanned,
+for compatibility with SVr4 curses.
+As of 2018, NetBSD curses also returns the number of items scanned.
+Both ncurses and NetBSD curses call \fBvsscanf\fP to scan the string,
+which returns \fBEOF\fP on error.
+.bP
+Portable applications should only test if the return value is \fBERR\fP,
+since the \fBOK\fP value (zero) is likely to be misleading.
+.IP
 One possible way to get useful results would be to use a "%n" conversion
 at the end of the format string to ensure that something was processed.
 .SH SEE ALSO
-\fBcurses\fR(3X), \fBcurs_getstr\fR(3X), \fBcurs_printw\fR(3X), \fBscanf\fR(3)
+.na
+\fBcurses\fR(3X),
+\fBcurs_getstr\fR(3X),
+\fBcurs_printw\fR(3X),
+\fBcurs_termcap\fP(3X),
+\fBscanf\fR(3).